低压低渗气藏钻探过程中的保护方案

Protection plan for drilling the low pressure and low permeability gas reservoir

针对鄂尔多斯塔巴庙区块低压低渗气藏物理特性复杂的情况,推荐一套切实可行的气层保护方案。即实行全面钻井液监控;采用欠平衡钻井技术;储层保护前期研究;采用与地层流体配伍性好的阳离子钻井液体系;降低钻井完井液的滤失量,API滤失量小于5 mL、高温高压滤失量小于15 mL、固相含量小于8％、含砂量小于0.3％;根据储层裂缝的宽度和走向使用保护剂;对裸眼完钻的气层利用洗井清除井壁附近的污染带,恢复储层原始渗透率;固井作业防止气窜;采用具有抑制地层水敏、速敏保护气层的优质射孔液;水力压裂优化压裂设计,严格压裂施工。总之,气层保护技术是一个系统工程.任何一个环节的问题,都将对气层产生伤害,因此需加强气层保护研究,做到在钻开气层到投产的每道工序都采取积极有效的气层保护措施。

In accordance with the complex physical characteristics of the pressure and low permeability gas reservoir in Tabamiao block of Erdos, a set of practical and feasible protection plan is recommended. This plan includes a series of measures and technologies, i. e. , carrying out the integral drilling fluid supervision; applying under-balanced drilling technology; initial study on formation protection; using the cationic drilling fluid systems with good compatibility with formation fluid; reducing the filtration of drill-in fluid, with API fluid loss less than 5 mL, HTHP fluid loss less than 15 mL, solids content less than 8% and sand content less than 0. 3%; using protecting agent in accordance with the width and extension of the reservoir fractures; Cleaning the contamination area near the wellbore by washing out for the open-hole completed gas reservoir, to restore the original permeability; preventing gas channeling during cementing; u-sing the high quality perforating fluid to inhibite water sensitivity and velocity sensitivity; optimizing the hydraulic fracturing design and carrying out the operation strictly. In general, the gas reservoir protection technology is a systemic project, thus its study should be strengthened and effective measures should be taken for each procedure form point of hitting the target to production.