Abstract: A sand consolidating method is provided for use in a borehole within an unconsolidated or loosely consolidated oil or gas reservoir which is likely to introduce substantial amounts of sand into the borehole and cause caving. After perforating the borehole's casing at an interval of the formation where sand will be produced, an aqueous silicate solution is injected into said interval. Next, a spacer volume of a water-immiscible hydrocarbonaceous liquid is introduced into the interval. Thereafter, a water-miscible organic solvent containing an alkylpolysilicate and inorganic salt or chelated calcium is injected into the interval. A permeability retentive silicate cement is formed in the interval. Injection of the aqueous silicate and organic solvent is continued until the interval has been consolidated by the silicate cement to an extent sufficient to prevent sand migration and thereby prevent caving.

Abstract: A method of forming a gel in the subsurface formation is provided whereby a self crosslinking monomer selected from hydroxy unsaturated carbonyl compounds is polymerized in the formation by a suitable initiator. In a preferred embodiment, the initiator is selected from ago compounds which are temperature activated over a range of temperatures.

Abstract: A method and composition for controlling the profile of a formation where temperatures higher than 400.degree. F. are encountered. An aqueous solution of an organoammonium silicate, alkali metal or ammonium silicate is injected into a zone of higher permeability in a formation. Subsequently, a spacer volume of a water-immiscible organic solvent is directed into said zone. Afterwards, a water-miscible organic solvent containing an alkylpolysilicate and an inorganic salt or a chelated calcium compound are injected into the higher permeability zone. A silicate cement is formed in-situ thereby substantially closing the higher permeability zone to fluid flow. Thereafter, a steam-flooding, water-flooding, carbon dioxide-flooding, or fire-flooding EOR operation is commenced in a lower permeability zone.

Abstract: Gas blowouts in wells are controlled by injecting a cohesive aqueous gel composition of hydroxypropyl guar gum, a borate salt cross-linking agent and a weighting agent such as silica flour, barite, hematite or iron oxide. The kill fluid is less susceptible to atomization than weighted drilling fluids, is readily available in most oil and gas field operations and may be rapidly prepared in quantities suitable for injecting into a well to control a gas blowout.

Abstract: The present invention relates to a method for reducing or completely stopping the influxes of water of a deposit in at least a portion of a borehole for the extraction of oil and/or hydrocarbon gas, which traverses a deposit, a solution of a polymer being introduced, starting from the borehole, into that portion of the deposit in which the influxes of water are to be reduced or stopped, and the bore subsequently being put into service for the extraction of oil and/or hydrocarbon gas, the fluids present in the deposit coming into contact with said portion of the deposit containing the polymer and the oil and/or hydrocarbon gas flowing through said portion of the deposit and reaching the borehole, wherein the non-aqueous solution of a hydrophobic, water-insoluble polymer is introduced into the deposit and the polymer precipitates in the presence of the connate water of the deposit.

Abstract: Improved methods of displacing a first liquid through a pipe with a second liquid while preventing the first and second liquids from mixing are provided. In accordance with the methods, a plug is formed in-situ in the pipe between the first and second liquids by injecting a self-thickening liquid therein and permitting the liquid to thicken. The formed plug and the first liquid are then displaced through the pipe with the second liquid. The methods are particularly suitable for carrying out subterranean well bore cementing operations wherein cement slurries are displaced through pipes disposed in well bores.

Abstract: Improved hydraulic cement compositions and methods for cementing wells drilled through low temperature earth formations wherein the cement is subjected to freeze-thaw cycling are provided. The compositions are comprised of a hydraulic cement, gypsum cement, fly ash, an alkali metal halide, water, and an alcohol freezing point depressant.

Abstract: Set retarded ultra fine cement compositions which remain pumpable for a predictable period of time at temperatures up to about 240.degree. F. are provided. The compositions are basically comprised of an ultra fine hydraulic cement, sufficient water to form a pumpable slurry and a set retarder comprised of a methylenephosphonic acid derivative.

