WO1997021018A1 - Polymer enhanced foam workover, completion, and kill fluids - Google Patents
Polymer enhanced foam workover, completion, and kill fluids Download PDFInfo
- Publication number
- WO1997021018A1 WO1997021018A1 PCT/US1996/017460 US9617460W WO9721018A1 WO 1997021018 A1 WO1997021018 A1 WO 1997021018A1 US 9617460 W US9617460 W US 9617460W WO 9721018 A1 WO9721018 A1 WO 9721018A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- foam
- polymer
- ppm
- solution
- gas
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/60—Compositions for stimulating production by acting on the underground formation
- C09K8/92—Compositions for stimulating production by acting on the underground formation characterised by their form or by the form of their components, e.g. encapsulated material
- C09K8/94—Foams
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/50—Compositions for plastering borehole walls, i.e. compositions for temporary consolidation of borehole walls
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S507/00—Earth boring, well treating, and oil field chemistry
- Y10S507/925—Completion or workover fluid
Definitions
- the present invention relates to a method for workover, completion, and kill operations in wells penetrating subterranean formations, and more particularly, to a method wherein a polymer enhanced foam is utilized as a wellbore fluid during workover, completion, and kill operations in wells penetrating subterranean formations.
- Subterranean well completion, workover, and kill operations are normally conducted while the well is filled with fluid.
- a completion, workover, or kill fluid is commonly placed in a wellbore prior to the operation and is often maintained in the wellbore for the duration of the operation.
- the completion, workover, or kill fluid applies a hydrostatic pressure against the formation fluid which is greater than the pressure exerted by the formation fluid attempting to intrude into the wellbore. This overbalanced hydrostatic pressure prevents the intrusion of formation fluids into the wellbore during performance of the given oil field wellbore operation which is necessary from an operational standpoint to prevent interference from formation fluids and which is also necessary from a safety standpoint to prevent blowouts and well kicks.
- weighting agents are generally inert inorganic solids in solution or suspension, to increase the density of the fluid.
- An inorganic solids in solution or suspension to increase the density of the fluid.
- An exemplary completion, workover, and kill fluid is a dispersion of clay and/or gypsum in water.
- Advantageous completion, workover, and kill fluids are those which prevent formation fluid intrusion into the wellbore while preventing appreciable wellbore fluid leakoff into the formation.
- Leakoff is the migration of the completion, workover, or kill fluid from the wellbore across the wellbore face into the surrounding formations, resulting in loss of the fluid.
- Fluid leakoff can undesirably result in formation damage, or permeability reduction, which is manifested in reduced hydrocarbon recovery from the formation or reduced injectivity into the formation.
- Reduction in the fluid flow capacity can arise from relative permeability effects when an aqueous fluid invades an oil- or gas-bearing formation or as a result of chemical reactions with minerals, such as clays, present in the formation.
- Leakoff is also undesirable because it requires replacement of the lost completion, workover, or kill fluid. Although it is possible to maintain the hydrostatic pressure overbalance in the face of severe fluid leakoff by replenishing the lost completion, workover, or kill fluid, this practice can be cost prohibitive. Thus, minimizing leakoff decreases the cost of the completion, workover, or kill operation. Leakoff can also result in a well blowout with serious safety and environmental consequences.
- lost circulation materials In response to the problem of leakoff, it is common to place a fluid in the wellbore containing additives termed, "lost circulation materials,” that specifically inhibit fluid communication between the wellbore and surrounding formations across the wellbore face. Lost circulation materials are frequently polymeric species as described in U.S. Patents 4,740,319; 4,726,906; 4,675,119; and 4,282,928. A liquid medium having a lost circulation material dissolved or dispersed therein is termed a lost circulation fluid. Despite the general effectiveness of many conventional lost circulation fluids, certain subterranean conditions remain problematic for such fluids. In particular, conventional lost circulation fluids often do not effectively inhibit lost circulation in formations having relatively high permeability matrix or relatively high permeability voids. Conventional lost circulation fluids may also be inapplicable in water-sensitive formations, formations susceptible to relative permeability effects, or formations susceptible to fracturing or parting.
- Thickeners are often included in weighted completion, workover, and kill fluids known in the art for leakoff inhibition. See, for example, Hudson et al., SPE Paper No. 10652, which discloses a weighted brine containing a fluid loss control agent, or U.S. Patent No. 4,391,925 to Mintz et al., which discloses a multiphase kill fluid comprising a number of constituents including a hydrocarbon, a surfactant, a clay, and an organic polymer.
- Conventional completion, workover, and kill fluids may also be unsuitable in water-sensitive formations because of the risk of formation damage due to incompatibilities between the completion, workover, and kill fluid and the formation, particularly when leakoff does occur. Further, conventional completion, workover, and kill fluids are often difficult to remove from the formation after any leakoff that occurs.
- Conventional foams may be more compatible with the formation, but they exhibit relatively high instability under certain formation conditions. For example, conventional foams tend to exhibit instability in the presence of crude oil and collapse rapidly into separate gas and liquid phases. They also generally lack adequate structure and healing capabilities to remain foams while tubulars and other well hardware are moved in the well. In addition, conventional foams often degrade when placed in formations having high downhole temperatures or in formations having brines exhibiting a high salt or hardness content.
- Crosslinked polymer gels as taught by U.S. Patent 4,989,673 have demonstrated performance advantages over the above-recited conventional completion, workover, and kill fluids and lost circulation fluids, because in many instances the gels effectively inhibit fluid loss in formations having high permeability matrix or high conductivity voids, while generally avoiding significant damage to water-sensitive formations.
- the relatively high chemical cost of crosslinked polymer gels however, often limits their practical utility from an economic standpoint.
- Crosslinked polymer gels also have a relatively high hydrostatic pressure gradient in the wellbore that is undesirable for formations susceptible to fracturing or parting by conventional fluids of normal density. Gels are also difficult to remove from the formation when leakoff has occurred.
- Foamed gels such as a polyacrylamide gel formed with a Cr(lll) crosslinker, have been used as workover, completion, and kill fluids.
- Foamed gels generally have superior leakoff properties, stability, and structure relative to polymer enhanced foams.
- the greater structure tends to interfere with movement of hardware in the wellbore,
- foamed gels do not reheal readily when hardware is moved.
- Cr(lll) is increasingly subject to environmental restrictions, particularly for well operations near the surface, where fluids could migrate from the well into aquifers which provide a domestic water supply. If foamed gels invade the subterranean formation significantly, they can be difficult to remove and generally require the use of a gel breaker.
