基于层析成像技术的页岩微裂缝扩展规律研究

发布时间：2018-03-10 22:19

本文选题：页岩　切入点：井壁稳定　出处：《中国科学:物理学力学天文学》2017年11期 　论文类型：期刊论文

【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.
[Abstract]:In this paper, the microstructure of Longmaxi Shale at different times under different fluid immersion conditions has been studied by means of computed Tomography scanning technique. The experimental results show that the fluid propagates along the microfracture, which is caused by the continuous invasion of the fluid. Permeability is the main cause of wellbore instability. Shale fractures have obvious directionality and transient, and they mainly occur within 2 hours before contact with fluid. The direction is parallel to the bedding surface. There are obvious differences in the variation of shale interior under different fluid immersion conditions. Under the condition of deionized water, the maximum and fastest formation of KCl-polymer drilling fluid, followed by SM-Shal eDrill and oil based drilling fluid immersion, has no obvious change. It is found that the width of the newly formed fractures after contact with the fluid remains basically constant. However, the width of microfractures in shale increases obviously after contact with the fluid.
【作者单位】：页岩油气富集机理与有效开发国家重点实验室;中国石化石油工程技术研究院;
【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
【分类号】：TE21

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