Abstract: High permeability zones in subterranean formations are reduced in permeability by the gelation of water soluble polymers of polyalkylenimines, polyalkylenepolyamines and mixtures thereof in such formations with cross-linking agents containing difunctional groups which are capable of cross-linking with said polymers.

Abstract: High permeability zones in subterranean formations are reduced in permeability by the gelation of water soluble polymers of polyalkylenimines, polyalkylenepolyamines and mixtures thereof is such formations with nonionic polymers which are hydrolyzable to anionic polymers which are capable of cross-linking with and gelling said water soluble polymers.

Abstract: The relatively highly permeable zones of a subterranean oil containing formation having a neutral to alkaline pH are selectively plugged by initially injecting an aqueous acid solution into the relatively highly permeable zones that lowers the pH of these zones to about 6 or less. Thereafter, an aqueous polysulfide solution is injected into the formation that preferentially enters the relatively highly permeable zones and allowed to disproportionate under the pH conditions within the relatively highly permeable zones to form a precipitate of elemental sulfur in situ which plugs the relatively highly permeable zones in the formation. Thereafter, improved sweep efficiency is realized in displacing oil from the lesser permeable zones. If the natural pH of the relatively highly permeable zones in the formation is about 6 or less, the initial treatment with the aqueous acid solution is unnecessary.

Abstract: A process for delaying the gelation rate of a polymer used in oil recovery applications. A gel is prepared by mixing a single aqueous gelation solution at the surface made up of a polyvalent metal cross-linking agent and a polyacrylamide having no hydrolysis or only a limited degree of hydrolysis. The solution is injected into a desired treatment region and gelled to completion in situ.

Abstract: Conformance improvement is achieved in a subterranean hydrocarbon-bearing formation using a gel comprising a high molecular weight, water-soluble, carboxylate-containing polymer, a chromium III/carboxylate complex capable of crosslinking the polymer and an aqueous solvent. The gel components are combined at the surface and injected into the desired treatment zone via a wellbore to form a continuous single-phase gel.

Abstract: A method of enhancing the amount of oil recovered from a subterranean oil-bearing formation by controlling the profile of the formation by introducing a predetermined first amount of a permeability control agent in a non-gelatinous state into the formation so that it contacts at least a portion of the formation. A portion of the pores of the formation are plugged by allowing contact to be maintained for a sufficient period of time allowing the first portion to gel. The first amount constitutes a portion of the total amount required to improve the profile of the formation. A predetermined second amount of permeability control agent is thereafter introduced, in a non-gelatinous state, into the formation which contacts the first amount and the portion of the formation not contacted by the first amount for a time period sufficient to gelatinize the second amount so as to plug the remaining unproductive pores of the formation.

Abstract: In a continuous or cyclic steam foam drive, recovery of an acidic reservoir oil (1) is improved by injecting steam accompanied by (a) enough dissolved alkaline monovalent salt to ion-exchange multivalent cations from the reservoir rocks and precipitate those ions in compounds which are insoluble in an alkaline aqueous liquid as well as forming soaps of the reservoir oil acids and (b) surfactants for foaming the steam and increasing the salt tolerance of an aqueous surfactant system containing the soaps of the reservoir oil acids, and (2) is further improved by using trona or an equivalent mixture of alkali metal carbonates and bicarbonates as the alkaline monovalent salt.

Abstract: A process for accelerating the gelation rate of a carboxylate-containing polymer used in oil recovery applications. A gel is prepared by mixing a single aqueous gelation solution at the surface made up of the polymer and a crosslinking agent containing a chromic carboxylate complex and a simple mineral acid. The concentration of the simple mineral acid is selected at a level which achieves the desired rate of gelation for a given application.

