WO2015044905A1

WO2015044905A1 - Processing of petroleum and/or petroleum residues

Info

Publication number: WO2015044905A1
Application number: PCT/IB2014/064863
Authority: WO
Inventors: John Toft
Original assignee: Pme Enterprises Company Limited
Priority date: 2013-09-26
Filing date: 2014-09-26
Publication date: 2015-04-02
Also published as: GB201317143D0

Abstract

This invention relates to compositions and methods of processing petroleum and/or petroleum- based residues, particularly where said petroleum and/or petroleum-based residues are difficult to extract or obtain. The compositions of the invention generally help to reduce the viscosity of petroleum and/or petroleum-based residues, such as crude oil, and thereby enhance its ability to flow. The compositions of the invention comprise a non-fatty acid-based unsaturated organic component and a fatty-acid based organic component.

Description

Processing of Petroleum and/or Petroleum Residues

INTRODUCTION

[0001 ] This invention relates to compositions and methods of processing petroleum and/or petroleum-based residues, particularly where said petroleum and/or petroleum-based residues are difficult to extract or obtain. The compositions of the invention generally help to reduce the viscosity of petroleum and/or petroleum-based residues, such as crude oil (especially heavy crudes prone to precipitating waxy deposites), and thereby enhance its ability to flow.

BACKGROUND

[0002] It is well known that petroleum and/or petroleum-based residues, such as crude oil residues that can precipitate or otherwise settle from crude oil, can be extremely viscous and difficult to handle. Such residues are commonly heterogeneous mixtures of heavy oils with high densities and/or high specific gravities. Heavy oil fractions of crude oil typically contain both paraffin waxes and asphaltenes, each of which can precipitate (together or separately) to yield residues that differ markedly in their properties. For instance, paraffin waxes tend to precipitate as microcrystalline waxes that can, to some extent at least, be mobilized (i.e. with improved flow properties) by heat and/or an appropriate solvent. In contrast, asphaltenes tend to precipitate as resinous substances that are very difficult to mobilize. [0003] It is extremely difficult to simultaneously mobilize (i.e. improve flow of) both paraffin waxes and asphaltenes after their precipitation. It is moreover difficult to treat crude oil in a manner which simultaneously prevents or inhibits precipitation or settling of both paraffin waxes and asphaltenes. For instance, paraffin waxes are generally at least partially soluble in light oil fractions of petroleum (e.g. oil fractions with boiling points less than 150°C), whereas asphaltenes are not.

[0004] These residues, by virtue of their viscous nature, are extremely problematic to extract and transport over large distances, for example through pipelines. These viscous heterogeneous petroleums and/or residues thereof also exhibit increased viscosity at lower temperatures, making them even more problematic to handle in cold environments. Therefore, there is a need for commercially viable techniques by which the viscosity of these petroleums and/or residues thereof can be reduced in order to facilitate their extraction and convenient transport, for example through a pipeline.

[0005] Due to the temperature dependent nature of the viscosity of these petroleums and/or residues thereof, one current approach is to use steam to heat the fluid and reduce their viscosity, thereby facilitating their extraction. To enable the transport of such petroleums and/or residues thereof, the heated/lower viscosity fluid needs to flow through insulated pipelines to maintain its temperature. The use of steam extraction and insulated pipeline transport is, however, extremely expensive and this can limit its commercial viability in certain circumstances.

[0006] An alternative approach to reduce the viscosity of petroleum based fluids such as crude oil, involve the use of gasses (for example carbon dioxide), which are pumped into the petroleum and/or residues thereof to provide a means of reducing the viscosity. Another approach involves the use of solvent additives to dissolve or partially dissolve components of oil and thereby reduce its viscosity. However, there still remains a need for improved, commercial viable approaches for reducing the viscosity of petroleum and/or residues thereof in order to facilitate their extraction and transport. There is also a need for commercially viable approaches for extracting oil from problematic sources, such as, for example, tar sand, which is a source of a particularly viscous and hard to handle crude oil. [0007] The selection of suitable viscosity modifying additives for petroleum and/or residues thereof is problematic because very few additives can provide a sufficiently uniform reduction in the viscosity of the oil, especially at low operating temperatures. Furthermore, the heterogeneous nature of these petroleums and/or residues thereof provides a further challenge because the additive needs to be able to uniformly penetrate throughout the petroleum and/or residues thereof and render it more homogenous in nature. Ideally, the additive should also be non-toxic / environmentally friendly and easy to separate from the petroleum-based fluid (as cleanly as possible) once the extraction and/or transport of the fluid is complete. Lastly, the additive needs to be inexpensive, plentiful is supply and minimise the need for heat to reduce the viscosity of the petroleum and/or residues thereof. This will render the extraction and transport procedures more economically viable. Such additives would also enable the oil to be extracted from alternative sources that are generally regarded as less economically viable, such as, for example, tar sands.

[0008] It is therefore an object of the present invention to provide an improved additive composition for reducing the viscosity of petroleum and/or residues thereof, such as crude oil, and which possess at least some of the optimal properties outlined above.

[0009] It is a further object of the present invention to provide improved compositions for reducing the viscosity of petroleum and/or residues thereof, such as crude oil, and facilitate its extraction from alternative sources, such as, for example, tar sand. [0010] It is a further object of the present invention to provide compositions which facilitate the separation of oil from oil-water mixtures.

[0011 ] It is a further object of the present invention to provide improved compositions for processing petroleum and/or residues thereof which can in turn be recovered or otherwise separated from the petroleum and/or residues thereof following processing.

BRIEF SUMMARY OF THE DISCLOSURE

[0012] According to a first aspect of the present invention there is provided a method of processing petroleum and/or petroleum-based residues, the method comprising mixing the petroleum and/or petroleum-based residues with a petroleum additive composition or with the individual components of the petroleum additive composition; wherein the petroleum additive composition comprises:

- A non-fatty acid-based unsaturated organic component; and

- A fatty-acid based organic component.

[0013] According to a second aspect of the present invention there is provided a method of extracting, storing and/or transporting petroleum and/or petroleum-based residues, the method comprising: i) mixing the petroleum and/or petroleum-based residues with a petroleum additive composition, or with the individual components of the petroleum additive composition, to produce a treated petroleum-based composition; and ii) extracting, storing and/or transporting the treated petroleum-based composition; wherein the petroleum additive composition comprises: - A non-fatty acid-based unsaturated organic component; and

- A fatty-acid based organic component.

[0014] According to a third aspect of the present invention, there is provided a use of a petroleum additive composition or a kit comprising the individual components of the petroleum additive composition to modify the viscosity of petroleum and/or petroleum-based residues; wherein the petroleum additive composition comprises:

- A non-fatty acid-based unsaturated organic component; and

- A fatty-acid based organic component.

[0015] According to a fourth aspect of the present invention, there is provided a use of a petroleum additive composition or a kit comprising the individual components of the petroleum additive composition to extract, store and/or transport petroleum and/or petroleum-based residues; wherein the petroleum additive composition comprises:

- A non-fatty acid-based unsaturated organic component; and

- A fatty-acid based organic component.

[0016] According to a fifth aspect of the present invention, there is provided a petroleum additive composition comprising:

- A non-fatty acid-based unsaturated organic component; and

- A fatty-acid based organic component.

[0017] According to a sixth aspect of the present invention, there is provided a kit of parts comprising: - A non-fatty acid-based unsaturated organic component; and

- A fatty-acid based organic component. [0018] According to a seventh aspect of the present invention, there is provided a treated petroleum-based composition comprising:

- petroleum and/or petroleum-based residues:

- A non-fatty acid-based unsaturated organic component; and - A fatty-acid based organic component.

[0019] According to an eighth aspect of the present invention, there is provided a method of recovering a petroleum additive composition from a treated petroleum-based composition (e.g. for example, that of the seventh aspect), the method comprising separating the petroleum additive composition from the treated petroleum-based composition by centrifugation and/or distillation; wherein the treated petroleum-based composition comprises:

- petroleum and/or petroleum-based residues:

- A non-fatty acid-based unsaturated organic component; and

- A fatty-acid based organic component; and wherein the petroleum additive composition comprises: - A non-fatty acid-based unsaturated organic component; and

- A fatty-acid based organic component.

[0020] According to a ninth aspect of the present invention there is provided a petroleum additive composition obtainable by, obtained by, or directly obtained by the method of recovering a petroleum additive composition of the eighth aspect. [0021 ] According to a tenth aspect of the present invention there is provided a petroleum- based product obtainable by, obtained by, directly obtained by the method of the first, second, or eighth aspects.

[0022] According to an eleventh aspect of the present invention there is provided a method of separating water from an oil-water mixture, the method comprising: (a) providing a treated oil-water mixture comprising:

^■ water; ^■ petroleum and/or petroleum-based residues; and

^■ a petroleum additive composition as defined herein or the individual components of the petroleum additive composition as defined herein;

(b) separating at least some of the water from the oil-water mixture to provide a clean water phase.

[0023] According to a twelfth aspect of the present invention there is provided a method of disposing of water from an oil-water mixture, the method comprising separating water from an oil-water mixture as defined in the eleventh aspect to thereby provide a clean water phase, and thereafter disposing of some or all of the clean water phase. [0024] The compositions of the present invention have surprisingly been found to possess a number of advantageous properties. Firstly, the additive compositions have been found to uniformly penetrate throughout (heterogeneous) crude oil fractions and thereby effectively reduce viscosity or otherwise mobilize said crude oil to enable the oil to flow. The additive compositions also typically act as plasticizers for waxy petroleum-based residues. Without wishing to be bound by any particular theory, the inventors believe that the combination of ingredients of the compositions of the invention act synergistically: to mobilize the paraffin waxes through effective penetration, lubrication, and solubilisation thereof; to mobilize the asphaltenes through the plasticization and solubilisation thereof; and to stabilize the resulting mobile fluid. As such, the compositions of the invention represent broad spectrum mobilizing agents having the flexibility and versatility required to cope with the diverse range of residues within crude oil. Moreover, the skilled person can easily adapt the compositions of the invention, for instance, by judiciously varying (e.g. increasing) the proportions of any aromatic hydrocarbons (e.g. with a phenyl ring) or aromatic organic compounds (e.g. benzyl acetate) to cater for high asphaltene contents of crude oil or its residues. [0025] Secondly, the additive compositions of the present invention are relatively inexpensive and are acceptable from an environmental perspective (e.g. biodegradable). Furthermore, the specific gravity of the composition can be controlled so that it is sufficiently different to that of the petroleum or residues thereof to enable it to be easily recovered from the petroleum/residues by centrifugation when desired. Such compositions may also be recovered or otherwise separated from the petroleum/residues by distillation, including during an oil refining process.

