Abstract: High fluid loss acid soluble lost circulation material and spotting pill comprising the lost circulation material. The spotting pill preferably is weighted to a density substantially the same as the drilling fluid used to treat the formation.

Abstract: An oil-based drilling fluid having a polymer latex capable of providing a deformable latex film on at least a portion of a subterranean sand formation has been discovered to inhibit or control fluid loss and act as a sealing agent when used to drill in sand formations for hydrocarbon recovery operations. Typically, the polymer latex is an aqueous suspension of particles formed by emulsion polymerization that is in turn emulsified into a hydrocarbon base fluid. The polymer particles of suitable size precipitate onto the pores of a subterranean sand formation to at least partial seal the formation with a deformable polymer film.

Abstract: A water-based drilling fluid having a polymer latex capable of providing a deformable latex film on at least a portion of a subterranean formation has been discovered to provide reduced drilling fluid pressure invasion when used to drill in shale formations for hydrocarbon recovery operations. A precipitating agent such as a silicate or an aluminum complex (e.g. sodium aluminate) is preferably used in conjunction with the polymer. Typically, the water present contains a salt to form a brine, often to saturation, although the invention may be practiced with fresh water. If a salt is employed, it is often helpful to additionally employ a surfactant, such as a betaine, for example.

Abstract: A brine for use during drilling operations, preferably a completion brine, comprising an amount of a low molecular weight water-soluble organic compound effective to reduce the crystallization point of the brine. The low molecular weight water soluble organic compound can be a variety of compounds, with preferred compounds being ethylene glycol, tripropylene glycol bottoms, and combinations thereof. A method of lowering the crystallization point of the brine using a low molecular weight water soluble organic compound also is provided.

Abstract: High fluid loss acid soluble lost circulation material and spotting pill comprising the lost circulation material. The spotting pill preferably is weighted to a density substantially the same as the drilling fluid used to treat the formation.

Abstract: A water-based drilling fluid having a polymer latex capable of providing a deformable latex film on at least a portion of a subterranean formation has been discovered to provide reduced drilling fluid pressure invasion when used to drill in shale formations for hydrocarbon recovery operations. A precipitating agent such as a silicate or an aluminum complex (e.g. sodium aluminate) is preferably used in conjunction with the polymer. Typically, the water present contains a salt to form a brine, often to saturation, although the invention may be practiced with fresh water. If a salt is employed, it is often helpful to additionally employ a surfactant, such as a betaine, for example.

Abstract: A drilling fluid system for use in oil and gas well drilling operations is described having a rheological modifier/control agent comprising a polyalkyl methacrylate copolymer containing a small amount of vinyl pyrrolidone, a weighting agent, optionally an organophilic clay, with a base fluid making up the balance. The drilling fluid may be oil, invert emulsion, and in particular synthetic base fluid where the continuous phase may be synthetic esters olefins, paraffins, mineral oil or diesel oil, and the like. These copolymers prevent or reduce barite sag and provide cutting transport in these drilling systems.

Abstract: The invention concerns a method for determining the presence and quantity of an amine-based additive in fluids, particularly aqueous fluids used in hydrocarbon recovery such as drilling fluids, drill-in fluids, completion fluids, and the like. It was discovered that, after isolating the amine-based additive, the amount of clay stabilizer is linearly dependent upon the spectrometric count of its peak fluorescent spectrum. The method is reproducible and is not bothered by the presence of lignosulfonate and/or lignite which interferes with conventional methods.

Abstract: A drilling, drill-in, or completion fluid comprising water as a continuous phase, said continuous phase comprising a gas hydrate inhibiting amount of a blend comprising an ethylene glycol derivative and a propylene glycol derivative. The propylene glycol derivative is present in an amount effective to inhibit hydration of shale by the water base. The density of the fluid may be reduced by substituting the blend for salt, and by increasing the amount of propylene glycol derivative in the blend. The blend preferably should comprise at least about 10 vol % of the fluid, and a preferred ratio in the blend is about 35 vol % tripropylene glycol bottoms to about 65 vol % ethylene glycol.

Abstract: The present invention provides a method for suppressing the formation of hydrates during drilling operations under conditions that are conducive to hydrate formation comprising using a water based fluid selected from the group consisting of a drilling, a drill-in, and a completion fluid, wherein said water based fluid comprises as an integral component a hydrate suppressing amount of a water-soluble organic compound having a molecular weight below about 800 and said fluid has effective rheology and fluid loss control properties.

Abstract: The present invention provides a method of preparing a fluid for use in drilling and completion operations comprising mixing a fluid comprising a salt of an alkaline earth metal with a nonionic colloid-forming material in an amount and under conditions sufficient to convert a majority of said nonionic colloid-forming material into water insoluble hydrated colloidal complexes comprising hydrated ions of said alkaline earth metal complexed with said nonionic colloid-forming material, said complexes being effective to improve a property of said fluid selected from the group consisting of rheology, fluid loss control, and a combination thereof.

