渝东南地区页岩气钻井泥浆优化技术

Optimization Technology of Shale Gas Drilling Mud in Southeast Chongqing

针对渝东南地区页岩气井页岩层段井壁失稳的钻井工程技术难题,研究有机胺复配甲基葡萄糖甙的新型强抑制钻井液。一方面利用了有机胺对泥岩高效抑制性能,另一方面应用了甲基葡萄糖甙仿油基的高效抑制性能。实验表明新型钻井液对ZY5井页岩段岩心滚动回收率达到97.60%,膨胀率仅为10.13%,钻井液润滑系数Ep达到0.163 4。钻井实践表明,应用新型强抑制钻井液,井径扩大率可控制在5.8%,较该地区已钻井井径扩大率下降了72%。新钻井液体系能够有效抑制页岩层段井壁失稳,满足渝东南地区页岩气井页岩层段井壁稳定的需要。

Wellbore instability of shale gas reservoirs in southeast Chongqing has always been one of the technical difficulties in the drilling projects. So, in order to solve this technical problem, a new kind of inhibition drilling fluid, organic amine compound methyl glucoside, is utilized in this study, which has both advantages in effective inhibition performance of organic amines on mudstone and in high inhibition performance of methyl glucosinolates. The experiment results indicate that the rolling recovery rate reaches 97.60%, and the drilling lubricating rate （Ep） reaches 0. 163 4, while the expansion rate is only 10.13% in well ZY5. The drilling experience shows that the organic amine compound methyl glucoside inhibiting drilling fluidcan can restrict the enlargement rate under 5. 8%, and the average enlargement rate has been decreased by 72% within the study area. The new drilling fluid system can effectively reduce the instability of shale layers, which further meets the needs of layer stability in the shale -gas wells in southeast Chongqing.