Abstract: A method of forming a gel in a subsurface formation is provided whereby a monomer is polymerized in the formation in the presence of a crosslinker by an initiator selected from azo compounds which are temperature activated over a range of temperatures. The method is particularly useful to substantially terminate or at least decrease the flow of water from a subterranean formation into a wellbore penetrating the formation.

Abstract: A novel process for sustaining microbial activity in subterranean formations which comprises introducing as a microbial nutrient, a phosphite salt. This process may include the sequential injection of sources of individual nutrient components which are deficient in said subterranean formation, whereby the injected phosphorus source is selected from the group consisting of a phosphite salt and a phosphorous acid.

Abstract: The present invention is directed to a process for improving the dispersibility and the filterability of scleroglucan powders, in which a surfactant is incorporated in the coagulated polymer. The powder obtained according to the process has a dispersibility and a filterability after drying of the coagulum which are greatly superior to those of a powder treated after drying with the same quantity of surfactant or of a powder in solution treated with this same quantity of surfactant. The present invention is also directed to methods for preventing the sudden rush of well water into the strata of petroleum fields, to methods for modifying the injection profile, and to methods for improved hydrocarbon recovery from petroleum fields.

Abstract: The invention has as its object the use of new composition of gels that can be used for the reduction of the production of water in oil- or gas-producing wells.The compositions of gels comprise a solution of at least one water-soluble complex of a polyvalent metallic cation such as zirconium lactate able to cross link a nonionic polysaccharide such as scleroglucan, at a concentration of 2 to 10,000 parts per million of parts, expressed by weight of metal dioxide. With a preferred concentration of 2 to 100 ppm, the oil permeability is not appreciably affected.The compositions make possible the formation of aqueous gels of scleroglucan that can be used for the prevention of inflows of water into the hydrocarbon-producing wells.

Abstract: A process to temporarily seal an upper zone of higher permeability. Coiled tubing is used to cover a zone of lower permeability with a gel block containing rock salt. A lower density, more stable, slower yielding gel block having a gel breaker is squeezed into the upper zone. The well is shut-in and the low density gel plug becomes rigid. Water is then circulated down the coiled tubing to dissolve the high density gel block out of the wellbore and re-open lower perforations which allows the low permeability interval to be treated.

Abstract: In the cementing of oil wells, gas wells, or geothermal wells, wherein, under appropriate conditions, a suitable drilling fluid is injected, then optionally a slug fluid and finally a composition comprising water, a cement, at least one viscosity-enhancing additive, optionally at least one retarding agent and optionally at least one silica characterized in that the viscosity-enhancing agent is a scleroglucan solution. It applies particularly to the high temperature cementing of wells.

Abstract: A surfactant is added to a cement containing a polymer fluid loss additive, to synergistically reduce fluid loss from the cement before it hardens.

Abstract: A dispersant for spacer fluids, cement slurries, completion fluids and mixtures of drilling fluids and cement slurries used for drilling and cementing subterranean wells.

Abstract: The invention is a method for increasing the effectiveness of steam or carbon dioxide foaming operations for improving conformance during steam or carbon dioxide floods by adding to the surfactant foaming solution a fatty acid having about 12 to about 20 carbon atoms in a concentration such that the ratio of fatty acid to surfactant in the foaming solution is between about 1:4 and about 3:2.

Abstract: A sand consolidation method to provide for use in a borehole having an unconsolidated or loosely consolidated oil or gas reservoir which is likely to introduce substantial amounts of sand into the borehole and cause caving. After perforating the borehole's casing at an interval of the formation where sand will be produced, an aqueous slug of hydroxide is injected into said interval. Next, a spacer volume of a water-immiscible hydrocarbonaceous liquid slug is injected into the interval. Thereafter, a water-miscible solvent slug of an alkylpolysilicate is injected into the interval. A permeability retaining silica cement is formed in the interval. Injection of aqueous hydroxide and alkylpolysilicate slugs is continued until the interval has been consolidated by the silica cement to an extent sufficient to prevent sand migration and thereby prevent caving.

