Abstract: Liquid water loss reducing additives for use in cement slurries are provided comprised of aqueous solutions of low molecular weight carboxymethylhydroxyethylcellulose polymers. Methods of using the additives are also provided.

Abstract: A fluid loss additive and method are shown for use in cementing oil and gas well bores which comprises the reaction product of a polyamine compound and a high molecular weight sulfonated polymer. The polyamine and high molecular weight sulfonated polymer are prereacted in solution and dried to form a dry product which can be added to the dry cement blend on the shelf or added to the mixing water during the formation of the cement slurry at the well site. The prereacted additive is effective to control fluid loss in cement slurries at 350.degree. F. and higher.

Abstract: Methods of inhibiting the flow of water into and from subterranean well formations wherein one or more gelling agents having the property of forming highly viscous gels in the presence of water are injected into the formation.

Abstract: The present invention relates generally to the composition and method for reducing the permeability of subterranean formations penetrated by a wellbore. The composition of the present invention comprises a wellbore fluid having dispersed therein a fluid loss control agent comprising a polyester polymer which is substantially insoluble in the wellbore fluid. The polymer degrades in the presence of water at an elevated temperature to form small molecules which are soluble in a fluid in the subterranean formation. The method of the present invention comprises reducing the permeability of subterranean formations penetrated by a wellbore by placing the composition of the present invention down the wellbore.

Abstract: Gelled compositions suitable as fracture fluids and water diversion agents comprising water, a polymeric viscosifier, an aldehyde component, and at least one phenolic component such as resorcinol, catechol, and the like, as well as selected oxidized phenolic materials such as 1,4-benzoquinone of natural or synthetic origin and natural and modified tannins. The gelled compositions can additionally contain gel stabilizers and chemical buffering agents.

Abstract: A process for cementing adjacent a subterranean gas-containing zone, in which process a cement slurry containing a stabilized, dispersed gas is placed adjacent the zone. Sufficient gas is present in the cement slurry or is capable of being generated within the slurry to prevent the connate formation gas under pressure from passing into or around the cement prior to the time the cement has set up.

Abstract: Shear-thickening aqueous compositions useful as workover fluids in producing or injection wells, as water diversion agents and mobility control fluids in post-primary oil recovery operations, and as hydraulic fracturing fluids well stimulation treatments are provided comprising the reaction product formed from a high molecular weight polyalkylene oxide polymer and a synthetic resin produced from aldehydes and phenols in an alkaline environment.

Abstract: Shear-thickening aqueous compositions useful as workover fluids in producing or injection wells, as water diversion agents and mobility control fluids in post-primary oil recovery operations, and as hydraulic fracturing fluids well stimulation treatments are provided comprising the reaction product formed from a high molecular weight polyalkylene oxide polymer and a synthetic resin produced from aldehydes and phenols in an alkaline environment.

Abstract: A fracturing fluid composition consisting essentially of a viscous aqueous solution having a high concentration of cations, an anionic or nonionic viscosifier imparting a high viscosity to the composition, and an anionic, polymeric fluid loss material which is substantially insoluble in the aqueous solution, and is soluble in fresh water substantially free of the cations in the fracturing fluid.In the method of fracturing using the fracturing fluid compositions of the invention, the composition is injected into the fracture via the well bore to enlarge and/or extend the fracture. Completion of fracturing is followed by injection of fresh water into the fracture from the well bore to dissolve the anionic, polymeric fluid loss material, and displace the fracturing fluid composition into the formation upon continuation of a water flood operation.

Abstract: An improved fluid loss additive for use in well cements, preferably comprising from about 30 to about 70 weight percent polyvinylpyrrolidone, from about 5 to about 19 weight percent carboxymethylhydroxyethyl cellulose, and the sodium salt of naphthalene sulfonate. Improved cement slurries comprising the subject fluid loss additive and an improved method for cementing well bores through use of the novel slurries are also provided. The improved cement slurries of the invention preferably comprise from about 26 to about 60 percent water and from about 0.75 to about 2 percent of the improved fluid loss additive, by weight of the cement.

