Patent ID: 6426321
Filing Date: 2002-07-30
Classification: C09K

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: Râ€”[NHâ€”CH2]nâ€”COâ€”NH2â€ƒâ€ƒ(I) Râ€”NHâ€”[COâ€”NH]mâ€”Hâ€ƒâ€ƒ(II) â€ƒwherein 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 as a mixture, and plant or animal oils, the percentages by volume being relative to the volume of the organic phase without additives, and comprising weighting additives, viscosifying additives, a filtrate reducer, emulsifiers and optionally alkaline agents, which contribute the desired physicochemical properties to the drilling mud.