[0026] A further advantage associated with the compositions of the present invention is that can inhibit corrosion in pipelines. This "anti-corrosive" property reduces the need for corrosion inhibitors to be added to the petroleum/residues.

[0027] A further advantage associated with the compositions of the present invention is that they can facilitate extraction/separation of the petroleum/residues from aqueous mixtures, whether via standard heterogeneous liquid-liquid phase separations (i.e. separation of layers) or via centrifugation. For instance, petroleum/residues extracted from reservoirs with water and/or steam need to be separated from said water following extraction. The compositions of the invention can facilitate formation of polyphasic (e.g. biphasic or triphasic) mixtures that can be more easily handled to extract petroleum/residues therefrom. For instance, using the compositions of the present invention, cleaner interfaces between aqueous and oil phases can be obtained. Moreover, the compositions of the invention can facilitate demulsification to some extent, thereby increasing the amount of the oil phase that can be simply "tapped/skimmed off". On the other hand, the compositions of the invention facilitate centrifugation of oil-water mixtures thereby allowing oil and water phases to be effectively separated from one another. In some case, the compositions of the invention allow for such clean separations that the water phase can be easily purified to allow for its safe discharge into the natural environment. [0028] Using petroleum additive compositions of the invention can conveniently avoid the need for heat to mobilize or otherwise fluidize petroleum and/or petroleum-based residues.

[0029] Using petroleum additive compositions of the invention conveniently can facilitate filtration of fluidized or partially fluidized petroleum and/or petroleum-based residues, and may in some cases facilitate nanofiltrations that would otherwise be impossible. [0030] Using petroleum additive compositions of the invention conveniently can facilitate rapid processing of petroleum and/or petroleum-based residues which could otherwise only be processed at a slow flow rate due to their relative high viscosity. For instance, using petroleum additive compositions of the invention may allow petroleum and/or petroleum-based residues obtained from oil reservoirs to be directly centrifuged without the need for pre-treatments. [0031 ] Petroleum additive compositions of the invention can help to revolutionize the safety of what are otherwise highly dangerous operations. For instance, whereas previously waxy deposits from petroleum and/or petroleum-based residues may have been manually removed by labourers in highly flammable and potentially toxic environments (e.g. oil tanks), instead the petroleum additive compositions of the invention can be used to either prevent or reduce waxy deposits forming in the first place, or to mobilize waxy deposits in situ to facilitate their facile removal in safe manner (e.g. via pumping).

[0032] Features, including optional, suitable, and preferred features of any aspect of the present invention may, where appropriate, be also features, including optional, suitable, and preferred features of any other aspect of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

[0033] Herein, the term "petroleum" is well understood in the art and generally refers to synthetic or naturally occurring complex mixtures of hydrocarbons of various molecular weights and optionally other organic compounds. The petroleum may include unprocessed (i.e. unrefined) crude oil, but in some cases includes petroleum products derived from refined crude oil. In preferred embodiments, the "petroleum" referred to herein is naturally occurring petroleum or petroleum-based residues, or are otherwise petroleum-based residues (e.g. waste or otherwise disgarded products) derived from naturally occurring petroleum (e.g. following initial refinement of naturally occurring petroleum). The petroleum may include crude oil from crude oil reservoirs, or otherwise petroleum and/or petroleum residues from oil sands or oil shales, etc.

[0034] Herein, unless stated otherwise, viscosities are generally quoted in "centistokes" (cSt) at 25°C as measured using a Brookfield Viscometer.

[0035] Herein, a "non-fatty acid-based unsaturated organic component" is an organic compound (or mixture of one or more such compounds), suitably an organic solvent, which is not derived from fatty acids, and which comprises at least one unsaturated carbon-carbon bond (e.g. a double bond). The unsaturated organic component may comprise one or more alkenyl groups and/or aromatic groups.

[0036] Herein, a "fatty acid-based organic component" is an organic compound (or mixture of one or more such compounds), suitably an organic solvent, which is derived from fatty acids (e.g. fatty acids, fatty acid esters, etc.). [0037] Herein, "free-flowing liquid" has its ordinary dictionary meaning, and refers to a liquid that can be readily poured.

[0038] Herein, the term "standard ambient temperature and pressure (SATP)" is well understood in the art, and refers to a temperature of 25°C and a pressure of 100kPa (kilo- Pascals). This is to be distinguished from standard temperature and pressure (STP) which refers to a temperature of 0°C and a pressure of 100kPa. Unless stated otherwise, any of the parameters and values stated herein may refer to said parameter and values at SATP.

[0039] Herein, the term "extracting" when used in relation to the extraction of petroleum and/or petroleum-based residues refers to any form of extraction, including extraction of said petroleum/residues from a reservoir (e.g. underground or underwater oil reservoir), from oil sands or shale, or even from a mixture with other components (e.g. from mono, bi-, or tri-phasic mixtures with water).

[0040] Herein, the term "transporting" when used in relation to the transport of petroleum and/or petroleum-based residues, may include any movement of said petroleum/residues, in particular through pipework or in tankers (marine or road-based). [0041 ] Herein, the term "processing" when used in relation to the processing of petroleum and/or petroleum-based residues, may include any form of processing known in the art, for example, extracting, transporting, or simple treating. In a particular embodiment, the "processing" refers to extracting and/or transporting of petroleum and/or petroleum-based residues. [0042] Herein, amounts stipulated for components and ingredients, whether specified in terms of "parts", ppm (parts per million), percentages (%, e.g. wt%), or ratios, are intended to be by weight, unless stated otherwise. However, since many of the components have a density of approximately 1 , alternative embodiments of the invention provide that all weight amounts, weight proportions, and weight ratios may instead be volume amounts, volume proportions, and volume ratios. As such, in alternative embodiments, wherever an amount, proportion, or ratio is given by weight, this may be converted to a volume amount, proportion, or ratio of the same value (i.e. x wt% may be translated to x vol%). [0043] A specific gravity is suitably calculated by first measuring the density of the material using either a hydrometer (e.g. as detailed in ASTM D1298) or with an oscillating U-tube as per ASTM D4052. The density may be established at standard ambient temperature and pressure by making the appropriate corrections if required. Specific gravity may then be calculated as:

Specific Gravity (SG) = (p_Sam_Pie)/(pwat_er) where p_sam ie is the density of the sample, and p_water is the density of water.

[0044] American Petroleum Institute (API) gravity of a petroleum sample is quoted in degrees (i.e. °) and is suitably measured at 60°F (i.e. 15.55°C) and is derivable from the specific gravity of the petroleum sample via the following formula:

API gravity = (141 .5/SG) - 131 .5 [0045] Herein, unless stated otherwise, the term "parts" (e.g. parts by weight, pbw) when used in relation to multiple ingredients/components, refers to relative ratios between said multiple ingredients/components.

[0046] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise. [0047] Herein, a composition said to "consist essentially of" a particular set of one or more components, suitably comprises at least 80% w/w of said component(s), more suitably at least 90% w/w of said components, more suitably at least 95% w/w of said components, and most suitably at least 98% w/w of said components. [0048] In this specification the term "alkyl" includes both straight and branched chain alkyl groups. References to individual alkyl groups such as "propyl" are specific for the straight chain version only and references to individual branched chain alkyl groups such as "isopropyl" are specific for the branched chain version only. For example, "(1 -6C)alkyl" includes (1 -4C)alkyl, (1 - 3C)alkyl, propyl, isopropyl and f-butyl. A similar convention applies to other radicals, for example "phenyl(1 -6C)alkyl" includes phenyl(1 -4C)alkyl, benzyl, 1 -phenylethyl and 2-phenylethyl.

[0049] The term "(m-nC)" or "(m-nC) group" used alone or as a prefix, refers to any group having m to n carbon atoms.

[0050] "(3-8C)cycloalkyl" means a hydrocarbon ring containing from 3 to 8 carbon atoms, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or bicyclo[2.2.1 ]heptyl.

[0051 ] "(3-8C)cycloalkenyl" means a hydrocarbon ring containing at least one double bond, for example, cyclobutenyl, cyclopentenyl, cyclohexenyl or cycloheptenyl, such as 3-cyclohexen-1 - yl, or cyclooctenyl.

[0052] The term "aryl" means a cyclic or polycyclic aromatic ring having from 5 to 12 carbon atoms. The term aryl includes both monovalent species and divalent species. Examples of aryl groups include, but are not limited to, phenyl, biphenyl, naphthyl and the like. In particular embodiment, an aryl is phenyl.

[0053] The term "aryl(1 -6C)alkyl" means an aryl group covalently attached to a (1 -6C)alkylene group, both of which are defined herein. Examples of aryl-(1 -6C)alkyl groups include benzyl, phenylethyl, and the like

[0054] The term "arylalcohol", such as an "aryl(m-nC)alcohol", refers to an alkyl alcohol bonded to an aryl group, such as an (m-nC)alkyl alcohol. An example phenyl methyl alcohol (i.e. benzyl alcohol).

