Abstract: A method for tagging an oil so that subsequently it may be identified as to source by incorporating into the oil as a tracer material a minor amount of certain halohydrocarbons or halocarbons, utilizing the so-tagged oil in any desired manner wherein control of the oil is at least temporarily lost, and thereafter analyzing an oil suspected to contain at least a portion of the so-tagged oil for the presence of the tracer material by gas chromatography, using a pulsed election capture detector.

Abstract: A method for placing a perforated liner in a well penetrating a reservoir containing a high pressure fluid, for example, a geothermal fluid. The holes in one or more sections of a preperforated liner are temporarily closed by inserting therein hollow plugs having an open flange end at the outer surface of the liner and a closed end projecting into the bore of the liner. The lower end of a first section of liner is also closed as with a solid plug. The liner, made up of one or more of the above-described sections which have been joined together, is run into the well through a pressure sealing device at the wellhead, such as a stripper rubber or rotating head. When the liner has been properly positioned in the well, a cutting or scraping tool is run down the inside of the liner to remove the closed end of each plug projecting into the liner, thus opening the perforations in the liner. Reservoir fluids can be produced through the well around the outside of the liner while the liner is being placed.

Abstract: A method for treating formations which contain particulate fines to decrease movement of or swelling of the fines when a fluid passes through the formation, thus maintaining the permeability of the formation, comprising injecting into the formation an organosilane or an ester of an organosilane, preferably in a hydrocarbon carrier liquid.

Abstract: The permeability of subterranean hydrocarbon-producing reservoirs is increased by introducing therein a mixture containing a tertiary carboxylic acid alkylated amide and a glycol ether in combination with an aqueous solution of an acid and, optionally, including a water-soluble polymer, preferably a nitrogen-containing polymer.

Abstract: Subterranean reservoirs having temperatures above about 250.degree. F. are acidized by atomizing an acid precursor in an anhydrous gas to form a mist, mixing the mist with water in the borehole of a well penetrating the reservoir to form a treating fluid comprising a dispersion of fine particles of acid precursor and anhydrous gas in water, and injecting the treating fluid into the reservoir. The acid precursors are normally liquid halogenated hydrocarbons which hydrolyze in the presence of water to generate a hydrohalic acid.

Abstract: A method for acidizing siliceous subterranean formations wherein the acidizing composition penetrates the formation to a greater extent before spending comprising injecting into the formation first an organosilane or an ester of an organosilane, preferably in a hydrocarbon carrier liquid, and thereafter an aqueous acidizing composition containing (1) a non-oxidizing mineral acid, acid precursor, low molecular weight organic acid or halogenated derivative thereof, and (2) a fluorine-containing acid or salt.

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: A method for inhibiting the dissolution of silica from the matrix around a well during injection of steam into the matrix by adding to the feedwater used to generate the steam or the steam itself an inhibitor comprising an ammonium or substituted ammonium compound selected from the group consisting of ammonium halides, ammonium salts of inorganic acids, ammonium salts of carboxylic acids, quaternary ammonium halides, and amine or substituted amine hydrochlorides.

Abstract: A method for selectively reducing the permeability of the higher permeability zones of a subterranean reservoir having heterogeneous permeability, such permeability reduction occurring a substantial distance away from a well in which there is injected into the reservoir an aqueous solution or solutions of a water-soluble polymer, a material capable under certain conditions of at least partially cross-linking the polymer to form a gelatinous precipitate, and a water-soluble alkaline material in an amount sufficient to maintain the pH of the polymer-containing composition above about 9 until the composition has passed a substantial distance through the reservoir.

Abstract: A method for capping an idle geothermal steam well so as to prevent hydrogen sulfide emissions and well damage due to steam condensation includes replacing geothermal steam in a well borehole with gas, perferably an inert gas such as nitrogen, and sealing the well at the wellhead. Thereafter additional quantities of the gas are bled into the well borehole at a rate that substantially prevents steam condensation in the borehole. The method includes purging the well bore with air sufficiently to assure all steam is swept out of the well before the gas is introduced.