Abstract: An improved method for reducing fluid loss during high pressure hydraulic fracturing of well formations using an aqueous foam involving adding to the foam from about 0.0005 to 0.5% by weight of an additive selected from the group consisting of a C.sub.5 to C.sub.10 unsubstituted monocarboxylic aliphatic acid, a C.sub.5 to C.sub.10 unsubstituted aliphatic alcohol, malonic acid, lower n-alkyl diesters of malonic acid and their mixtures. The new additives are shown to be as effective in reducing fluid loss during fracturing as the commercial practice employing hydroxy ethyl cellulose at a fraction of the cost of hydroxy ethyl cellulose without depositing polymer within the formation.

Abstract: Shear-thickening aqueous compositions useful as workover fluids in producing or injection wells, as water diversion agents and mobility control fluids in post-primary oil recovery operations, and as hydraulic fracturing fluids in well stimulation treatments are provided comprising the reaction product formed from a high molecular weight polyalkylene oxide polymer and a synthetic resin produced from aldehydes and phenols in an alkaline environment.

Abstract: The present invention relates to methods and compositions for treating high temperature well formations whereby highly viscous crosslinked gels are formed in the formations.

Abstract: A non-damaging variable-density low fluid loss well completion and workover fluid composition which is a dispersion of finely divided slowly oil-soluble, water-insoluble solid particulate matter in a thickened aqueous salt solution. The fluid composition is a mixture of an aqueous solution of a water-soluble inorganic salt, a first high softening point resin fluid loss control additive, a microemulsion fluid loss control additive, and, optionally, a water-dispersible thickening agent and/or a pH control agent. The microemulsion contains water, an oil-soluble surface active agent, a water-dispersible surface active agent, and, as a fluid loss control additive, a mixture of a wax and a second low softening point resin. The microemulsion also optionally contains an additive to prevent phase separation and/or a bactericide. Also disclosed is a method for using this composition in various well drilling, completion and treating operations.

Abstract: The reaction product of a hydroxy ether and a pentavalent phosphorus compound with a short chain and/or long chain alcohol can be employed to gel organic liquids by mixing the reaction product with an organic liquid in the presence of certain aluminum activator compounds.

Abstract: A method and composition for fracturing a subterranean formation which comprises (1) contacting a subterranean formation with an aqueous liquid comprising a propping agent and a composition containing water, acrylamide:methacrylate copolymer cross-linked with chromium (III) ion, in presence of carbonate ion, oxalate ion, and, optionally, persulfate ion, (2) applying pressure to said liquid, (3) maintaining said pressure to fracture said formation, (4) and said gel breaking within 24 hours of gel formation.

Abstract: A well acidizing or fracturing composition is prepared by adding to an aqueous acid solution or emulsion or fracturing composition, a cross-linked copolymer of a sulfonic acid-modified acrylamide and a polyvinyl cross-linking agent. The cross-linked copolymer functions as an effective fluid loss additive and/or diverting agent. From about 25 pounds to about 100 pounds of the additive is utilized per 1000 gallons of the aqueous acid solution or acid emulsion.

Abstract: In cementing a well with a thixotropic cement, such as with the portland cement/CaSO.sub.4.1/2H.sub.2 O/water slurry described in U.S. Pat. No. 3,563,313, an effective means for controlling fluid loss from the slurry is to precede the slurry with a fluid comprising water, a water soluble alkali metal compound capable of releasing a multivalent metal cation to react with the soluble silicate to form a pumpable gel, and a water dispersible cellulose compound and an inert particulate which together impart fluid loss control to the fluid. Optionally, the fluid may contain one or more of: a chelating agent for polyvalent metal cations; a weighing material; a material to minimize lost circulation, and a salt to stabilize fresh water sensitive sandstones and shales, e.g., those having a high clay content.

Abstract: Acids, particularly dilute acid solutions thickened with copolymers of dimethyl diallyl ammonium chloride and a monomer capable of postreaction after polymerization to provide branching or partial crosslinking, are useful as oil well drilling and fracturing fluids for stimulating well production.