- the completion, workover, or kill fluid should be inexpensive and easily prepared at the wellsite from readily available constituents.
- the fluid should be nonflammable, non-toxic, and chemically unreactive with surface and wellbore hardware. Further, the fluid should have a consistency which permits downhole operations through it. In addition, the fluid should be easy to remove completely from the wellbore after the completion, workover, or kill operation is finished.
- the present invention is a process for use during hydrocarbon well completion, workover, and kill operations.
- An aqueous solution of a water-soluble, substantially noncrosslinked polymer and a water-soluble surfactant is prepared.
- the solution is substantially free of agents capable of crosslinking the polymer.
- a gas is added to the aqueous solution so as to form a polymer enhanced foam which is placed in a well penetrating a subterranean formation.
- FIG. 1A is a graph showing the weight per cent of water drained from polymer-enhanced and conventional foam samples as a function of foam aging time in a graduated cylinder;
- FIG. 1B is a graph showing the percentage of original foam height as a function of aging time for the foam samples of FIG. 1A and an additional conventional foam sample;
- FIG. 2 is a graph of the apparent viscosity of a bulk sample of a polymer enhanced foam of the present invention as a function of the shear rate;
- FIG. 3 is a graph of the average apparent effective viscosity in a sand pack as a function of foam quality for conventional and polymer enhanced foams;
- FIG. 4 is a graph of the average apparent effective viscosity in a sand pack as a function of the apparent frontal advance rate for a polymer-surfactant solution and for a polymer enhanced foam generated from the same solution;
- FIG. 5 is a graph showing the average apparent effective viscosity as a function of the apparent frontal advance rate for the same polymer enhanced foam injected into a sand pack at atmospheric backpressure and at 3,450 kPa injection pressure
- FIG. 6 is graph showing the average apparent effective viscosities as a function of apparent frontal advance rate in a sand pack for a series of polymer enhanced foams having different polymer concentrations;
- FIG. 7 is a graph showing the average apparent effective viscosities as a function of apparent frontal advance rate in a sand pack for a series of polymer enhanced foams having different surfactant concentrations;
- FIG. 8 is a graph showing the average apparent effective viscosities as a function of apparent frontal advance rate in a sand pack for a series of polymer enhanced foams generated with different gases and having similar foam qualities;
- FIG. 9 is a graph showing the average apparent effective viscosities as a function of apparent frontal advance rate in a sand pack for a series of polymer enhanced foams having fresh water and brine solvents and polyacrylamide polymers with different degrees of hydrolysis;
- FIG. 10 is a graph showing the average apparent effective viscosities as a function of apparent frontal advance rate in a sand pack for a series of polymer enhanced foams containing polyacrylamide polymers of differing molecular weights;
- FIG. 11 is a graph showing the average apparent effective viscosities as a function of apparent frontal advance rate in a sand pack for polymer enhanced foams having aqueous phase pH values of 7.5 and 10, respectively.
- a subterranean hydrocarbon-bearing formation is a geological structure comprising a substantially continuous geological material.
- the term "wellbore" is defined herein as a bore hole extending from the earth surface to a subterranean hydrocarbon-bearing formation.
- a wellbore is a conduit providing fluid communication between the surface and the formation penetrated thereby.
- a production wellbore enables the removal of fluids from the formation to the surface and an injection wellbore enables the placement of fluid into the formation from the surface. It is noted that a given wellbore can function interchangeably as a production wellbore or an injection wellbore depending on whether a fluid is being removed from or placed in the wellbore.
- the term "well” is synonymous with the term “wellbore.”
- a "foam” is a stabilized gas dispersion maintained within a liquid phase, wherein a plurality of gas bubbles are separated from one another by interfacially stabilized liquid films. The dispersed gas phase constitutes at least 20 per cent of the total volume of the foam.
- Conventional oilfield foams consist of a gas dispersed in a surfactant solution made up of a surfactant and a solvent.
- the surfactant acts as a foaming agent to facilitate and stabilize the gas dispersion within the liquid phase.
- a "polymer enhanced foam” is a specific type of oilfield foam comprising a gas dispersed in an aqueous surfactant solution, wherein the aqueous surfactant solution further includes a polymer dissolved therein.
- Other terms used herein have the same definitions as ascribed to them in U.S. Patent No. 5,129,457, incorporated herein by reference, or have definitions in accordance with the conventional usage of a skilled artisan, unless otherwise defined hereafter.
- the process of the present invention is performed by generating and placing a polymer enhanced foam within a wellbore in the specific manner described hereafter.
- the polymer enhanced foam is generated from a substantially noncrosslinked water soluble polymer, an aqueous solvent, a surfactant, and a gas. It is important to note that the foam composition is substantially free of any polymer crosslinking agent which could otherwise crosslink the polymer and convert the liquid phase of the foam to a crosslinked polymer gel at some point in the process.
- the polymer component of the foam is substantially any water-soluble, viscosity-enhancing polymer that is substantially noncrosslinked.
- a biopolymer or a synthetic polymer has utility herein.
- Biopolymers having utility herein include polysaccharides and modified polysaccharides, such as xanthan gum, guar gum, succinoglycan, scleroglycan, polyvinylsaccharides, carboxymethylcellulose, o-carboxychitosans, hydroxyethylcellulose, hydroxypropylcellulose, and modified starches.
- Synthetic polymers having utility herein include polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, and acrylamide polymers.
- Exemplary acrylamide polymers are polyacrylamide; partially hydrolyzed polyacrylamide; acrylamide copolymers; acrylamide terpolymers containing acrylamide, a second species, and a third species; and acrylamide tetrapolymers containing acrylamide, acrylate, a third species, and a fourth species.
- Polyacrylamide (PA) is defined as an acrylamide homopolymer having substantially less than about 1% of its acrylamide groups converted to carboxylate groups.
- Partially hydrolyzed polyacrylamide (PHPA) is an acrylamide homopolymer having more than about 1%, but not 100%, of its acrylamide groups converted to carboxylate groups.
- Useful acrylamide polymers are prepared according to any conventional method, but preferably have the specific properties of an acrylamide polymer prepared according to the method disclosed in U.S. Patent No. Re. 32,114, incorporated herein by reference.
- the average molecular weight of an acrylamide polymer having utility herein is generally in a range between about 10,000 and about 50,000,000, preferably between about 250,000 and about 20,000,000, and most preferably between about 1 ,000,000 and about 18,000,000.
- the polymer concentration in the liquid phase of the foam is generally at least about 500 ppm, preferably at least about 2,000 ppm, and most preferably within a range between about 3,000 ppm and about 10,000 ppm.
