火山岩复杂地层控压钻井技术应用

火山岩地层存在地层硬、研磨性强、岩石可钻性差和裂缝性漏失等客观条件,严重制约了火山岩的勘探开发。KLML气田前期钻探工作中,钻井遇到了3个突出难题：频繁井漏、机械钻速低、井壁容易失稳。常规钻井工艺已不能解决这些复杂情况同时存在的情况,造成钻井工艺在油气勘探上的极大制约。控压钻井利用专用井口控制设备在井口产生一个回压,根据地层孔隙压力和地层坍塌压力等因素,精确调节节流阀的开启程度来改变井口回压的大小,从而改变井内钻井液当量密度的压力剖面。它具备防漏、防喷、提高机械钻速和防止井壁失稳等问题的技术优势,应用于KLML气田钻井实践证实：该方法在实践过程中有效防止了漏失和井壁不稳,同时较大幅度地提高了机械钻速。在复杂地层钻井中,控压钻井将成为不可缺少的重要手段。

Application of managed pressure drilling technique in complex volcanic rock formation

The exploration and development of volcanic rock formation are greatly restricted by some objective conditions,such as hard formation,strong abrasive porperty,poor drillability and fractured leakage.Three problems,i.e.frequent circulation loss,low ROP and borehole wall instability,are encountered during early drilling operation in KLML Gas Field.Because conventional drilling technology can not solve these complex simultaneous problems,the drilling technology of oil and gas exploration has been greatly restr...