Abstract: A water dispersible particulate organic polymer is coated with a polyvinyl lactam-containing polymeric material to provide a particulate material which is readily dispersible in aqueous solutions with a minimum of agglomeration of the water soluble polymer.

Abstract: A water dispersible particulate organic polymer is coated with a polyvinyl lactam-containing polymeric material to provide a particulate material which is readily dispersible in aqueous solutions with a minimum of agglomeration of the water soluble polymer.

Abstract: The present invention relates to a crosslinked aqueous gel for fracturing and placing propping agents within subterranean formations, said gel having a viscosity in said formations greater than about 20,000 centipoises and having pumping characteristics in turbulent flow approaching those of water.

Abstract: Alcohols, particularly anhydrous alcohols, thickened with aminomethylated polyacrylamide, used as fracturing fluids for stimulating well production.

Abstract: A water-insoluble particulate composition having controlled slow oil-solubility at temperatures in excess of 350.degree. F. is disclosed. The composition is comprised of solid particles of a homogeneous mixture of (1) polyethylene, ethylene-vinyl acetate copolymer containing about 15 to 30 weight percent vinyl acetate, or admixtures of these polymers; (2) a polyamide having a melting point of between about 400.degree. F. and 460.degree. F.; and (3) a softening agent such as a long chain aliphatic diamide having a melting point between about 280.degree. F. and 300.degree. F., or a polyterpene resin having a melting point of between 230.degree. F. and 275.degree. F. Also disclosed is a method of using this particulate composition in well drilling and treating operations where formation temperatures of 350.degree. F. or above are encountered.

Abstract: A process using discrete solid particles of polyvinyl acetate as diverting agents in acid treating subterranean geological formations penetrated by a well.

Abstract: A method for reducing the loss of fluid through the walls of a well penetrating a permeable subterranean formation during completion, workover and other operations. The method provides for the use of a fluid comprising an aqueous dispersion of finely divided, slowly oil-soluble, water-insoluble solid particles in an aqueous salt solution containing chrome lignite, hydroxyethyl cellulose and xanthan gum. The density of the fluid is controlled by varying the concentration of salt dissolved in the solution. The finely divided solid particles consist of a homogeneous solid solution of (1) wax; (2) an oil-soluble surface active glyceryl or sorbitan partial ester of a saturated higher fatty acid; and (3) a water-dispersible surface active polyethylene glycol monoester of a saturated higher fatty acid. The particles may optionally include an ethylene/vinyl acetate copolymer, and/or a fatty alcohol.

Abstract: Well drilling, completion and workover operations, hydraulic fracturing, acidizing, and other well treating operations are improved by the addition to the drilling or treating fluid of an oil-soluble, water-insoluble low fluid loss agent comprising a particulated, homogeneous solid solution of (1) wax; (2) an oil-soluble polyhydroxy higher fatty acid partial ester surface active agent; and (3) a water-dispersible surface active agent such as polyoxyethylene alkyl phenol, a polyethylene glycol higher fatty acid ester, a polyoxyethylene polyhydroxy higher fatty acid ester, a polyoxyethylene tertiary fatty amine, or a polyoxyethylene fatty amide condensate. The agent can optionally include small amounts of a polymeric material and/or a higher fatty alcohol.

Abstract: An oil-soluble, water-insoluble low fluid loss additive composition comprising a particulated, homogeneous solid solution of (1) wax; (2) an oil-soluble polyhydroxy higher fatty acid partial ester surface active agent; and (3) a water-dispersible surface active agent such as a polyoxyethylene alkyl phenol, a polyethylene glycol higher fatty acid ester, a polyoxyethylene polyhydroxy higher fatty acid ester, a polyoxyethylene tertiary fatty amine, or a polyoxyethylene fatty amide condensate. The composition can optionally include small amounts of a polymeric material and/or a higher fatty alcohol. The low fluid loss additive composition can be employed in well drilling, completion and workover operations, and in hydraulic fracturing, acidizing, and other well treating applications.