- the aqueous solvent of the present polymer enhanced foam is substantially any aqueous liquid capable of forming a solution with the selected polymer.
- solution as used herein, in addition to true solutions, is intended to broadly encompass dispersions, emulsions, or any other homogeneous mixture of the polymer in the aqueous solvent.
- the solvent is preferably either a fresh water or a brine, such as a produced water from the subterranean formation. Produced water can be advantageous because of its low-cost availability and because it enables the practitioner to return the produced water to the formation, thereby eliminating disposal thereof.
- the surfactant of the polymer enhanced foam is substantially any water-soluble foaming agent suitable for oilfield use that is compatible with the specific polymer selected as will be evident to the skilled artisan.
- the surfactant can be anionic, cationic, or nonionic.
- a preferred surfactant is selected from the group consisting of ethoxylated alcohols, ethoxylated sulfates, refined sulfonates, petroleum sulfonates, and alpha olefin sulfonates.
- the concentration of surfactant in the liquid phase of the foam is in a range between about 20 ppm and about 50,000 ppm, preferably between about 50 ppm and about 20,000 ppm, and most preferably at least about 1000 ppm.
- the performance of the polymer enhanced foam in the method of the present invention is relatively insensitive to the particular species and concentration of the surfactant selected, subject to the above-recited criteria, particularly when the selected polymer is an acrylamide polymer.
- any gas can be employed in the present polymer enhanced foam to the extent the gas is substantially chemically inert with respect to the other foam components and with respect to wellbore production or injection equipment.
- a preferred gas is one which is readily available in the field. Such gases include nitrogen, air, carbon dioxide, flue gas, produced gas, and natural gas.
- the quality of the polymer enhanced foam product i.e., the volume percentage of gas in the foam, is typically between about 20% and about 99%, more preferably between about 60% and about 98%, and most preferably between about 70% and about 97%. As is apparent to one skilled in the art, foam density decreases with increasing foam quality.
- CO 2 may become liquids or supercritical fluids under temperature and pressure conditions likely to be encountered in a well. In either case, the foam may become a high viscosity emulsion. C0 2 emulsions have significantly lower densities than water. An emulsion can be used in many situations where it is desirable to use a low density workover, completion, or kill fluid. CO 2 emulsions containing polymers expand with decreasing pressure and are energized fluids. As used herein, the term "polymer enhanced foam" includes emulsions.
- Foam generation requires mixing the liquid phase and the gas either at a high velocity or through a small orifice as can be provided by any conventional artificial foam generator.
- the liquid phase is preferably preformulated by dissolving the surfactant and polymer in the aqueous solvent prior to foam generation.
- the foam is then generated, for example, at the surface by passing the liquid phase and gas through a foam generator, and the resulting foam is delivered to the wellbore for injection therein.
- the foam is generated at the surface by coinjecting the gas and liquid phase into the wellbore across an injection tee acting as a foam generator.
- the foam is generated downhole by coinjecting the gas and liquid phases via a common tubing string or separate tubing strings into the wellbore and passing the two streams through a downhole foam generator.
- a foam breaker and/or other materials known to those skilled in the art may be added to the foam or to the aqueous solution.
- the pH of the liquid phase in the polymer enhanced foam is generally within a range of about 4 to about 10. In most cases, the pH of the liquid phase inherently falls within the above-recited range without any pH adjustment thereof. However, the pH of the liquid phase can be adjusted in any manner known to the skilled artisan in accordance with conventional oilfield procedures to achieve a desired pH range. Nevertheless, it has been found that the present process is relatively insensitive to the pH of the liquid phase.
- the polymer enhanced foam may be placed in a wellbore as either a completion fluid, a workover fluid, or a kill fluid. Placement of the foam is further facilitated by the relatively highly shear thinning properties of the polymer enhanced foam.
- the polymer enhanced foam exhibits relatively high effective viscosities under low shear conditions at the surface and in the relatively low shear regions within the wellbore where the foam is placed.
- the polymer enhanced foam exhibits relatively low effective viscosities under the high flow rate and high shear rate conditions encountered as it is pumped into the wellbore due to the ability of the foam to highly shear thin.
- the high shear thinning ability and the low friction loss qualities of the foam allow the foam to be pumped easily.
- the polymer enhanced foam beneficially shear thickens, thereby achieving a sufficient degree of structure and a sufficient critical pressure gradient for flow to limit invasion of the polymer enhanced foam into the subterranean formation adjacent the wellbore.
- the polymer enhanced foam is highly stable over a wide range of temperatures, pressures, water salinities, and water hardnesses.
- the polymer enhanced foam also resists collapse and fluid drainage in the presence of many environmental contaminants.
- the polymer enhanced foam is stable in the presence of liquid hydrocarbons, unlike most conventional foams.
- the foam can be self healing so that if foam degradation occurs as equipment is moved through the foam, the foam is capable of reforming itself.
- the polymer enhanced foam resists flow from the wellbore and does not substantially invade the adjacent formation. If the formation is invaded, the energized nature of the foam aids in its removal. If the pressure is reduced, the gas bubbles in the foam expand and push a substantial portion of the foam out of the formation.
- the gas, surfactant, and polymer resulting from foam breakdown may enhance fluid flow between the formation and the well.
- the gases, surfactants, and polymers of polymer enhanced foams are commonly used as enhanced or improved oil recovery agents.
- a conventional breaker can be injected into the treatment region of the wellbore and/or any invaded near-wellbore portion of the formation to degrade the foam or polymer in situ and restore the wellbore and near-wellbore region of the formation to their original condition.
- Polymer enhancement of the foam also advantageously increases the structural strength and critical pressure gradient for flow of the foam relative to conventional polymer-free foams.
- the term "strength" refers to the resistance of a foam to deformation when pressure or force is applied to the foam, and the "critical pressure gradient for flow” is defined herein as the maximum pressure that can be applied to the foam without foam flow.
- the polymer enhanced foam of the present invention should have a significant degree of structure.
- the viscosity and degree of structure of the polymer enhanced foam formulated in the manner of the present invention are primarily functions of the polymer properties and the polymer concentration.
- the viscosity and degree of structure of a polymer enhanced foam containing an acrylamide polymer are increased by increasing the polymer concentration of the liquid phase.
- a more cost-effective and often preferred means for achieving the same effect is to employ a higher molecular weight polymer or, in some cases, a polymer having a higher degree of hydrolysis at a relatively fixed polymer concentration.