Abstract: An enhanced oil recovery method is provided utilizing an alkaline waterflood injection fluid including a water-soluble precipitation inhibitor such as a polyacrylate, an acrylate-containing copolymer, an organophosphonate, a carboxylate-containing organophosphonate or a polymaleic anhydride whereby divalent metal cations dissolved within the injection fluid or within the reservoir water in the immediate vicinity of the injection well are substantially prevented from precipitating. Additionally, the injection fluid preferably provides sufficient alkaline material whereby beyond the immediate vicinity of the injection well the permeability characteristics of the reservoir are modified by precipitation of, e.g., divalent metal hydroxides or divalent metal carbonates.

Abstract: The permeability of subterranean formations, and hence, the mobility of fluids through the formation, can be controlled by introducing a carboxamide polymer and a hypohalite such as sodium hypochlorite to the formation at conditions such that the polymer has been cross-linked, either prior to its introduction or in situ, to form a gel. By this method, the permeability of highly porous zones can selectively be reduced. Therefore, in an enhanced recovery operation wherein a drive fluid is injected into the subterranean formation to force hydrocarbon therefrom, the drive fluid can more uniformly sweep the formation resulting in a more effective recovery process.

Abstract: A non-crosslinking salt of a monovalent cation is added to a gelation solution comprising an acrylamide polymer and a redox crosslinking system to render the viscosity and uniformity of the resulting gel less sensitive to the concentrations of the gel components. The gel is used for conformance correction treatments of subterranean hydrocarbon-bearing formations to reduce the permeability of a high permeability zone adjacent a low permeability zone.

Abstract: Conformance improvement is achieved in a subterranean hydrocarbon-bearing formation using a gel comprised of a high molecular weight water-soluble acrylamide polymer, a chromium III/carboxylate complex capable of crosslinking the polymer and an aqueous solvent. The gel components are combined at the surface and injected into the desired treatment zone via a wellbore to form a continuous single-phase gel. The gel is tailored to a specific subterranean application by first determining the treatment demands of the desired subterranean zone, then predetermining the gelation rate and resultant gel strength and stability which are required of a gel to meet the demands, and finally producing the gel having the required predetermined properties under controlled surface conditions by utilizing observed correlations between specific controllable gelation parameters and resultant gel properties.

Abstract: A gelation system for reducing the permeability of a subterranean region is provided by sequentially injecting slugs of a polymer solution and a crosslinking agent solution capable of crosslinking the polymer. The viscosity of the crosslinking agent solution is adjusted to facilitate mixing of the slugs in the desired treatment region to a form gel therein and minimize premature gelation outside of the treatment region.

Abstract: A gel-forming composition is provided comprising a first substance selected from the group consisting of a polyvinyl alcohols, polyvinyl alcohol copolymers, and mixtures thereof, a second substance selected from the group consisting of aldehydes, aldehyde generating substances, acetals, acetal generating substances, and mixtures thereof capable of crosslinking with the first substance through the formation of acetal crosslinkages, and water, and which requires contacting with a sorbed substance or brine which has sorbed substantial amounts of carbon dioxide before the gel-forming composition will form a gel. The gel-forming composition is useful for retarding the flow of carbon dioxide and other fluids in subterranean formations. For example, a method is provided for preventing the loss of carbon dioxide to nonproductive parts of an oil reservoir.

Abstract: A gel-forming composition is provided comprising a PVA based substance selected from the group consisting of a polyvinyl alcohol, a polyvinyl alcohol copolymer, and mixtures thereof, an aldehyde operable for crosslinking with the PVA based substance, and water. The gel-forming composition is useful for reducing steam channeling in subterranean formations. For example, a method is provided for diverting the flow of injected steam in nonproductive steam channels in an oil reservoir during waterflood and steam cycling operations.

Abstract: The permeability of subterranean oil-bearing formations is controlled by injection of an organic polysilicate ester. The ester may be derived from simple, monohydroxylic alcohols such as methanol, ethanol, propanol or butanol, from diols such as ethylene glycol, from polyols such as glycerol and alkylene oxide polymerization products and from other organic compounds containing function hydroxy groups, for example, partial ethers and esters of glycols and polyols. The polysilicates are injected into a formation through injection wells, suitably in an amount from 10 to 100% of the pore volume of the zone to be treated. In the formation, the polysilicate esters form gels which selectively plug the high permeability regions of the formation, to divert the flow of flooding liquid used in flooding operations to the less permeable regions of the formation.

