Abstract: A method for reducing the permeability in a desired area of a formation wherein a solid foam is formed in situ by injecting a one phase solution into the formation. Said solution comprises an alkali metal silicate, a chemical surfactant, and an alkali metal salt of azodicarboxylic acid in an amount sufficient to produce a foam. The azodicarboxylic acid salt decomposes when the pH is reduced to less than about 12 and generates gas in an amount sufficient to form a foam which subsequently hardens. When hardened the foam reduces the permeability in a desired area.

Abstract: The invention concerns an enhanced oil recovery process improving the gas sweeping of an oil formation reservoir comprising at least one injection, through at least one injection well, either simultaneously or separately, of a plug of solution, preferably aqueous, of at least one surfactant and of a gas and/or steam plug (or "slug"), so as to form a foam.At least a portion of said reservoir is swept by said foam and the hydrocarbons are recovered through at least one producing well. The surfactant complies with the general formula R.sub.F --Y--X wherein R.sub.F is a perfluoric carbon radical, Y is a single bond or a divalent carbon radical containing at least one oxygen, sulfur and/or nitrogen atom, and X is a hydrophilic group.

Abstract: A method for recovering oil from a subterranean formation is disclosed wherein an aqueous surfactant solution is injected into the formation to reduce the mobility of gas in a gas-flooding process. The gas may include hydrocarbon gas, inert gas, carbon dioxide, and steam. The surfactant is represented by the general formula ##STR1## where R is a linear or branched chain alkyl group with n carbon atoms wherein n ranges from 0 to about 18, except that if the gas is steam n ranges from about 9 to about 30;x ranges from 0 to about 20 and y ranges from 0 to about 20, provided x+y does not exceed about 20;R' is a linear or branched chain alkyl group with m carbon atoms wherein m ranges from 0 to 4, except that if the gas is steam m ranges from 1 to 4, with the proviso that the sum of x+y+m is at least one; andeach M.sup.+ is a cation.

Abstract: A process for enhancing the recovery of oil from a subterranean oil-containing reservoir having a temperature of at least about 40.degree. C., which comprises steps for(a) injecting into an injection well in the reservoir substantially liquid CO.sub.2 and an aqueous mixture containing between about 50 and 10,000 parts per million by weight, calculated on the weight of the water, of one or more surfactants of the formulaR--(OCH.sub.2 CH.sub.2).sub.x --Zwherein R represents an alkyl group of about 8 to 16 carbon atoms, x is an integer having an average value of about 5 to 20, and Z represents either a --OCOOM formate group or a --OCH.sub.2 COOM acetate group, with M representing a mono-valent inorganic cation, to displace oil from the reservoir, and(b) recovering the displaced oil from one or more recovery wells in the reservoir.The alcohol ethoxycarboxylate surfactants utilized in this process provide excellent control over the mobility of the CO.sub.

Abstract: The invention provides a surfactant mixture, comprising a zwitterionic surfactant, a nonionic surfactant and a cationic surfactant, which forms a foamable liquid composition upon addition to aqueous media including fresh water, brines, acids and water/alcohol mixtures. The foams prepared from the foamable liquid composition have utility as fracturing fluids and well cleaning fluids.

Abstract: Oil recovery from a petroleum reservoir using a miscible gas, such as carbon dioxide, nitrogen or methane is enhanced by injecting a preformed stable foam into the reservoir. The foam composition is formed by an effective amount of an alpha olefin sulfonate (AOS) capable of forming a foam with water having a salt content similar to that in the reservoir and the miscible gas. Preferably, the alpha olefin sulfonates have from 8 to 24 carbon atoms. In a preferred form the AOS has on average a carbon content of less than about 12 carbon atoms in higher salt content brines and less than about 12 carbon atoms in lower salt content brines. Most preferably, in brines having a salt concentration of at least 10 weight percent, the AOS has on average about 10 carbon atoms; in brines having a salt concentration of from 2 to 10 weight percent the AOS has on average about 12 carbon atoms; and in brines having less than 2 weight percent salt and AOS has on average about 14 carbon atoms.