Abstract: A process for stabilizing silica-rich geothermal brine to prevent silica scaling comprises selectively providing a supply of ferric ions, allowing the silica-rich brine to combine with the ferric ions to form insoluble, iron-rich siliceous material and separating the insoluble siliceous material from the brine to form a brine having a silica content which is reduced below the saturation level required for substantially scale-free handling of the brine. In one embodiment of the process in which the brine contains sufficient dissolved ferrous ions, the process comprises selectively contacting the brine with an oxidizing agent, preferably by aerating the brine, to oxidize a selected portion of the ferrous ions to ferric ions, which then combine with silica to form the insoluble iron-rich siliceous material. The ferric ion content of an iron-deficient brine may be augmented by adding ferric and/or ferrous ions to the brine.

Abstract: A composition and method for reducing the pour point of syncrude, such as those from oil shale, tar sands, oil-impregnated diatomite ore, or coal, by adding thereto an effective amount of a nitrogen-containing compound such as ammonia, ammonium hydroxide or a primary, secondary or tertiary water-soluble aliphatic amine or alkanolamine having one or more alkyl groups containing 1 to 4 carbon atoms.

Abstract: Cementing casing in an offshore well by displacing a drilling fluid with a settable cement slurry wherein there is injected into the annulus between the sidewall of the well and the casing ahead of the cement slurry a slug of a visually identifiable marker fluid containing cement, water, particulate carbon black, coal dust, and a surface active agent; visually observing when the fluid being displaced from the annulus changes from drilling fluid to marker fluid, and shutting in the well to allow the cement slurry to set.

Abstract: A method for the enhanced recovery of oil from subterranean reservoirs having connate water containing dissolved divalent metal cations wherein there is injected via an injection well a slug of an aqueous solution containing a water-soluble alkaline material and an aminopolycarboxylic acid or a salt thereof as a chelating agent followed by an aqueous drive fluid while producing fluids from the reservoir via a production well.

Abstract: A method for restricting fluid flow in depth outwardly from the bore hole through the medium to high permeable zones of a subterranean reservoir of nonuniform permeability in which there is injected into the reservoir aqueous solutions of a water-soluble polymer and an alkali metal silicate. The injected solutions are either admixed at the surface prior to injection, simultaneously injected or injected sequentially.

Abstract: A method for conducting foam drilling and workover operations in a bore hole penetrating a subterranean reservoir, particularly a high-temperature reservoir such as a geothermal reservoir, employing an aqueous foaming solution of about 0.08 to 1.0 percent by weight of an amphoteric betaine, about 0.02 to 0.4 percent by weight of a salt of a linear aliphatic or alkyl aryl hydrocarbon sulfonate, and, optionally, from 0.03 to 3.5 percent by weight unneutralized ammonia.

Abstract: A method of acidizing and/or fracturing a subterranean reservoir with a minimum of damage to the reservoir by the displacement fluid used to displace the acidizing or fracturing fluid into the reservoir and by the fluid used to kill the well wherein a restriction means having a seat for a closure means is located in a well conduit above a point of fluid entry into the reservoir, a slug of acidizing and/or fracturing fluid is injected into the reservoir, a slug of displacement fluid containing the closure means is injected down the well conduit, and a slug of weighted kill fluid is injected down the well conduit, said injection continuing until the closure means seats in the seat.

Abstract: A non-damaging variable-density low fluid loss well completion and workover fluid composition which is a dispersion of finely divided slowly oil-soluble, water-insoluble solid particulate matter in a thickened aqueous salt solution. The fluid composition is a mixture of an aqueous solution of a water-soluble inorganic salt, a first high softening point resin fluid loss control additive, a microemulsion fluid loss control additive, and, optionally, a water-dispersible thickening agent and/or a pH control agent. The microemulsion contains water, an oil-soluble surface active agent, a water-dispersible surface active agent, and, as a fluid loss control additive, a mixture of a wax and a second low softening point resin. The microemulsion also optionally contains an additive to prevent phase separation and/or a bactericide. Also disclosed is a method for using this composition in various well drilling, completion and treating operations.

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: An apparatus and method for handling a fluid stream containing gas, liquid and solid particulate matter, which fluid stream issues from a conduit at a high velocity, such as from a geothermal well during the drilling, producing, testing or treating of the well. The fluid is passed first through an expansion conduit comprising a series of axially-aligned sections of increasing cross-sectional area and then through a vertical separator for particulate matter and noxious materials. Means is provided for injecting a treating material into either the conduit leading from the well to the expansion-conduit, the expansion conduit or the vertical separator.