WO2010059874A1

WO2010059874A1 - Viscosity reduction process for hydrocarbon production

Info

Publication number: WO2010059874A1
Application number: PCT/US2009/065215
Authority: WO
Inventors: Vicente Gonzalez Davila
Original assignee: Green Zone, S.A. De C.V.
Priority date: 2008-11-19
Filing date: 2009-11-19
Publication date: 2010-05-27
Also published as: MX2008014694A

Abstract

A system, composition, and method for reducing the viscosity of hydrocarbons to decrease difficulties and costs associated with refining and transport. An embodiment of a system having the features of the present invention comprises a production tubing string providing a communication path to a hydrocarbon reservoir and the surface, a storage tank in selective communication with the production tubing string, a volume of viscosity-reducing fluid derived from a vegetable oil, a pump in selective communication with the volume of viscosity-reducing fluid, and a secondary tubing providing a communication path between the pump and the reservoir. A composition of the present invention consists of a first volume of Jatropha curcas vegetable oil extract is transesterified in an alkaline environment with a second volume of methanol that is between 2% and 10% by volume, inclusive, of the first volume to produce a solution..

Description

INVENTOR: Vicente Gonzalez DAVILA

TITLE: Viscosity Reduction Process for Hydrocarbon Production

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of Mexican Patent Application Serial No. MX/a/2008/014694, filed November 19, 2008, which is incorporated by reference herein for all purposes.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR

DEVELOPMENT [0002] Not applicable. BACKGROUND OF THE INVENTION

1. Field of the Invention.

[0003] The present invention relates to a system, method, and composition for use in hydrocarbon production. More specifically, the invention is a system, method, and composition for producing hydrocarbons, and heavy oils in particular, from a formation by reducing the viscosity of the hydrocarbons with a viscosity-reducing fluid derived from a vegetable oil extract.

2. Description of the Related Art.

[0004] Heavy oils, which traditionally are defined as oil having an API gravity below 22.3, have always presented substantial difficulties relating to production and transportation. Because heavy oils are highly viscous, the flow through production equipment and pipelines is inefficient, thus requiring additional energy and increased costs associated with transport and refining. In addition, oil with high viscosity requires higher energy for heating and production of petroleum-based products.

[0005] One methodology for addressing this problem is injection of water-based products that are immiscible with the hydrocarbons. For example, United States Published

Application 2008/0017594, entitled "System and Method for the Production and Handling of Heavy Oil," and incorporated by reference herein, describes a system for introducing an immiscible viscosity-reducing fluid into the heavy oil at an upstream end of a flow line to create a dispersion of oil and the viscosity-reducing fluid. One drawback to using immiscible viscosity reducers is that, because they are immiscible, they must be removed following transport of the hydrocarbons.

[0006] An alternative methodology uses miscible aromatic compounds. However, these compounds are expensive and damage plastic materials in the system, such as pump seals.

BRIEF SUMMARY OF THE INVENTION [0007] To address the aforementioned problems, the present invention provides a system, method, and composition for reducing the viscosity, and thus density, of hydrocarbons, and particularly heavy oils, to decrease costs associated with producing, refining, and transport. The present invention contemplates a miscible viscosity-reducing fluid that does not have a destructive effect on system components like aromatic compounds, and need not be removed following transport or prior to production. The viscosity-reducing fluid of the present invention combusts with the saleable hydrocarbons and has no negative effect from the mixing process.

[0008] The present invention may be used in a variety of well conditions, including when the well is producing under natural well pressure or when additional pumping methodologies are required. The present invention is also useful in typical pipelines, and may be particularly useful in underwater pipelines where low temperature significantly affects the viscosity of the hydrocarbons during transport.

[0009] An embodiment of a system having the features of the present invention comprises a production tubing string providing a communication path to the reservoir, a storage tank in selective communication with the production tubing string, a supply of viscosity-reducing fluid derived from a vegetable oil extract (e.g., canola oil, cotton oil, coconut oil, Jatropha curcas oil, and the like), a pump in selective communication with the supply of viscosity-reducing fluid, and a secondary tubing providing a communication path between the pump and the reservoir,.

[0010] According to a first embodiment of the composition, the viscosity-reducing fluid consists of a first volume of Jatropha curcas vegetable oil extract transesterified in an alkaline environment with a second volume of methanol, which second volume is between

2% and 10%, inclusive, of the first volume. According to a second embodiment of the composition, the viscosity-reducing fluid consists of a first volume of Jatropha curcas vegetable oil extract transesterified with a second volume of methanol, which second volume is between 2% and 10%, inclusive, of the first volume, and reacted with a third volume of phosphoric acid and a fourth volume of 32% hydrochloric acid. The third volume of phosphoric acid is between 5% and 10% by volume, inclusive, of the first volume. The fourth volume of hydrochloric acid is between 15% and 20% by volume, inclusive.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0011] Figure 1 shows an embodiment of the system having the features of the present invention.

[0012] Figures 2 A and 2B show a graph and table wherein a heavy oil is mixed with a Jatropha curcas vegetable oil extract.

