Abstract: Process for using biodegradable drilling muds, characterized in that a able surface sludge which is stable up to about 100° C., with an adjustable filtrate-reducing power of from 2 to 13 cm3 depending on the amount of filtrate-reducing agent used, and with an electrical stability of greater than or equal to 1000 volts, is introduced into the well at the start of drilling, and in that, when the temperature of the terrain passed through reaches 100° C., the surface sludge is replaced with a bottom sludge which is stable at a temperature above 200° C., the volume of the surface sludge representing from 60 to 80% by volume relative to the total volume of sludge used.

Abstract: A biodegradable drilling mud, comprising a water/organic phase reverse emulsion in a volume ratio ranging from 50/50 to 10/90, which contains: a) from 1 to 5% by volume of at least one nitrogen compound selected from the group consisting of amino acids, carbamic mono- and polyamides and mono- and polycarbamic amides, of formulae (I) and (II) respectively, taken alone or as a mixture: R—[NH—CH2]n—CO—NH2  (I) R—NH—[CO—NH]m—H  (II)  wherein R is hydrogen or an alkyl group comprising from 1 to 10 carbon atoms and n and m are integers ranging from 1 to 5, b) from 2 to 10% by volume of at least one phosphorus derivative selected from the group consisting of surfactant phosphorus compounds, and c) from 2 to 10% by volume of at least one oxygenated compound selected from the group consisting of fatty acids, fatty acid esters of fatty alcohols comprising carbon-based chains comprising from 12 to 24 carbon atoms, alone or

Abstract: Process for treating an aqueous solution of acrylamide resin, characterized in that an emulsifier which is preferably nonionic or anionic, a solution of initiator comprising an organic peroxide, preferably a diperoxide, and optionally a solution of a retarder preferably consisting of a phenol derivative or an alkali metal inorganic derivative are added slowly and with stirring, preferably in the form of a pre-emulsion, to an aqueous solution of acrylamide resin monomer.