Abstract: Compositions containing a peroxide or peracid and an organic acid salt buffer are disclosed. The compositions are useful for removing polymers from oil and gas wells, while simultaneously dissolving encountered calcium carbonate deposits.

Abstract: A cementitious composition for cementing an oil or gas well and which exhibits when cured, increased flexural strength and a flexural strength to compressive strength ratio between from about 0.29 to about 0.80, contains a hydraulically-active cementitious material, such as Portland cement, and substantially spherical zeolite. Representative zeolites include natrolite, heulandite, analcime, chabazite, stilbite, and clinoptilolite. The weight percent of zeolite in the cement composition is generally less than or equal to 15 percent. In practice, a well bore may be cemented by pumping the activated slurry and pumping it within the well bore to a pre-selected location and allowing it to solidify.

Abstract: An aqueous organic acid composition containing a terpene as corrosion inhibitor intensifier is especially suitable for use in acidizing subterranean formations and wellbores. The composition substantially reduces the corrosive effects of the acidic solution on metals in contact with the acidic solution. Suitable terpenes include carotene, limonene, pinene, farnesene, camphor, cymene and menthol.

Abstract: A cementitious composition for cementing an oil or gas well and which exhibits, when cured, increased flexural strength and a flexural strength to compressive strength ratio between from about 0.29 to about 0.80, contains a hydraulically-active cementitious material, such as Portland cement, and substantially spherical zeolite. Representative zeolites include natrolite, heulandite, analcime, chabazite, stilbite, and clinoptilolite. The weight percent of zeolite in the cement composition is generally less than or equal to 15 percent. In practice, a well bore may be cemented by pumping the activated slurry and pumping it within the well bore to a pre-selected location and allowing it to solidify.

Abstract: A storable, hydraulically-active, cementitious slurry is made and used to cement within subterranean foundations for oil and gas wells. The slurry is made from a hydraulically-active cementitious material, a suspending agent, and, as a retarder, boric acid. The boric acid is present in the cementitious slurry in an amount sufficient to lower the pH of the storable cementitious slurry to at least 12.0, preferably to at least 11.0 or preferably, for reasons of longevity, to a pH of at least 9.0. Generally the amount of boric acid in the cementitious slurry is between from about 1 to about 6 percent by weight. Preferred as suspending agent are iota carrageenan as well as poly (methyl vinyl ether/maleic anhydride) decadiene copolymer. The slurry remains liquid during storage. The slurry is activated when needed for cementing and is pumped into the subterranean formation where it is allowed to set.

Abstract: A method of stimulating subterranean formations in oil and gas wells using a high pH buffered acid system. The method may be used to treat sandstone formations wherein the pH buffered acid system is used as the preflush or overflush or both. The method consists of introducing into the well a hydrofluoric acid containing sandstone acidizing solution either prior to or subsequent to introduction of the pH buffered acid system. The pH buffered acid system may further be used in the treatment of carbonate reservoirs. The pH of the buffered acid solution is substantially equivalent to that of the pH of the acidizing solution. The buffered acid solution is void of either hydrofluoric acid or hydrofluoric acid precursors.

Abstract: A well fracturing fluid comprising one or more anionic viscoelastic surfactants and one or more polymers is described. The fluids can contain an aqueous or non-aqueous fluid and/or a buffer for adjusting the pH of the fracturing fluid. The well service fluid can be used as a fracturing fluid in order to control water production from a well, while simultaneously increasing the oil production from the well.

Abstract: A viscous fluid is shown which is useful in treating subterranean formations. The fluid is formulated from an aqueous base, an alkyl sarcosinate surfactant and a buffer suitable for adjusting the pH of the blended fluid to a range in which the fluid is suitably viscosified. The fluid can also include an additional source of anions, such as chloride or fluoride ions, in order to increase the temperature stability of the fluid. The fluids have application for conventional well fracturing, coiled tubing fracturing, gravel packing and frac packing, as well as for use as selective water control additives and other applications.

Abstract: A viscous fluid is shown which is useful in treating subterranean formations. The fluid is formulated from an aqueous base, an alkyl sarcosinate surfactant and a buffer suitable for adjusting the pH of the blended fluid to a range in which the fluid is suitably viscosified. The fluid can also include an additional source of anions, such as chloride or fluoride ions, in order to increase the temperature stability of the fluid. The fluids have application for conventional well fracturing, coiled tubing fracturing, gravel packing and frac packing, as well as for use as selective water control additives and other applications.

Abstract: In the method of the invention, a storable hydraulically-active cementitious slurry is made and used to cement within subterranean foundations for oil and gas wells. The slurry is made from hydraulically-active, cementitious material suitable for oil field purposes and can be stored until needed. During storage, the slurry remains liquid. The slurry is activated when needed for cementing. After pumping the activated slurry into the wellbore, the set cement has properties acceptable for well cementing.

Abstract: In the method of the invention, a storable hydraulically-active cementitious slurry is made and used to cement within subterranean foundations for oil and gas wells. The slurry is made from hydraulically-active, cementitious material suitable for oil field purposes and can be stored until needed. During storage, the slurry remains liquid. The slurry is activated when needed for cementing. After pumping the activated slurry into the wellbore, the set cement has properties acceptable for well cementing.