Abstract: An iron control agent capable of reducing ferric iron containing compounds to ferrous iron containing compounds in an acidic solution, such as one used for formation acidizing. The iron control agent comprises a combination of a sulfur dioxide, sulfurous acid, sulfite salts, bisulfite salts, or thiosulfate salts or mixtures thereof, with a source of copper ions and a source of iodine or iodine ions. The iron control agent may also include small amounts of an adjunct such as stannous chloride, 2-mercaptoethanol, and thioglycolic acid and its salts.

Abstract: A solubilized iron reducing additive for acid solutions and method for preparing such a solubilized iron reducing additive. The additive includes an iron reducing agent reactable with ferric ions to produce therefrom ferrous ions and a spent iron reducing compound. The spent iron reducing compound is incapable of reacting with ferric ions to produce ferrous ions. So that the reducing process may continue, a regenerating agent is mixed with the iron reducing agent, the regenerating agent being reactable with the spent iron reducing compound for regenerating the spent iron reducing compound back to the iron reducing agent state. Because it has been found that the iron reducing agent and regenerating agent readily fall out of suspension as precipitates after short periods of time after mixing, a solubility facilitator is admixed thereto for facilitating establishment of the solubilized additive for acid solutions.

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: A composition for and method of treating a subterranean hydrocarbon producing formation is provided. The treatment, when conducted in the presence of ferric ions, prevents the development of insoluble ferric iron-containing compounds and also prevents the development of sludge in heavy crude.

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: Retarded acid soluble well cement compositions which set into hard substantially impermeable masses and methods of using such compositions for forming removable cement plugs or seals in subterranean zones are provided. The compositions are comprised of magnesium oxychloride cement and a set retarder comprised of a water soluble borate and a sugar.

Abstract: Retarded acid soluble well cement compositions which set into hard substantially impermeable masses and methods of using such compositions for forming removable cement plugs or seals in subterranean zones are provided. The compositions are comprised of magnesium oxychloride cement and a set retarder comprised of a water soluble borate and a sugar.

Abstract: A gelable silicate solution prepared by mixing fumed silica and an alkali metal hydroxide with water is provided. The silicate solution is used to form a seal or plug in one or more subterranean formations or in a well bore penetrating the formations by pumping the solution into a desired location in the well bore or formations and allowing the silicate solution to gel therein.

Abstract: This invention relates to a method of repairing holes, channels, voids and microannuli in a cement sheath situated in the annular space between a casing and the wall of a wellbore penetrating a subterranean earth formation, which method involves the use of a hydraulic cement consisting of discrete particles having a particle size not greater than about 30 microns. The cement, which is utilized in a water slurry, has a low density, good thixotropic properties and, in one embodiment, expansive characteristics.

Abstract: This invention relates to a method of cementing a cylinder in a bore, such as a casing in a wellbore, which method involves the use of a hydraulic cement consisting of discrete particles having a particle size not greater than about 30 microns. The cement which is utilized in a water slurry, has a low density, good thixotropic properties and, in one embodiment, expansive characteristics.

Abstract: This invention relates to a method of repairing a hole in and thereby terminating the undesirable flow of fluid through a hole in a casing disposed in a wellbore penetrating a subterranean earth formation which method involves the same use of a hydraulic cement consisting of discrete particles having a particle size not greater than about 30 microns. The cement, which is utilized in a water slurry, has a low density, good thixotropic properties and, in one embodiment, expansive characteristics.

Abstract: Set retarded cement compositions which are substantially non-thinning at high temperatures are provided. The compositions are comprised of hydraulic cement, sufficient water to form a pumpable slurry, a set retarder and a galactomannan gum which has been treated with a hydrophobing agent whereby the hydration rate of the gum is retarded at temperatures below about 120.degree. F. and at pH levels above about 10. The delayed hydration of the treated gum offsets the thinning of the cement compositions at temperatures above about 120.degree. F. Methods of cementing subterranean zones penetrated by well bores utilizing the cement compositions are also provided.

Abstract: A formation control additive is utilized in stimulation fluids to minimize formation permeability damage as a result of formation contact by the stimulation fluid. The formation control additive can comprise N-alkypyridinium halides, N,N,N-trialkylphenylammonium halides, N,N,N-trialkylbenzylammonium halides, N,N-dialkylmorpholinium halides, alkyl quaternary ammonium salt of 2 mole oligomer of epihalohydrin wherein the alkyl radical is selected from the group of methyl, ethyl, propyl and butyl radicals and compounds of the general formula: ##STR1## wherein R is independently a methyl, ethyl, propyl or butyl radical and X is a compatible anion.

Abstract: A process for treating clayey geological formations to prevent, inhibit or reduce swelling or migrating clay particles in a formation by treating the formation with an effective amount of a quaternized oligomer which comprises a methyl quaternary amine containing an average of from about 3 to about 6 moles of epihalohydrin. The treatment is effected by introducing the oligomer into the formation in an aqueous fluid which can comprise brine, salt solutions, acid solutions, gelled fluids and the like.

Abstract: The gelation testing apparatus includes a closed fluid circuit in which a sample of the substance to be tested is contained. A pressurizing device, such as a pump, is connected into the closed fluid circuit so that the pressure within the closed circuit can be changed. A pressure detecting device, such as a differential pressure transducer, is connected into the closed fluid circuit for detecting a pressure differential across the sample in response to the operation of the pressurizing device. Through the pressurizing device, the system pressure can be subjected to oscillating pressure pulses. The apparatus also can have the ability to control the temperature of the sample. This apparatus is used by placing the sample in the closed fluid circuit, creating a pressure pulse within the closed fluid circuit on one side of the sample, and detecting whether the pressure pulse is transmitted across the sample. This can be performed under controlled pressure and temperature conditions.

Abstract: A thermally responsive aqueous silicate composition consisting essentially of an aqueous solution containing an alkali metal silicate and a thermally responsive silicate gelation activator. The thermally responsive silicate gelation activator is a reducing sugar selected from the group consisting of lactose, dextrose, fructose, galactose, mannose, maltose, xylose and mixtures thereof. The aqueous silicate composition can be utilized in treating a subterranean formation for the purpose of sealing the formation.