- a reduction in viscosity and the degree of structure is achieved by using a lower molecular weight polymer, a lower polymer concentration, or, in some cases, a polymer having a lower degree of hydrolysis.
- the skilled practitioner can modify the viscosity and the degree of structure of the present polymer enhanced foam in the above-described manner to correspond with the leakoff potential of the region of the formation adjacent the wellbore in which the completion, workover, or kill fluid is used.
- the low leakoff characteristics of the polymer enhanced foam are a function of its critical pressure gradient for flow, which can alternatively be termed yield pressure.
- the critical pressure gradient for flow is defined herein as the maximum pressure under specified conditions that can be applied to the foam without foam flow.
- the foam should exhibit a critical pressure gradient for foam flow higher than the pressure gradient across the wellbore face or existing in the near-wellbore region. By satisfying this criterion, the foam will not flow into or through the formation adjacent the wellbore. Because the polymer enhanced foam of the present invention has a relatively high critical pressure gradient for foam flow, particularly in comparison to conventional foams, the polymer enhanced foam also performs well as a low leakoff fluid. Embodiments of the present process have been described above wherein the polymer enhanced foam is generated prior to or during placement of the foam in the wellbore. It is apparent to the skilled artisan from the instant disclosure that there are numerous other related applications within the scope of the present invention.
- foams are generated by coinjecting a foam-forming solution and a gas into a high permeability foam generating sand pack. All experiments are conducted at room temperature unless otherwise noted. The foam forms within about the first 2.5 cm of the sand pack and then advances through the rest of the sand pack.
- the foam generating sand pack may function as a foam generating device, as a model of a porous medium, or both simultaneously.
- a single sand pack if a single sand pack is utilized, it performs both functions, and if two sand packs are utilized, the first sand pack is for foam generation and the second is a test sand pack serving as a model of a porous medium.
- Foam properties such as average apparent viscosity, are determined from data obtained for the foam in the sand pack, based on the entire length of the sand pack. Properties of bulk foam samples are similar to those observed in sand packs.
- Conventional and polymer enhanced foams are prepared to compare their stability and, in particular, their resistance to physical foam collapse and water drainage under the influence of gravity.
- One of the conventional foams and the polymer enhanced foam are substantially identical in composition except for the presence of an unhydrolyzed polyacrylamide at a concentration of 7,000 ppm in the aqueous phase of the polymer enhanced foam.
- the molecular weight of the polymer is 11,000,000.
- the liquid phase of both foams is made up of a fresh water solvent containing 1,000 ppm of an ethoxylated sulfate surfactant marketed commercially as Enordet 1215-3S by Shell Chemical Co., Enhanced Oil Recovery Chemicals, P. O. Box 2463, Houston, Texas 77001.
- the surfactant has the formula C 12 .
- a second conventional foam is prepared with the same solvent and 5,000 ppm of Enordet 1215-3S surfactant in the aqueous phase.
- the foam samples are generated by coinjecting the liquid phase and N 2 gas into a foam generating sand pack.
- the sand pack has a permeability of 67 darcies, a length of 30 cm and a diameter of 1.1 cm. All flooding is conducted at 170 kPa constant differential pressure across the sand pack and atmospheric backpressure.
- the polymer enhanced foam propagates at a frontal advance rate of 207 rn/day and exhibits an average apparent effective viscosity within the sand pack of 89 cp, while the first conventional foam propagates at a frontal advance rate of 8,230 m/day and exhibits an average apparent effective viscosity of only
- the polymer enhanced foam has a substantially larger effective viscosity than the counterpart conventional foam.
- a 100 cm 3 sample of each fine-textured foam is collected as effluent from the sand pack and placed in a stoppered graduated cylinder for aging at ambient temperature.
- the positions of the foam water and foam/air interfaces in the graduated cylinders are measured as a function of time to determine the rates of water drainage and foam collapse, respectively for each of the samples.
- the results are shown in Figures 1 A and 1 B, respectively. It is apparent therein that the rates of water drainage and foam collapse are much greater for the conventional polymer-free foam than the polymer enhanced foam.
- a 100 cm 3 sample of the 5,000 ppm surfactant conventional foam is also obtained in the same manner. The results are highly comparable to the conventional foam sample with 1,000 ppm surfactant, as shown in FIG. 1B.
- this example shows that the polymer enhanced foam is more stable with respect to water drainage and foam collapse under the influence of gravity than the conventional polymer-free foam.
- Rheometer viscosity A polymer enhanced foam is prepared in a foam generating sand pack by combining N 2 gas with a solution of a produced reservoir brine containing 7,000 ppm PHPA and 2,000 ppm of Stepanfio 20, a C 14 . 1 ⁇ alpha olefin sulfonate surfactant marketed by Stepan Chemical Co., 22 Frontage Road, Northfield, Illinois 60093.
- the brine contains 5,800 ppm total dissolved solids and has principle constituents in the following concentrations: 560 ppm Ca" 1"* , 160 ppm Mg , 1,500 ppm Na * , 200 ppm K * , 2,200 ppm SO/ 2 , and 1 ,400 Cl'.
- the PHPA is 30 per cent hydrolyzed and has a molecular weight of 11 ,000,000, and the foam quality is 88 per cent as produced.
- the foam is aged for five minutes, and viscosity measurements are then made on the bulk foam in a Rheometrics RFS rheometer using the steady shear-rate mode. Shear rates from 0.15 to 700 sec '1 are studied.
- the polymer enhanced foam is a shear-thinning fluid over the entire range of shear rates. The minimum measured viscosity is 250 cp, and the maximum viscosity is over 40,000 cp.
- the results are shown in FIG. 2, with the power law curve fit shown as a solid line.
- the polymer enhanced foam exhibits substantial shear-thinning viscosity behavior, indicating that the foam would be relatively easy to pump into and through wellbore tubulars.
- a conventional foam is also prepared without the surfactant, and it is so unstable that is not readily feasible to obtain similar measurements.
- the polymer enhanced foam also contains 7,000 ppm in the aqueous phase of 30 per cent hydrolyzed
- PHPA with a molecular weight of 11 ,000,000.
- the tap water contains 30 ppm of
- the critical pressure gradient for foam flow is determined for the polymer enhanced foam in a sand pack having a permeability of 140 darcies and a length of 30 cm.
- the sand pack is used in this case as a model of a porous medium. Flooding experiments are conducted at atmospheric backpressure and at 3100 kPa backpressure for foam qualities between 57 and 93 per cent
- the critical pressure gradient for foam flow of the polymer enhanced foam is in the range of 452 to 678 kPa/m.