Abstract: A method and apparatus for generating foam in a well bore, the apparatus being a foam generator comprising a tubular body having a plurality of apertures circumferentially spaced about the wall thereof, the tubular body containing a choke therein disposed above said apertures as the foam generator is positioned in the well bore. The foam generator is located in a tubing string in the well bore, preferably with at least one stand of tubing between it and the area of the well bore to be treated with the foam. The liquid component of the foam, which may or may not carry solid particles such as fracturing proppants, is pumped down the well bore annulus, while the gaseous component of the foam is introduced through the tubing string.

Abstract: A method of treating wells with the use of a foam as a circulating fluid provides for the steps of generating a stable foam, circulating the foam up the well to remove loose solids and fluids from the well, injecting solvents to dissolve liquid and solid hydrocarbons, circulating a mixture of foam and mineral acid to remove ferrous salts and calcium carbonate from the well, circulating a calcium sulfate converter to remove calcium sulfate, cleaning up any residue by circulating the foam up the well. The method also provides for the use of iron chelator and corrosion inhibitor. The method has applications in stimulation of the well production, when such production becomes adversely affected by a build-up of solids, during stimulation of water injection, stimulation of a source well, treatment of a disposal well, as well as treatment of a gas producing well.

Abstract: A method of reducing the permeability of an area of a subterranean formation is disclosed. An alkali metal silicate foam is produced by injecting into the formation a solution of alkali metal silicate and a chemical surfactant, and a non-condensible gas. The foam hardens into a substantially impermeable solid. The foam may be used to reduce permeability in areas of the formation which have been steam swept during steam stimulation cycles. Thus, subsequent steam stimulation cycles will be directed to uncontacted areas of the formation.

Abstract: In a steam-foam-displacement of oil within a reservoir formation having a significant ion-exchange capacity for releasing multivalent cations, the rate of the steam foam propagation is increased by injecting a mixture of steam and a steam-foaming surfactant mixture comprising an independently effective steam-foaming sulfonate surfactant mixed with a lesser amount of an alkyl or alkylarylpolyalkoxyalkylene sulfonate cosurfactant.

Abstract: The disclosed invention is a group of steam foaming agents for injection with steam and a non-condensable gas to decrease permeability in steam swept zones and increase oil recovery. The foaming agents have the general formula:RO(R'O).sub.n R"CO.sub.2 Mwhere R is an alkyl radical, branched or linear, having from about 8 to about 24 carbon atoms in the alkyl chain, R' is ethylene, propylene or a mixture of ethylene and propylene, n has an average value of about 3 to about 11, R" is methylene or ethylene, and M is an alkali metal or ammonium ion.

Abstract: A self-breaking, foamed, oil-in-water emulsion contains a water-immiscible organic solvent for paraffins and asphaltenes, an aqueous nonformation-damaging component, an inert gas, and surface active agents selected to promote a stable foamed emulsion despite contact of the treating fluid with the hydrocarbon and aqueous environment in the reservoir. Under conditions of agitation, the treating fluid is a stable foamed emulsion which undergoes spontaneous breakdown into two liquid phases under quiescent conditions. The treating fluid is injected and/or circulated as a stable foamed emulsion to dissolve paraffin and asphaltene-containing deposits from various substrata, such as a subterranean reservoir penetrated by a well, the well itself, or an industrial vessel or conduit. When injection or circulation is stopped, the foamed emulsion spontaneously breaks down so that the treating fluid can be readily pumped from the well.

Abstract: In a steam flood oil recovery process wherein the oil-containing formation has a natural brine salinity concentration within the range of 10 to 20% by weight, sweep efficiency is improved by injecting steam until steam breakthrough occurs at the production well after which a mixture of steam, a noncondensible gas, and a surfactant comprising a C.sub.12 alpha olefin sulfonate is injected into the formation. The C.sub.12 alpha olefin sulfonate forms a stable foam with the formation oil at formation conditions that reduces the permeability of the highly permeable steam swept zones thereby diverting the steam to other portions of the formation containing unswept oil. If the formation does not contain a natural brine salinity concentration, then the salinity of the mixture of steam, noncondensible and surfactant is controlled to a concentration of about 10% by weight by adding a salt thereto.

