Texaco Inc.

Wilbur L Hall

Alfred Brown

Ching H Wu

Ralph J Korstad

Charles R French

John F Wiechel

Vernon H Schievelbein

Wann-Sheng Huang

Russell D Shupe

Alvin J Sustek, Jr

Jeffrey T Hawkins

Zean Z Gassmann

Thomas S Teasdale

Kenny Wong

Brian L Reynolds

The condition known as steam override is overcome by the use of a blocking agent to obstruct fluid flow in part of the override region combined with the closing of all passages of egress for injected steam except those having access to the region where by-passed oil has been banked.

Vertical conformance steam drive oil recovery method

The disclosed invention is a group of steam foaming agents for injection with steam and a non-condensable gas to decrease permeability in steam swept zones and increase oil recovery. The foaming agents have the general formula:

Method of improving conformance in steam floods with steam foaming agents

This invention relates to a method for treating wells completed in subterranean formations which contain unconsolidated sand particles, so as to form a permeable barrier which will permit the flow of liquids therethrough while restraining the flow of the unconsolidated sand particles into the well bore. The method comprises saturating sand adjacent the well bore to be treated with petroleum having a high asphaltic content and thereafter contacting the asphaltic petroleum with a solvent capable of solubilizing non-asphaltic fractions of the petroleum and precipitating or causing deposition of the asphaltic or bituminous portions of the petroleum. A heated fluid such as steam is thereafter injected into the formation to cause solidification of the asphaltic materials which effectively binds the sand grains together to form a porous mass which will effectively restrain the movement of said particles in the well bore upon subsequently placing the well on production. Suitable materials for causing precipitation of the asphaltic or bituminous portion of the petroleum include halogen substituted, oil soluble hydrocarbons having at least one halogen substituent and having less than 6 carbon atoms per molecule, such as methyl chloroform. Steam or a mixture of steam and non-condensable gas such as nitrogen, or mixture of steam and air are then injected into the formation to dehydrate and otherwise solidify the precipitated asphaltic material.

Sand control employing halogenated, oil soluble hydrocarbons

The present invention is a sequenced method of increasing the injectivity of oil bearing formations and increasing hydrocarbon recovery. The method of the invention is initiated by injecting an aqueous fluid at an ambient temperature into the formation through an injection well while concurrently recovering fluid at a production well. The first injection stage is followed by the injection of fluid of gradually increasing temperature until a temperature of about 75.degree.-100.degree. C. is reached. Finally, steam is injected into the formation.

Varying temperature oil recovery method

A method is disclosed for selectively reducing the permeability of water producing intervals in a hydrocarbon formation without reducing oil permeability. A soluble oil followed by water is injected into the formation to lower the residual oil saturation. The well is then produced to remove water from any oil zones before injection of an isobutyl-methacrylate solution in acetone. A slug of a non-condensable gas follows the treating solution before the shutting in of the well for up to about one day.

Selective water exclusion

Disclosed is an improved viscous oil recovery method employing the injection of a thermal recovery fluid which may be steam or a mixture of steam and additives, and cycles of pressurization and drawdown. First the thermal recovery fluid is injected and production is restricted in order to increase the pressure in the reservoir. Injection is then terminated or decreased and production is increased in order to effect a pressure drawdown in the reservoir. Thereafter the production rate is decreased or production wells are shut in completely and non-condensable gas is injected to raise the pressure in the reservoir to a value which is from 50 to 90 percent of the final target pressure, after which the thermal recovery fluid is again injected into the formation to rebuild reservoir pressure with restricted production. Finally, production rate is increased and thermal recovery fluid injection is reduced or terminated in order to accomplish another reservoir drawdown cycle. Additional cycles of partial repressuring with non-condensable gas followed by steam injection followed by pressure drawdown production cycles may be employed.

Viscous oil recovery method

Viscous petroleum including bitumen may be recovered from unconsolidated sand formations such as tar sand deposits by hydraulic mining. Hot water of steam and an amine are introduced into the subterranean deposit with sufficient velocity to dislodge bitumen and particles of sand therefrom. The process is a single wellbore operation using rotatable vertically moveable injection string with one or more jets near the bottom thereof, with separate return flow path to surface, the inlet to which may be on the bottom of the injection string. The injection string may be raised or lowered while rotating and jetting so the full vertical thickness of tar sand interval is contacted by aqueous mining fluid. Jet pump may be used to pump petroleum to surface. The aqueous hydraulic mining fluid comprises hot water or steam and an amine having the following formula:

Hydraulic mining technique for recovering bitumen from tar sand deposit

A process for enhanced recovery of petroleum from subterranean formations wherein a vapor mixture of steam and a petroleum fraction containing naturally occurring phenolic and carboxylic compounds is injected via an injection well, and a mixture of steam condensate and petroleum is produced via a production well.