- the critical pressure gradient for foam flow for a conventional foam having the same composition but without the polymer is 136 to 158 kPa/m.
- the higher critical pressure gradient of the polymer enhanced foam indicates that the polymer enhanced foam has significantly more structure and less leakoff tendency than the conventional foam.
- the critical pressure gradient for foam flow is also determined for the polymer enhanced foam flowing through a 1.45 mm ID tube.
- the tube is used as a model of narrow tubing.
- the critical pressure gradient for flow is less than 2 kPa/m, indicating that the foam has a negligible yield strength and yield pressure as it passes through the tube.
- the foam should flow readily through wellbore tubulars and be easy to pump through well tubulars.
- the polymer enhanced foam of the present invention has a greater critical differential pressure gradient for foam flow, yield pressure, yield strength, and structure than its counterpart conventional foam.
- the polymer enhanced foam has better leakoff properties than conventional foams.
- the polymer enhanced foam has a negligible yield strength and yield pressure as it flows through pipes and tubulars.
- a sampie of a polymer enhanced foam and a sample of a conventional polymer-free foam that is substantially identical in composition to the polymer enhanced foam except for the absence of a polymer component are prepared to compare the effective viscosities of the two foams as a function of foam quality.
- Both foams are formulated from N 2 and a brine solvent having a C 14 _ 1 ⁇ alpha olefin sulfonate surfactant dissolved therein at a concentration of 2,000 ppm.
- the brine contains 5,800 ppm total dissolved solids and has principle constituents in the following concentrations: 560 ppm Ca ** , 160 ppm Mg**, 1,500 ppm Na*, 200 ppm K * . 2,200 ppm SO 4 '2 , and 1 ,400 ppm Cl " .
- the aqueous phase of the polymer enhanced foam additionally contains a partially hydrolyzed polyacrylamide at a concentration of 7,000 ppm.
- the partially hydrolyzed polyacrylamide has a molecular weight of 11 ,000,000 and is 30% hydrolyzed.
- a sand pack substantially the same as that of Example 2 is flooded with each foam over a range of foam qualities.
- a first polymer enhanced foam sample is flooded at a backpressure of 1 ,725 kPa and a differential pressure of 345 kPa. The first sample propagates at an apparent frontal advance rate of between about 158-198 /day.
- a second polymer enhanced foam sample is flooded at a backpressure of 3,100 kPa and a differential pressure of 345 kPa, and the apparent frontal advance rate is between 146 and 213 m/day.
- the conventional foam sample is flooded at atmospheric backpressure and a differential pressure of 138 kPa and propagates at a frontal advance rate between about 335 and 1 ,463 m/day.
- the results are set forth in FIG. 3 and indicate that the sensitivity of the average apparent viscosity of the polymer enhanced foam to foam quality is much less than that for the counterpart conventional foam. Furthermore, the effective viscosity of the polymer enhanced foam at any given foam quality is much greater than that of the conventional foam.
- "PEF” refers to polymer enhanced foam
- BP refers to backpressure.
- a polymer enhanced solution is prepared, also using a reservoir brine and the same surfactant and polymer as in Examples 3 and 4.
- the solution contains 2,000 ppm surfactant and 7,000 ppm of PHPA.
- a portion of the solution and then another portion of the solution and N 2 gas are injected into a 170 darcy sand pack at atmospheric backpressure and 22° C, with a constant pressure drop between
- the sand pack is 30 cm long and has an inner diameter of
- FIG. 4 shows the apparent average effective viscosity (AAE) of the aqueous polymer solution and polymer enhanced foams as a function of the apparent frontal advance rate.
- the polymer enhanced foam is a shear thinning fluid, and the viscosity behavior conforms to the power-law model over the range of frontal advance rates and shear rates studied.
- the viscosity and shear thinning properties of the polymer enhanced foam mirror the viscosity and shear thinning properties of the polymer solution.
- the viscosity of the polymer enhanced foam is very similar to the viscosity of the polymer solution.
- the quantity of polymer can be significantly reduced by using a foam rather than a polymer solution, resulting in similar theological performance with a significant decrease in the cost of the polymer and polymer solution used in a completion, workover, or kill operation.
- Polymer enhanced foams are prepared using a solution of 2,000 ppm surfactant and 7,000 ppm of PHPA with a molecular weight of 11,000,000 in a reservoir brine and using N 2 as the gas phase.
- the brine, surfactant, and polymer are the same as those used in Example 4.
- the foam qualities range from 81 to
- One set of foams is formed by injecting the polymer/surfactant solution and the gas directly into a 120 darcy test sand pack at 22° C and atmospheric backpressure.
- the sand pack is 30 cm long and has an inner diameter of 1.0 cm.
- the sand pack functions as a foam generating device and a model of a porous medium.
- the second flood is preformed in a 120 darcy foam generating sand pack and then injected into a 120 darcy test sand pack at 3,450 kPa injection pressure and 22° C.
- FIG. 5 shows the average apparent effective viscosity as a function of the apparent frontal advance rate for the in-situ-generated foam and the preformed foam.
- the high pressure data shown in FIG. 5 are comparable to the atmospheric pressure data of Example 5, which are plotted as triangles. These data and the data shown in FIG. 4 (Example 5) indicate that the apparent viscosities of the polymer enhanced foams are nearly independent of pressure. Additionally, it is shown that very large effective viscosities can be attained at low shear rates, and the Theological properties of preformed and in-situ-generated foams are nearly identical.
- EXAMPLE 7 Effect of temperature on foam stability
- a polymer enhanced foam is prepared using the reservoir brine containing 2,000 ppm of surfactant, 7,000 ppm of PHPA with a molecular weight of 11 ,000,000, and N 2 .
- the surfactant, polymer, and brine are the same as those used in Example 4.
- the polymer enhanced foam is generated in a 170 darcy foam generating sand pack at an apparent frontal advance rate of about 1,524 m/day.
- the sand pack has a length of 30 cm and a diameter of 1.1 cm, and the experiment is conducted at 22° C and repeated at 51° C. 100 ml of each foam effluent is collected in a stoppered graduated cylinder and aged at 22° C and 51° C, respectively.
- the effective viscosity of the foam decreases as the temperature increases.
- the effective viscosity of the polymer enhanced foam is proportional to the effective viscosity of the polymer solution alone, which is inversely proportional to the temperature.
- EXAMPLE 8 Effect of polymer concentration
- Polymer enhanced foams are prepared with an aqueous phase consisting of 2,000 ppm of an alpha olefin sulfonate surfactant, a reservoir brine, and PHPA concentrations of 1,500; 2,500; 3,500; 5,000; and 7,000 ppm, and with N 2 as the gas phase.
