米泉区块井壁稳定性分析及钻井液的优选

准噶尔盆地南缘山前构造带米泉区块由于构造运动激烈，地层稳定性差，存在大段强水敏性泥岩和煤层。根据米泉1井实钻资料和岩屑分析了易塌和易水化缩径地层的地质特点，编制了米泉区块复杂地层三项压力预测软件，应用米泉1井测井数据计算了3个压力剖面，并据此分析了坍塌地层合理的钻井液密度窗口。在此基础上，对比研究了加入聚合醇的甲酸盐钻井液体系和两性离子钻井液体系。实验和现场应用结果表明，甲酸盐钻井液体系具有稳定井壁、抑制造浆、润滑防卡、抗黏土污染、流变性能好等特点，更适合米泉区块钻井的需要。

Study on borehole stability in Miquan Area at Piedmont Tectonic Zone of Junggar Basin Southern Margin

The stratum of piedmont tectonic zone of Junggar Basin southern margin is rather fragmentized and not stable because of tectonic movement,and it includes large section of highly water sensitive mudstone and coal bed,so the wellbore is easily washed out and collapsed during the process of drilling operation.Based on the drilling data and rock debris collected at Miquan Well 1,the geological characteristics of easily collapsed and hydrated stratum are analyzed,and the software to calculate three pressure profiles is coded.the formate and zwitterion drilling fluid are studied comparatively.The results of indoor test and filed application show that the formate drilling fluid can resist mud-making,stabilize wellbore,prevent sticking by lubricating wellbore,and prevent the pollution of clay,and has a good rheological property,so it meets the requirements of drilling operation at the piedmont tectonic zone of Junggar Basin southern margin.