Oil-based drilling fluid comprising a temperature-stable and non-polluting emulsifying system
AssigneesInstitut Francais du Petrole, Rhodia Chimie
InventorsChristine Dalmazzone, Annie Audibert-Hayet, Bruno Langlois, Sylvie Touzet
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Abstract
A temperature-stable, non eco-toxic oil-base well fluid that is particularly suitable for high pressure/high temperature drilling comprises an emulsification system comprising at least one superamide that may or may not be polyalkoxylated, optionally associated with a non-ionic co-surfactant. The oil-base well fluid comprising such a system can be used at temperatures of up to about 200° C. due to the production of highly temperature-stable reverse emulsions.
Claims10
A method for well drilling, completion or workover operation, comprising circulating an oil-based well fluid that is temperature-stable and particularly suitable for high pressure/high temperature drilling, comprising an aqueous phase dispersed in a non-miscible continuous phase, and comprising a liquid emulsification system comprising:
- a) at least one superamide having at least 90% by weight of at least one compound of the following formulae:
- [R1—CON(R2)—CH2CHR3—O]pX (I)
- where
- R1 represents a linear or branched, saturated or unsaturated C7-C30 hydrocarbon radical, optionally carrying at least one hydroxyl group;
- R2 represents a hydrogen atom;
- R3 represents a hydrogen atom or a C1-C4 hydrocarbon radical;
- X represents a hydrogen atom, a C1-C6 hydrocarbon radical, a phosphate, carboxylate, sulphate or sulphonate group;
- p is 1 or 2 depending on the nature of X;
- (b) and at least one co-surfactant selected from the group consisting of fatty acids, dicarboxylic acids and carboxylates,
- wherein co-surfactant b) represents from 40 to 90% by weight of the liquid emulsification system.
Dependencies are inferred from the claim text.