[0055] An "acylated" species is a species which is bonded to an acyl group (i.e. a carbonyl). Examples are acetylated species, which are bonded to an acetate group. By way of example, benzyl acetate is an example of an acylated arylalcohol since it is acetylated benzyl alcohol.

[0056] The term "optionally substituted" refers to either groups, structures, or molecules that are substituted and those that are not substituted. [0057] Where optional substituents are chosen from "one or more" groups it is to be understood that this definition includes all substituents being chosen from one of the specified groups or the substituents being chosen from two or more of the specified groups.

[0058] Features, integers, characteristics, compounds, chemical moieties or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, and abstract), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Petroleum Additive Compositions

[0059] As previously stated, the present invention provides a petroleum additive composition comprising:

[0060] The petroleum additive composition is suitably for reducing the viscosity of petroleum and/or petroleum-based residues.

[0061 ] The petroleum additive composition is suitably a free-flowing liquid at standard ambient temperature and pressure. [0062] The petroleum additive composition is suitably for facilitating extraction of petroleum and/or petroleum-based residues. The petroleum additive composition is suitably for reducing the viscosity of petroleum and/or petroleum-based residues, especially of petroleum and/or petroleum residues comprising significant quantities of heavy oil fractions. [0063] The synergistic interaction between the non-fatty acid-based unsaturated organic component and the fatty-acid based organic component affords many advantages, and enables the almost universal extraction of petroleum and/or petroleum-based residues over a range of specific gravities. For instance, the additive compositions of the invention facilitate mobilization and/or extraction of heavy oil, such as bitumen, which is a sticky, black, tar-like form of crude oil which is so thick and heavy that it must usually be heated and/or diluted before it can flow.

[0064] The compositions of the present invention are suitably biodegradable, suitably comprising greater than 98% w/w biodegradable ingredients, suitably greater than 99%.

[0065] The compositions of the present invention are suitably recoverable from petroleum and/or petroleum-based residues after mixing therewith. Such recovery may suitably be effected by centrifugation and/or distillation.

[0066] The compositions of the present invention suitably have a specific gravity that is sufficiently lower than that of the petroleum and/or petroleum-based residues to enable the composition of the invention to be separated from the petroleum and/or petroleum-based residues by centrifugation. Suitably, the specific gravity of the composition of the invention is at least 10% less than that of the petroleum and/or petroleum-based residues. In an embodiment of the invention, the specific gravity of the composition is within the range 0.8 to 0.89. In an embodiment of the invention, the specific gravity of the composition is within the range 0.84 to 0.88. Suitably, the specific gravity of the composition is within the range 0.86 to 0.88. [0067] The flash point of the composition of the invention (i.e. the lowest temperature at which it can vaporise to form an ignitable mixture in air) is suitably greater than 50 °C. More suitably, the flash point is greater than 54 °C.

[0068] It will be appreciated that the constituents making up the composition of the invention can be varied in order to optimise its properties for the particular petroleum and/or petroleum- based residues concerned. For example, the specific gravity of the composition may need to be optimised for a particular application. Furthermore, the relative amounts of the constituents may be varied to optimise the viscosity lowering effect of the composition for a particular petroleum and/or petroleum-based residues. [0069] Suitably, the non-fatty acid-based unsaturated organic component and the fatty-acid based organic component account for greater than or equal to 50% w/w of the total composition, suitably greater than or equal to 70% w/w of the total composition, suitably greater than or equal to 85% w/w of the total composition. Suitably, the non-fatty acid-based unsaturated organic component and the fatty-acid based organic component account for less than or equal to 98% w/w of the total composition, suitably less than or equal to 95% w/w of the total composition, suitably less than or equal to 92% w/w of the total composition.

[0070] The non-fatty acid-based unsaturated organic component suitably constitutes 5 to 95% w/w of the petroleum additive composition, suitably 15 to 90% w/w, suitably 30 to 85% w/w, more suitably 40 to 80% w/w, most suitably 55 to 65% w/w.

[0071 ] The fatty-acid based organic component suitably constitutes 5 to 95% w/w of the petroleum additive composition, suitably 10 to 60% w/w, suitably 15 to 45% w/w, more suitably 20 to 40% w/w, most suitably 25 to 35% w/w.

[0072] In a particular embodiment, the petroleum additive composition comprises: - 30-120 parts non-fatty acid-based unsaturated organic component; and

15-60 parts fatty-acid based organic component.

(this equates to a weight ratio of 30-120 : 15-60 of the abovementioned ingredients) [0073] In a particular embodiment, the petroleum additive composition comprises:

- 40-80 parts non-fatty acid-based unsaturated organic component; and - 20-40 parts fatty-acid based organic component.

- (this equates to a weight ratio of 40-80 : 20-40 of the abovementioned ingredients)

[0074] The petroleum additive composition may suitably comprise one or more additional constituents. The petroleum additive composition may comprise 2-20 parts additional constituents relative to the abovementioned amounts of non-fatty acid-based unsaturated organic component and fatty-acid based organic component. As such, the petroleum additive composition may comprise a non-fatty acid-based unsaturated organic component, a fatty-acid based organic component, and one or more one or more additional constituents in a weight ratio of 30-120 : 15-60 : 2-20 respectively. The petroleum additive composition may comprise 5-15 parts additional constituents relative to the abovementioned amounts of non-fatty acid- based unsaturated organic component and fatty-acid based organic component. In some embodiments the additional constituents may comprise, consist of, or consist essentially of a hydrophilic component, suitably a hydrophilic organic component (which is suitably not derived from petroleum and/or petroleum-based residues). In some embodiments, the additional constituents may comprise, consist of, or consist essentially of an additional hydrophobic component (which is suitably not derived from petroleum and/or petroleum-based residues).

[0075] In some embodiments, the petroleum additive composition consists of or consists essentially of a non-fatty acid-based unsaturated organic component, a fatty-acid based organic component, and optionally one or more one or more additional constituents as defined herein. However, in other embodiments, the petroleum additive composition may comprise a further diluent. Such a diluents may optionally be derived from petroleum and/or petroleum-based residues. Any such diluent suitably constitutes less than or equal to 90% w/w of the petroleum additive composition, suitably less than or equal to 70% w/w, suitably less than or equal to 50% w/w, suitably less than or equal to 20% w/w, most suitably less than or equal to 10% w/w.

Non-fatty acid-based unsaturated organic component

[0076] The compositions of the invention may suitably comprise one or more non-fatty acid- based unsaturated organic components, suitably selected from any of the non-fatty acid-based unsaturated organic components hereindescribed.

[0077] The non-fatty acid-based unsaturated organic component is not derived from fatty acids. The non-fatty acid-based unsaturated organic component comprises at least one unsaturated carbon-carbon bond, which may be a double bond or triple bond, most suitably a double bond.

[0078] The non-fatty acid-based unsaturated organic component is suitably substantially immiscible with water. The non-fatty acid-based unsaturated organic component is suitably miscible with light oil fractions of petroleum (e.g. oil fractions with boiling points less than 150°C), such as gasoline. The non-fatty acid-based unsaturated organic component may also suitably be miscible with heavy oil fractions. The non-fatty acid-based unsaturated organic component suitably penetrates heavy oil fractions. The non-fatty acid-based unsaturated organic component suitably lowers the surface tension of petroleum and/or petroleum-based residues when mixed therewith. The non-fatty acid-based unsaturated organic component suitably lowers the viscosity of petroleum and/or petroleum-based residues when mixed therewith.

[0079] In an embodiment, the non-fatty acid-based unsaturated organic component is a hydrocarbon (i.e. an unsaturated hydrocarbon) or an oxygen-containing derivative thereof, suitably that is miscible with light oil fractions of petroleum, such as gasoline.

[0080] In an embodiment, the non-fatty acid-based unsaturated organic component is a hydrocarbon. In a particular embodiment, the non-fatty acid-based unsaturated organic component is a (5-35C)hydrocarbon (i.e. C5-C35 hydrocarbon). In a particular embodiment, the non-fatty acid-based unsaturated organic component is a (6-22C)hydrocarbon. In a particular embodiment, the non-fatty acid-based unsaturated organic component is a (8-12C)hydrocarbon. The non-fatty acid-based unsaturated organic component suitably comprises at least one alkenyl moiety, suitably at least two. In a particular embodiment, the non-fatty acid-based unsaturated organic component is or comprises a terpene.

[0081 ] In an embodiment, the non-fatty acid-based unsaturated organic component is or comprises an aromatic hydrocarbon (e.g. with a phenyl ring, e.g. toluene) and/or an aromatic organic compound (e.g. benzyl acetate). The non-fatty acid-based unsaturated organic component may be or comprise toluene and/or benzyl acetate.

[0082] The fatty acid-based unsaturated organic component is suitably selected from terpenes (or derivatives thereof - e.g. terpenoids, terpene alcohols such as terpeneol, or acylated derivatives thereof), acylated arylalkyl alcohols (e.g. benzyl acetate), or a mixture thereof. Where the fatty acid-based unsaturated organic component is or comprises a terpene derivative, said derivative may comprise a terpene core as per any of the terpene definitions presented herein.

[0083] The fatty acid-based unsaturated organic component may be any one of the compounds defined herein in relation to the fatty acid-based unsaturated organic component or any suitable mixtures thereof. For instance, the fatty acid-based unsaturated organic component may comprise a mixture of a terpene (e.g. D-limonene) and benzyl acetate.

[0084] In a particular embodiment, the fatty acid-based unsaturated organic component is or comprises a terpene.

[0085] In a particular embodiment, the fatty acid-based unsaturated organic component is or comprises benzyl acetate (i.e. the condensation product of benzyl alcohol and acetic acid).

