复合盐水低伤害钻井液在桃7-9-5AH水平井的应用

Application of Combined Salt Low-damage Drilling Fluid in Well 7-9-5AH

针对苏里格地区低孔低渗砂岩气藏的特点,依据ASS-1全酸溶钻井(完井)液在该地区探井的应用经验,研制出了复合盐水低伤害钻井完井液。该钻井液在常规条件下对地层的平均伤害率仅为5.9%,在特殊模拟井下条件下,对气层的平均伤害率为13.64%,暂堵性好,井壁上形成的暂堵滤饼通过气层压力完成解堵,简化了完井、投产作业。该钻井液在桃7-9-5AH井水平段施工过程中,起下钻无阻卡,井底无沉砂,解决了因泥页岩水化膨胀而引起的缩径和坍塌、高摩阻大扭矩、PDC钻头泥包等一系列技术难题,创造了长庆区块水平段一只φ152.4 mm钻头810 m进尺的记录,并获得无阻流量150×104 m3/d的高产气流。

A combined salt low-damage drilling fluid is developed for drilling operation in Sulige,based on the successful experience of ASS-1 total acid soluble drilling(completion) fluid.Under the normal condition,the formation damage rate is only 5.9% and it is 13.64% in condition of simulated down hole condition.Forming temporary blocking cake to break down,the drilling fluid has good temporary blocking performance and simplifies the completion and production operation.The application in well Tao 7-9-5AH shows good capability of inhibition,lubricity and carrying cuttings of this drilling fluid,and many drilling problems such as tight hole,caving,high drag and torque and bit bailing have been overcome.A record is created that one bit drills for 810 meters in horizontal section in Changqing Block,and the production of 150×104 m3/d is obtained.