硬脆性页岩基础物性实验及井壁稳定性分析  

Experiment of the Fundamental Physical Properties and Analysis of the Wellbore Stability on Hard Brittle Shale

作　　者：雷梦[1] 梁利喜[1] 熊健[1] 庄大林[1] 罗超[1] 

机构地区：[1]油气藏地质及开发工程国家重点实验室,西南石油大学,成都610500

出　　处：《科学技术与工程》2015年第7期34-40,共7页Science Technology and Engineering

基　　金：国家自然科学基金联合基金重点项目(U1262209);国家自然科学基金面上项目(51274172)资助

摘　　要：近年来,由于世界能源的需求量剧增,页岩气的勘探、开发、研究已成为石油行业关注的焦点,其中最令人关注的工程难题之一就是钻井过程中的井壁失稳问题。龙马溪组页岩更是频繁的发生严重的井壁垮塌事故,给钻井施工造成了很大的困难。通过室内实验分析龙马溪组页岩露头的矿物成分、微观结构以及力学性质,研究了其井壁失稳机理。岩心轴向与层理面法向夹角为45°~70°之间时,其破坏形式主要表现为沿层理面的剪切滑移;当夹角为60°左右时,岩石的抗压强度最低。龙马溪组页岩在纵向上呈层状分布,微孔隙、微裂缝发育,表现出很强的各向异性。采用常规的均质模型,坍塌压力计算结果往往会偏低,因此考虑含弱面结构的破坏准则进行井壁稳定性分析更接近真实情况。With the increase of quantity demand on energy source, the research, exploration and development on shale gas have become the focus of oil industry, one of the most difficult project concerned is the instability of wellbore during drilling. The serious wellbore collapse happened frequently in Longmaxi formation cause a big problem in drilling work. Through indoor experiment of mineral composition, micromechanism and mechanical property on Longmaxi outcrop, the its mechanism of wellbore instability were studied. The fracture plane along the stratification when the intersection angle between the normal direction of the stratification plane and the axial range from 45° -70°, and when the angle is 60° the compressive strength of the rock reach to the lowest. The distribution of Longmaxi shale formation presents stratiform in vertical, mieropore and microcrack are highly developed, performance strong anisotropy, if utilize the homogenized model to calculate the collapse pressure, the result will be on the low side, thus the failure criterion which contains the plane of weakness will be more close to the true situation.

关 键 词：各向异性 井壁垮塌 弱面破坏准则 坍塌压力 

分 类 号：TE21[石油与天然气工程—油气井工程]