Abstract: A method of gravel packing a well. A flow-reducing material is introduced into the annulus between a tubular liner and the well bore so as to collect at the perforations in the well bore and the apertures in the liner. This slows gravel slurry flow to the screen inner annulus and to the perforations to prevent gravel from bridging the annulus at these locations. The material is removed after the risk of bridging has passed. Various flow-reducing materials, such as wax flakes, salt, clay and gel, may be employed. The method is particularly useful in deviated wells.

Abstract: A cross-linking system using boron alpha-hydroxy carboxylic acid salts is shown for use in a water based well treating fluid. The cross-linker will gel the water based fluid usually after a delay at a relatively neutral pH. The cross-linker is provided as a concentrated stable solution containing borate ion as boric acid in a concentration of from less than 1% up to 25% by weight. The cross-linking solution additionally may contain from 1% to 10% of EDTA and/or Glycerine, however, without these additives the cross-linking solution is stable through temperature changes and freeze-and-thaw cycles. Water based fracturing fluid is shown using galactomannan guar polymers, hydroxypropyl guar polymers or derivatives thereof.

Abstract: A method and composition for controlling the profile of a formation where temperatures higher than 400.degree. F. are encountered. An aqueous solution of an organoammonium silicate, alkali metal or ammonium silicate is injected into a zone of higher permeability in a formation. Subsequently, a spacer volume of a water-immiscible organic solvent is directed into said zone. Afterwards, a water-miscible organic solvent containing an alkylpolysilicate and an inorganic salt or a chelated calcium compound are injected into the higher permeability zone. A silicate cement is formed in-situ thereby substantially closing the higher permeability zone to fluid flow. Thereafter, a steam-flooding, water-flooding, carbon dioxide-flooding, or fire-flooding EOR operation is commenced in a lower permeability zone.

Abstract: A cross-linking system using boron alpha-hydroxy carboxylic acid salts is shown for use in a water based well treating fluid. The cross-linker will gel the water based fluid usually after a delay at a relatively neutral pH. The cross-linker is provided as a concentrated stable solution containing borate ion as boric acid in a concentration of from less than 1% up to 25% by weight. The cross-linking solution additionally may contain from 1% to 10% of EDTA and/or Glycerine, however, without these additives the cross-linking solution is stable through temperature changes and freeze-and-thaw cycles. Water based fracturing fluid is shown using galactomannan guar polymers, hydroxypropyl guar polymers or derivatives thereof.

Abstract: A cross-linking system using boron alpha-hydroxy carboxylic acid salts is shown for use in a water based well treating fluid. The cross-linker will gel the water based fluid usually after a delay at a relatively neutral pH. The cross-linker is provided as a concentrated stable solution containing borate ion as boric acid in a concentration of from less than 1% up to 25% by weight. The cross-linking solution additionally may contain from 1% to 10% of EDTA and/or Clycerine, however, without these additives the cross-linking solution is stable through temperature changes and freeze-and-thaw cycles. Water based fracturing fluid is shown using galactomannan guar polymers, hydroxypropyl guar polymers or derivatives thereof.

Abstract: A cross-linking system using boron alpha-hydroxy carboxylic acid salts is shown for use in a water based well treating fluid. The cross-linker will gel the water based fluid usually after a delay at a relatively neutral pH. The cross-linker is provided as a concentrated stable solution containing borate ion as boric acid in a concentration of from less than 1% up to 25% by weight. The cross-linking solution additionally may contain from 1% to 10% of EDTA and/or Glycerine, however, without these additives the cross-linking solution is stable through temperature changes and freeze-and-thaw cycles. Water based fracturing fluid is shown using galactomannan guar polymers, hydroxypropyl guar polymers or derivatives thereof.