Abstract: The permeability of subterranean oil-bearing formations is selectively reduced by the injection into the formation of the non-xanthan, anionic heteropolysaccharide S-130 produced by fermentation with a microorganism of the Alcaligenes species. The polymer forms shear-thinning, viscous solutions which selectively enter the more highly permeable regions of the formation and form a gel plug in them to reduce their permeability. The polymer forms gels which are stable under a wide range of reservoir conditions including high temperatures.

Abstract: A process for the correction of oil well productivity, or injection profiles, or both, is disclosed. The process includes injecting a dilute solution of hydrochloric acid having a concentration less than 1% via an oil well into an adjacent subsurface formation, followed by injecting a solution of sodium silicate and hydrochloric acid into the formation, and then shutting in the well for several hours. The dilute hydrochloric acid solution and the sodium silicate-hydrochloric acid solution may each be displaced into the formation with injection water. Best results are achieved when systems based on sodium silicate and hydrochloric acid of long-curing time are injected, followed by systems based on sodium silicate and hydrochloric acid of short-curing time.

Abstract: A process and composition for modifying hydrocarbons and/or recovering hydrocarbons from hydrocarbon-bearing formations involving mixing controlled quantities of alkali metal hydroxide and silicon in an aqueous medium to produce an oil modification agent. When recovering hydrocarbons, the composition can be injected into a hydrocarbon-bearing formation to react with and/or thin the entrapped hydrocarbons within the formation. The composition also provides a dispersing agent which aids in release of the hydrocarbon from its entrappment and enhances recovery from the formation.

Abstract: Finely divided, preferably colloidally sized magnesium metal particles in an aqueous suspension are infused throughout a hydrocarbon-bearing formation and combusted or reacted with water for in-situ combustion to heat the formation.

Abstract: Polymers used in enhanced oil recovery operations, including polysaccharides, polyamides and cellulose derivatives may be crosslinked by the use of organic nitrogen compounds bearing at least two positively charged nitrogen atoms. Suitable crosslinking agents include the salts of aliphatic and aromatic diamines and bis (quaternary ammonium) compounds. The crosslinked copolymers may be used for mobility and permeability control purposes. The crosslinking agents are effective over a wide range of pH conditions to form stable gel structures with the polymers.

Abstract: In a continuous or cyclic steam foam drive, recovery of an acidic reservoir oil is improved by injecting steam accompanied by (a) enough dissolved alkaline monovalent salt to ion-exchange multivalent cations from the reservoir rocks and precipitate those ions in compounds which are insoluble in an alkaline aqueous liquid as well as forming soaps of the reservoir oil acids and (b) surfactants for foaming the steam and increasing the salt tolerance of an aqueous surfactant system containing the soaps of the reservoir oil acids.

Abstract: Polymers used for the control of permeability in stratified subterranean formations are gelled in a controlled manner by the use of rapid and delayed gelling agents. The polymer is first gelled lightly by the use of a rapid gelling agent which partly cross-links the polymer to produce a viscous solution which will selectively enter only the more permeable regions of the formation but can still be readily injected. A delayed cross-linking agent completes the cross-linking process after the polymer has been selectively emplaced to form a firm, full strength gel. Suitable rapid cross-linking agents may be formed by the reaction of alkalies and chromic salts at specified ratios or by the redox reduction of chromium from its higher oxidation states under certain specified conditions. Delayed cross-linking agents are exemplified by chromic salts. Polymers which may be used include polyacrylamides and polysaccharide biopolymers.

