一种环保油基钻井液体系

针对目前油基钻井液存在因所含矿物油和处理剂的生物毒性大，而被限制或禁止排放的问题，制备出生物毒性低的油基钻井液基油，合成高效低毒的一体化乳化剂和新型高凝胶改性有机土，并对钻井液处理剂及加量进行优选，最终形成了一套环保型油基钻井液体系。该钻井液体系的生物毒性LC₅₀达到15 000 mg/L以上，生物可降解性好；体系的流变性良好，破乳电压达到800 V以上，高温高压滤失量小于6 mL；钻井液体系能抗5%石膏、5%钻屑和15%盐水污染；该油基钻井液应用性良好，油水比可在60/40～90/10的范围内调节，密度可在1.25～2.0 g/cm3范围内调节，抗温可达220 ℃，高温稳定性良好。研究结果表明，环保型油基钻井液具有低毒环保、可降解等优势，抗污染、抗高温、稳定性强、可调节范围广，完全可满足较复杂地层和环境保护要求高区块对钻井液的要求。 

An Environmentally Friendly Oil Base Mud

Mineral oils and several oil base mud additives presently in use are highly biologically toxic and the discharge of oil base muds formulated with them are prohibited or limited. To minimize the toxicity of oil base muds, an environmentally friendly oil base mud was formulated with a weakly biologically toxic base oil, a high efficiency low-toxicity all-in-one emulsifier, a new modified high-gel organophilic clay and other additives developed. The concentrations of these additives were optimized to obtain an oil base mud with satisfactory performance. The oil base mud has LC₅₀ of greater than 15,000 mg/L and is biologically degradable. The oil base mud has good rheology, and its electrical stability is at least 800 V. The HTHP filtration rate is less than 6 mL. This oil base mud is resistant to contamination from 5% gypsum or 5% drilled cuttings or 15% salt water. The oil/water ratio of the mud can be adjusted between 60/40 and 90/10, and the density can be controlled between 1.25 g/cm3 and 2.0 g/cm3. This oil base mud has good high temperature stability, it functions normally at 220 ℃. These properties can satisfy the needs of drilling in wells penetrating complex formations and in area with stringent environment protection requirements.