Abstract: Gels stable in a subterranean formation at a temperature greater than about 175.degree. F. are formed using, inter alia, a stabilizing agent (e.g., a buffer having a buffering capacity at a pH of at least about 8 and/or a chelating agent).

Abstract: A method for reducing the amount of liquids produced from a selected geologic formation of a gas producing well is disclosed. A solution comprising controlled quantities of a scaling cation brine and scaling anion brine such that a scale will precipitate, and a controlled quantity of a scale inhibitor such that the scale precipitation will be delayed, is injected into the formation. The well is then shut-in long enough to allow the injected mixture to precipitate scale and to reduce the permeability of the formation such that a substantial portion of liquids that had been produced before, no longer are produced upon a resumption of gas production.

Abstract: A method for improving the sweep efficiency of gas or steam flooding operations by reducing the permeability of relatively high permeability thief zones of an oil bearing subterranean reservoir having heterogeneous and/or fracture permeability and that is penetrated by at least one well is disclosed. A controlled quantity of a surfactant is injected into a high-permeability zone of a reservoir. Controlled quantities of a gas and a subsequent surfactant are then injected, simultaneously or alternatively into the same well, so that a controlled amount of foam having a controlled quality is generated in the high permeability zone, thereby reducing permeability. Following foam emplacement, a chase gas may be injected, and the steps of injecting surfactant and gas may be repeated as necessary to lower the gas-oil ration of non-problem offset producing wells to a preset limit.

Abstract: A clay control additive for cement composition of the general formula: ##STR1## wherein the R groups are selected from a C.sub.1 to C.sub.4 substituted alkyl.

Abstract: A method for the disposal of waste water in a formation having varying permeability zones therein where a higher permeability zone is first closed to fluid flow via a solidifiable gellable mixture. This mixture forms a solid gel in the higher permeability zone. Afterwards, waste water is injected into a zone of lesser permeability which allows increased amounts of water to be placed into the formation.

Abstract: A method of degrading a blocking gel in a subterranean formation of a well bore is shown in which a gellable blocking fluid is first formed by blending together an aqueous fluid, a hydratable polymer, a suitable crosslinking agent for crosslinking the hydratable polymer to form a polymer gel. The polymer gel may contain an enzyme breaker incorporated within. The cross-linked polymer gel is pumped into the well bore. If required, an externally applied enzyme breaker is added prior to gel degradation. The enzyme breaker is allowed to degrade the cross-linked polymer with time to reduce the viscosity of the fluid so that the fluid can be removed from the formation back to the well surface. The particular enzyme breaker utilized has an activity in the pH range from about 1.0 to 8.0 and is effective to attack only specific linkages in the cross-linked polymer gel.

Abstract: A method of control of the porosity of wells with a fibrous fluid blocking layer disposed on formation faces is provided. By means of mineral fiber pellets of critical dimensions wherein the mineral fibers are highly soluble in acid, a fluid blocking layer formed of semi-dispersed pellets can bridge formation face pores subject to removal at will by acid treatment. Thus after well rework the plugging layer is treated by an acid solution after sealing the formation faces to prevent fluid losses to quickly dissolve the mineral fibers to the desired extent for control the porosity. A novel well workover product making the method possible is formed from raw material clinkers of highly acid soluble mineral fibers of between 5 to 15 microns in diameter by grinding in a hammermill into pellets of a range of 1/32 inch to 1/2 inch in diameter with an average being between 1/16 inch to 1/8 inch and with fiber lengths between 1/64 inch to 3/8 inch.

Abstract: A method for gravel packing perforations in a wellbore where an acid is directed into the perforations so as to dissolve formation fines in channels contained in said perforations. The acid is of a strength sufficient to dissolve said fines. After the fines are dissolved, a three slug sand consolidating agent is introduced into the perforations before the channels can be filled with formation fines. The consolidating agent remains in the perforations for a time sufficient to form a silicate cement in situ which cement has permeability retentive characteristics. The cement forms pores of a size sufficient to exclude formation fines from the wellbore. Thereafter, the wellbore is packed with gravel to remove any escaping fines from hydrocarbonaceous fluids produced to the surface.

