考虑弹塑性变形机制的储层天然裂缝闭合模型

发布时间：2018-02-28 03:34

本文关键词： 天然裂缝弹塑性闭合模型微凸体　出处：《大庆石油地质与开发》2017年01期 　论文类型：期刊论文

【摘要】：针对裂缝闭合模型中存在的不足,提出一种新的弹塑性裂缝闭合模型。该模型基于经典接触力学理论,作出微凸体由弹性压缩首先转化为弹塑性压缩,最终转化为塑性压缩的过程是连续且光滑的假设。引入样板函数,对微凸体的完全弹性和完全塑性的压缩状态进行衔接,并推导出微凸体压缩过程中的状态方程。在此基础上,采用微凸体概率分布理论,导出裂缝复合表面与光滑平面之间的接触面积、平均接触压力、法向应力和裂缝闭合量之间的函数关系式。将建立的模型同完全弹性和完全塑性模型进行对比,结果表明新模型能够良好地描述裂缝闭合时上下两表面接触面积和平均接触压力的变化规律,同时对于法向应力对裂缝闭合的影响更加符合直觉和实验观察,能够合理地描述裂缝的闭合规律。
[Abstract]:A new elastic-plastic fracture closure model is proposed, which is based on the classical contact mechanics theory, and the micro-convex body is firstly converted from elastic compression to elastic-plastic compression. It is assumed that the process of plastic compression is continuous and smooth. A template function is introduced to link the complete elastic state of a microconvex body with the fully plastic state of compression, and the state equation in the compression process of a microconvex body is derived. By using the probability distribution theory of microconvex body, the contact area and the average contact pressure between the crack composite surface and the smooth plane are derived. The functional relationship between normal stress and crack closure. The established model is compared with the complete elastic and plastic model. The results show that the new model can well describe the change of the contact area and the average contact pressure between the upper and lower surfaces, and the effect of normal stress on fracture closure is more intuitively and experimentally observed. The fracture closure law can be described reasonably.
【作者单位】：中国石油大学石油工程教育部重点实验室;中国石油长庆油田分公司第十一采油厂;中国石油塔里木油田分公司;
【基金】：国家自然科学基金项目“多尺度离散裂缝油藏有限元数值模拟研究”(51204204)
【分类号】：TE311

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