Abstract: An alkaline-reserve-free, oil-based drilling fluid is disclosed as comprising an oleaginous liquid, and an amine surfactant having the structure R-NH.sub.2, wherein R represents a C.sub.12 -C.sub.22 alkyl group or alkenyl group. Such fluid is particularly useful in the drilling of subterranean wells in which CO.sub.2, H.sub.2 S or other acidic gases which adversely effect the rheologies and other properties of the drilling fluid are encountered. The alkaline-reserve-free oil-based drilling fluid permits the logging of acidic gases which otherwise could not be logged in the presence of lime or other alkaline.

Abstract: This invention relates to drilling fluid additives that suppress clay swelling within a subterranean well and to methods for controlling clay swelling during the drilling of a subterranean well. In one embodiment trihydroxy alkyl amine is reacted with an alkyl halide or a water soluble quaternary amine to form a quaternized trihydroxy alkyl amine. The reaction products can also include condensed reaction products of quaternized trihydroxy alkyl amines. In another embodiment a choline derivative is used. The quaternized reaction products and choline derivatives are characterized by low toxicity and compatibility with anionic drilling fluid components. The products are added to water base drilling fluids which are circulated throughout a well. The drilling fluid additives and the method of controlling clay swelling provide for improved control of the rheological properties of drilling fluids along with increased environmental and drilling fluid compatibility.

Abstract: A method of removing the filter cake formed from invert emulsion compositions including an oleaginous, a non-oleaginous and an acid sensitive surfactant in an oil and gas well are disclosed. The acid sensitive surfactant is selected so that the invert emulsion can be broken and residual filter cake solids made water-wet upon the addition of an acidic wash fluid to the well.

Abstract: The present invention relates to an oil-based drilling fluid, a continuous phase for an oil-based drilling fluid, and additives for an oil-based drilling fluid. The drilling fluid, the continuous phase of the drilling fluid, and the additives for the oil-based drilling fluid are characterized by non-fluorescence (defined as a fluorescence intensity of 800 or less) when exposed to ultraviolet light. The continuous phase of the drilling fluid is composed of synthetic hydrocarbons selected from the group consisting of oligomers synthesized from one or more alphaolefins containing a C.sub.2 to C.sub.14 chain length, wherein the oligomers have an average molecular weight of from 120 to 100, and additives. The additives of the continuous phase include surfactants, wetting agents and/or emulsifiers.

Abstract: This invention relates to an improved water based drilling fluid containing a controlled cross-linked polymeric fluid loss control agent. The novel polymeric fluid loss control agent of this invention exhibits improved thermal stability and other enhanced drilling fluid additive properties. The controlled cross-linking of the polymer of this invention results from the addition of specific amounts and types of cross-linking agents.

Abstract: An essentially non-polluting, substantially non-toxic drilling fluid composition has been discovered that is particularly useful as a lubricant or spotting fluid in drilling oil and gas wells. The fluid comprises silicone which may be is mixed with an emulsifier for application in the water base mud system.

Abstract: The present invention relates to an improved continuous phase for a drilling fluid and specifically a silicone continuous phase which is non-polluting and substantially non-toxic. Preferred silicones for use in the invention are dimethylsiloxane polymers. In the drilling fluid compositions, suitable emulsifiers, wetting agents, viscosifiers, weight materials and fluid loss additives may be added in conjunction with water and/or a brine phase for desired rheological properties.

Abstract: A water based drilling fluid which is environmentally non-toxic containing a sodium alkylsufosuccinate and well drilling additives, said sodium alkylsulfosuccinate is water dispersible and imparts anti-bit balling, lubricity and environmentally non-toxicity properties to said drilling fluid and does not precipitate in the presence of the said well drilling additives.

Abstract: The present invention provides a water-based drilling fluid that reduces water adsorption and hydration of argillaceous rocks. The drilling fluid comprises a glycol with a molecular weight of less than about 200, an organic cationic material such as salts of choline or an organic salt of potassium, a filtration control agent, a viscosifier and water.

Abstract: This invention relates to drilling fluid additives that suppress clay swelling within a subterranean well and to methods for controlling clay swelling during the drilling of a subterranean well. In one embodiment trihydroxy alkyl amine is reacted with an alkyl halide or a water soluble quaternary amine to form a quaternized trihydroxy alkyl amine. The reaction products can also include condensed reaction products of quaternized trihydroxy alkyl amines. In another embodiment a choline derivative is used. The quaternized reaction products and choline derivatives are characterized by low toxicity and compatibility with anionic drilling fluid components. The products are added to water base drilling fluids which are circulated throughout a well. The drilling fluid additives and the method of controlling clay swelling provide for improved control of the rheological properties of drilling fluids along with increased environmental and drilling fluid compatibility.

Abstract: This invention relates to drilling fluid additives that suppress clay swelling within a subterranean well and to methods for controlling clay swelling during the drilling of a subterranean well. A trihydroxy alkyl amine is reacted with an alkyl halide or a water soluble quaternary amine to form a quaternized trihydroxy alkyl amine. The reaction products can also include condensed reaction products of quaternized trihydroxy alkyl amines. The quaternized reaction products are characterized by low toxicity and compatibility with anionic drilling fluid components. The products are added to water base drilling fluids which are circulated throughout a well. The drilling fluid additives and the method of controlling clay swelling provide for improved control of the rheological properties of drilling fluids along with increased environmental and drilling fluid compatibility.