Abstract: Disclosed are cementing compositions and methods of using wherein the cementing compositions comprise: (a) aqueous solution, (b) hydraulic cement, (c) a N-vinylpyrrolidone-acrylamide random copolymer, and (d) a sulfonate containing cement dispersant. The copolymer is present in the composition in an amount of from 0.05 to 5.0 weight percent based on the weight of dry cement. Use of the present invention as a fluid loss additive will result in significant reductions in water loss rate.

Abstract: A method of stabilizing a wellbore being drilled through both shale and sandstone zones. A shale stabilizing agent and finely divided particulate material are combined in a water based drilling fluid to provide the stabilization.

Abstract: The invention relates to the treatment by a fluid, or more generally by an acid fluid, of subterranean formations located in particular around an oil, gas, water or geothermal well.Acid is diverted towards the zone to be treated by a surfactant flush, the injection of a foam and then the injection of an acid/surfactant composition. These operations are repeated as often as required, increasing at each stage representing approximately 80 cm (20 to 25 inches) of treatment in terms of height the quantity of foam injected.

Abstract: A method of treating a clay-containing subterranean formation with an aqueous fluid is disclosed. The method features the use of quaternary ammonium compounds as additives to control formation damage caused by contacting the formation with the aqueous fluid.

Abstract: A method for recovering hydrocarbons from a reservoir during gas injection into the reservoir comprises at least periodically injecting a gas comprising steam and a foam-forming composition which includes at least one steam foam diversion surfactant into a reservoir which contains at least one multivalent cation. The foam forming composition comprises water, an effective foam-forming amount of the surfactant which preferably comprises an alkyl aromatic sulfonate and a precipitation control additive. This precipitation-control additive preferably comprises an alpha-olefin sulfonate dimer (AOSD). The method further comprises contacting the hydrocarbons in the resevoir with the foam and the gas so as to assist in the recovery of hydrocarbons from the reservoir.

Abstract: A sand consolidation method is provided for use in a borehole having an unconsolidated or loosely consolidated oil or gas reservoir which is likely to introduce substantial amounts of sand into the borehole and cause caving. After perforating the borehole's casing at an interval of the formation where sand will be produced, an aqueous silicate solution is injected into said interval. Next, a spacer volume of a water-immiscible hydrocarbonaceous liquid is introduced into the interval. Thereafter, a water-miscible organic solvent containing an alkylpolysilicate is injected into the interval. A permeability retaining silica cement is formed in the interval. Injection of the aqueous silicate and organic solvent containing an alkylpolysilicate is continued until the interval has been consolidated by the silica cement to an extent sufficient to prevent sand migration and thereby prevent caving.

Abstract: The water permeability and the production of salt water from a subterranean oil bearing formation is reduced by introducing a viscous aqueous polymer composition into the formation which will subsequently form a crosslinked gel therein, and thereafter introducing a hydrocarbon cement slurry into the formation.

Abstract: A microbial system is provided for selective plugging of permeable regions of a subterranean formation, for use in conjunction with injection of surfactant-containing foams. Bacteria indigenous to the target formation are isolated, and selected for ability to degrade the surfactant of interest. Small, non-adherent ultramicrobacteria, or UMB, are prepared from the selected culture by starvation. The UMB and the surfactant-containing foam are then injected into the target formation. The surfactant allows the foam to penetrate into the formation. The UMB then revive to their vegetative state, degrade the surfactant and produce exopolymer, thus plugging the formation.

Abstract: The invention is a method for forming a high viscosity gel by mixing about 0.9% to about 3.0% by weight of hydroxy propyl cellulose having an average molecular weight greater than about 1,000,000 about 0.4% to about 3.0% by weight of an alkali metal dodecyl sulfate in the ratio of about 3:1 to about 1:1.5 of cellulose to sulfate, and a brine having a salinity greater than about 20,000 ppm TDS.

