中文摘要：

针对井壁崩落和井壁漏失是钻井过程中井壁失稳破坏的主要形式,由于吉林油田松辽盆地深层致密火山岩气储层地层层序和岩性多样,井壁破坏机理复杂,目前还没有形成系统的方法来预测井壁破坏情况,大大影响了钻前可行性分析及钻井方案优化设计。针对上述问题,提出了一种预测致密火山岩气井的井壁破坏的方法。以线弹性力学的基础理论为基础,对断层摩擦强度控制下的原地应力场和近井壁局部应力场叠加作用下的周向应力场进行分析,建立了致密火山岩气井井壁崩落和漏失模型。基于上述井壁破坏模型和理论推导,在Matlab数值仿真软件中,对井壁崩落和漏失情况进行预测和可视化仿真输出,并与井下的井壁破坏实际观测结果进行对比,验证预测方法的可靠性。仿真结果表明,致密火山岩气井的井壁破坏预测结果与工程实际吻合度较高,可视化仿真直观、形象、准确,可以很好地为火山岩气井施工现场井壁失稳问题的分析和预测提供依据。

英文摘要：

Wellbore breakout and drilling induced fractures are the main type of wellbore failures during drilling.The stratigraphic sequence and rock properties are complicated in volcanic gas reservoir of Songliao Basin,and the downhole accidents are frequent. In this paper,based on linear elasticity theory,wellbore stress was analyzed and the model of borehole breakout and leak off was established. Using this physical model,the authors performed numerical stimulation programs depending on Matlab,and predicted wellbore failures. The results show that the model of borehole breakout and leak off based on linear elasticity theory can obtain accurate and credible results,which is in consistent with engineering practice. Meanwhile,the simulation results show that it is meaningful for the study on wellbore stability of tight volcanic gas wells.