Abstract: The invention relates to clay stabilizing agents for use in an alkaline water-base fluid such as a drilling mud and the use of such clay stabilizing agents in the drilling of wells. The clay stabilizing agent comprises a polyfunctional polyamine reaction product prepared by the reaction of a polyamine base reactant with urea or a dialkylcarbonate or by reaction with urea and a dialkylcarbonate. The stabilizing agent is subject to subsequent acidification to reduce the pH thereof to a value of about 7 or less. The polyamine base reactant is selected from the group consisting of an aliphatic polyamine, a polyaliphatic polyamine, a heterocyclic polyamine, an alkylalkanol polyamine and mixtures thereof. Specifically, the base reactant comprises an aliphatic polyamine selected from the group consisting of ethylenediamine, diethylenetriamine, tetraethylenetetramine, and tetraethylenepentamine and mixtures thereof.

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: 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.