Abstract: An improved cyclic steam injection process for recovering hydrocarbons from a subterranean formation. The process includes the use of alpha-olefin sulfonate dimer surfactants in the steam to form a foam-steam drive medium which is injected into the formation through an injection well to enhance the recovery of hydrocarbons from said well when it is in a production well mode of operation.

Abstract: A selective injection of gaseous fluid into a portion of a subterranean reservoir is improved by positioning an impedance to fluid flow in the annulus between a pipe string and a surrounding permeable-walled conduit, ensuring the presence of granular solids between the permeable-walled conduit and the reservoir, injecting the gaseous fluid through the pipe string to a point below the impedance and injecting fluid which is more viscous than the gaseous fluid down the annulus to restrict bypassing of the impedance.

Abstract: The disclosed invention is a method of injecting steam foaming agents in conjunction with steam and usually, a non-condensable gas into production wells producing a substantially high water to oil ratio. The most preferred production wells for foaming agent injection are corner production wells of flooding patterns such as inverted 5- and 9-spots, especially when the flooding pattern contains infill wells between the central injection well and the corner production wells.Although the method of injecting foaming agent, steam and usually, a non-condensable gas is effective with any foaming agent, the method works particularly well with foaming agents of the general formula:RO(R'O).sub.n R"SO.sub.

Abstract: An improved non-condensible gas injection process for recovering hydrocarbons from a subterranean formation. The process includes the use of alpha-olefin sulfonate monomer and alpha-olefin sulfonate dimer surfactants along with the gas to form a gas-foam drive medium which is injected into the formation through at least one injection well to enhance the recovery of hydrocarbons from at least one production well.

Abstract: An improved non-condensible gas injection process for recovering hydrocarbons from a subterranean formation. The process includes the use of alpha-olefin sulfonate surfactants along with the non-condensible gas to form a gas-foam drive medium which is injected into the formation through at lest one injection well to enhance the recovery of hydrocarbons from at least one production well.

Abstract: A method and apparatus are shown for treating a subsurface earth formation penetrated by a well bore. A proppant is blended with a foamable carrier to form a slurry and the slurry is pressurized to a desired pressure. A gas is added to the pressurized slurry to form a foam. Proppant is then added pneumatically to the pressurized slurry after foaming the slurry and the pressurized fluid is injected into the well bore. The proppant is fed to a manifold which is connected to a source of pressurized gas whereby the application of gas pressure to the manifold serves to blow the proppant into the pressurized foam stream. The foam containing the proppant is then injected into the well in the conventional manner to prop open the fracture.

Abstract: An improved steam injection process for recovering hydrocarbons from a subterranean formation. The process includes the use of alpha-olefin sulfonate dimer surfactants in the steam to form a foam-steam drive medium which is injected into the formation through at least one injection well to enhance the recovery of hydrocarbons from at least one production well.

Abstract: The disclosed invention is a group of novel steam foaming agents for injection with steam to decrease permeability in steam sept zones. They are effective without the coinjection on a non-condensable gas.The foaming agents have the general formula:RO(R'O).sub.n R"SO.sub.3 Mwhere R is an alkyl radical, branched or linear, having from about 15 to about 21 carbon atoms in the alkyl chain, R' is ethyl or propyl, n has an average value of about 2 to about 5, R" is ethyl, propyl, hydroxypropyl or butyl and M is an alkali metal or ammonium ion.