Abstract: A method for the recovery of mineral resources, such as metallic minerals, petroleum, etc., from solid materials, such as subsurface earth formations, including; partially burning a hydrogen-containing fuel in the presence of an oxidizing agent under conditions to produce partial oxidation products, such as alcohols, hydrogen peroxide, aldehydes, ketones, etc., terminating the burning to prevent decomposition of the partial oxidation products and contacting the solid materials with the partial oxidation products and contacting the solid materials with the partial oxidation products and an alkaline or acidic material.

Abstract: A process for recovering petroleum from a subterranean containing formation comprising injecting a polymerizable surfactant containing oil displacing fluid into the formation to reduce the permeability of the oil depleted high permeable zone.

Abstract: Polyfunctional anionic polymers are useful for inhibiting the adsorption of surfactants and organic polymers in formations such as clay-containing oil reservoirs or clay-containing oil reservoirs which have previously been treated with polyfunctional cationic polymers.

Abstract: A water permeability contrast correction process to improve the sweep efficiency of waterflooding which involves the sequential injection of (1) an optional aqueous preflush slug to adjust connate water salinity, (2) an aqueous thickened slug comprising a sequestered polyvalent metal cation such as aluminum citrate and a gelable polymeric viscosifier such as polyacrylamide, (3) carbon dioxide to decrease the pH of the polymer slug which triggers the delayed in-situ gelation of said thickened slug to preferentially decrease water permeability in highly permeable thief zones, and (4) an aqueous drive fluid.

Abstract: Enhanced oil recovery process comprising the injection of aqueous alkaline hypochlorite solution and aqueous alkaline alcohol solution into a subterranean formation to react with crude oil and form carboxylate surfactants in-situ. In a preferred embodiment, aqueous alkaline hypochlorite solution is followed by injection of an aqueous alcohol solution to form a carboxylate-alcohol surfactant system and then an aqueous mobility buffer.

Abstract: A water permeability correction process, and composition therefor, to improve the sweep efficiency of waterflooding which involves the sequential injection of (1) an optical aqueous preflush slug to adjust connate water salinity, (2) an aqueous sequestered polyvalent metal cation, such as chromium, wherein the sequestering anion is bactericidal, such as propionate, (3) a gelable polymeric viscosifier, such as polyacrylamide, and, preferably, (4) an aqueous drive fluid.

Abstract: A process for recovering hydrocarbons from a subterranean hydrocarbon bearing formation penetrated by injection well and a production well includes the steps of injecting into the formation via an injection well an aqueous drive fluid comprising water and more than about 200 parts per million of Beta-(1.fwdarw.6)-D-glucan having an average molecular weight of more than about 2.times.10.sup.4 and comprising recurring units of the disaccharide gentiobiose: ##STR1## forcing said aqueous drive fluid through the formation and recovering hydrocarbons from the production well. The process also includes using a more concentrated solution of the glucan, more than about 2,000 parts per million, as a vertical conformance agent. The invention also includes a concentrate of the glucan in dimethylsulfoxide or in a 4 molar or higher concentration of aqueous urea which is diluted to form the aqueous drive fluid.

Abstract: Compositions and process employing same for enhancing the recovery of residual acid crudes, particularly heavy crudes, by injecting a composition comprising caustic in an amount sufficient to maintain a pH of at least about 11, preferably at least about 13, and a small but effective amount of a multivalent cation for inhibiting alkaline silica dissolution with the reservoir. Preferably a tall oil pitch soap is included and particularly for the heavy crudes a polymeric mobility control agent.

Abstract: The production of water from a subterranean formation is reduced by contacting the formation with a water dispersible hydrophilic organic polymer having a molecular weight greater than 100,000 and containing carboxyl functionality and a crosslinking composition comprising water, a zirconium compound having a value of 4+, an alpha-hydroxy acid and an amine compound.

