钻井液不落地技术在白鹭湖井工厂的应用

Application of Drilling Fluid Zero-discharge Technology in Bailu Lake Multi-well Pad

白鹭湖井工厂项目位于风景区,环保要求严格,不允许废钻井液固化填埋,为了保护环境和实现钻井液重复利用,在该项目施工完成的43口井应用钻井液不落地技术。现场施工难点有机械钻速快、随钻处理量大、压滤水重复利用难、设备多且占地面积大、长裸眼段对钻井液性能要求高,所钻遇上部地层造浆严重、下部地层易塌,因此优选了氯化钙强抑制环保钻井液体系。改进后形成了粗颗粒岩屑不加药离心分离固化,细颗粒脱稳压滤处理的钻井液不落地处理技术;另一方面,处理剂由过去的直接加入改成以药液方式加入,压滤时间由原先的60 min减少至20 min,最大处理量达到了9 m^3/h;再者,岩屑搅拌罐进压滤机管路在原有的砂泵供料基础上,增加立式液压柱塞供料泵;改进后的岩屑槽设计了辅助冲水管线,解决了岩屑槽内的堆积问题。钻井实践表明,在大型丛式井组井工厂施工中,应用钻井液不落地技术,及配套的环保型钻井液体系,能够满足严格的环保要求及提高钻井液的重复利用率,并且大幅提高机械钻速,降低了钻井成本。

The Bailu Lake multi-well pad is located in a scenic area where environmental protection requirements are tough and solidifcation of waste drilling fluid for burial is prohibited. Multi-well pad technology was adopted in the drilling of 43 wells in this area to conform to the environmental protection requirements. Diffculties encountered during drilling included fast drilling, large amount of drilling fluid to be treated, reuse of fltered water, too much equipment which occupied large area, tough requirements on drilling fluid for drilling long open section, hydration and swelling of the shallow shales, and instability of the deep borehole wall. A calcium chloride drilling fluid was chosen to drill these wells. The coarse drill cuttings, without treatment by additives, were separated out from liquid phase and solidifed. The fne drill cuttings, on the other hand, were fltered under pressure to remove the liquid phase. Since the additives were added in solution form instead of being added directly into the drilling fluid, time required for the separation of the fne cuttings and liquid phase was shortened from 60 min to 20 min, and the maximum treatment rate reached 9 m3/h. Furthermore, the pipeline between the cuttings agitator and the flter was modifed, adding a vertical hydraulic piston charging pump to enhance treatment effciency. An auxiliary water flushing pipeline was installed on cutting trough to avoid the piling of cuttings therein. Drilling practice has shown that in multi-well pad drilling, using drilling fluid zero-discharge technology and environmentally friendly drilling fluid formulation can satisfy the needs of tough environmental protection and reuse of drilling fluid. The rate of penetration can also be greatly improved, effectively reducing drilling cost.