Abstract: Set retarded cement compositions for cementing across a zone or zones in a well having enhanced compressive strength and rapid gel strength development after placement. The cement compositions are comprised of hydraulic cement, sufficient fresh water to form a pumpable slurry, a set retarder comprising a copolymer of 2-acrylamido, 2-methylpropane sulfonic acid and acrylic acid having a average molecular weight below about 5000 and any other desired additives. Methods of cementing utilizing the cement composition also are provided.

Abstract: The invention relates to pharmaceutical compositions containing novel nitrate esters, of which it was found that they are useful for the treatment of ischemiatic heart diseases, decompensatio cordis, myocardial infarction and hypertension.

Abstract: A process for preparing an explosive comprising contacting a ketone with a compound capable of producing a product, or compound, containing nitro groups for a time sufficient to obtain a product having a high-energy content and the product resulting therefrom.

Abstract: The present invention relates to a process and compositions for delaying the gelling of vinyl monomers in an aqueous medium in the presence of a polymerization initiator, by employing a polymerization inhibitor consisting of an N-nitrosophenylamine salt in combination with an aminocarboxylic acid. The composition is used for plugging circulation losses when drilling at great depth.

Abstract: The present invention provides pharmaceutical compositions effective against angina-like heart and circulatory diseases containing at least one nitroxyalkylamine derivative of the general formula: ##STR1## wherein R.sub.1 is a hydrogen atom, a lower-alkyl radical, a C.sub.3 -C.sub.8 -cycloalkyl or C.sub.3 -C.sub.8 -cycloalkenyl radical, an aminocarbonyl, C.sub.1 -C.sub.6 -mono- or di-alkylaminocarbonyl radical, R.sup.2 is a hydrogen atom, a lower-alkyl radical or a C.sub.3 -C.sub.8 -cycloalkyl or cycloalkenyl radical or R.sup.2, together with R.sup.1 and the nitrogen atom to which they are attached, form a heteroaliphatic ring containing up to 6 carbon atoms, A is a valency bond or a straight-chained or branched lower-alkylene radical, in which a --CH.sub.2 -- group can be replaced by a cycloalkylene radical, B is a lower-alkylene radical, in which a --CH.sub.2 -- group can be replaced by a cycloalkylene radical and X is an --NR.sup.3 --CO-- or --CO--NR.sup.3 -- radical, in which R.sup.

Abstract: An aqueous fluid for treating underground, carbon dioxide-containing formations penetrated by casing regions of a wellbore, prior to the cementing of casings into the wellbore, comprises: (i) water, (ii) an agent which substantially increases (preferably by at least about 50 percent) the solubility of lime in water, and (iii) lime in an amount at least about saturating the water in the fluid. The lime in the treatment fluid reacts with carbon dioxide in penetrated formations to produce insoluble calcium carbonate, which blocks pores in the formations. Insoluble calcium hydroxide, formed by reaction of the lime with the water in the treatment fluid, deposits as an insoluble filter cake on the walls of the borehole where the fluid penetrates formations. The calcium hydroxide filter cake may react with the carbon dioxide to form additional calcium carbonate which helps the filter cake form a tight, impermeable barrier at the borehole.

Abstract: A concentrate which forms an acid internal microemulsion well treatment composition when added to an acid treatment fluid. The concentrate comprises in the range of from about 20% to about 98% by weight of a hydrocarbon carrier fluid, in the range of from about 1% to about 50% by weight of an alkyl alcohol having from 4 to 18 carbon atoms and in the range of from about 1% to about 50% by weight of an emulsifying agent comprising at least one compound selected from the group consisting of sulfate esters, phosphate esters, alkyl aromatic sulfonic acids, amine salts having ester or amide linkages, quaternary ammonium compounds having ester of amide linkages, propoxylated fatty acids, and propoxylated alcohols. Also disclosed are an acid internal microemulsion well treatment composition and a method of treating a subterranean formation to increase the production of hydrocarbons therefrom.

Abstract: In treating oil well down hole bores, a method of treating subterranean formations by fracturing by utilization of a fluid loss additive (FLA) comprising starch or a mixture of natural and modified starches plus an enzyme which degrades the alpha linkage of starch and does not the degrade the beta linkage of guar and modified guar where used as a viscosity modifier. Natural/modified starches are utilized in a preferred ratio of 3:7 to 7:3 or 1:9 to 9:1 with optimum at 1:1, and the mix is used in the dry form for application from the surface down the bore hole.

Abstract: An additive for reducing the water loss and improving other properties of well treating fluids in high temperature subterranean environments and well treating fluids including the additive are provided. The additive comprises a mixture of a water soluble polymer and an organic compound, the water soluble polymer being comprised of N-vinyl lactam monomers, or vinyl-containing sulfonate monomers, or both. The organic compound can be selected from lignites, tannins, asphaltic materials, derivatives thereof and mixtures of such dispersants.

