Abstract: A process of treating a plurality of wells involved in an enhanced oil recovery process so that oil and/or gas can be displaced from a reservoir in a more uniform manner comprising treating the formation surrounding and in the immediate vicinity of each well involved in the process with a solution that sets with time to form a plug in the more permeable zones of the reservoir surrounding each well.

Abstract: An enhanced oil recovery process for subterranean reservoirs wherein there is injected into the reservoir a relatively large slug of a dilute aqueous alkali metal silicate solution. It is optional to follow the silicate solution with an aqueous drive fluid. In treating heterogeneous reservoirs, it is further optional, prior to injecting the large slug of silicate solution, to inject one or more small slugs of the silicate solution alternately with one or more small slugs of a dilute aqueous solution of an agent that reacts with the alkali metal silicate to form a gelatinous precipitate. In the latter instance a small spacer slug of water is injected between successive slugs of the reactant solutions to separate the reactants during injection.

Abstract: A process for recovering oil from a heterogeneous subterranean reservoir having strata of widely varying permeability by injecting therein via a well a slug of a micellar solution followed by an aqeuous drive fluid wherein, at some time prior to the injection to all of the slug of the micellar solution, there is injected into the reservoir one or more aqueous solutions of reagents that react in the reservoir to form a plugging material, one of which reagents contains a polyvalent cation. After the plugging material has formed, the well is produced to remove from the reservoir the unreacted reagent containing a polyvalent cation which polyvalent cation would otherwise react with and reduce the efficiency of the subsequently injected micellar solution.

Abstract: A composition and method for providing improved mobility control in secondary and tertiary recovery processes obtained by injecting into a subterranean hydrocarbon-bearing formation, as part of the secondary or tertiary recovery fluid, an aqueous solution of a mixture of a heteropolysaccharide produced by bacteria of the genus Xanthomonas together with a polyacrylamide or a chemically altered derivative of a polyacrylamide.

Abstract: A method for conducting foam drilling and workover operations in a bore hole penetrating a subterranean reservoir employing an aqueous solution of a biodegradable foaming agent composition containing about 0.3 to 3 parts by weight of an N-fatty ethyl sulfonic acid salt having the formula: ##STR1## per part by weight of an N-fatty propionic acid salt having the formula: ##STR2## wherein R and R.sub.1 are straight chain alkyl radicals having from 10 to 16 carbon atoms, and M and M.sub.1 are alkali metal or ammonium cations. A particularly preferred foaming agent composition contains sodium 2-(N-lauryl) ethyl sulfonic acid and sodium 2-(N-lauryl) propionic acid.

Abstract: A method for conducting foam drilling and workover oprations in a bore hole penetrating a subterranean reservoir employing an aqueous solution of a biodegradable foaming agent composition containing about 0.1 to 1 part by weight of an N-fatty ethyl sulfate salt having the formula: ##STR1## wherein R is a straight chain alkyl radical having from 10 to 16 carbon atoms and M is an alkali metal or ammonium cation, per part per weight of a fatty acid salt having the formula: ##STR2## wherein R.sub.1 is a straight chain alkyl radical having from 9 to 15 carbon atoms and M.sub.1 is an alkali metal or ammonium cation. A particularly preferred foaming agent composition contains sodium 2-(N-lauryl) ethyl sulfate and sodium laurate.

Abstract: A method for determining the fluid saturation, for example the hydrocarbon saturation, the residual oil saturation or water saturation, of a reservoir following a secondary recovery operation wherein there is injected into the reservoir via a well first hydrocarbons and then a secondary recovery medium to return the portion of the reservoir in the immediate vicinity of the well to the same fluid saturation as exists in the bulk of the reservoir. The reservoir is then logged with a logging instrument to determine the hydrocarbon saturation, gas saturation, residual oil and/or water saturation.

Abstract: An acid composition comprising a substantially anhydrous liquid mixture of (1) about 50 to 99 weight percent of polyphosphoric acid having about 5 to 90 weight percent of the total P.sub.2 O.sub.5 present as polymeric P.sub.2 O.sub.5, and (2) about 1 to 25 weight percent of hydrofluoric acid, and in which the H.sub.2 O/P.sub.2 O.sub.5 mole ratio of the overall acid mixture is less than 3.4; and a method for increasing the permeability of siliceous subterranean formations in which the formation is treated with this composition. Also, the composition can optionally contain a catalyst such as a strong mineral acid, a carboxylic acid, an oxidizing agent, or mixtures thereof.

Abstract: A stable, non-aqueous acid emulsion composition comprising an admixture of a substantially anhydrous polyphosphoric acid-based mixture, an organic solvent, and a surfactant; and a method for increasing the permeability of siliceous subterranean geological formations.