Abstract: A hydraulic fracturing method wherein a viscous oil-in-water emulsion is injected into a formation under sufficient pressure to fracture the formation. The emulsion contains from about 70 to about 90 volume percent of an internal liquid hydrocarbon phase, from about 10 to about 30 volume percent of an external aqueous phase and sufficient amounts of a nonionic surfactant to stabilize and viscosify the emulsion. The preferred hydrocarbon phase concentration is between about 75 and 85 volume percent. The nonionic surfactant also gives the emulsion a breaking temperature which is not greater than the temperature of the formation. Preferably, an electrolyte is used to adjust the temperature at which the emulsion will break. After fracturing is completed the emulsion is then left in the wellbore for a sufficient time to permit the temperature of the emulsion to reach its breaking temperature. Upon breaking, the emulsion reverts to a low viscosity fluid which is readily removable from the formation.

Abstract: Underground strata surrounding a coal seam are prestressed by repeated fracturing with a settable material to strengthen and seal the strata to contain a hydrostatic pressure in the coal seam of about 100 to about 500 atmospheres, thereby providing a gas and liquid-tight seal surrounding and within the coal seam. After the strata surrounding the coal seam and the coal seam itself are sealed, an hydrogenating agent is supplied to the coal seam and is maintained at a temperature of approximately 300 to 500 degrees centigrade and a pressure of from about 100 to about 500 atmospheres to liquefy and hydrogenate the coal in situ. When a region of coal is liquefied out to the boundary of the prestressing, the liquefied coal is pumped out for use.

Abstract: As an aqueous fracturing fluid is pumped into a well bore penetrating a subterranean formation a galactomannan gum, a buffer which promotes an initial acidic pH in the fluid, a borate ion releasing compound and a compound which functions to shift the pH of the fluid to the basic side after a certain short period of time are dispersed into the fluid. The resulting viscous fracturing fluid is employed to fracture a subterranean formation to, for example, stimulate the flow of fluids therefrom.

Abstract: Viscous aqueous solutions are prepared which maintain a certain viscosity range over a predetermined period of time (i.e., induction period) and which thereafter break, i.e., decrease in viscosity over a very short period of time. The viscous aqueous solution comprises a polysaccharide having an ability to thicken water and dispersed or dissolved in the aqueous solution an effective quantity of an organic ester which, at a temperature at which it is desired to break the viscous solution, hydrolyzes over a delayed period of time to form an acid which degrades the polysaccharide, thus causing a splitting of the polysaccharide chain and a decrease in the viscosity of the solution.

Abstract: A water-insoluble particulate composition having controlled slow oil-solubility at temperatures in excess of 350.degree. F. is disclosed. The composition is comprised of solid particles of a homogeneous mixture of (1) polyethylene, ethylene-vinyl acetate copolymer containing about 15 to 30 weight percent vinyl acetate, or admixtures of these polymers; (2) a polyamide having a melting point of between about 400.degree. and 460.degree. F.; and (3) a softening agent such as a long chain aliphatic diamide having a melting point between about 280.degree. and 300.degree. F., or a polyterpene resin having a melting point of between 230.degree. and 275.degree. F. Also disclosed is a method of using this particulate composition in well drilling and treating operations where formation temperatures of 350.degree. F. or above are encountered.

Abstract: A subterranean formation is treated by injecting into the formation an aqueous acid solution comprising a water soluble vinyl compound (preferably polyvinyl alcohol or polyvinylpyrrolidone), a natural gum (preferably guar gum or gum karaya) and finely divided particulate material (preferably silica sand).

Abstract: Well productivity is increased by multiple hydraulic fracturing cycles. A double cycle first creates a long primary fracture by fluid injection and forms spalls by subsequently allowing the pressure in the fracture to drop below the initial fracturing pressure by discontinuing injection and shutting the well in or allowing it to flow back, resuming injection to displace said spalls longitudinally in said fracture and again discontinuing injection, whereupon the fracture is propped open by the displaced spalls.Multiple applications of this double cycle successively create transversely directed secondary long fractures.