HIGH TEMPERATURE ENVIRONMENTALLY BENIGN DRILLING FLUID, AND VISCOSIFYING ADDITIVES FOR USE THEREWITH

摘要

An oil base environmentally benign drilling fluid composition having a stable high viscosity and high gel strength at use temperatures of up to at least 450 ~F. The drilling fluid includes a low toxicity biodegradable oil vehicle, and as a viscosifying agent an organoclay which is the reaction product of a mineral clay mixture and an alkyl quaternary ammonium salt. The mineral clay mixture comprises at least 50 % by weight of a mineral clay selected from the group consisting of sepiolite, palygorskite and mixtures of sepiolite and palygorskite; and substantially the balance of the mixture is a smectite. Conventional additives such as emulsifiers and fillers may also be present in the drilling fluid.