[0086] The compositions of the invention may suitably comprise one or more non-fatty acid- based unsaturated organic components, suitably selected from any of the non-fatty acid-based unsaturated organic components hereindescribed. The compositions of the invention may suitably comprise two or more non-fatty acid-based unsaturated organic components, suitably selected from any of the non-fatty acid-based unsaturated organic components hereindescribed. The non-fatty acid-based unsaturated organic component(s) may include both a (5-35C)hydrocarbon (e.g. a terpene or derivative thereof) and an aromatic hydrocarbon (e.g. with a phenyl ring) or an aromatic organic compound (e.g. benzyl acetate). In some cases, the proportions of aromatic hydrocarbon or aromatic organic compound may be increased within the composition to cater for high-asphaltene containing petroleum and/or petroleum-based residues. In a particular embodiment, the one or more non-fatty acid-based unsaturated organic component(s) comprises or consists of a terpene (or derivative thereof) and benzyl acetate and/or toluene. In a particular embodiment, the one or more non-fatty acid-based unsaturated organic component(s) comprises or consists of a terpene (or derivative thereof), benzyl acetate and toluene.

[0087] The fatty acid-based unsaturated organic component is suitably biodegradable. The fatty acid-based unsaturated organic component is suitably recoverable from petroleum and/or petroleum-based residues when mixed therewith, suitably via centrifugation and/or distillation.

Terpenes

[0088] Any suitable terpene may be used in the compositions of the present invention. [0089] The terpene may be or include a (5-35C)terpene (i.e. C5-C35 terpene). In a particular embodiment, the non-fatty acid-based unsaturated organic component is a (6-20C)terpene. In a particular embodiment, the non-fatty acid-based unsaturated organic component is a (8- 12C)terpene. In a particular embodiment, the non-fatty acid-based unsaturated organic component is a C10 terpene.

[0090] Suitably, the terpene is selected from the groups consisting of limonene, pine oil, diterpene, turpentine, dipentene and other cyclohexene derivatives.

[0091 ] Suitably, the terpene is monoterpene.

[0092] More suitably, the terpene is a monocyclic terpene. [0093] In a particular embodiment, the terpene is limonene.

[0094] In a specific embodiment, the terpene is D-limonene.

[0095] The amount of the terpene present in the composition of the invention is suitably 5 to 95% w/w of the total composition.

[0096] In an embodiment of the invention, the terpene is present in the composition at a concentration of 15 to 90% w/w of the total composition.

[0097] In a further embodiment of the invention, the terpene is present in the composition at a concentration of 30 to 85% w/w of the total composition.

[0098] In a further embodiment of the invention, the terpene is present in the composition at a concentration of 40 to 80% w/w of the total composition. [0099] In a further embodiment of the invention, the terpene is present in the composition at a concentration of 55 to 65% w/w of the total composition.

[00100] In a particular embodiment of the invention, the terpene is present in the composition at a concentration of 60% w/w of the total composition.

Acylated arylalkyl alcohol

[00101] Any suitable acylated arylalkyl alcohol may be employed. Suitably the acylated arylalkyl alcohol is an acylated aryl(1 -2C)alkyl alcohol, suitably an acylated benzyl alcohol. The acyl group of the acylated arylalkyl alcohol is suitably a (1 -6C)alkanoyl group, suitably an acetyl group.

[00102] In a particular embodiment, the acylated arylalkyl alcohol is benzyl acetate. [00103] The amount of the acylated arylalkyl alcohol present in the composition of the invention is suitably 5 to 95% w/w of the total composition.

[00104] In an embodiment of the invention, the acylated arylalkyl alcohol is present in the composition at a concentration of 15 to 90% w/w of the total composition.

[00105] In a further embodiment of the invention, the acylated arylalkyl alcohol is present in the composition at a concentration of 30 to 85% w/w of the total composition.

[00106] In a further embodiment of the invention, the acylated arylalkyl alcohol is present in the composition at a concentration of 40 to 80% w/w of the total composition.

[00107] In a further embodiment of the invention, the acylated arylalkyl alcohol is present in the composition at a concentration of 55 to 65% w/w of the total composition. [00108] In a particular embodiment of the invention, the acylated arylalkyl alcohol is present in the composition at a concentration of 60% w/w of the total composition.

Fatty-acid based organic component

[00109] The fatty-acid based organic component is suitably substantially immiscible with water. The fatty-acid based organic component is suitably miscible with heavy oil fractions of petroleum (e.g. oil fractions with boiling points greater than 300°C), such as bitumen. The fatty- acid based organic component may also suitably be miscible with light oil fractions. The fatty- acid based organic component suitably dissolves heavy oil fractions and thereby mobilizes them. The fatty-acid based organic component suitably lowers the viscosity of petroleum and/or petroleum-based residues when mixed therewith. The fatty-acid based organic component suitably serves as a plasticizer for heavy oil fractions (e.g. bitumen).

[00110] The fatty-acid based organic component is derived from one or more fatty acids. The fatty-acid based organic component suitably is or comprises one or more fatty acids or esters thereof, suitably greater than or equal to 80% w/w one or more fatty acids or esters thereof, more suitably greater than or equal to 90% w/w one or more fatty acids or esters thereof, suitably greater than 95% w/w one or more fatty acids or esters thereof. [00111] The fatty acids or esters thereof suitably comprise a hydrocarbyl group attached to a carboxylate group. The carboxylate group is suitably either a carboxylic acid or carboxylate ester (e.g. optionally substituted alkyl ester). The fatty-acid based organic component suitably comprises a mixture of different fatty acids or esters thereof.

[00112] In a particular embodiment, the one or more fatty acids or esters thereof of the fatty- acid based organic component are selected from compounds of Formula I:

RiC(0)₂R₂ (Formula I) wherein Ri is hydrocarbyl, and R₂ is hydrogen or optionally substituted hydrocarbyl.

[00113] Ri may be a saturated or unsaturated hydrocarbyl. Suitably, the one or more fatty acids or esters thereof comprise a mixture of saturated or unsaturated Ri moieties. Ri is suitably (2-40C)hydrocarbyl, more suitably (4-30C) hydrocarbyl, most suitably (7- 25C) hydrocarbyl. Suitably, the one or more fatty acids or esters thereof comprise a mixture of Ri moieties.

[00114] R₂ may be hydrogen (i.e. so that the fatty acid derivative is a carboxylic acid). R₂ may be a saturated or unsaturated hydrocarbyl (optionally substituted), most preferably optionally substituted saturated hydrocarbyl. R₂ may be optionally substituted alkyl (i.e. a fatty acid alkyl ester). The alkyl groups of said optionally substituted alkyl ester may comprise 1 to 20 carbon atoms. Typically, the ester will be an alkyl ester comprising 1 to 10 or, more typically, 1 to 3 carbon atoms. Methyl or ethyl esters are generally preferred.

[00115] In particular embodiments, the one or more fatty acids or esters thereof of the fatty-acid based organic component comprise greater than or equal to 80% w/w fatty acid esters, suitably greater than or equal to 90% w/w fatty acid ester, suitably greater than or equal to 95% w/w fatty acid ester. Suitably, the fatty-acid based organic component comprises greater than or equal to 80% w/w fatty acid esters, suitably greater than or equal to 90% w/w fatty acid ester, suitably greater than or equal to 95% w/w fatty acid ester. Fatty acid esters are generally preferred in the additive compositions of the present invention because fatty acid ester mixtures are typically more consistent in terms of their distribution of fatty acids.

[00116] The fatty-acid based organic component may suitably be or comprise vegetable oil or an esterified form thereof. Preferably, the vegetable oil is in the form of a vegetable oil ester. The esterified vegetable oil may be an alkyl or substituted alkyl ester as defined above. In an embodiment, the vegetable oil is soya bean oil, sunflower oil or rapeseed oil or an ester thereof. In a specific embodiment, the vegetable oil is soya bean oil methyl ester.

[00117] The vegetable oil suitably constitutes 5 to 95% w/w of the petroleum additive composition, suitably 10 to 60% w/w, suitably 15 to 45% w/w, more suitably 20 to 40% w/w, most suitably 25 to 35% w/w.

[00118] In an embodiment of the invention, the amount of the vegetable oil present in the composition is less than the amount of the terpene.

Additional constituents

[00119] The additional constituent(s) may comprise, consist of, or consist essentially of a hydrophilic component, suitably a hydrophilic organic component (which is suitably not derived from petroleum and/or petroleum-based residues). Such a hydrophilic component may facilitate clarification (e.g. demulsification) of a water-oil phase interface when extracting petroleum and/or petroleum-based residues from aqueous mixtures thereof. It may also help the general physical form of aqueous petroleum mixtures to facilitate extraction of the petroleum therefrom. For instance, the hydrophilic component may assist the separation of water and oil into separate phases and thereby provide an increased quantity of oil in the oil phase which can be easily separated without further processing. [00120] The additional constituent(s) may comprise, consist of, or consist essentially of an additional hydrophobic component (which is suitably not derived from petroleum and/or petroleum-based residues). The hydrophobic component may facilitate clarification (e.g. demulsification) of a water-oil phase interface when extracting petroleum and/or petroleum- based residues from aqueous mixtures thereof. It may also help the general physical form of aqueous petroleum mixtures to facilitate extraction of the petroleum therefrom.

[00121] The additional constituent(s) may comprise, for example, bulking agents, agents that modify the specific gravity of the composition, agents that modify the flash point of the composition, demulsifying agents, coagulants, flocculating agents, corrosion inhibitors, and/or agents that function as penetration enhancers (to enable the composition to effectively break up high viscosity lumps that are present in the petroleum-based fluid and thereby uniformly reduce the viscosity).

[00122] These additional constituents may typically be present in range of 0 to 40% w/w of the total petroleum additive composition. Suitably, these additional constituents together account for 5 to 40% w/w of the total composition. More suitably, these additional constituents account for 5 to 25% w/w of the total composition. Even more suitably, these additional constituents account for 5 to 20% w/w of the total composition.

