Abstract: Liquid water loss reducing additives for use in cement slurries are provided comprised of aqueous solutions of low molecular weight carboxymethylhydroxyethylcellulose polymers. Methods of using the additives are also provided.

Abstract: An on-site, in-line process and system for recovering oil from oil-bearing subterranean formations which involves the production, modification, dilution and injection of a polymer solution, preferably consisting essentially of an aqueous solution of a partially hydrolyzed polyacrylamide, having injectivity and mobility properties capable of meeting the specific permeability requirements of substantially any subterranean formation to be achieved. The polymer solutions prepared by the process and system can be used as drive fluids for displacing oil (secondary polymer flood) in an oil-bearing formation, as mobility buffers to follow micellar dispersion floods in the conjoint presence of chemical reagents in other chemical floods (e.g., surfactant, caustic, etc.), or they can follow a water flood. The solutions can also be used to promote pipelining of high viscosity crude oil.

Abstract: A process for improving areal conformance of fluids injected into or produced from a subterranean formation via a multiwell system wherein significantly greater amounts of fluid than desired are injected into or produced from at least one well of the multiwell system than from other wells of the system. An aqueous caustic solution, an aqueous solution containing a polyvalent cation dissolved therein, and a hydrocarbon spacer separating the aqueous solutions are injected into the hydrocarbon formation. The aqueous solutions are caused to mix in the near well bore environment of said at least one well thereby forming an insoluble precipitate which reduces the permeability of the near well bore environment over substantially the entire well bore interval.

Abstract: A process for improving areal conformance of fluids injected into or produced from a subterranean formation via a multiwell system wherein significantly greater amounts of fluid than desired are injected into or produced from at least one well of the multiwell system than from other wells of the system. An aqueous caustic solution and an aqueous solution containing a polyvalent cation dissolved therein are caused to mix in the near well bore environment of said at least one well thereby forming an insoluble precipitate which reduces the permeability of the near well bore environment over substantially the entire well bore interval.

Abstract: A process for forming a compact, water-repellant, non-polluting mass of waste material which includes adding to the waste material a binder and forming a flowable, water-repellant mixture which is placed within a preselected site and hardened in place. A hardening agent can include waste, or polluted, water.

Abstract: The vertical conformance of a steam drive process is improved by conducting the steam flood process in two stages. In the first stage, steam is injected into the lower portion of the formation via an injection well and oil is recovered from the upper portion of the formation via a spaced apart production well. Once there is a breakthrough of steam at the production well, injection of steam and production are terminated. In the second stage, the roles of the injection well and production well are reversed. A thermal recovery fluid comprising steam or hot water is injected into the lower portion of the formation via the production well and oil is recovered from the lower portion of the formation via the injection well until the oil recovered contains an unfavorable amount of steam or water.

Abstract: Depleted zones or channels in in situ retorts that bypass unretorted zones can be plugged selectively by contacting the depleted zones in the in situ oil shale retort with an aqueous liquid, substantially free of a formation plugging amount of a solute, to increase the resistance of the depleted zone or channel to the passage of retorting gases.

Abstract: Oil is recovered from an oil-bearing reservoir in a process employing an in-situ combustion process utilizing a combustion-supporting gas containing at least 75% by volume pure oxygen, and preferably substantially pure oxygen, and a sequence in which the production well or wells are cyclically throttled. In place of using an in-situ combustion process, mixtures of steam and carbon dioxide or mixtures of steam and low molecular weight C.sub.3 -C.sub.8 hydrocarbons are injected into the reservoir and the production well is cyclically throttled. The production well flow rate is restricted until the bottom-hole pressure of the well has increased to an amount of about 30% to about 90% of the fluid injection pressure at the injection well. Thereafter, the production well is opened and oil is recovered therefrom as the bottom-hole pressure declines. The throttled production cycle may be repeated at appropriate intervals during the process.

Abstract: Oil is recovered from an oil-bearing reservoir in a process employing an in-situ combustion process utilizing a combustion-supporting gas containing at least 75% by volume pure oxygen, and preferably substantially pure oxygen, and a sequence in which the production well or wells are cyclically throttled. In place of using an in-situ combustion process, mixtures of steam and carbon dioxide or mixtures of steam and low molecular weight C.sub.3 -C.sub.8 hydrocarbons are injected into the reservoir and the production well is cyclically throttled. The production well flow rate is restricted until the bottom-hole pressure of the well has increased to an amount of about 30% to about 90% of the fluid injection pressure at the injection well. Thereafter, the production well is opened and oil is recovered therefrom as the bottom-hole pressure declines. The throttled production cycle may be repeated at appropriate intervals during the process.

Abstract: Discloses a method and apparatus to help provide fluid pressure in a well bore sufficient to overcome in situ earth formation pressures by perforating a circulation port through the sidewall of a drill collar above the drill bit to provide circulation of weighted drilling fluid down through the drill spring and back up the well annulus. Includes the lowering of a chemical reactant wireline perforating tool to a designated position within a drill collar, placing a single chemical flow jet into position addressing the sidewall of the drill collar, forcing the chemical reactant through the jet under high pressure and at high temperature to react with the drill collar metal and thereby remove a portion of the metal with the remaining metal defining a fluid circulation port through the drill collar wall, and pumping fluid through the port to establish circulation.