Abstract: The disclosed invention is a group of steam foaming agents for injection with steam and a non-condensable gas to decrease permeability in steam swept zones and increase oil recovery. The foaming agents have the general formula:RO(R'O).sub.n R"SO.sub.3 Mwhere R is an alkyl radical, branched or linear, or an alkylbenzene, alkyltoluene or alkylxylene group, having from about 8 to about 24 carbon atoms in the alkyl chain, R' is ethyl, propyl or a mixture of ethyl and propyl, n has an average value of about 1 to about 20, R" is ethyl, propyl, hydroxypropyl or butyl and M is an alkali metal or ammonium ion.

Abstract: In a steam soak oil recovery process in a heavy oil reservoir which is susceptible to gravity override, improved results are obtained by injecting the steam in the form of a steam-foam-forming mixture which has a chemical selectivity for being more mobile within the reservoir in contact with the reservoir oil than in the absence of that oil.

Abstract: A method of fracturing a subterranean formation with a stabilized foamed fracturing fluid comprising from about 30 percent to in excess of about 95 percent by volume of carbon dioxide with the remainder comprising a substantially anhydrous liquid and a selected surfactant. The foam is formed in situ by injection of a stabilized liquid-liquid emulsion containing liquid carbon dioxide into a well bore penetrating the formation. The temperature and pressure of the emulsion is controlled to maintain the carbon dioxide in the liquid phase during injection into the well bore. Thereafter, the carbon dioxide is heated by the subterranean formation to a temperature above about 88.degree. F. at which time the stabilized emulsion spontaneously forms a high quality stabilized foam.

Abstract: An improved particulate material is disclosed for use in a method for altering the permeability of a gravity override or relatively high permeability path through a subsurface earth formation resulting from fluid injection into the subsurface formation. The method includes adding selectively sized, finely divided, amorphous non-abrasive particulate material to a fluid and injecting the fluid into the gravity override or relatively high permeability path to deposit the particulate material thus altering the permeability in the override, or relatively high permeability path. The particulate material may include graphite, carbon black, clay suspensions, quartz, or other minerals reduced in size range to behave as non-abrasive amorphous material which will present a non-abrasive characteristic in injection wells and if the particulate material is produced with formation fluids from the treated formation.

Abstract: Permeable portions of a subterranean formation are temporarily plugged by driving a foam formed by interacting an aqueous surfactant solution and dense fluid carbon dioxide into the permeable portions of the formation. In an embodiment of the invention the aqueous surfactant solution and the dense fluid carbon dioxide are introduced into the formation by sequential slug injections of the foam generating compositions. In another embodiment oil is displaced from an oil-bearing underground formation by plugging more permeable portions of the formation as described above, introducing a drive fluid into the formation and producing recovered oil and drive fluid from a well penetrating the formation.

Abstract: Materials in and around a well are acidized with chemically heated, hot acid by injecting a solution of both nitrogen and heat generating reactants and a mixture of weak acid and weak acid salt that both buffers the relation and provides a weak acid acidizing solution.

Abstract: A method for packing particulate material in the annulus surrounding a liner in a subsurface well having a substantial deviation from vertical. Foam carrier fluid is employed for placing the particulate material. The geometry of the apparatus at the location where the material is to be placed is described.

Abstract: A foam generating apparatus (10) is provided for circulation of foam within a well (12) for drilling, operation or clean out. A liquid foam generating solution (38) is pressurized by a pump (48). The solution flows through a passage in a mixing tee (66). The mixing tee has a second passage which permits a pressurized gaseous aeration agent (35) to be entrained within the fluid flow. The turbulence of flow and downstream pressures permit onset of foam generation within the well. The foam consistency can be controlled by varying the pressure of the aeration agent and foam generating solution to maximize the effectiveness of the circulation. The ratio of aeration agent and fluid generating solution can also be varied.

Abstract: A method for recovering oil from a subterranean oil-bearing reservoir by steam stimulation where the reservoir includes a permeable zone and an oil-bearing strata utilizing a non-condensible, thermally insulating foam injected into the reservoir to substantially fill an expanse of the permeable zone in proximity with the portion of the oil-bearing strata to be stimulated.