Abstract: The present invention relates to an improved continuous phase for an oil based drilling fluid and specifically a synthetic hydrocarbon continuous phase which is non-polluting and minimally toxic. The invention provides excellent drilling fluid properties under a wide variety of drilling conditions. The synthetic hydrocarbons are selected from the group consisting of branched chain oligomers synthesized from one or more olefins containing a C.sub.2 to C.sub.14 chain length and wherein the oligomers have an average molecular weight of from 120 to 1000. In the drilling fluid compositions, suitable emulsifiers, wetting agents, viscosifiers, weight materials and fluid loss additives are utilized in conjunction with water and/or a brine phase for the desired rheological properties.

Abstract: This invention relates to drilling fluid additives that suppress clay swelling within a subterranean well and to methods for controlling clay swelling during the drilling of a subterranean well. Aliphatic polyamines and aliphatic acids react to form polyamides and polyamino acids that are water soluble, that have molecular weights of less than about 1000, and that have low toxicity levels. The polyamides and polyamino acids are added to water base drilling fluids which are circulated throughout a well.When X in the acid is a hydroxyl group, the polyamide products have the following general structure: ##STR1## When X in the acid is a halogen such as chlorine, the polyamino acid products have the following general structure: ##STR2## The drilling fluid additives and the method of controlling clay swelling provide for improved control of the rheological properties of drilling fluids along with an increased environmental compatibility.

Abstract: This invention relates to an improved aqueous based drilling fluid and specifically to a water soluble polymer that imparts desirable performance characteristics to the final drilling fluid. The invention also relates to the method for preparation of the polymer and drilling fluid. The water soluble polymer is especially useful in that it exhibits superior tolerance to divalent cations, salts, solids and elevated temperatures when added to aqueous drilling fluids. The polymer additive is characterized by increased viscosity at low shear rates and improved fluid loss control thereby exhibiting superior rheological and thixotropic properties. The polymer consists of reaction products of sulfonated monomers and monomers added to enhance the functional characteristics of the polymer.

Abstract: This invention relates to an improved oil-base drilling fluid composition and its use. The improved oil-base drilling fluid composition of this invention is characterized by thixotropic properties which result in a yield point of at least 4.0. The composition includes an oil-base continuous phase and a gelling composition. The gelling composition includes a latex material in combination with one or more functional monomers selected from the group consisting of amides, amines, sulfonates, monocarboxylic acids, dicarboxylic acids and combinations thereof and wherein at least one of the monomers includes a nitrogen containing material.

Abstract: On occasion, during drilling operations employing oil base drilling muds, conditions occur that cause the surface of the solid materials in the mud to be water wet, changing the rheology of the drilling mud such that it is unusable and has to be discarded. In accordance with this invention, a novel method is provided to reverse this condition so that the water wet surfaces of the solid particles become oil wet again, restoring the drilling mud to substantially its original condition or level or to such a condition that it can continue to be used in drilling operations. This is accomplished by adding to the drilling mud containing water wet particles at least one of a specific and critical group of imidazolines.The imidazolines may be added to stable oil mud drilling fluids to decrease possible water wetting of the particle surfaces therein.

Abstract: A novel ammonium salt of quebracho prepared by reacting quebracho with alkyl quaternary ammonium salts is an effective fluid loss control agent when used in oil base drilling fluids for use in drilling oil and gas wells, especially in water in oil emulsion drilling mud formulations, controlling filtrate loss of the oil-base mud under high temperature and high pressure conditions.

Abstract: A novel ammonium salt of quebracho prepared by reacting quebracho with alkyl quaternary ammonium salts is an effective fluid loss control agent when used in oil base drilling fluids for use in drilling oil and gas wells, especially in water in oil emulsion drilling mud formulations, controlling filtrate loss of the oil-base mud under high temperature and high pressure conditions.

Abstract: The present invention relates to an improved water based drilling fluid and an improved spotting fluid utilizing unhydrogenated synthetic hydrocarbon compositions which are non-polluting and minimally toxic. The invention provides excellent drilling fluid properties under a wide variety of drilling conditions. The synthetic hydrocabons are selected from the group consisting of branched chain oligomers synthesized from one or more olefins containing a C.sub.2 to C.sub.14 chain length and wherein the oligomers have an average molecular weight of from 120 to 1000. The compositions of these hydrocarbons are free of aromatics and petroleum based toxic impurities. The synthetic hydrocarbons are unhydrogenated.

Abstract: An emulsion and emulsion drilling fluid are disclosed. The emulsion has utility as an oil based drilling fluid comprising a glycol emulsified in a synthetic hydrocarbon material. The synthetic hydrocarbon material has an average molecular weight of from about 120 to 1,000 and is synthesized from one or more olefinic monomers having a chain length of C.sub.2 to C.sub.14.