[00123] In an embodiment of the invention, the additional constituents may be selected from one or more of the following:

(i) Glycols (including glycol derivatives);

(ii) higher alcohols;

(iii) higher alkyl acetates;

(iv) higher alkanes; (v) ethoxy diglycol;

(vi) triacetin;

(vii) alkoxylated alcohols;

(viii) sorbitan ester;

(ix) sulphosuccinate; and (x) octyl acetate.

[00124] The petroleum additive composition may suitably comprise a glycol (or derivative thereof).

(i) Glycols

[00125] The term "glycols" is used herein to refer to one or more glycol containing compounds. Suitably, a glycol is an ethylene or propylene glycol compound.

[00126] In an embodiment, the glycol is an ethylene of propylene glycol ether.

[00127] In an embodiment, the glycol has the formula:

R³-0-CH₂-CHR⁴-0-R⁵ wherein: R³ is alkyl, hydroxyalkyl or alkanoyl;

R⁴ is hydrogen or methyl; and R⁵ is alkyl, hydroxyalkyl or alkanoyl. [00128] Suitably, any R³ or R⁵ group comprises 1 to 5 carbon atoms.

[00129] In a further embodiment, the glycol is an ethylene or propylene glycol ether acetate. The glycol may be propylene glycol methyl ether acetate or ethoxy diglycol, or a mixture thereof.

[00130] An example of a suitable glycol is Dowanol PMA (Dow Chemical Company; propylene glycol methyl ether acetate)

[00131] A glycol, if present, may constitute 1 to 25% w/w of the total composition. More typically, a glycol, if present, may constitute 5 to 25% w/w of the total composition. In an embodiment, a glycol is present at 5 to 20% w/w of the total composition.

[00132] The glycol may be used as an additional aid to reduce the viscosity of the composition of the invention.

(ii) -(iv) higher alcohols, higher alkanes or higher alkyl acetates [00133] A higher alcohol, alkane or alkyl acetate will typically comprise 8 to 13 carbon atoms. [00134] A single alkyl chain length may be present in the composition or the higher alcohol, alkane or alkyl acetate may be a broad cut mixture comprising a range of different alkyl chain lengths.

[00135] A higher alcohol, alkane and/or alkyl acetate, if present, may constitute 1 to 25% w/w of the total composition. More typically, a higher alcohol, alkane and/or alkyl acetate, if present, may constitute 5 to 25% w/w of the total composition. In an embodiment, a higher alcohol, alkane and/or alkyl acetate is present at 5 to 20% w/w of the total composition.

(v) Ethoxy diglycol [00136] In an embodiment, the composition of the invention comprises 0.5 to 5% w/w of ethoxy diglycol.

[00137] In an embodiment, the composition of the invention comprises 2 to 5% w/w of ethoxy diglycol.

(vi) Triacetin

[00138] In an embodiment, the composition of the invention comprises 0.5 to 5% w/w of triacetin.

[00139] In an embodiment, the composition of the invention comprises 2 to 5% w/w of triacetin.

(vii) Alkoxylated alcohol

[00140] In an embodiment, the composition of the invention comprises 0.5 to 5% w/w of an alkoxylated alcohol.

[00141] In an embodiment, the composition of the invention comprises 2 to 5% w/w of alkoxylated alcohol. [00142] Suitably, the alkoxylated alcohol is an ethoxylated C₈ to Ci₃ alcohol. (viii) Sorbitan ester

[00143] In an embodiment, the composition of the invention comprises 0.5 to 5% w/w of sorbitan ester.

[00144] In an embodiment, the composition of the invention comprises 2 to 5% w/w of sorbitan ester.

(ix) Sulphosuccinate

[00145] In an embodiment, the composition of the invention comprises 0.5 to 5% w/w of sulphosuccinate. [00146] In an embodiment, the composition of the invention comprises 2 to 5% w/w of sulphur suxonate.

(x) Octyl acetate

[00147] In an embodiment, the composition of the invention comprises 0.5 to 20% w/w of octyl acetate.

[00148] In an embodiment, the composition of the invention comprises 5 to 15% w/w of octyl acetate.

Specific Embodiments of the Petroleum Additive Compositions [00149] In a specific embodiment, the present invention provides a petroleum additive composition for reducing the viscosity of crude oil, the composition comprising:

(i) a terpene; and

(ii) a vegetable oil as defined herein.

[00150] Suitably, the terpene and the vegetable oil account for greater than 50% w/w of the total composition. More suitably, the terpene and the vegetable oil account for greater than 70% w/w of the total composition. Even more suitably, the terpene and the vegetable oil account for greater than 75% w/w of the total composition and most suitably more than 80% w/w of the total composition.

[00151] In another specific embodiment, the present invention provides a petroleum additive composition for reducing the viscosity of crude oil, the composition comprising: (i) benzyl acetate; and

(ii) a vegetable oil as defined herein.

[00152] Suitably, the benzyl acetate and the vegetable oil account for greater than 50% w/w of the total composition. More suitably, the benzyl acetate and the vegetable oil account for greater than 70% w/w of the total composition. Even more suitably, the benzyl acetate and the vegetable oil account for greater than 75% w/w of the total composition and most suitably more than 80% w/w of the total composition.

[00153] In a particular embodiment, the present invention provides a petroleum additive composition for reducing the viscosity of crude oil, the composition comprising:

(i) a terpene (or derivative thereof), benzyl acetate, or a mixture thereof; (ii) a vegetable oil as defined herein;

(iii) a glycol (or derivative thereof) as defined herein.

[00154] In a particular embodiment, the present invention provides a petroleum additive composition for reducing the viscosity of crude oil, the composition comprising:

(i) 40-80 parts terpene (or derivative thereof), benzyl acetate, or a mixture thereof; (ii) 20-40 parts vegetable oil as defined herein;

(iii) 5-15 parts glycol (or derivative thereof) as defined herein.

[00155] In another specific embodiment, the present invention provides a petroleum additive composition for reducing the viscosity of crude oil, the composition comprising:

(i) A terpene (or derivative thereof) and either or both of benzyl acetate and toluene; and (ii) a vegetable oil as defined herein. Kit of Parts

[00156] The present invention provides a kit of parts comprising:

- A non-fatty acid-based unsaturated organic component; and

- A fatty-acid based organic component. [00157] When all mixed together, the components of the kit of parts of the invention suitably form a free-flowing liquid at standard temperature and pressure.

[00158] The kit may suitably comprise any of the components described herein in relation to the petroleum additive composition, and any of said components may be provided within the kit as separate components (e.g. separately packaged) or mixed together with one or more other components.

[00159] The kit may be used in the same manner as described herein in relation to the petroleum additive compositions. Some or all of the components of the kit may be pre-mixed prior to use in the methods of the invention, or alternatively some or all of the components may be added separately (whether sequentially or simultaneously) to the petroleum and/or petroleum-based residues in question.

Petroleum and/or Petroleum-based Residues

[00160] The petroleum and/or petroleum-based residues may suitably possess a high viscosity. The or some of the petroleum and/or petroleum-based residues may be a petroleum fluid at standard ambient temperature and pressure. The or some of the petroleum and/or petroleum- based residues may be substantially non-flowing at standard ambient temperature and pressure, for instance, in the form of a solid or wax. Typically the petroleum and/or petroleum- based residues will possess a specific gravity of greater than 0.88. In an embodiment of the invention, the petroleum and/or petroleum-based residues will possess a specific gravity within the range 0.88 to 0.98. In an embodiment, the petroleum and/or petroleum-based residues is crude oil, for example, heavy crude oil (or extra heavy crude oil) which suitably does not readily flow. Heavy crude oil is closely related to bitumen and is associated with oil or tar sand reserves. The heavy crude oil suitably has an API gravity less than 20°. Extra heavy oil is defined with a gravity of less than 10° API (i.e. with density greater than 1000 kg/m³ or, equivalently, a specific gravity greater than 1 and a reservoir viscosity of no more than 10,000 cSt.

[00161] In a particular embodiment, the petroleum and/or petroleum-based resides is a petroleum-based fluid, in that it is a free-flowing fluid at standard ambient temperature and pressure.

[00162] The petroleum and/or petroleum-based residues may be selected from any one of the following:

• Petroleum and/or petroleum-based residues within a crude oil reservoir;

• Petroleum and/or petroleum-based residues within a lagoon;

• Petroleum and/or petroleum-based residues within a pipeline;

• Petroleum and/or petroleum-based residues within a tanker;

• Petroleum and/or petroleum-based residues that have settled to the bottom of a vessel;

• Petroleum and/or petroleum-based residues that are non-flowing;

• Petroleum and/or petroleum-based residues causing a blockage (e.g. in a pipeline);

• Waste petroleum and/or petroleum-based residues (e.g. waste products from refineries);

• Petroleum and/or petroleum-based residues mixed with water (e.g. such as mixtures obtained from extracting petroleum/residues using water or steam).

• Bitumen;

• Petroleum and/or petroleum residues from oil sands;

• Petroleum and/or petroleum residues from oil shale (e.g. kerogen).

[00163] According to an aspect of the present invention, there is provided a treated petroleum- based composition comprising:

- petroleum and/or petroleum-based residues:

[00164] Such a treated petroleum-based composition may be petroleum and/or petroleum- based residues that has been treated with the petroleum additive composition of the invention or with the components of the kit of parts of the invention. The presence of the abovementioned components of the petroleum additive composition(s) of the invention within petroleum and/or petroleum-based residues indicates that the methods of the present invention have been employed.

[00165] Such treated petroleum-based compositions may be processed so as to recover some or all of the components of the petroleum additive composition therefrom (e.g. via centrifugation and/or distillation). In a particular embodiment, such treated petroleum-based compositions may be transported for later processing or use.

Uses of and Methods of Using Petroleum Additive Compositions of the Invention

[00166] The present invention provides a method of processing petroleum and/or petroleum- based residues as defined herein.