Abstract: Recovery of oil from an oil-containing formation is effected by injection of steam followed by a soak period, if desired, and then injecting a mixture of sodium bicarbonate and citric acid that react in the formation to form carbon dioxide in situ. A driving fluid, preferably hot water or low quality steam (less than 20%), is then injected to displace the carbon dioxide and oil toward a production well for recovery. The process may be operated under conditions wherein the carbon dioxide formed in situ is miscible with the formation oil at the pressure and temperature of the formation thereby effecting miscible displacement and enhancing oil recovery.

Abstract: In the process for recovering petroleum having acidic components from a geological formation containing it by injecting steam in the formation, the improvement comprising conducting the steam injection in the presence of one or more water-soluble amines.

Abstract: Enhanced oil recovery process comprising the injection of an aqueous solution of an aldehyde and a sulfite into a subterranean formation to react with crude oil and form a surfactant in situ. In a preferred embodiment, an aldehyde/sulfite solution is followed by injection of an aqueous alcohol solution and then an aqueous mobility buffer.

Abstract: The instant invention is directed to shear thickening fluids to prevent unwanted flow in wells penetrating subterranean formations. The shear thickening fluids comprise (1) a water swellable granular clay present in sufficient quantity so that, upon interaction with an aqueous phase, a stiff paste rapidly forms having a strength of at least 2000 lbs/100 ft.sup.2, (2) a nonaqueous phase comprising a hydrocarbon material and a surfactant, and (3) an aqueous phase comprising water and a watersoluble polymer. The granular clay and water-polymer solution are kept separated by the intervening hydrocarbon-surfactant composition, which is the continuous phase. The intervening oil phase prevents the interaction between the water-polymer phase and the granular clay and results in a stable, nonreacting, pumpable composite until such time as the granular clay is fragmented by application of a sufficiently high shear force.

Abstract: Oil is recovered from an acidic oil reservoir by injecting an alkaline, saline, aqueous solution containing proportions of preformed cosurfactant which are decreased as increasing amounts of the solution are injected.

Abstract: An aqueous solution containing a high molecular weight organic polymer and an aqueous solution containing a cross-linking agent are sequentially injected into the near well bore environment of a subterranean formation interposed by a hydrocarbon spacer. The spacer causes the two aqueous solutions to mix in the near well bore environment and a gel is formed which preferentially plugs the relatively highly permeable zones in the near well bore environment thereby improving conformance and flow profiles of fluids subsequently injected into or produced from the formation.

Abstract: A method and fluid for selectively reducing the permeability of an oil-bearing subterranean formation is disclosed, wherein a cross-linkable polymer, a cross-linking agent and a spacer fluid are alternately injected. The spacer, such as sodium citrate, permits repeated injection cycles of the polymer and cross-linking agents without excessive polymer retention at or near the formation face. Such retention filters out polymers and inhibits polymer propagation throughout the formation. The present invention also permits controlled deep penetration of the cross-linked polymer into the formation to increase oil recovery.

Abstract: Highly permeable zones in a subterranean formation are selectively plugged by injecting an aqueous solution of an acrylamide polymer, a phenol and an aldehyde via a well into the highly permeable zones. The solution forms a non-flowing, water insoluble polymer resin in situ at a temperature of from about 50.degree. C. to 100.degree. C. and an alkaline pH over a period of from about 1 to 10 days. The polymer resin plugs the highly permeable zones of the formation.

Abstract: In the process for recovering petroleum having acidic components from a geological formation containing it by flooding the formation with water, the improvement comprising conducting the flooding in the presence of 2-amino-2-methylpropanol in an amount sufficient to form soaps with the acidic components.

Abstract: The ammonium ions in a subterranean clay-containing formation may be removed by flushing the formation with a calcium ion containing restoration fluid having substantially the highest pH effective to prevent precipitation of calcium hydroxide from said restoration fluid. The calcium ion concentration in the restoration fluid is maintained between about 10,000 and 100,000 ppm until the ammonia concentration in the produced fluid peaks or is less than about 100 ppm. Thereafter the calcium ion concentration is maintained at about 400 to about 600 ppm until the desired level of ammonia is obtained, usually about 1-3 ppm.