Abstract: The present invention provides non-toxic, biodegradable purified paraffins which may be used as lubricants, rate of penetration enhancers, and/or spotting fluids for water-based drilling muds. When used as a spotting fluid additive, the paraffin isomers preferably are supplemented with functional additives, namely emulsifiers, viscosifiers, surfactants, and/or brine. When used as lubricants and/or rate of penetration enhancers, the paraffin isomers preferably are used alone or in combination with surfactants.

Abstract: Brine-in-glycol emulsions are shown for use as well working fluids. The fluids have a glycol external phase and a brine internal phase. The separate phases are emulsified to create an emulsion and weighted with traditional weighting agents. The external phase is soluble or dispersible in sea water when diluted upon discharge.

Abstract: Brine-in-glycol emulsions are shown for use as well working fluids. The fluids have a glycol external phase and a brine internal phase. The separate phases are emulsified to create an emulsion and weighted with traditional weighting agents. The external phase is soluble or dispersible in sea water when diluted upon discharge.

Abstract: The present invention provides a modified liquid phase drilling fluid having desirable properties of shale swelling inhibition, lubrication, and high temperature performance. The fluid does not rely on the incorporation of inorganic salts or high molecular weight water soluble polymers for control of shale swelling or shale disintegration and exhibits performance characteristics, approaching those of oil base drilling fluids, without the objectionable properties of hydrocarbon oils or its potential hazardous impact on the environment.

Abstract: The present invention provides a modified liquid phase drilling fluid having desirable properties of shale swelling inhibition, lubrication, and high temperature performance. The fluid does not rely on the incorporation of inorganic salts or high molecular weight water soluble polymers for control of shale swelling or shale disintegration and exhibits performance characteristics, approaching those of oil base drilling fluids, without the objectionable properties of hydrocarbon oils or its potential hazardous impact on the environment.

Abstract: The present invention provides a modified liquid phase drilling fluid having desirable properties of shale swelling inhibition, lubrication, and high temperature performance. The fluid is comprised of the following: (1) a liquid phase containing: (a) a water phase comprising fresh water, seawater, brine, simulated brine, or mixtures thereof; and (b) a water-soluble component selected from the class consisting of polyhydric alcohols, glycol, glycol ethers, polypropylene glycols, polyethylene glycols, ethylene oxide-propylene oxide copolymers ("EO-PO"), alcohol-initiated EO-PO copolymers and/or mixtures thereof, the ratio of said water-soluble component in the total liquid phase being from about 5% to about 50% by volume; (2) a viscosifier for suspension of solids in said liquid phase; and (3) a filtration control agent.

Abstract: The present invention relates to a filtration control additive for use in invert emulsion drilling fluids; the method of preparing such additives; the invert emulsion drilling fluid produced therefrom; and a method of drilling, completing, and working over a subterranean well, utilizing such drilling fluid containing the filtration control additive which is utilized in a water-in-oil, emulsion-type subterranean drilling fluid. The additive comprises the pyrolyzed product obtained by intermixing and heating a finely divided humic acid-containing material and a primary amine having an alkyl radical of 10 to 20 carbon atoms or a primary amine having one alkyl-substituted phenyl radical, the alkyl radical having 10 to 20 carbon atoms. The amine may also be a secondary amine having at least one alkyl radical of 8 to 20 carbon atoms.

Abstract: The present invention relates to a filtration control additive for use in invert emulsion drilling fluids; the method of preparing such additive; the invert emulsion drilling fluid produced therefrom; and a method of drilling, completing, and working over a subterranean well, utilizing such drilling fluid containing the filtration control additive which is utilized in a water-in-oil, emulsion-type subterranean drilling fluid. The additive comprises the pyrolyzed product obtained by intermixing and heating a finely divided humic acid-containing material and a primary amine having an alkyl radical of 10 to 20 carbon atoms or a primary amine having one alkyl-substituted phenyl radical, the alkyl radical having 10 to 20 carbon atoms. The amine may also be a secondary amine having at least one alkyl radical of 8 to 20 carbon atoms.

Abstract: The present invention relates to a surfactant for use in invert emulsion drilling fluids, the invert emulsion drilling fluid produced therefrom, and a method of drilling, completing and working over a subterranean well utilizing said drilling fluid. The drilling fluid comprises an emulsion formed by producing a diamide having from between about 20 mole percent and about 35 mole percent of a polyamine, and from between about 30 mole percent and about 70 mole percent of a fatty acid having from between about 6 to about 20 carbon atoms therein, the diamide thereafter being further reacted with from between about 15 mole percent and about 35 mole percent of a tricarboxylic acid. The total amine value of said oligamide being from between about 10 to about 30, and the acid value of said oligamide being from between about 26 to about 46. When the surfactant is diluted to about 70 w/w percent concentration with a suitable solvent, the ES.sub.