[00167] The "processing" may refer to or result in any one or more of the following: i) mobilizing the petroleum and/or petroleum-based residues; reducing the viscosity of the petroleum and/or petroleum-based residues; reducing surface tension of the petroleum and/or petroleum-based residues; plasticizing waxy petroleum and/or petroleum-based residues; extracting or facilitating extraction of the petroleum and/or petroleum- based residues; vi) storing or facilitating storage of the petroleum and/or petroleum-based residues (especially without unwanted settling out of petroleum residues) vii) transporting or facilitating transportation of the petroleum and/or petroleum-based residues; viii) separating or facilitating separation of aqueous and oil phases in aqueous mixtures of the petroleum and/or petroleum-based residues; ix) clarifying interfaces between aqueous and oil phases in aqueous mixtures of the petroleum and/or petroleum-based residues; increasing the extraction yields of petroleum and/or petroleum-based residues; xi) reducing the amount of oil/water emulsion from which petroleum and/or petroleum-based residues are extracted.

[00168] In a particular embodiment, the "processing" comprises extracting, storing and/or transporting petroleum and/or petroleum-based residues.

[00169] The method of processing is suitably a method of reducing the viscosity of petroleum and/or petroleum-based residues.

[00170] The processing involves mixing the petroleum and/or petroleum-based residues with the petroleum additive composition or individual components thereof to form treated petroleum and/or petroleum-based residues (i.e. treated petroleum-based composition). Such mixing may occur at any point in the overall process.

[00171] The processing may involve extracting, storing and/or transporting the treated petroleum-based composition.

[00172] The processing may involve treating petroleum and/or petroleum-based residues so as to prevent or reduce precipitation or settling of waxy deposits therefrom.

[00173] The processing may involve treating waxy deposits that have already precipitated or settled out from petroleum and/or petroleum-based residues, for instance, to solubilise or otherwise mobilize said waxy deposits. This is particularly useful where waxy deposits need to be removed from a vessel (e.g. oil tank) or from pipes (e.g. in a pipeline, e.g. a blocked or partially blocked pipeline).

[00174] The processing may involve adding the petroleum additive composition or individual components thereof directly to a relevant vessel, pipelines, or flowlines. The processing may involve adding adding the petroleum additive composition or individual components thereof to the flowlines of a wellhead.

[00175] The process may furthermore involve eventually recovering the petroleum additive composition, or some or all of the individual components thereof, from the treated petroleum- based composition.

[00176] The process may involve separating water from an oil-water mixture, such as via a method defined herein, and optionally further disposing of a clean water phase obtained therefrom, again via a method defined herein.

Mixing

[00177] The petroleum additive composition or individual components thereof may be mixed with the petroleum and/or petroleum-based residues at any stage in the processing, though most suitably at a stage when its effects are most advantageous (e.g. where the petroleum/residues need mobilizing to enable the transport/movement thereof; and/or where the petroleum/residues need to be more clearly or cleanly separated from an aqueous phase).

[00178] The amount of petroleum additive composition (or individual components thereof) mixed with petroleum and/or petroleum-based residues is suitably less than or equal to 30% w/w of the petroleum and/or petroleum-based residues, suitably less than or equal to 20% w/w of the petroleum and/or petroleum-based residues, suitably less than or equal to 10% w/w of the petroleum and/or petroleum-based residues. T he amount of petroleum additive composition (or individual components thereof) mixed with petroleum and/or petroleum-based residues is suitably greater than or equal to 0.5% w/w of the petroleum and/or petroleum-based residues, suitably greater than or equal to 1% w/w of the petroleum and/or petroleum-based residues, suitably greater than or equal to 2% w/w of the petroleum and/or petroleum-based residues. [00179] The step of mixing suitably reduces the viscosity of the petroleum and/or petroleum- based residues.

[00180] In a particular embodiment, the petroleum additive composition or individual components thereof are added to and mixed with petroleum and/or petroleum-based residues in situ. "In situ" ma refer to the original source of the petroleum and/or petroleum-based residues, e.g. where they naturally occur (e.g. at source within natural oil reservoirs, lagoons, oil sands, or oil shale, especially in oil reservoirs) or where they occur artificially (e.g. as a result of waste disposal of petroleum residues - e.g. oil slops). Alternatively, "in situ" may refer to a site at which the relevant petroleum and/or petroleum-based residues have been partially or fully immobilized, such as in an oil tank (e.g. in an oil tanker, whether seafaring or road going), where certain residues may stick to bottom or sides thereof, or a pipeline, where residues may cause a blockage or otherwise clog the pipes. Such in situ treatment of the petroleum and/or petroleum- based residues may suitably precede (and suitably facilitates) extraction (e.g. pumping) of the treated petroleum and/or petroleum-based residues from source. Thus, this may be considered a pre-treatment regime. Such extraction is suitably facilitated by the mobilizing/fluidizing effect of the petroleum additive composition upon petroleum and/or petroleum-based residues in question. Typically, adding the compositions of the invention to viscous, waxy, or solid petroleum and/or petroleum-based residues reduces the viscosity of the petroleum and/or petroleum-based residues and enables the treated petroleum and/or petroleum-based residues to be transported/moved and optionally subsequently processed.

[00181] Where the petroleum and/or petroleum-based residues are treated (i.e. mixed) with the petroleum additive composition or individual components thereof in situ at source, such treatment may reduce the viscosity of the petroleum and/or petroleum-based residues. This may facilitate "natural lift" (i.e. natural reservoir pressure to force the treated petroleum and/or petroleum-based residues to the surface) or "artificial lift" (i.e. where artificial pressure is applied to force the treated petroleum and/or petroleum-based residues to the surface - e.g. via waterflooding, injecting steam, carbon dioxide, or other pressurising gases into the reservoir).

[00182] In other embodiments, the petroleum additive composition or individual components thereof are added to and mixed with petroleum and/or petroleum-based residues that have been already removed from source (e.g. their naturally occurring environment, or oil waste disposal zone). Such a process may be considered a post-treatment regime. In some embodiments, prior to mixing, the petroleum and/or petroleum-based residues is first removed or extracted from source and thereafter transferred into an appropriate vessel for subsequent mixing with the petroleum additive composition (or components thereof). Such a process is particularly appropriate for extracting petroleum and/or petroleum-based residues from oil/tar sand and oil shale deposits, since oil/tar sand and oil shale deposits are typically first mined before they are subsequently treated to extract the petroleum and/or petroleum-based residues therein. The petroleum additive compositions of the invention can be added directly to said oil/tar sands and oil shale deposits and suitably mixed therewith and the mixture subsequently processed (e.g. filtered, decanted, or otherwise separated) to isolate treated petroleum and/or petroleum-based residues.

[00183] However, such post-treatments are also appropriate to facilitate extraction/separation of petroleum and/or petroleum-based residues from aqueous mixtures thereof (e.g. oil-in-water emulsions). Such aqueous mixtures of petroleum and/or petroleum-based residues may arise from the "artificial lift" process, which involves water or steam pressurized removal of the petroleum and/or petroleum-based residues from their natural environment (e.g. oil reservoirs). Alternatively, such aqueous mixtures may arise naturally (e.g. within the natural environment), such that the water carries through with the petroleum and/or petroleum-based residues as the petroleum and/or petroleum-based residues are removed from their natural environment. Post- treatment with compositions of the invention can facilitate separation of the oil and water phases. For instance, treatment with compositions of the invention can facilitate direct centrifugation of oil/water mixtures, for example, by sufficiently reducing the viscosity to aid efficient centrifugation. On the other hand, treatment with compositions of the invention may allow for more facile separation of an oil layer (e.g. by "skimming off") from a heterogeneously partitioned oil/water phase mixture. Such post-treatments may also help to clarify oil/water phase interfaces or minimize interfacial oil/water emulsion layers.

[00184] In some embodiments, the method may involve both "pre-treatment" and "post- treatment" as described above.

[00185] In some embodiments, in addition to mixing the petroleum additive composition (or individual ingredients thereof) of the present invention with the petroleum and/or petroleum- based residues, the method may additionally involve mixing additional ingredients with the petroleum and/or petroleum-based residues, for example, any one or more of the additional constituents as define herein, or one or more additional bulking agents, agents that modify the specific gravity of the composition, agents that modify the flash point of the composition, demulsifying agents, coagulants, flocculating agents, corrosion inhibitors, and/or agents that function as penetration enhancers (to enable the composition to effectively break up high viscosity lumps that are present in the petroleum-based fluid and thereby uniformly reduce the viscosity).

Extraction

[00186] Extracting or extraction may refer to and/or include the removal of petroleum and/or petroleum-based residues from their source (whether natural or otherwise) or from a site at which the relevant petroleum and/or petroleum-based residues are partially or fully immobilized (e.g. tanker, pipeline, or wellhead). Such extraction may merely require pumping (using natural or artificial pressure) of the relevant petroleum and/or petroleum-based residues, where they are sufficiently fluid or otherwise mobilized through pre-treatments with compositions of the invention. As aforementioned, mixing of the petroleum and/or petroleum-based residues with the petroleum additive composition or individual components thereof may precede such extraction, especially if such a pre-treatment helps to mobilize the petroleum and/or petroleum- based residues to facilitate what would otherwise be a difficult extraction process.

[00187] Extracting or extraction may also refer to and/or include the separation/extraction of petroleum and/or petroleum-based residues from water and/or other unwanted residues in aqueous mixtures of the petroleum and/or petroleum-based residues. As aforementioned, such aqueous mixtures may arise naturally at source of may arise artificially during the process of initially extracting the petroleum and/or petroleum-based residues from source.