[0013] Figures 3 A and 3B show a graph and table of the results of a first implementation of the method of the present invention present invention, wherein a heavy oil is mixed with a first embodiment of the viscosity-reducing fluid consisting on Jatropha curcas vegetable oil transesterified with methanol.

[0014] Figures 4 A and 4B show a graph of the result of a second implementation of the method of the present invention, wherein heavy oil is mixed with a second embodiment of the viscosity-reducing fluid comprising Jatropha curcas vegetable oil transesterified with methanol and reacted with phosphoric acid and hydrochloric acid. [0015] Figure 5 A and 5B show the effect on density of the viscosity-reducing fluid described with reference to Figures 4 A & 4B.

DETAILED DESCRIPTION OF THE INVENTION

[0016] Figure 1 shows the present invention in use with a hydrocarbon production well 20 having a casing 22 and a production tubing string 24 extending from the surface 26 to a hydrocarbon reservoir 28. The casing 22 and tubing string 24 are connected at the surface

26 to a wellhead 29, which has a plurality of valves 30a-30c attached thereto providing multiple access points to the tubing string 24. A pipe 32 provides a communication path between the wellhead 29 and a first storage tank 34 for hydrocarbons flowing out from the reservoir 28, which communication path may be selectively opened or closed with the attached connecting valve 30c.

[0017] A viscosity-reducing fluid 40 is stored in a second tank 42. By selectively opening a connected tank valve 44, the viscosity-reducing fluid 40 is permitted to flow through a second connecting pipe 46 and is pumped into the reservoir 28 by a pump 36 through a secondary tubing 48 nested within the tubing string 24 to the depth of the reservoir 28. The amount to be injected is determined based on the viscosity to be achieved as a function of the desired production volume from the well per day.

[0018] As is known in the chemical arts, transesterification is the process of exchanging the organic group of an ester with the organic group of an alcohol. These reactions are often catalyzed by the addition of an acid or base and may require application of heat and/or pressure to facilitate the reaction, as is known in the art.

[0019] In the preferred embodiment, the viscosity-reducing fluid 40 consists of a first volume of Jatropha curcas vegetable oil extract transesterified in an alkaline environment with a second volume of methanol, which second volume is between 2% and 10% by volume, inclusive, of the first volume. According to an alternative embodiment of the composition, the viscosity-reducing fluid consists of a first volume of Jatropha curcas vegetable oil extract transesterified in an alkaline environment with a second volume of methanol, which second volume is between 2% and 10% by volume, inclusive, of the first volume, and further reacted with a third volume of phosphoric acid and a fourth volume of 32% hydrochloric acid. The third volume of phosphoric acid is between 5% and 10% by volume, inclusive, of the first volume. The fourth volume of hydrochloric acid is between 15% and 20% by volume, inclusive.

[0020] Figures 2A and 2B show the results of mixing heavy oil having an initial viscosity of 10,880 centipoise with a renewable vegetable oil extracted from Jatropha curcas, and further showing the viscosity reduction. The x-axis represents the percentage of the extract used relative to the total volume of heavy oil to be produced during a given time period. The y-axis represents viscosity in centipoises (cP) of the heavy oil. Measurement points correspond to the centipoises obtained on each percent of the first viscosity reducer using the total volume of heavy oil, which are respectively: 0%, 1%, 2%, 3%, 5%, 7%, 10% and 15% (by volume). [0021] Figure 3 A and Figure 3B show results of mixing heavy oil with a first embodiment of a viscosity-reducing fluid consisting of a first volume of Jatropha curcas vegetable oil transesterified with a second volume of methanol that is between 2% and 10% of the first volume of vegetable oil. The x-axis represents the percentage of the first embodiment of viscosity-reducing fluid applied to the total volume of heavy oil. The y-axis represents heavy oil viscosity in centipoises. Viscosity measure points corresponds to obtained centipoises on each percent of the first embodiment of viscosity reducing fluid, using the total volume of heavy oil, which are respectively: 0%, 1%, 3%, 5%, 7%, 19% and 15% (by volume). The result of this implementation of the invention shows a viscosity reduction on the heavy oil by applying an increasing percentage of the second embodiment of viscosity-reducing fluid. [0022] Figures 4A and 4B show results obtained by mixing a heavy oil with a second embodiment of viscosity-reducing fluid consisting of a first volume of Jatropha curcas vegetable oil transesterified in an alkaline environment with a second volume of methanol that is between 2% and 10% of the first volume of vegetable oil, and further reacted with a third volume of phosphoric acid that is between 5% to 10% of the first volume of vegetable oil and a fourth volume of 32% of hydrochloric that is between 15% and 20%, inclusive, of the first volume.. The x-axis represents the percentage of the second embodiment of viscosity-reducing fluid applied to the total volume of heavy oil. The y-axis represents the viscosity (centipoise) of the heavy oil. Viscosity measurement points of the graph correspond to obtained centipoises at each percentage of the viscosity reducer, using the total volume of heavy oil, which are respectively: 0%, 1%, 3%, 5%, 7%, 10%, and 15% (by volume). This graph shows a reduction on the heavy oil viscosity by applying each time a greater percentage of the second embodiment of viscosity-reducing fluid.