- the brine, surfactant, and PHPA are the same as those of Example 4.
- the polymer solution viscosities are 50, 280, 800, 3,300 and 4,800 cp, respectively, at a shear rate of 1.0 sec' 1 .
- the foams are generated in a 140 darcy sand pack with a pressure drop of 138-1 ,380 kPa and a frontal advance rate of 61- 3,048 mday.
- the sand pack serves both foam generating and test functions and has a length of 30 cm and a diameter of 1.1 cm.
- the foam qualities range between 85 and 89 per cent.
- significant viscosities are observed for all polymer concentrations studied, and the average effective viscosity is proportional to the polymer concentration.
- Polymer enhanced foams are prepared using a reservoir brine containing
- the brine, surfactant (alpha olefin sulfonate, or AOS), and polymer are the same as those used in Example 4.
- the foams are generated with N 2 in a 140 darcy foam generating and test sand pack with a pressure drop of 138-1,380 kPa, and the foam qualities are between 85 and 89 per cent.
- the sand pack is 30 cm long and has an inner diameter of 1.1 cm.
- the surfactant concentration has little or no effect on polymer enhanced foam viscosity over a broad range of surfactant concentrations.
- the concentration of surfactant in the foam can be kept relatively low without decreasing the viscosity or changing the foam's theological properties, thereby reducing the cost of the completion, workover, or kill operation.
- EXAMPLE 10 Effect of gas composition
- Polymer enhanced foams are prepared using 7,000 ppm PHPA and 2,000 ppm Bio-Terge AS-40 surfactant in a reservoir brine and with different gases.
- the brine, surfactant, and PHPA are the same as those used in Example 4.
- the solution pH is 7.5.
- Foam qualities range between 85 and 90 per cent with N 2 , 85 and 89 per cent with CH 4 , and 87 and 89 per cent with CO 2 .
- Frontal advance rates are observed in a 150 darcy sand pack with a pressure drop between 207 and 1 ,380 kPa.
- the polymer enhanced foam performances are very similar with all three gases, as shown in FIG. 8.
- PHPA and unhydrolyzed PA both having molecular weights of 11 ,000,000, and with fresh water and brine.
- the brine contains 5,700 ppm total dissolved solids, with high concentrations of Ca 2 *, Mg 2* , and SO 4 2" .
- the polymer concentration in the aqueous phase is 7,000 ppm
- the surfactant is Bio-Terge AS-40 at a concentration of 2,000 ppm in the aqueous phase
- the gas is N 2 .
- Foams are formed in a foam generating sand pack as described above. As shown in FIG.
- the effective viscosity of each polymer enhanced foam is proportional to the viscosity of the aqueous polymer solution from which it was formed.
- the viscosities of polymer solutions with higher salinity are less than the viscosities of fresh water solutions which contain the same polymer concentration.
- the polymer enhanced foams generated with those solutions also have similar viscosities.
- the percent of hydrolysis of the polymer has the same effect on the rheology of the polymer solution and the polymer enhanced foam, with greater effective viscosities for otherwise identical polymer solutions and polymer enhanced foams containing polymers with higher levels of hydrolysis.
- Polymer enhanced foams are prepared in a foam generating sand pack as described above, using N 2 ; 2,000 ppm of Bio-Terge AS-40 surfactant in the aqueous phase ("AQ. SOLN.”); and unhydrolyzed polyacrylamide concentrations in the aqueous phase and molecular weights as shown in FIG. 10.
- AQ. SOLN Bio-Terge AS-40 surfactant in the aqueous phase
- polyacrylamide concentrations in the aqueous phase and molecular weights as shown in FIG. 10.
- Increasing the polymer molecular weight increases the viscosity of the polymer solution and the polymer enhanced foam formed from the solution.
- the viscosity of the aqueous phase from which the polymer enhanced foam is formed controls the effective viscosity of the polymer enhanced foam.
- the same viscosity performance can be achieved for a given polymer enhanced foam by increasing the polymer molecular weight and using less polymer in the foam, resulting in significant cost savings.
- the brine is the same as that used in Example 11
- the PHPA is the same as that used in Example 4.
- the pH of one solution is adjusted to 7.5
- the pH of the other is adjusted to 10.
- Polymer enhanced foams are formed with N 2 in a 30 cm long combined foam generating and test sand pack having a permeability of 150 darcies. Atmospheric backpressure is maintained, with a pressure drop across the sand pack of 138-1,380 kPa. As shown in FIG. 11 , the average effective viscosity and rheological performance of these polymer enhanced foams are essentially independent of the pH over the range studied.