Abstract: Nitrobenzenes are prepared by nitrating benzenes in vapor phase using nitric acid as a nitrating agent and under continuous or intermittent feeding of sulfuric acid as a catalyst in the presence of a catalyst comprising sulfuric acid supported on a carrier or in the presence of only a carrier. This process can provide very high and prolonged nitration activity.

Abstract: An additive for well servicing fluids containing a partially hydrolyzed acrylamide for use in downhole environments having a high calcium ion content comprising an alkali metal bicarbonate, a water-soluble carboxylic acid and a copolymer of acrylamide, an acrylic acid and 2-acrylamido-2-methylpropanesulfonic acid, the additive being used to formulate aqueous well servicing fluids, particularly drilling fluids, and for a method of treating an aqueous well servicing fluid containing partially hydrolyzed acrylamide to prevent unwanted reactions between calcium ions and the partially hydrolyzed polyacrylamide.

Abstract: Drilling mud additives based on a polymer mixture of 20 to 80% by weight carboxymethyl cellulose and 80 to 20% by weight of a polycarboxylic acid selected from polyacrylate, polymethacrylate and/or copolymers thereof and/or salts thereof, in which the carboxymethyl cellulose, which has been obtained from raw linters and/or wood cellulose by the slurry process, is mixed in wet, alcohol-moist form with the polycarboxylic acid and dried, to their use in drilling muds or workover and packer liquids, and to a process for their production.

Abstract: An aqueous polymeric gel-forming composition of improved stability for selectively plugging highly permeable zones in subterranean oil-bearing formations. The composition comprises an aqueous solution of a water-dispersible polymer present in a viscosifying amount, a crosslinking agent present in an amount sufficient to cause gelation and a stabilizing agent in an amount effective to reduce syneresis of the gelled composition.

Abstract: A water soluble polymer which is characterized by the formula: ##STR1## wherein x is 50 mole percent or 662/3 mole percent or 75 mole percent and y+z is 50 mole percent, when x is 50 mole percent, y+z is 331/3 mole percent, when x is 662/3 mole percent, and y+z is 25 mole percent, when x is 75 mole percent, wherein the molar ratio of y to z is about 100:1 to 1:100, and M.sup.+ is hydrogen or a metal cation selected from the group consisting of lead, aluminum, iron and Groups IA, IIA, IB and IIB of the Periodic Table of Elements and the level of sulfonation based upon the styrene monomer is about 75 to about 100 mole percent.

Abstract: Disclosed is a method for selectively separating 2-nitrosophenol from an isomeric mixture containing 2-nitrosophenol and 4-nitrosophenol by contacting the mixture with an organic solvent so as to preferentially dissolve the 2-nitrosophenol from the mixture.

Abstract: A composition of matter wherein amino resins such as melamine formaldehyde ("MF") resins co-gel and crosslink with polymers useful for profile control where said polymers have amine, amide, hydroxyl and thiol functionalities. Resulting gels are useful as permeability control agents for high temperature reservoirs during a water-flooding operation.

Abstract: The present invention relates to a process for purifying an aromatic nitration product mixture comprising a nitrated aromatic compound, water, and nitric or sulfuric acid which comprises without regard to sequence: (a) removing at least a portion of said water from said product mixture by contacting and reacting said water in said mixture with magnesium nitrate trihydrate to form magnesium nitrate pentahydrate or magnesium nitrate hexahydrate and removing said magnesium nitrate pentahydrate or magnesium nitrate hexahydrate from said nitrated aromatic compound in said product mixture, and (b) removing at least a portion of said acid from said product mixture by contacting and reacting said acid with an ionic or non-ionic absorbent to form a reacted absorbent and removing said reacted absorbent from said nitrated aromatic compound in said product mixture.

Abstract: A fluid loss control additive for aqueous fracturing media including a blend of two or more modified starches or a blend of one or more natural starches with one or more modified starches.

Abstract: The invention relates to hydraulic fracturing of geological formations at selected levels of wells drilled for recovery of hydrocarbons. It resides in the addition of relatively small quantities of a bacterial cellulose to hydraulic fracturing fluids to improve their rheological properties. Proppant suspension is markedly improved and friction loss through well casings is significantly reduced, resulting in lower pumping energy requirements. Computer models also indicate that formation fractures will also be propagated for greater distances as will the propped portion of the fracture. Normally only about 5-15 lb of bacterial cellulose per 1000 gallons (0.60-1.8 g/L) of fracturing fluid is needed. A preferred bacterial cellulose is one made in agitated fermenters using mutation resistant strains of a bacterium from the genus Acetobacter.

Abstract: A device for measuring the activity of carbonate ions and hydrogen ions comprises a carbonate ion selective electrode pair and a hydrogen ion selective electrode pair. Each ion selective electrode comprises a metal layer, metal halide layer and ion selective layer superposed in this order. A porous bridge is disposed so as to achieve a liquid junction between the ion selective electrodes of each electrode pair.