摘要
本文采用电子计算机X射线断层扫描技术(Computed Tomography),研究了龙马溪页岩在不同流体浸泡条件下,不同时刻微观结构的变化情况.实验表明流体沿微裂隙不断侵入导致的裂缝扩展、贯通是井壁失稳的主要原因.页岩裂缝产生具有明显的方向性和瞬时性,裂缝主要产生于与流体接触的前2h之内,且方向平行于层理面.不同流体浸泡条件下页岩内部变化具有明显的差异,去离子水条件下裂缝产生最多最快,KCl-聚合物钻井液次之,SM-Shal eDrill和油基钻井液浸泡下无明显变化.实验发现对于与流体接触后新产生的裂缝,其宽度基本维持恒定不变,不再随时间发生变化.而页岩中已经存在的微裂隙,其宽度在与流体接触后有一个明显的增大过程.
Basing drilling on the CT tomography They technique,the micro structure changes of Longmaxi Shale were studied fluid in four oil different fluids.are that deionized micro water,KCl-polymer drilling fluid,SM-Shaledrill fluid drilling along and based is mud.main mainly Experiments reason showed fracture propagation which caused propagate fluids.by invasion the micro-fracture the of shale wellbore instability.And micro fractures directively and instantaneously,fractures are the developed plane in the previous two hours when changes immersed obvious in And when drilling micro fractures are mostly parallel fluids.to bedding fractures of shale.The micro and structure differently immersed fluid in different next;drilling shale Micro propagated fluid most fastest mud in no But deionized obvious water,change.of KCl-polymer As is the and in SM-Shaledrill width drilling maintain and oil based has for the newly developed micro fractures,an of fractures constant contact once with developed.the width the existing micro fractures in shale have obviously increasing process when fluid.
作者
林永学
高书阳
曾义金
LIN YongXue GAO ShuYang ZENG YiJin(State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development, Beijing 100101, China Sinopec Research Institute of Petroleum Engineering, Beijing 100101 China)
出处
《中国科学：物理学、力学、天文学》
CSCD
北大核心
2017年第11期55-61,共7页
Scientia Sinica Physica,Mechanica & Astronomica
基金
国家自然科学基金(编号:51490650)
页岩油气富集机理与有效开发国家重点实验室开发基金资助
关键词
页岩
井壁稳定
层析成像
裂缝扩展
钻井液
shale
wellbore stability
tomographic technique
fracture progagation
drilling fluid