[0023] Figure 5 A shows a graph detailing the resulting density reduction created by the mixing of heavy using the viscosity-reducing fluid described with reference to Figure 4 A and 4B. . In this graphical representation, the x-axis represents the percentage of the viscosity-reducing fluid applied to the total volume of heavy oil. The y-axis represents density (gr/cm3) of heavy oil. In the graph, the density measurement points correspond to the density obtained on each percent of the density reducer using the total volume of heavy oil, which are respectively: 0%, 1%, 2%, 3%, 5%, and 7% (by volume). The results from this implementation show a density reduction of heavy oil by applying a higher percent of the viscosity-reducing fluid.

[0024] The present invention is described above in terms of a preferred illustrative embodiment of specifically described methods, systems and compositions. Those skilled in the art will recognize that alternative constructions and implementations of such an apparatus can be used in carrying out the present invention. Other aspects, features, and advantages of the present invention may be obtained from a study of this disclosure and the drawings, along with the appended claims.

Claims

CLAIMS I claim:

1. A viscosity-reducing fluid for use with hydrocarbons, which viscosity-reducing fluid is produced by the process of transesterifying a first volume of vegetable oil extract with a second volume of methanol, wherein said second volume is between 2% and 10% by volume, inclusive, of the first volume to produce a solution.

2. The viscosity-reducing fluid of Claim 1 wherein the vegetable oil extract is derived from Jatropha curcas.

3. A viscosity-reducing fluid for use with hydrocarbons, which viscosity-reducing fluid is produced by the process of transesterifying a first volume of vegetable oil extract with a second volume of methanol, wherein said second volume is between 2% and 10% by volume, inclusive, of the first volume to produce a solution, wherein said solution is further reacted with a third volume of phosphoric acid and a fourth volume of hydrochloric acid, wherein said third volume is between 5% and 10%, inclusive, of said first volume, and wherein said fourth volume is between 15% and 20% of said fourth volume, inclusive.

4. The viscosity-reducing fluid of Claim 3 wherein the vegetable oil extract is derived from Jatropha curcas.

5. The viscosity-reducing fluid of Claim 3 wherein said hydrochloric acid is 32% hydrochloric acid.

6. A method of producing a target volume of hydrocarbon fluid from a hydrocarbon reservoir, the method comprising: supplying an amount of viscosity-reducing fluid to a location proximal to the production well, wherein said viscosity-reducing fluid is derived from a vegetable oil extract; adding a volume of viscosity-reducing fluid to said hydrocarbon reservoir, wherein said volume is between 1% and 15% of said target volume, inclusive, to the hydrocarbon reservoir to produce a solution of the hydrocarbon fluid and the viscosity-reducing fluid; and removing the target volume from said hydrocarbon reservoir.

7. The method of Claim 6 wherein said viscosity-reducing fluid is the fluid produced by the process of transesterifying a first volume of vegetable oil extract with a second volume of methanol, wherein said second volume is between 2% and 10%, inclusive, of the first volume.

8. The method of Claim 7 wherein said vegetable oil extract is derived from Jatropha curcas.

9. The method of Claim 6 wherein said viscosity-reducing fluid is the fluid produced by the process of transesterifying a first volume of vegetable oil extract with a second volume of methanol, wherein said second volume of methanol is between 2% and 10%, inclusive, of the first volume, further reacted with a third volume of phosphoric acid and a fourth volume of hydrochloric acid, wherein said third volume is between 5% and 10%, inclusive, of said first volume, and wherein said fourth volume is between 15% and 20% of said first volume, inclusive

10. The method of Claim 9 wherein said vegetable oil extract is derived from Jatropha curcas.

11. The method of Claim 9 wherein said hydrochloric acid is 32% hydrochloric acid.

12. A system for producing heavy oil from a hydrocarbon production reservoir, the system comprising: a production tubing string providing a communication path to the reservoir; a storage tank in selective communication with said production tubing string; a supply of viscosity-reducing fluid derived from a vegetable oil; a pump in selective communication with said supply of viscosity-reducing fluid; and a secondary tubing providing a communication path between said pump and the reservoir.

13. The system of Claim 12 wherein said secondary tubing is nested within said production tubing string.

14. The system of Claim 12 wherein said viscosity-reducing fluid is the fluid produced from the process of transesterifying a first volume of vegetable oil extracted from Jatropha curcas with a second volume of methanol, wherein said second volume is between 2% and 10%, inclusive, of the first volume.

15. The system of Claim 12 wherein said viscosity-reducing fluid is the fluid produced from the process of transesterifying a first volume of vegetable oil extracted from Jatropha curcas with a second volume of methanol, wherein said second volume is between 2% and 10%, inclusive, of the first volume, further reacted with a third volume of phosphoric acid and a fourth volume of hydrochloric acid, wherein said third volume is between 5% and 10%, inclusive, of said first volume, and wherein said fourth volume is between 15% and 20%, inclusive, of said first volume.

16. The viscosity-reducing fluid of Claim 15 wherein said hydrochloric acid is 32% hydrochloric acid.