Abstract: Water production from a wellbore is reduced by sequentially or simultaneously injecting (a) a hydrophilic polymer-containing organic carrier fluid and (b) a crosslinking agent-containing fluid into at least a portion of a subterranean formation. The cross-linking agent reacts with the polymer in the presence of water to form a gel in at least a portion of the subterranean formation. The gel obstructs the flow of water in the subterranean formation, thereby reducing the production of water from the wellbore.

Abstract: Well completion methods utilizing rubber latex compositions are provided. The compositions are comprised of an aqueous suspension of rubber, a vulcanizing agent and a vulcanization activator, and are placed in a subterranean formation or a well bore at a desired location therein and allowed to vulcanize whereby a solid rubber plug or seal is formed.

Abstract: A method to prevent damage to a water-sensitive hydrocarbonaceous fluid-producing zone of a formation which is penetrated by a well which has a water-influx problem. A gellable petroleum mixture is injected into the well where it forms a solid hydrophobic gel in situ sufficient to temporarily close pores in the water-sensitive zone. The mixture is allowed to remain in the water-sensitive zone for a time sufficient to form a solid gel so as to preclude fluid entry into the water-sensitive zone. Afterwards, an aqueous based gel mixture is injected into the water-influx zone where it forms a solid hydrophilic gel which is substantially stable thereby precluding fluid entry into the well. Subsequently, the solid petroleum gel degrades at formation conditions and opens the water-sensitive zone to production of hydrocarbonaceous fluids. Thereafter, substantially water-free hydrocarbonaceous fluids are produced from the water-sensitive zone.

Abstract: Cement compositions which have improved properties such as increased stability, reduced settling tendencies, enhanced fluid loss properties and the like and methods of using such cement compositions are provided. The cement compositions are comprised of water, hydraulic cement and an aqueous colloidal silicic acid suspension wherein the colloidal silicic acid particles have a specific surface area in the range of from about 50 m.sup.2 /g to about 1000 m.sup.2 /g.

Abstract: A method of reducing the water produced from a subterranean formation penetrated by a wellbore without appreciably reducing the oil produced therefrom is provided. In accordance with the method, the formation is contacted with a hydrocarbon treating solution having dissolved therein a surface active agent comprosed of one or more fatty acid imidazolyl compounds.

Abstract: Gels containing gas precursors and/or pathways are used to selectively reduce the flow of aqueous fluids with respect to the flow of nonaqueous fluids to enhance the recovery of the nonaqueous fluids from subterranean formations. The gels, while stable at reservoir conditions, are also readily degraded by gel degrading agents such as acids and therefore are also employed as fail-safe gels in subterranean gel treatments. In another embodiment, selective permeability is restored to a previously treated well by injecting a gas into the previous treated portions of the subterranean formation to displace any aqueous fluid obstructing the passage of the nonaqueous fluid through the polymer-coated pores or gel.

Abstract: The permeability of high-permeability zones in a oil reservoir can be reduced by using a gellable aqueous composition with delayed gelation.The composition comprises:a) water;b) a high-molecular weight natural or synthetic water-soluble polymer cross-linkable by means of Cr.sup.3+ ions;c) a water-soluble inorganic Cr.sup.

Abstract: Visible gels are formed by mixing an inorganic crosslinking agent with a low viscosity aqueous solution having a low polyacrylamide content. The visible gels are employed to reduce the water/hydrocarbon permeability ratio of subterranean formations.

Abstract: A process for the manufacture of a water based drilling fluid additive comprising the steps of: (a) mixing hydrophobic carbon black and either a surfactant or a dispersant and (b) shearing the mixture of step (a) under a sufficiently high mechanical shear for a sufficient time to convert the hydrophobic carbon black into hydrophilic carbon black. This invention is also directed to a water based drilling fluid additive prepared according to the above process and the use of the additive in a water based drilling fluid.