Abstract
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU76010/96A AU7601096A (en) | 1995-12-07 | 1996-10-28 | Polymer enhanced foam workover, completion, and kill fluids |
GB9811191A GB2322892B (en) | 1995-12-07 | 1996-10-28 | A process in which a foamed cell is used as a workover, completion, or kill fluid |
NO982600A NO982600D0 (en) | 1995-12-07 | 1998-06-05 | Transition, distillation and quench fluids consisting of a polymer enhanced foam |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/568,869 US5706895A (en) | 1995-12-07 | 1995-12-07 | Polymer enhanced foam workover, completion, and kill fluids |
US08/568,869 | 1995-12-07 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997021018A1 true WO1997021018A1 (en) | 1997-06-12 |
Family
ID=24273058
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US1996/017460 WO1997021018A1 (en) | 1995-12-07 | 1996-10-28 | Polymer enhanced foam workover, completion, and kill fluids |
Country Status (7)
Country | Link |
---|---|
US (1) | US5706895A (en) |
AU (1) | AU7601096A (en) |
CA (1) | CA2234173A1 (en) |
GB (1) | GB2322892B (en) |
MX (1) | MX9803724A (en) |
NO (1) | NO982600D0 (en) |
WO (1) | WO1997021018A1 (en) |
Families Citing this family (37)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5834406A (en) * | 1996-03-08 | 1998-11-10 | Marathon Oil Company | Foamed gel for permeability reduction or mobility control in a subterranean hydrocarbon-bearing formation |
US5881826A (en) | 1997-02-13 | 1999-03-16 | Actisystems, Inc. | Aphron-containing well drilling and servicing fluids |
US7939601B1 (en) | 1999-05-26 | 2011-05-10 | Rhodia Inc. | Polymers, compositions and methods of use for foams, laundry detergents, shower rinses, and coagulants |
WO2000071591A1 (en) * | 1999-05-26 | 2000-11-30 | Rhodia Inc. | Block polymers, compositions and methods of use for foams, laundry detergents, shower rinses and coagulants |
ATE374235T1 (en) | 1999-05-26 | 2007-10-15 | Procter & Gamble | LIQUID DETERGENT COMPOSITIONS CONTAINING BLOCK POLYMERS FOAM FORMERS |
US20050124738A1 (en) * | 1999-05-26 | 2005-06-09 | The Procter & Gamble Company | Compositions and methods for using zwitterionic polymeric suds enhancers |
EP1180130A1 (en) | 1999-05-26 | 2002-02-20 | The Procter & Gamble Company | Liquid detergent compositions comprising polymeric suds enhancers |
US7241729B2 (en) * | 1999-05-26 | 2007-07-10 | Rhodia Inc. | Compositions and methods for using polymeric suds enhancers |
US6649571B1 (en) | 2000-04-04 | 2003-11-18 | Masi Technologies, L.L.C. | Method of generating gas bubbles in oleaginous liquids |
US6376631B1 (en) | 2000-09-27 | 2002-04-23 | Rhodia, Inc. | Processes to control the residual monomer level of copolymers of tertiary amino monomer with a vinyl-functional monomer |
US6800592B2 (en) * | 2001-08-28 | 2004-10-05 | Intevep, S.A. | Polymer-enhanced foamable drilling fluid |
JP2003159026A (en) * | 2001-11-22 | 2003-06-03 | Ajinomoto Co Inc | Method for producing stable aspartame slurry and judging method |
US7183239B2 (en) * | 2001-12-12 | 2007-02-27 | Clearwater International, Llc | Gel plugs and pigs for pipeline use |
US8273693B2 (en) * | 2001-12-12 | 2012-09-25 | Clearwater International Llc | Polymeric gel system and methods for making and using same in hydrocarbon recovery |
US6739414B2 (en) | 2002-04-30 | 2004-05-25 | Masi Technologies, L.L.C. | Compositions and methods for sealing formations |
US7199083B2 (en) * | 2002-12-06 | 2007-04-03 | Self Generating Foam Incoporated | Self-generating foamed drilling fluids |
US7124822B2 (en) * | 2004-11-02 | 2006-10-24 | Halliburton Energy Services, Inc. | Foamed completion fluids and methods |
US8099997B2 (en) | 2007-06-22 | 2012-01-24 | Weatherford/Lamb, Inc. | Potassium formate gel designed for the prevention of water ingress and dewatering of pipelines or flowlines |
US8065905B2 (en) | 2007-06-22 | 2011-11-29 | Clearwater International, Llc | Composition and method for pipeline conditioning and freezing point suppression |
US7806186B2 (en) * | 2007-12-14 | 2010-10-05 | Baker Hughes Incorporated | Submersible pump with surfactant injection |
US9033045B2 (en) * | 2010-09-21 | 2015-05-19 | Baker Hughes Incorporated | Apparatus and method for fracturing portions of an earth formation |
US9140107B2 (en) * | 2011-07-08 | 2015-09-22 | Schlumberger Technology Corporation | Downhole polymer foam applications |
US9494025B2 (en) | 2013-03-01 | 2016-11-15 | Vincent Artus | Control fracturing in unconventional reservoirs |
EP3126015B1 (en) | 2014-04-02 | 2020-08-19 | Tyco Fire Products LP | Fire extinguishing compositions |
US10793767B2 (en) | 2018-11-29 | 2020-10-06 | Saudi Arabian Oil Company | Stabilized foams with tailored water chemistry for mobility control in gas injection processes |
US11447687B2 (en) * | 2020-09-29 | 2022-09-20 | Saudi Arabian Oil Company | Enhancing rheological properties of foam using aloe-barbadensis gel |
CN112377164B (en) * | 2020-11-16 | 2022-06-28 | 东北石油大学 | Foaming mechanism, high-energy gas foam fracturing device and process |
CN113004878A (en) * | 2021-03-23 | 2021-06-22 | 四川省贝特石油技术有限公司 | Leakage-proof leakage-stopping type micro-foam drilling and repairing liquid as well as preparation method and application thereof |
US11673010B2 (en) | 2021-05-14 | 2023-06-13 | Tyco Fire Products Lp | Fire-fighting foam concentrate |
US11673011B2 (en) | 2021-05-14 | 2023-06-13 | Tyco Fire Products Lp | Firefighting foam composition |
US11666791B2 (en) | 2021-05-14 | 2023-06-06 | Tyco Fire Products Lp | Fire-fighting foam composition |
CA3218574A1 (en) | 2021-05-14 | 2022-11-17 | Joanna M. Monfils | Fire-fighting foam concentrate |
US11497952B1 (en) | 2021-05-14 | 2022-11-15 | Tyco Fire Products Lp | Fire-fighting foam concentrate |
EP4337340A1 (en) | 2021-05-14 | 2024-03-20 | Tyco Fire Products LP | Fire-fighting foam concentrate |
US11961702B2 (en) | 2021-12-09 | 2024-04-16 | Saudi Arabian Oil Company | Fabrication of in situ HR-LCTEM nanofluidic cell for nanobubble interactions during EOR processes in carbonate rocks |
US11787993B1 (en) | 2022-03-28 | 2023-10-17 | Saudi Arabian Oil Company | In-situ foamed gel for lost circulation |
US11913319B2 (en) | 2022-06-21 | 2024-02-27 | Saudi Arabian Oil Company | Sandstone stimulation |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3530940A (en) * | 1969-02-05 | 1970-09-29 | Pan American Petroleum Corp | Increasing foam stability in earth formations |
US3637021A (en) * | 1970-01-30 | 1972-01-25 | Chevron Res | Method and apparatus for removal of petroliferous adherent solids from an inaccessible surface |