Abstract: A composition and method for drilling wells through subterranean strata containing high temperature aqueous fluids using a gas-containing aqueous drilling fluid containing an alkaline material to raise the pH of the drilling fluid to provide corrosion protection in the liquid phase and a volatile water-soluble nitrogen-containing compound to provide corrosion protection in the gaseous phase.

Abstract: A method and solvent composition for removing viscous crude oil, waxes, asphaltenes and resin precipitates of petroleum origin from oil wells, flow lines and pore spaces of oil-bearing formations. The solvent composition is a mixture of about 45 to about 85 volume percent of a nornally liquid aliphatic hydrocarbon boiling in the range of about 120.degree. F. to about 550.degree. F., between about 5 to 45 volume percent of a normally liquid aromatic hydrocarbon, between about 0.5 to about 6 volume percent of an ether of an aliphatic polyhydric alcohol, and between about 1 to about 15 volume percent of a lower alkyl monohydric alcohol.

Abstract: A method of conducting an enhanced oil recovery process in a subterranean reservoir wherein, as part of the process, there is injected into the reservoir as a sweep fluid a foam containing carbon dioxide, water and a foaming agent having the formula: ##STR1## wherein R is a straight chain alkyl radical having from 10 to 16 carbon atoms; and M is an alkali metal or ammonium cation, with sodium being preferred. A particularly preferred foaming agent is sodium lauryl sulfoacetate.

Abstract: Composition and method for drilling a well into a high temperature subterranean reservoir, such as one containing a geothermal fluid, wherein there is used an aqueous foam drilling fluid containing (1) water, (2) gas, (3) a foaming agent, (4) an erosion and corrosion inhibitor, (5) a water-soluble or water-dispersible carboxyalkyl cellulose ether or polyalkylene oxide polymer which both controls the fluid loss of the foam and toughens it, and, optionally, (6) a bit lubricant and/or (7) an anti-torqueing agent.

Abstract: In gas/liquid contact processes for the absorption of sulfur gas streams using alkaline, oxygen regenerated washing solutions, for example as in the Stretford process, the washing solution is treated with a soluble aldehyde to control the rate of formation of thiosulfate salts in the solution. The thiosulfate is thus oxidized to sulfate which is subsequently recovered without any substantial loss of washing solution.

Abstract: An enhanced oil recovery process for subterranean reservoirs wherein there is injected into the reservoir a relatively large slug of a dilute aqueous alkali metal silicate solution. It is optional to follow the said silicate solution with an aqueous drive fluid. In treating heterogeneous reservoirs, it is further optional to also inject a small slug of a dilute aqueous solution of an agent that reacts with the alkali metal silicate to form a gelatinous precipitate. In the latter instance a small spacer slug of water is injected between successive slugs of the reactant solutions to separate the reactants during injection.

Abstract: A method of forming a mixed plug in the more permeable zones of a subterranean reservoir of nonuniform permeability in which there is injected into the reservoir aqueous solutions of: a polymer, a material that reacts with the polymer to form a time-delayed polymer-containing plug, an alkali metal silicate and a material that reacts with the silicate to form a time-delayed silicate-containing plug. The injected solutions are either admixed at the surface prior to injection or are simultaneously injected so that a mixed polymer-silicate plug is formed in the reservoir.

Abstract: A composition and method for enhanced oil recovery utilizing an aqueous displacement fluid containing or contaminated by brine and containing a polyacrylamide or polyacrylamide derivative as a thickener and "OK Liquid" detergent.

Abstract: An apparatus and method for directing steam into selected strata of a relatively thick subterranean formation penetrated by a well. The apparatus includes an elongated housing attachable to the lower end of the well tubing, the housing having a closed lower end and a plurality of jets spaced around the sidewall thereof so as to be positioned opposite the strata to be treated. The jets direct the steam outwardly and downwardly against the formation face, causing it to preferentially enter the selected strata.

Abstract: A method for inhibiting the deposition of wax onto a solid surface from wax-containing petroleum and other wax-containing oils in contact with such solid surface comprising adding to such oils a synergistic mixture of a copolymer of ethylene and a monoethylenically unsaturated ester and one or more fatty derivatives, such as a high molecular weight alcohol, a natural wax, or a fatty acid.

Abstract: A composition and method for drilling a well into a subterranean reservoir containing a high temperature aqueous liquid which composition contains as a scale inhibitor (i) a water-soluble substituted iminodi(methylene phosphonic acid) compound having a carbon-to-phosphorus bond or a water-soluble salt thereof, (ii) a dicarboxylic acid, (iii) a lower alkyl ester or hydroxy derivative of a dicarboxylic acid, (iv) hexamethylenetetramine, (v) thiourea, or (vi) the amide reaction product of a polycarboxylic acid and an aliphatic amine, an aliphatic hydroxyl amine, or a heterocyclic nitrogen-containing compound.