页岩气水平井开发用高效水基钻井液体系研究

Study on high efficiency water-based drilling fluid system for shale gas horizontal wells development

针对涪陵地区页岩气水平井开发特点,通过室内试验开发了一套适合目标区块页岩气水平井的高效水基钻井液体系,并对其综合性能进行了评价。结果表明:高效水基钻井液体系具有良好的耐温性能,在140℃下老化后,体系的流变性能和滤失量均无明显升高。体系具有较强的抑制性能和润滑性能,对目标区块储层段岩屑的滚动回收率可以达到98%以上,具有较低的极压润滑系数和泥饼黏附系数。此外,该高效水基钻井液体系的EC50值可以达到30000 mg/L以上,属于无毒级别,具有良好的环保性能。

In order to improve the development efficiency of shale gas horizontal wells in Fuling area,the technical difficulties of drilling fluid for horizontal wells in target block are analyzed,and corresponding solutions are proposed.A set of high-efficiency waterbased drilling fluid system suitable for shale gas horizontal wells in target block is developed through laboratory experiments,and its comprehensive performance is evaluated in laboratory.The results show that the high efficiency water-based drilling fluid system has good temperature resistance,the rheological properties and filtration loss of the system do not increase significantly after aging at 140℃,the system has strong inhibition and lubrication performance,and the rolling recovery rate of cuttings in the target block reservoir section can reach more than 98%,and has low extreme pressure lubrication coefficient,mud cake adhesion coefficient.In addition,the EC50 value of the high-efficiency water-based drilling fluid system can reach more than 30000 mg/L,which belongs to the non-toxic level and has good environmental protection performance.