Abstract: For enhanced recovery of petroleum, particularly for recovery of residual oil during conventional water-flooding, an aqueous solution of peroxide is injected into an oil-bearing formation. The concentration of peroxide in the aqueous solution ranges from about 0.1 to about 3.0 weight percent, and injection of peroxide need not be followed or accompanied by injection of alkaline solution. The aqueous peroxide solution may then be displaced toward the producing well or wells to sweep out residual oil.

Abstract: An arrangement for full hole drilling, wherein a drilling bit having a passage for drilling fluid is attached to a drill pipe string. A hole wall former is provided above the bit for closing the space between the hole walls and the drill pipe string. A container containing a plugging material is provided in the interior of the drill pipe string immediately above the bit, which is adapted to let drilling fluid between the walls of said container and said drill pipe string. The bit has an axial bore of a diameter which is greater than the inside diameter of the container and which is adapted to receive the lower end of said container.

Abstract: This invention relates to the use of silicone-induced hydrocarbon foams as well stimulants, for example as illustrated by their use in fracturing well formations, removal of paraffin in wells, removal of condensate hydrocarbons from blocked gas wells, etc.

Abstract: A well, such as an oil well, may be plugged, on command, from the well head, by activating a plurality of preplaced motor-driven, foam generating capsules causing a foam to be generated and forced into the well hole where it hardens.

Abstract: A process for producing a solid foaming agent, and a process for using the foaming agent for the removal of water from flooded gas wells is provided. The foaming agent is formed by first combining a water soluable, nonionic polyethoxylated surfactant with urea to form a solid urea adduct, and compressing the urea adduct under high pressures into a shape of size and density to enable it to drop to the bottom of a column of water existing in the well. The urea adduct is dropped into the flooded well bore and gas produced through the water generates foam which is expelled from the well with the gas flow.

Abstract: Production is initiated from a gas well which is kept from producing by the hydrostatic pressure of the liquid it contains, by injecting an aqueous liquid that contains reactants which form nitrogen gas within the wall or reservoir and displaces enough liquid out of the well to lower the hydrostatic pressure to less than the fluid pressure in the adjacent portion of the reservoir and cause fluid to flow from the reservoir to the well.

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 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: Natural gas is subjected to partial oxidation with the hot effluent from the oxidation injected into an underground formation to provide hot contact fluid, solvent liquids, and drive force for recovering oil from the formation. In one embodiment liquid product, including methanol, is recovered from the hot oxidation effluent before injection of the effluent into the underground formation.

Abstract: A method of conducting foam drilling and workover operations in a bore hole penetrating a subterranean formation, particularly a high-temperature formation such as a geothermal formation, employing an aqueous solution of a N-acyl-N-methyltaurate foaming agent having the formula: ##STR1## wherein R is a straight chain alkyl group having from 9 to 15 carbon atoms; and M is an alkali metal or ammonium cation, with sodium being preferred. A particularly preferred foaming agent is sodium N-palmitoyl-N-methyltaurate.

Abstract: Organic disulfonic acids are produced by heating a sulfonate monomer at a temperature above 110.degree.C. in the substantial absence of water. Olefin sulfonation product mixtures, hydroxyalkane sulfonic acids, alkane sultones, alkene sulfonic acids and mixtures thereof are oligomerized under these conditions.

Abstract: Organic disulfonic acids are produced by heating a sulfonate monomer at a temperature above 110.degree.C. in the substantial absence of water. Olefin sulfonation product mixtures, hydroxyalkane sulfonic acids, alkane sultones, alkene sulfonic acids and mixtures thereof are oligomerized under these conditions.

Abstract: Production is initiated from a gas well which is kept from producing by the hydrostatic pressure of the liquid it contains, by injecting an aqueous liquid that contains reactants which form nitrogen gas within the wall or reservoir and displaces enough liquid out of the well to lower the hydrostatic pressure to less than the fluid pressure in the adjacent portion of the reservoir and cause fluid to flow from the reservoir to the well.