Abstract: A method of treating a hydrocarbon producing formation located downhole in a borehole, where the borehole has been cased and subsequently perforated, and the formation produces excessive water and an inadequate quantity of hydrocarbons through the perforations. Salt water is forced to flow down a tubing string, through the perforations, and out into the payzone. Thereafter, a spacer of fresh water follows the salt water, and thereafter a soluble alkali silicate solution flows behind the fresh water. Another spacer fluid of fresh water is forced to flow behind the silicate, followed by dilute acid. Next, the acid is displaced from the borehole and is forced out into the formation with flushing fluid, and the wellbore is then produced. The flow of the recited material through the perforations follows along the path of least resistance, which also is the flow path of the water intrusion. The salt water and silicate react with one another to form a barrier which prevents the water from invading the formation.

Abstract: Highly conductive zones of subterranean formations are treated with aqueous fluids containing gel-forming amounts of water-soluble basic lignins. Suitable treating fluids contain about 2 to about 8 wt. % sodium hydroxide solution. The lignin solutions gel within the formation due to reactivity with oil-water and/or the rock matrix. Alternately, following the injection of the gel-forming fluids, acidic gas is injected to cause gel formation.

Abstract: Sand grains coated with a solid non-cured epoxy resin with a softening point above 35.degree. C. are placed in a well for gravel pack, well repair or fracturing purposes. The epoxy resin softens at formation temperature and reacts with a hardener (such as a tertiary amine) diluted in water present in the pore space of the mass of sand grains. A consolidated mass of sand grains is thus obtained. The coated sand grains can be transported to the well site and stored over long periods at relatively high temperatures without risk of quality decrease.

Abstract: Sintered, spherical composite pellets or particles comprising one or more clays as a major component and bauxite, alumina, or mixtures thereof, are described, along with the process for their manufacture. The pellets may have an alumina-silica (Al.sub.2 O.sub.3 -SiO.sub.2) ratio from about 9:1 to about 1:1 by weight. The use of such pellets in hydraulic fracturing of subterranean formations is also described.

Abstract: Oil is recovered from an oil-bearing reservoir in a process employing an in-situ combustion process utilizing a combustion-supporting gas containing at least 75% by volume pure oxygen, and preferably substantially pure oxygen, and a sequence in which the production well or wells are cyclically throttled. In place of using an in-situ combustion process, mixtures of steam and carbon dioxide or mixtures of steam and low molecular weight C.sub.3 -C.sub.8 hydrocarbons are injected into the reservoir and the production well is cyclically throttled. The production well flow rate is restricted until the bottom-hole pressure of the well has increased to an amount of about 30% to about 90% of the fluid injection pressure at the injection well. Thereafter, the production well is opened and oil is recovered therefrom as the bottom-hole pressure declines. The throttled production cycle may be repeated at appropriate intervals during the process.

Abstract: Methods are provided for selectively consolidating sand grains within a subterranean formation. First an acidic salt catalyst such as ZnCl.sub.2 is injected into the subterranean formation, wherein the acidic salt catalyst is adsorbed to the surface of the sand grains. Next a polymerizable resin composition such as furfuryl alcohol oligomer is introduced into the well formation. Polymerization of the resin occurs upon exposure to the elevated well temperatures and contact with the acid salt catalyst adsorbed to the sand grains. The polymerized resin serves to consolidate the surfaces of the sand grains while retaining permeability through the pore spaces. An ester of a weak organic acid is included with the resin compositions to control the extent of a polymerization by consuming the water by-product formed during the polymerization reaction.

Abstract: A method of recovering natural gas entrapped in frozen subsurface gas hydrate formations in arctic regions. A hot supersaturated solution of CaCl.sub.2 or CaBr.sub.2, or a mixture thereof, is pumped under pressure down a wellbore and into a subsurface hydrate formation so as to hydrostatically fracture the formation. The CaCl.sub.2 /CaBr.sub.2 solution dissolves the solid hydrates and thereby releases the gas entrapped therein. Additionally, the solution contains a polymeric viscosifier, which operates to maintain in suspension finely divided crystalline CaCl.sub.2 /CaBr.sub.2 that precipitates from the supersaturated solution as it is cooled during injection into the formation.

Abstract: A method and apparatus are provided for producing gaseous hydrocarbons from formations comprising solid hydrocarbon hydrates located under either a body of land or a body of water. The vast natural resources of such hydrocarbon hydrates can thus now be economically mined. Relatively warm brine or water is brought down from an elevation above that of the hydrates through a portion of the apparatus and passes in contact with the hydrates, thus melting them. The liquid then continues up another portion of the apparatus, carrying entrained hydrocarbon vapors in the form of bubbles, which can easily be separated from the liquid. After a short startup procedure, the process and apparatus are substantially self-powered.

Abstract: An improved recovery process is provided for fluent petroleum in a porous formation having spaced injection means and production well recovery means which includes a concentrated brine drive and surfactant carrier system. By injecting an aqueous drive medium having gradually decreasing brine concentration, surfactant transport and petroleum recovery efficiency are improved. Advantageously, an effective aqueous surfactant composition is formulated containing a water-soluble ether-linked sulfonate surfactant, a cosurfactant alcohol, and at least one cosurfactant or sacrificial sulfonate material in a concentrated brine carrier.

Abstract: A method of preventing overdisplacement of propping agent particles during well treatments to hydraulically induce a fracture in a subterranean formation wherein buoyant or neutrally buoyant ball sealers are incorporated in the trailing end portion of the fracturing fluid. The ball sealers seat on at least some of the well perforations in final stages of particle injection thereby causing the surface pumping pressure to increase, signalling the end of the treating operation. This minimizes proppant overdisplacement and provides for a fully packed fracture in the near wellbore region.