Abstract: A method for recovering petroleum from a subterranean petroleum formation penetrated by at least one well in fluid communication with the formation, by a cyclic carbon dioxide injection procedure comprising injecting carbon dioxide into the well followed by a soak period, followed by a production of oil from the formation, wherein the improvement comprises introducing a predetermined quantity of hydrocarbon such as high API gravity crude oil, naphtha, kerosene, gasoline or aromatic solvent which will remain liquid at the temperature of the formation into the formation immediately after introducing the carbon dioxide slug and before the soak and production steps, to dissolve high molecular weight fraction of the crude oil left in the flow channels of the formation, which are recovered from the formation in the production phase. The volume of solvent use is sufficient to fill the well and saturate the formation for a distance of from 4 to 10 feet into the formation.

Abstract: Scale deposition is inhibited with a new scale inhibitor precipitation squeeze method wherein inhibitor solution is injected at a higher first pH into a subsurface brine producing formation. Thereafter, the solution is subjected to a fluid or substance which lowers the higher first pH of the scale inhibitor solution to a lower second pH, thereby causing precipitation of scale inhibitor in the formation. The scale inhibitor is characterized by the fact that the scale inhibitor exhibits a significant solubility decrease between the higher first pH and the lower second pH. The method of this invention, therefore, is based on decreasing the pH the scale inhibitor solution to deposit the scale inhibitor and does not use prior art divalent cation precipitation methods to precipitate inhibitors. This invention lessens the chances of formation damage or plugging. The preferred scale inhibitors are the amine phosphonates of a given general structure.

Abstract: The accumulation of inorganic mineral scale such as barium sulfate in oil field formations and/or production equipment is inhibited by adding to formation fluid or produced fluid a scale formation inhibitory amount of a polyalkoxy sulfonate of the general formula(RO[R'O].sub.x (CH.sub.2).sub.y SO.sub.3).sub.z Mwherein R is a hydrophobe, R'O is a C.sub.2 H.sub.4 O or a C.sub.3 H.sub.6 O group or some combination thereof, M is a monovalent or divalet cation, x is 2 to 10, y is 0 to about 4 and z is 1 or 2.

Abstract: The present invention relates to a composition for preventing deposition of inorganic salts. The composition incorporates 0.1-4.5% by weight and 1,3-diaminopropanol-2 and/or of a derivative of 1,3-diaminopropanol-2 of the general formula: ##STR1## wherein n=2 to 20, 5.0-50.0% by weight of a phosphonomethylated derivative of 1,3-diaminopropanol-2 in the form of a salt of an alkali metal and/or ammonium salt of the general formula: ##STR2## wherein n=1 to 20, M is an alkali metal or NH.sub.4, 3.0-12.0% by weight of an alkali metal chloride, ammonium chloride or a mixture of both and water to 100%. The composition effectively prevents scaling of inorganic salts, e.g. barium sulphate, calcium sulphate and calcium carbonate.

Abstract: The present invention relates to a composition for preventing deposition of inorganic salts. It comprises 5.0-50.0% by weight of a phosphonomethylated derivative of 1,3-diaminopropanol-2 of the general formula: ##STR1## wherein n=1 to 20; 5.0 to 10.0% by weight of 1,3-diaminopropanol-2 and/or a derivative of 1,3-diaminopropanol-2 of the general formula: ##STR2## wherein n=1 to 20; 3.0-30.0% by weight of hydrochloric acid, 3.0-7.0% by weight of an alkali metal chloride, 0.5-2.5% by weight of a product of interaction of benzyl chloride, chlorobenzyl chloride, benzylidene chloride or a mixture of these chlorinated compounds with hexamethylenetetramine at a molar ratio thereof equal to 1:0.25-0.45 respectively; 0.5-4.0% by weight of a water-soluble organic solvent and water being the balance. The protective effect of the composition against deposition of inorganic salts is as high as 100%. The freezing point is as low as -100.degree. C.

Abstract: There is provided a method for treating a subsurface oil field formation penetrated by an oil-producing well bore comprising: injecting into said formation an emulsified, oil soluble polymeric composition of a polymer.

Abstract: A composition is provided which, when applied to a metal surface, forms a corrosion-inhibiting film thereon. The composition comprises an amine, a hydrocarbon or alcohol diluent and carbon dioxide. The composition can be prepared by pressuring carbon dioxide gas into a solution of the amine. The composition is particularly useful in the treatment of down-well metal surfaces in oil and gas wells to inhibit the corrosion of the metal.