Recovering petroleum from subterranean formations

The vertical conformance of a steam drive process is improved and steam override reduced by penetrating the zone between one injector and one producer, with an infill well which is in fluid communication with the bottom half of the formation, and producing petroleum from the infill well after steam channeling has occurred at the production well. After the water cut of the fluids being produced from the infill well reaches 95 percent, the infill well is converted from a producer to an injector and hot water is injected into the lower portion of the formation via the infill well and fluids are produced from the production well. By this means, oil is recovered from the lower portions of the formation adjacent the production well. After water breakthrough occurs at the production well, steam is injected into the infill well and fluids are recovered from the production well. By this multi-step process involving the infill well, the amount of oil recovered from the portion of the formation in the recovery zone defined by the injection and production well is increased significantly.

High vertical conformance steam drive oil recovery method

Thermal oil recovery processes employing the injection of steam and/or hot water for mobilizing viscous petroleum sweep only a small fraction of the formation between the wells because of override, underride, or channeling resulting in poor vertical conformance, as well as poor horizontal conformance of the swept portion of the formation. Both vertical and horizontal conformance are improved significantly if steam is injected into a formation until channeling has begun, after which steam injection is terminated and an aqueous fluid is injected into the formation, which has a viscosity essentially the same as water and contains an emulsifying agent capable of forming a viscous emulsion in the portions of the formation where override, underride or channeling has occurred. After a small slug of emulsifying fluid has been injected, steam injection is resumed and as a consequence of the emulsion plug, moves into portions of the formation from which oil would not be recovered if the emulsion had not been injected. Multiple cycles of steam and emulsion injection may be applied to a formation to more completely sweep the full volume of the pattern. Surfactants suitable for use include organic sulfonates such as petroleum sulfonate, and solubilizing co-surfactants such as alkyl or alkylarylpolyethoxyalkylene sulfonates.

High vertical and horizontal conformance thermal oil recovery process

The vertical or both vertical and horizontal conformance of a steam drive process is improved and steam override reduced by penetrating the zone between one injector and one producer, with one or more infill wells in fluid communication with the bottom half or less of the formation, and producing petroleum from the infill well after steam channeling has occurred at the production well. After the water cut of the fluids being produced from the infill well reaches 95 percent, the infill well is converted from a producer to an injector and steam is injected into the infill well and fluids are recovered from the production well. When one infill well is employed in a more or less aligned arrangement between injection and production wells, the vertical conformance is improved. When one or more infill wells are positioned in an offset or nonaligned arrangement relative to each injector and producer, conformance in both the horizontal and vertical planes is improved. By this multi-step process involving the infill wells, the amount of oil recovered from the portion of the formation in the recovery zone defined by the injection and production well is increased significantly.

The vertical conformance of a steam drive process is improved and steam override reduced by penetrating the zone between one injector and one producer, with an infill well located between the injector and producer which is in fluid communication with no more than the bottom half of the formation. Steam is injected into the injection well in the first phase with production of fluids from the upper 1/3 or less of the formation via the production well. A separate flow path in communication with the bottom 1/3 or less of the formation is provided in the producing well, and is used during the first phase for push-pull treatment of the formation with solvent and steam or hot water. After production via the production well is terminated, petroleum is produced via the infill well until the fluid being produced from the infill well reaches 95 percent water cut, after which the infill well is converted from a producer to an injector and hot water is injected into the lower portion of the formation via the infill well and fluids are produced from the production well. After water breakthrough at the production well, steam is injected into the infill well and fluids are recovered from the lower 1/3 of the production well.

The vertical conformance of a steam drive process is improved and steam override reduced by penetrating the recovery zone between one injection well and one producing well, with at least one infill well which is in fluid communication with no more than the bottom half of the formation. Steam or a mixture of steam and hydrocarbon is injected into the injection well and fluids including oil are recovered from the producing well until live steam production occurs at the producing well. Petroleum production is then begun at the infill well and continued until the water cut of the fluids being produced from the infill well reaches 95 percent. The infill well is converted from a producer to an injector and hot water or cold water followed by hot water is injected into thelower portion of the formation via the infill well and fluids are produced from the production well. By this means, oil is recovered from the lower portions of the formation between the infill well and the production well. After water breakthrough occurs at the production well, steam is injected into the infill well and fluids are recovered from the production well. Hydrocarbon solvent is injected either as a slug prior to steam injection into the infill well or comingled with the steam being injected into the infill well. By this multi-step process involving the infill well, the amount of oil recovered from the portion of the formation in the recovery zone defined by the injection and production well is increased significantly.

Disclosed is a thermal oil recovery method suitable for recovering viscous oil by injecting steam and an amine compound having the following formula:

A process for enhanced recovery of petroleum from subterranean formations is disclosed, wherein steam is injected into a formation via an injection well, and a mixture of petroleum and steam condensate is produced via a production well, wherein the produced mixture is flashed for production of a steam-distilled hydrocarbon fraction, and wherein the steam distilled hydrocarbon fraction is injected, with additional steam, into a subterranean formation for increased recovery of petroleum. The process disclosed is particularly useful in recovery of heavy (low API gravity) petroleum.

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Bellaire, TX, United States of America

Wilbur L Hall