页岩地层产状对水平井井眼破坏的影响  

EFFECTS OF SHALE FORMATION OCCURRENCE ON HORIZONTAL WELLBORE FAILURE

作　　者：李绪锋 

机构地区：[1]胜利石油工程有限公司巴州钻井技术分公司

出　　处：《钻采工艺》2016年第5期14-16,100-101,共3页Drilling & Production Technology

摘　　要：页岩地层的钻井作业尤其是水平井的钻井作业持续增加,页岩地层的水平井钻井过程往往伴随着一系列井壁稳定问题。为此,利用坐标转换和弱面滑动破坏理论,建立了页岩地层水平井井眼破坏程度预测和坍塌压力计算模型。利用所建模型分析了页岩地层产状对水平井井眼破坏形状的影响和坍塌压力的影响。分析表明,页岩层理面滑动破坏后的水平井井眼总体呈"四叶状",破坏程度较小时可能呈"狗耳朵"状;垂直于层理面或与层理面夹角较小的水平井破坏程度较小,甚至不会发生层理面滑动破坏。所建模型及分析结果可用于优化页岩地层水平井钻井方向,避免钻井过程中发生层理面滑动破坏,防止水平井井眼稳定因页岩层理面而恶化。Drilling activities, especially horizontal well drilling,in shale formations continue to increase,while horizontal drilling in shale formation is often accompanied by a series of wellbore stability problems. For this reason,using coordinate transformation and weak plane sliding failure theory,a model for forecasting the failure degree and the collapse pressure of horizontal wellbore in shale formation was established,by which the effects of shale formation occurrence on the failure shape and collapse pressure of horizontal wellbore was analyzed. Analysis shows that the cross section of horizontal wellbore after bedding plane sliding failure was generally ' four leaf-shaped' and also like a ' dog ear' when the failure was slight; horizontal wellbore perpendicular to the bedding planes or at a smaller angle to bedding planes would experience a small damage,even not producing failure across bedding planes. The model and analysis results in this paper can be used to optimize the drilling direction of horizontal wells in shale formation to avoid the occurrence of bedding plane sliding failure and to prevent the horizontal wellbore stability from being worse due to shale beddings in the drilling process.

关 键 词：页岩地层 水平井 井壁稳定 井眼形状 坍塌压力 

分 类 号：TE243[石油与天然气工程—油气井工程]