US4440653A (en) * | 1982-03-08 | 1984-04-03 | Halliburton Company | Highly stable alcohol foams and methods of forming and using such foams |
US4995461A (en) * | 1989-07-14 | 1991-02-26 | Marathon Oil Company | Well kill treatment for oil field wellbore operations |
US5129457A (en) * | 1991-03-11 | 1992-07-14 | Marathon Oil Company | Enhanced liquid hydrocarbon recovery process |
US5358046A (en) * | 1993-01-07 | 1994-10-25 | Marathon Oil Company | Oil recovery process utilizing a supercritical carbon dioxide emulsion |
Family Cites Families (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4039459A (en) * | 1976-06-30 | 1977-08-02 | Union Oil Company Of California | Composition and method for drilling a reservoir containing a high temperature aqueous liquid |
US4282928A (en) * | 1977-07-08 | 1981-08-11 | The Dow Chemical Co. | Method for controlling permeability of subterranean formations |
US4247405A (en) * | 1978-06-30 | 1981-01-27 | Phillips Petroleum Company | Viscosity-stabilized aqueous solutions |
US4391925A (en) * | 1979-09-27 | 1983-07-05 | Exxon Research & Engineering Co. | Shear thickening well control fluid |
USRE32114E (en) * | 1981-06-19 | 1986-04-15 | Marathon Oil Company | Oil recovery process |
US4442018A (en) * | 1982-11-01 | 1984-04-10 | The United States Of America As Represented By The United States Department Of Energy | Stabilized aqueous foam systems and concentrate and method for making them |
US4740319A (en) * | 1984-04-04 | 1988-04-26 | Patel Arvind D | Oil base drilling fluid composition |
GB8419805D0 (en) * | 1984-08-03 | 1984-09-05 | Allied Colloids Ltd | Aqueous drilling and packer fluids |
US4726906A (en) * | 1984-11-23 | 1988-02-23 | Calgon Corporation | Polymers for use as filtration control aids in drilling muds |
US4681164A (en) * | 1986-05-30 | 1987-07-21 | Stacks Ronald R | Method of treating wells with aqueous foam |
US4989673A (en) * | 1989-07-14 | 1991-02-05 | Marathon Oil Company | Lost circulation fluid for oil field drilling operations |
US5307878A (en) * | 1993-01-07 | 1994-05-03 | Marathon Oil Company | Polymer enhanced foams for reducing gas coning |
US5372462A (en) * | 1993-01-07 | 1994-12-13 | Marathon Oil Company | Polymer enhanced foam for blocking fluid flow in soil |
-
1995
- 1995-12-07 US US08/568,869 patent/US5706895A/en not_active Expired - Fee Related
-
1996
- 1996-10-28 WO PCT/US1996/017460 patent/WO1997021018A1/en active Application Filing
- 1996-10-28 AU AU76010/96A patent/AU7601096A/en not_active Abandoned
- 1996-10-28 CA CA002234173A patent/CA2234173A1/en not_active Abandoned
- 1996-10-28 GB GB9811191A patent/GB2322892B/en not_active Expired - Fee Related
-
1998
- 1998-05-11 MX MX9803724A patent/MX9803724A/en unknown
- 1998-06-05 NO NO982600A patent/NO982600D0/en not_active Application Discontinuation
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3530940A (en) * | 1969-02-05 | 1970-09-29 | Pan American Petroleum Corp | Increasing foam stability in earth formations |
US3637021A (en) * | 1970-01-30 | 1972-01-25 | Chevron Res | Method and apparatus for removal of petroliferous adherent solids from an inaccessible surface |
US4440653A (en) * | 1982-03-08 | 1984-04-03 | Halliburton Company | Highly stable alcohol foams and methods of forming and using such foams |
US4995461A (en) * | 1989-07-14 | 1991-02-26 | Marathon Oil Company | Well kill treatment for oil field wellbore operations |
US5129457A (en) * | 1991-03-11 | 1992-07-14 | Marathon Oil Company | Enhanced liquid hydrocarbon recovery process |
US5358046A (en) * | 1993-01-07 | 1994-10-25 | Marathon Oil Company | Oil recovery process utilizing a supercritical carbon dioxide emulsion |
Also Published As
Publication number | Publication date |
---|---|
MX9803724A (en) | 1998-09-30 |
CA2234173A1 (en) | 1997-06-12 |
GB2322892B (en) | 1999-09-01 |
AU7601096A (en) | 1997-06-27 |
NO982600L (en) | 1998-06-05 |
GB9811191D0 (en) | 1998-07-22 |
GB2322892A (en) | 1998-09-09 |
US5706895A (en) | 1998-01-13 |
NO982600D0 (en) | 1998-06-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US5706895A (en) | Polymer enhanced foam workover, completion, and kill fluids | |
US5711376A (en) | Hydraulic fracturing process | |
EP2809742B1 (en) | Cellulose nanowhiskers in well services | |
AU780870B2 (en) | Latex additive for water-based drilling fluids | |
US8017563B2 (en) | Diverting compositions, fluid loss control pills, and breakers thereof | |
CA2564566C (en) | Inhibitive water-based drilling fluid system and method for drilling sands and other water-sensitive formations | |
US5358046A (en) | Oil recovery process utilizing a supercritical carbon dioxide emulsion | |
US7825072B2 (en) | Inhibitive water-based drilling fluid system and method for drilling sands and other water-sensitive formations | |
US5495891A (en) | Foamed gel employed as a drilling fluid, a lost circulation fluid, or a combined drilling/lost circulation fluid | |
US5513712A (en) | Polymer enhanced foam drilling fluid | |
Harris | Fracturing-fluid additives | |
US5346008A (en) | Polymer enhanced foam for treating gas override or gas channeling | |
EP1280975B1 (en) | Invert well service fluid and method | |
US5682951A (en) | Foamed gel completion, workover, and kill fluid | |
CA2782434A1 (en) | Thermally stable, nonionic foaming agent for foam fracturing fluids | |
CA2540988C (en) | Improved fracturing fluid and method of use | |
Poettmann | The use of non-Newtonian fluids in oil recovery |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
AK | Designated states |
Kind code of ref document: A1 Designated state(s): AL AM AT AU AZ BA BB BG BR BY CA CH CN CU CZ DE DK EE ES FI GB GE HU IL IS JP KE KG KP KR KZ LC LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK TJ TM TR TT UA UG UZ VN AM AZ BY KG KZ MD RU TJ TM |
|
AL | Designated countries for regional patents |
Kind code of ref document: A1 Designated state(s): KE LS MW SD SZ UG AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI |
|
DFPE | Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101) | ||
121 | Ep: the epo has been informed by wipo that ep was designated in this application | ||
ENP | Entry into the national phase |
Ref document number: 2234173 Country of ref document: CA Ref country code: CA Ref document number: 2234173 Kind code of ref document: A Format of ref document f/p: F |
|
WWE | Wipo information: entry into national phase |
Ref document number: PA/a/1998/003724 Country of ref document: MX |
|
NENP | Non-entry into the national phase |
Ref country code: JP Ref document number: 97521257 Format of ref document f/p: F |
|
REG | Reference to national code |
Ref country code: DE Ref legal event code: 8642 |
|
122 | Ep: pct application non-entry in european phase |