Abstract: An improved method for enhanced oil recovery utilizing caustic or alkaline water flooding which avoids precipitation of hydroxides in the injection water or plugging of the reservoir. A lignosulfonate material is blended with the injection water before the addition of the alkaline chemical, the amount of lignosulfonate being sufficient to prevent formation of any precipitates.

Abstract: In an acidic in situ leaching system, a short circuit passage through a subterranean formation between a fracture associated with an injection well and a fracture associated with a production well can be plugged by introducing a non-acidic liquid for displacing acidic leach liquid from the short circuit passage, introducing into the injection well a basic composition including a sealing material that gels under acidic conditions, and introducing sufficient liquid into the injection well to displace at least a portion of the basic composition containing sealing material from the injection well into the short circuit passage. Liquid flow between the injection well and the production well is then discontinued for a sufficient time for residual acid in the subterranean formation surrounding the short circuit passage to contact the sealing material and cause gelation of the sealing material in the short circuit passage. The introduction of acidic leach liquid to the formation can then continue.

Abstract: A process for improving areal conformance of fluids injected into or produced from a subterranean formation via a multiwell system wherein significantly greater amounts of fluid than desired are injected into or produced from at least one well of the multiwell system than from other wells of the system. An aqueous caustic solution, an aqueous solution containing a polyvalent cation dissolved therein, and a hydrocarbon spacer separating the aqueous solutions are injected into the hydrocarbon formation. The aqueous solutions are caused to mix in the near well bore environment of said at least one well thereby forming an insoluble precipitate which reduces the permeability of the near well bore environment over substantially the entire well bore interval.

Abstract: A process for improving areal conformance of fluids injected into or produced from a subterranean formation via a multiwell system wherein significantly greater amounts of fluid than desired are injected into or produced from at least one well of the multiwell system than from other wells of the system. An aqueous caustic solution and an aqueous solution containing a polyvalent cation dissolved therein are caused to mix in the near well bore environment of said at least one well thereby forming an insoluble precipitate which reduces the permeability of the near well bore environment over substantially the entire well bore interval.

Abstract: Highly conductive zones of subterranean formations are treated with aqueous fluids containing gel-forming amounts of water-soluble basic lignins. Suitable treating fluids contain about 2 to about 8 wt. % sodium hydroxide solution. The lignin solutions gel within the formation due to reactivity with oil-water and/or the rock matrix. Alternately, following the injection of the gel-forming fluids, acidic gas is injected to cause gel formation.

Abstract: A method for selectively reducing the permeability of the higher permeability zones of a subterranean reservoir having heterogeneous permeability, such permeability reduction occurring a substantial distance away from a well in which there is injected into the reservoir an aqueous solution or solutions of a water-soluble polymer, a material capable under certain conditions of at least partially cross-linking the polymer to form a gelatinous precipitate, and a water-soluble alkaline material in an amount sufficient to maintain the pH of the polymer-containing composition above about 9 until the composition has passed a substantial distance through the reservoir.

Abstract: The instant invention is directed to shear thickening fluids which comprise a water swellable clay capable of rapidly forming a paste having a strength of at least 2000 lbs/100 ft.sup.2 upon interaction with the aqueous phase employed and present in sufficient concentration to form such a paste, a nonaqueous phase comprising a hydrocarbon material and surfactant, and an aqueous phase comprising water and a water-soluble polymer, wherein the clay and the aqueous phase are kept separated by the intervening hydrocarbon-surfactant phase. The intervening oil phase prevents the interaction between the water-polymer phase and the clay and results in a stable, non-reacting, pumpable composite, until such time as the oil barrier is ruptured by deliberate application of a sufficiently high shear force. Upon such rupture, the materials interact resulting in a semi-rigid high strength paste.

Abstract: An aqueous alkaline oil recovery fluid containing monovalent salt, and, optionally, preformed cosurfactant, is improved by using a mixture of alkaline silicate and carbonate salts in specified proportions as the alkaline material.