[00188] Extractions of petroleum and/or petroleum-based residues from aqueous mixtures thereof may typically involve allowing an aqueous mixture to settle/partition into a polyphasic mixture. Such a polyphasic mixture suitably comprises a plurality of liquid layers, suitably at least an oil phase (suitably an upper layer) and an aqueous phase (a lower layer), but may also comprise a mixed phased comprising both water and oil (e.g. an oil/water emulsion). The interfaces between the liquid layers may lack clarity through being partially emulsified. The oil layer may be "skimmed off" or "tapped off", and thereby suitably separated from all other liquid layers and emulsified layer interfaces. The oil/water mixed emulsion layer may be processed to separate the petroleum and/or petroleum-based residues therein from the water and other unwanted residues, typically via centrifugation. The aqueous layer is suitably mixed with dense petroleum residues, which may be recovered (e.g. for us or reprocessing, optionally extracting again in accordance with the invention) or discarded.

[00189] Alternatively, separation/extraction of petroleum and/or petroleum-based residues from water and/or other unwanted residues in aqueous mixtures of the petroleum and/or petroleum- based residues may involve centrifugation (possible direct centrifugation of the entire oil-water mixture without any partition-separation of phases). The petroleum additive compositions of the invention allow oil-water mixtures to be centrifuged at a rate of 200 gallons per minute (gpm) or more, suitably a rate of 500 gallons per minute (gpm) or more. Centrifugation may be employed to separate aqueous mixtures of the petroleum and/or petroleum-based residues into three distinct phases: i) an oil phase; ii) a slurry phase; and iii) solids. The oil phase is essentially a petroleum-based product, which may be subsequently refined or optionally subsequently processed as defined anywhere herein. The slurry phase is typically a mixture of oil, water, and fine suspended solids. Water is typically separated from the slurry phase by techniques well known in the art, and the resulting clean water optionally disposed of (e.g. through discharge into the natural environment). The solids are suitably disposed of (e.g. in landfill sites) or otherwise used as fuel, for example, in concrete works.

[00190] The extracted petroleum and/or petroleum-based residues may then be stored (e.g. in an oil tank), used, transported, and/or subsequently processed (e.g. refined and/or have the petroleum additive composition removed therefrom).

[00191] Prior to any extraction/separation of oil and water phases, aqueous mixtures of petroleum and/or petroleum-based residues may be coarse filtered and the filtrate subsequently processed as described above. Water Separation

[00192] The present invention provides a method of separating water from an oil-water mixture, such as the oil-water mixtures defined herein, which may for example arise during extraction of petroleum and/or petroleum-based residues from source. The method suitably comprises: (a) providing a treated oil-water mixture comprising:

^■ water;

^■ petroleum and/or petroleum-based residues; and

^■ a petroleum additive composition as defined herein or the individual components of the petroleum additive composition as defined herein; (b) separating at least some of the water from the oil-water mixture to provide a clean water phase.

[00193] The treated oil-water mixture may be provided as a result of any "mixing" as defined herein in relation to the processing of the petroleum and/or petroleum-based residues. This may therefore involve mixing the petroleum and/or petroleum-based residues with the petroleum additive composition or individual components thereof prior to, after, or during bringing the petroleum and/or petroleum-based residues into contact with water.

[00194] Separating the water from the oil-water mixture may comprise any suitable method of separating, including any such method described herein in relation to the separation of petroleum and/or petroleum-based residues from water, including heterogeneous liquid-liquid phase separations and centrifugation. Suitably separating involves the use of centrifugation. Suitably at least 20 wt% of the total water content of the original oil-water mixture is separated to provide a clean water phase, more suitably at least 50 wt%, more suitably at least 70 wt%.

[00195] The separating may involve further treatments to clean the water thereby obtained, but in preferred embodiments requires no further cleaning steps. A particular advantage of the petroleum additive compositions of the invention is that they facilitate the separation of clean water which can then be optionally disposed of as defined herein, most preferably discharged into the natural environment. [00196] As such, the present invention provides a method of disposing of water from an oil- water mixture, wherein the method comprises separating water from an oil-water mixture as described above, to thereby provide a clean water phase, and thereafter disposing of some or all of the clean water phase, suitably into the natural environment.

Transport / Storage

[00197] Storing or storage refers to storing petroleum and/or petroleum-based residues, especially treated petroleum and/or petroleum-based residues in vessels such as containers or oil tankers. [00198] Transporting or transportation may refer to either transporting petroleum and/or petroleum-based residues in a vessel (e.g. container) upon a vehicle (e.g. marine or land-going oil tanker) or via pipework or a pipeline.

[00199] Pre-treatments, as described above, of petroleum and/or petroleum-based residues with petroleum additive composition of the invention or individual components thereof suitably facilitates transport of said petroleum and/or petroleum-based residues through pipework and pipelines.

[00200] When storing and/or transporting petroleum and/or petroleum-based residues within a vessel (e.g. upon a vehicle), it is common for viscous deposits/residues to settle to the bottom of the vessel and be thereafter difficult to extract. As such, a petroleum additive composition of the invention or individual components thereof may be added to the petroleum and/or petroleum-based residues prior to storage or transport to help prevent or delay such "settling- out" of deposits. In this manner, the compositions of the invention facilitate storage and/or transport of petroleum and/or petroleum-based residues.

[00201] Alternatively, the present invention may be employed to extract the "settled-out" viscous deposits from the vessel by: i) first extracting from the vessel the most mobile/free-flowing portion of the petroleum and/or petroleum-based residues; ii) then treating the viscous deposits left within the vessel with the petroleum additive composition of t e invention or individual components thereof to produce a treated petroleum-based composition; iii) extracting the treated petroleum-based composition from the vessel; iv) optionally removing the petroleum additive composition or individual components thereof from the treated petroleum-based composition; and v) optionally combining it with the mobile petroleum and/or petroleum-based residues removed in step i).

Recovery of the petroleum additive composition [00202] Following processing of petroleum and/or petroleum-based residues using compositions of the present invention (or the individual components thereof), the petroleum additive composition (or individual components thereof) may be recovered from the petroleum and/or petroleum-based residues. Suitably such recovery involves centrifugation and/or distillation. [00203] Compositions of the present invention (and individual components thereof) are or may be readily tuned (e.g. by adjusting the ingredients or relative amounts thereof) to have a specific gravity that differs from the petroleum and/or petroleum-based residues with which they are mixed, so that centrifugation can be used to recover said compositions. This allows compositions of the invention to be used to perform their role and subsequently recovered and thereby recycled.

[00204] Alternatively or additionally, the compositions of the invention (and individual components thereof) are or may be readily tuned (e.g. by adjusting the ingredients or relative amounts thereof) to have a boiling points that differ from the petroleum and/or petroleum-based residues with which they are mixed, so that distillation can be used to recover said compositions. This allows compositions of the invention to be used to perform their role and subsequently recovered and thereby recycled. This also allows compositions of the invention to be employed and subsequently removed during the oil refining process, to thereby reduce additional processing steps. [00205] Suitably, greater than 70% of the composition of the invention can be recovered by centrifugation and/or distillation. More preferably, greater than 85% and even more preferably greater than 90% of the composition is recovered by centrifugation and/or distillation.

Specific Embodiments relating to methods of the invention

[00206] The present invention further provides a process for reducing the viscosity of a petroleum based fluid, such as crude oil, the process comprising adding a composition as defined herein to the fluid.

[00207] In yet another aspect, the present invention provides a process for extracting and/or transporting a petroleum based fluid, the process comprising the steps of:

(i) mixing the petroleum based fluid with a composition as defined herein to reduce the viscosity of the fluid;

(ii) extracting and/or transporting the reduced viscosity petroleum based fluid; and

(iii) optionally separating the composition as defined herein from the petroleum based fluid by centrifugation and/or distillation.

[00208] The amount of the composition of the invention required to adequately lower the viscosity of the petroleum-based fluid will be determined by experimentation for the particular fluid concerned. For adequate flow properties, a viscosity of below 350 centistokes is desirable.

[00209] In some embodiments, the petroleum and/or petroleum-based residues may be pre- treated prior to performing any of the methods of the present invention. For instance, the petroleum and/or petroleum-based residues or aqueous mixtures thereof may be demulsified, for example, through the addition of a demulsifier.

EXAMPLES

[00210] The invention will now be described in more detail in relation to the following illustrative examples.

[00211] All constituents of the compositions described in the accompanying examples are sourced commercially.

Example 1

[00212] A first composition according to the present invention is prepared by mixing the following constituents in the proportions stated:

60% w/w D-limonene

25% w/w Soya methyl ester

15% w/w Dowanol PMA (Dow Chemical Company; propylene glycol methyl ether acetate)

Example 2

[00213] A composition according to the present invention is prepared by mixing the following constituents in the proportions stated:

80% w/w D-limonene

10% w/w Soya methyl ester

10% w/w Decanol

Example 3

[00214] A composition according to the present invention is prepared by mixing the following constituents in the proportions stated:

40% w/w D-limonene

35% w/w Soya methyl ester

10% w/w Octyl acetate

5% w/w Ethoxydiglycol

Example 4 - The effect of the composition of Example 1 on the viscosity of Venezuelan Crude Oil

[00215] Varying amounts of the composition of Example 1 is added to a representative heavy fuel oil, Venezuelan Crude Oil at 50 °C and 35 °C and the viscosity was measured using a Brookfield Viscometer. The temperatures of the experiments were maintained by the use of water baths. The results are shown in Table 1 below.

Table 1 - the effect of the composition of Example 1 on the viscosity of oil

[00216] The above data shows that the composition of formula A dramatically reduces the viscosity of the heavy oil at low concentrations.

Example 5

[00217] A composition according to the present invention is prepared by mixing the following constituents in the proportions stated: 60% w/w D-limonene

30% w/w Soya methyl ester

10% w/w Dowanol PMA (Dow Chemical Company; propylene glycol methyl ether acetate)

Example 6

[00218] A composition according to the present invention is prepared by mixing the following constituents in the proportions stated:

60% w/w D-limonene

30% w/w Soya methyl ester

10% w/w Ethoxydiglycol

Example 7

[00219] A composition according to the present invention is prepared by mixing the following constituents in the proportions stated: 60% w/w Benzyl acetate

30% w/w Fish oil ester

Example 8 - Use of Compositions of the Invention

[00220] 50g of the composition of Example 5 (i.e. 5% w/w relative to oil) was added to and mixed with (using a mechanical stirrer) 1 kg of a representative heavy fuel oil, Venezuelan Crude Oil. [00221] The heavy fuel oil became significantly more mobile and less viscous, and thereby easier to handle, extract, and transport.