Abstract: A method for removing scale and inhibiting the formation of scale in a well penetrating a subterranean formation for the production of fluids from the formation, the method comprising;(a) injecting an aqueous solution of EDTA into the well in an amount and for a time effective to remove scale from the well; and,(b) injecting a scale inhibitor through the well and into the subterranean formation surrounding the well.

Abstract: Step declines in the production rate from a well following an acid treatment, and a scale inhibitor treatment are reversed by use of an EDTA treatment.

Abstract: A method for treating a hot water-containing fluid stream passing through a conduit, under conditions of temperature and pressure whereupon at least a portion of the water flashes to steam, to inhibit the formation of scale deposited on the conduit and/or dissolve any such scale already formed, and to inhibit corrosion of the conduit wherein there is added to the fluid stream an effective amount of a solution of a water-soluble compound which provides a nitrogen-containing cation capable of flashing to become a gas at high temperatures selected from the group consisting of ammonium halides, ammonium salts of inorganic acids, ammonium salts of organic acids, ammonium salts of alpha hydroxy organic acids, quaternary ammonium halides, quaternary ammonium salts of inorganic acids, quaternary ammonium salts of organic acids, amine salts of inorganic acids, amine salts of organic acids and amides. Optionally the solution or dispersion also contains a water-soluble or dispersible polymer and/or a buffering agent.

Abstract: Gas is yielded and may be subsequently withdrawn from a subsurface formation of hydrocarbon material by passing a controlled amount of current from a direct source through the formation. The gas produced by this process has a high quality Btu content and is produced, in situ, under relatively moderate operating conditions. Furthermore, the gas yielded by this method has a reduced amount of hydrogen sulfide present therein.

Abstract: Microcapsules containing a gas hydrate inhibitor, such as a glycol, are suspended in a carrier fluid and injected directly into a gas-bearing formation via a producing well. The microcapsules release the hydrate inhibitor in situ at varying rates to provide a relatively continuous flow of inhibitor into the produced gas-water mixture over a long period of time.

Abstract: The scaling of a production well in a clay-containing reservoir is inhibited by injecting a scale inhibitor dissolved in an aqueous solution having a pH and ratio of monovalent-to-multivalent cations such that multivalent cation salts of the inhibitor are precipitated as a result of a cation-exchange within the reservoir.

Abstract: The scaling of a producing well is inhibited by injecting a self-reacting alkaline aqueous solution of a pH-lowering reactant, a compound containing scale-inhibiting anions and a compound containing multivalent cations, which solution subsequently precipitates a slightly soluble scale inhibitor within the reservoir.

Abstract: Barium sulfate scale is dissolved by contacting it with an aqueous solution of: a bicyclic macrocyclic polyether in which the intramolecular cavity or cript is preferentially receptive to the cations of alkaline earth metals, at least a catalytically effective proportion of an alkali metal salt of an organic acid, and enough dissolved alkaline inorganic alkali metal or ammonium compound to provide a solution pH of at least about 8.

Abstract: A method for reducing the relative water/petroleum movement in a reservoir wherein there is injected a slug of an oil containing both an oil-soluble thickening agent and a suspension of a solid particulate water-soluble thickening agent.

Abstract: This invention relates to the recovery of oil from underground deposits. The invention relates to novel gel compositions consisting of water, a polysaccharide polymer, an acid generating salt and a melamine resin. The invention also relates to the method of utilizing said composition to recovery underground oil.

Abstract: A method for shutting off or decreasing the production of water from an oil well. An oil well producing excess water is taken off production and a gas is injected into the well, followed by a slug of clean oil containing an emulsifier. The well is then produced as fast as possible. The previously injected gas and water in water-producing zones begin to finger back through the oil slug and forms a viscous emulsion which blocks the further flow of water into the producing well.

Abstract: A method of inhibiting the formation of scale from aqueous solutions containing scale-forming ions at temperatures of up to 400.degree. F. and above during production and utilization of such aqueous solutions comprising adding to the solutions certain amines, amides, thioamides, carboxylic acids or amide reaction products of carboxylic acids and various amines.

Abstract: A barium sulfate scale or solid can be dissolved economically by flowing a stream of relatively dilute aqueous solution of aminopolyacetic acid salt chelating agent into contact with and along the surfaces of the scale while correlating the composition and flow rate of the solution so that each portion of solution contains an amount of chelant effective for dissolving barium sulfate and the upstream portions of the scale are contacted by portions of the solution which are unsaturated regarding the barium-chelant complex.

Abstract: A method of inhibiting the formation of scale from aqueous solutions containing scale-forming ions at temperatures of 400.degree. F. and above during production and utilization of such aqueous solutions comprising adding to the solutions certain substituted iminodi(methylene phosphonic acid) compounds or a water-soluble salt thereof.