Abstract: Described is the use of surface-active alpha-sulfofatty acid di-salts as ecologically compatible emulsifiers of the W/O type and O/W type, respectively, in fluid and pumpable drilling fluids and other fluid drilling-hole treatment agents which comprise a continuous or a dispersed oil phase together with an aqueous phase and which are suitable for an environmentally acceptable exploitation of geological resources, for example oil or natural gas deposits. The invention further relates to inverted drilling fluids based on a continuous oil phase and, present therein, a dispersed aqueous phase which, in addition to the emulsifiers, contain further conventional auxiliary agents such as thickeners, fluid-loss additives, weighting agents, water-soluble salts and/or alkali reserves.

Abstract: Well fluids such as drilling muds, especially useful in offshore drilling, are formulated with a hydrocarbon oil blend of a low viscosity poly alpha-olefin (PAO) such as a low molecular weight oligomer of decene together with a C.sub.10 to C.sub.18 paraffinic hydrocarbon of petroleum origin and a C.sub.10 to C.sub.18 olefin such as dodecene-1 or tetradecene-1. The fluids exhibit good biodegradability and are non-toxic to marine organisms; they also meet viscosity and pour points specifications for formulation into oil based muds.

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: A non-polluting dispersing agent for drilling fluids based on soft water or salt water.A dispersing agent for aqueous drilling fluids, optionally saline, belonging to the group of polymers and/or copolymers containing acid functions which is characterized in that, to ensure that these fluids retain their rheological characteristics, even under the extreme temperature and pressure conditions prevailing in deep bore holes, said dispersing agent is a salt of said polymers and/or copolymers of which the salifying cation corresponds to a metal having a Pauling electronegativity at least equal to 0.95 and preferably greater than 1.

Abstract: A non-toxic drilling fluid (drilling mud), for use in rotary-type well-drilling operations, comprises a non-toxic base-oil consisting essentially of branched-chain paraffins which may or may not contain ester functionalities, the base-oil having: (i) between about 16 and about 40 atoms per molecule, (ii) a kinematic viscosity, at 40.degree. C., of between about 1 and about 16.5 centistokes; (iii) a flash point of at least about 90.degree. C.; and (iv) a pour point of less than about -40.degree. C. Preferably, the branched-chain paraffin used as the base-oil consists essentially of the dimer of 1-decene, which has a viscosity of about 5 centistokes at 40.degree. C. and which has 20 carbon atoms per molecule. The drilling fluid can be about 100 percent base-oil or can be an emulsion of the base-oil in water, in which case the amount of base-oil is at least about 30 volume percent, and is more preferably between about 65 and about 95 volume percent.

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.