[00222] The treated heavy fuel oil was then thoroughly mixed with 1 kg of water in a separating funnel. The mixture was left to separate into layers over a 24 hour period, after which time a triphasic mixture formed consisting of a top oil layer, a bottom aqueous layer mixed with solid residues, and a middle mixed emulsified oil/water layer.

[00223] The same experiment was performed through mixing 1 kg of untreated heavy fuel oil with 1 kg of water in a separating funnel. Again, the mixture was left to separate into layers over a 24 hour period, after which time a triphasic mixture was forming consisting of a top oil layer, a bottom aqueous layer mixed with solid residues, and a middle mixed emulsified oil/water layer. [00224] The triphasic mixture for the in the treated example differed markedly from the triphasic mixture of the untreated example. The top oil layer was much larger in the case of the treated example, and the interfaces were much cleaner. The middle mixed layer was much larger in the case of the untreated example.

[00225] The entire triphasic mixture of the treated example was further processed by centrifugation to yield three distinct phases - i) an oil phase; ii) a slurried aqueous emulsion phase; iii) solids. Such centrifugation was made possible through the viscosity lowering effect of the petroleum additive composition used.

[00226] The oil phase yielded clean heavy oil mixed with the petroleum additive composition. The middle layer was a slurry of water, fine particulates, and some oil. This aqueous slurry could be filtered to afford sufficiently clean water for discharging back into the natural environment. The solids could be disposed of.

[00227] The clean heavy oil phase was further processed to remove the additive composition itself via further centrifugation.

[00228] Through experiment the inventors have demonstrated that the compositions of the invention can be used to reduce viscosity of petroleum and petroleum-based residues to facilitate the transport and extraction thereof, and also to facilitate separation from water in aqueous mixtures. It is has also been demonstrated that the composition may be subsequently recovered and reused.

Claims

1 . A method of processing petroleum and/or petroleum-based residues, the method comprising mixing the petroleum and/or petroleum-based residues with a petroleum additive composition or with the individual components of the petroleum additive composition; wherein the petroleum additive composition comprises:

- a non-fatty acid-based unsaturated organic component; and

- a fatty-acid based organic component.

2. The method as claimed in claim 1 , wherein the method of processing is a method of extracting, storing and/or transporting petroleum and/or petroleum-based residues.

3. The method as claimed in any preceding claim, wherein the non-fatty acid-based unsaturated organic component is an unsaturated hydrocarbon or an oxygen-containing derivative thereof.

4. The method as claimed in any preceding claim, wherein the fatty acid-based unsaturated organic component is selected from terpenes (or derivatives thereof), acylated arylalkyl alcohols, or a mixture thereof.

5. The method as claimed in any preceding claim, wherein the fatty acid-based unsaturated organic component is or comprises a terpene and/or benzyl acetate.

6. The method as claimed in any preceding claim, wherein the fatty acid-based unsaturated organic component is a terpene.

7. The method as claimed in any preceding claim, wherein the fatty acid-based unsaturated organic component is D-limonene.

8. The method as claimed in any preceding claim, wherein the fatty-acid based organic component comprises greater than or equal to 80% w/w one or more fatty acids or esters thereof.

9. The method as claimed in claim 8, wherein the one or more fatty acids or esters thereof of the fatty-acid based organic component are selected from compounds of Formula I:

RiC(0)₂R₂ (Formula I) wherein Ri is saturated or unsaturated (7-25C)hydrocarbyl, and R₂ is hydrogen or optionally substituted hydrocarbyl.

10. The method as claimed in claim 9, wherein R₂ is methyl or ethyl.

1 1. The method as claimed in any preceding claim, wherein the fatty-acid based organic component is vegetable oil or an esterified form thereof.

12. The method as claimed in claim 1 1 , wherein the vegetable oil is soya bean oil methyl ester.

13. The method as claimed in any preceding claim, wherein the petroleum additive composition comprises: - 40-80 parts non-fatty acid-based unsaturated organic component; and

20-40 parts fatty-acid based organic component.

14. The method as claimed in any preceding claim, wherein the non-fatty acid-based unsaturated organic component and the fatty-acid based organic component account for greater than or equal to 70% w/w of the total composition.

15. The method as claimed in any preceding claim, wherein the petroleum additive composition comprises a glycol or derivative thereof.

16. The method as claimed in claim 15, wherein the glycol has the formula:

R³-0-CH₂-CHR⁴-0-R⁵ wherein: R³ is alkyl, hydroxyalkyl or alkanoyl;

R⁴ is hydrogen or methyl; and R⁵ is alkyl, hydroxyalkyl or alkanoyl.

17. The method as claimed in claim 15, wherein the glycol is propylene glycol methyl ether acetate, ethoxy diglycol, or a mixture thereof.

18. The method as claimed in any preceding claim, wherein the petroleum additive composition comprises: (i) a terpene; and

(ii) a vegetable oil (or esterified derivative thereof).

19. The method as claimed in any of claims 1 to 17, wherein the petroleum additive composition comprises: (i) benzyl acetate; and

(ii) a vegetable oil (or esterified derivative thereof).

20. The method as claimed in any of claims 1 to 18, wherein the petroleum additive composition comprises:

(i) a terpene (or derivative thereof), benzyl acetate, or a mixture thereof; (ii) a vegetable oil (or esterified derivative thereof); and

(iii) a glycol (or derivative thereof).

21 . The method as claimed in any of claim 20, wherein the petroleum additive composition comprises:

(i) 40-80 parts terpene (or derivative thereof), benzyl acetate, or a mixture thereof; (ii) 20-40 parts vegetable oil (or esterified derivative thereof); and

(iii) 5-15 parts glycol (or derivative thereof).

22. The method as claimed in any preceding claim, wherein the specific gravity of the petroleum additive composition is within the range 0.8 to 0.89.

23. The method as claimed in any preceding claim, wherein the amount of petroleum additive composition (or individual components thereof) mixed with petroleum and/or petroleum- based residues is less than or equal to 20% w/w of the petroleum and/or petroleum-based residues.

24. The method as claimed in any preceding claim, wherein the step of mixing suitably reduces the viscosity of the petroleum and/or petroleum-based residues.

25. The method as claimed in any preceding claim, wherein mixing the petroleum and/or petroleum-based residues with a petroleum additive composition or with the individual components of the petroleum additive composition produces a treated petroleum-based composition, and the method additionally comprises extracting and optionally thereafter storing and/or transporting the treated petroleum-based composition; wherein extracting includes either: a) removal of petroleum and/or petroleum-based residues from their source; b) removal of petroleum and/or petroleum-based residues from a site at which the relevant petroleum and/or petroleum-based residues are partially or fully immobilized; and/or c) separation/extraction of petroleum and/or petroleum-based residues from water and/or other unwanted residues in aqueous mixtures of the petroleum and/or petroleum-based residues.

26. The method as claimed in claim 25, wherein extracting includes separation/extraction of petroleum and/or petroleum-based residues from water and/or other unwanted residues in aqueous mixtures of the petroleum and/or petroleum-based residues.

27. The method as claimed in claim 26, wherein separation/extraction of petroleum and/or petroleum-based residues from water and/or other unwanted residues in aqueous mixtures of the petroleum and/or petroleum-based residues involves centrifugation of the aqueous mixtures.

28. The method as claimed in claim 27, wherein prior to separation/extraction, the aqueous mixture is subject to coarse filtration, and the filtrate subsequently separated/extracted.

29. The method as claimed in any preceding claim, wherein the method additionally comprises recovering the petroleum additive composition (or individual components thereof) from the petroleum and/or petroleum-based residues.

30. The method as claimed in claim 29, wherein recovering the petroleum additive composition (or individual components thereof) from the petroleum and/or petroleum-based residues is performed via centrifugation.

31. A petroleum additive composition comprising: - a non-fatty acid-based unsaturated organic component; and - a fatty-acid based organic component.

32. A kit of parts comprising: - a non-fatty acid-based unsaturated organic component; and

- a fatty-acid based organic component.

33. A treated petroleum-based composition comprising:

- petroleum and/or petroleum-based residues: - a non-fatty acid-based unsaturated organic component; and

- a fatty-acid based organic component.

34. A method of recovering a petroleum additive composition from the treated petroleum- based composition of claim 33, the method comprising separating the petroleum additive composition from the treated petroleum-based composition by centrifugation and/or distillation; and wherein the petroleum additive composition comprises:

- a non-fatty acid-based unsaturated organic component; and

- a fatty-acid based organic component.

35. A petroleum additive composition obtainable by the method of recovering a petroleum additive composition of claim 34.

36. A petroleum-based product obtainable by the method of any of claims 1 to 30.

37. A method of separating water from an oil-water mixture, the method comprising:

(a) providing a treated oil-water mixture comprising:

^■ water;

^■ petroleum and/or petroleum-based residues; and ■ a petroleum additive composition as defined in any preceding claim or the individual components of the petroleum additive composition as defined in any preceding claim;

38. A method of disposing of water from an oil-water mixture, the method comprising separating water from an oil-water mixture by the method of claim 37 to thereby provide a clean water phase, and thereafter disposing of some or all of the clean water phase.

39. The method as claimed in claim 38, wherein disposing of the water involves discharging the clean water phase into the natural environment.

40. A method, a petroleum additive composition, a kit of parts, a treated petroleum-based composition, a petroleum-based product, as substantially hereinbefore described with reference to the accompanying Examples.