一种基于接触性理论的储层裂缝闭合新模型

发布时间：2018-04-08 10:52

本文选题：天然裂缝　切入点：裂缝闭合模型　出处：《断块油气田》2017年05期

【摘要】：运用弹塑性理论,提出了一种更加合理的基于微观结构的新型裂缝闭合模型。在新模型中,首先,运用经典的接触力学理论,将裂缝表面微凸体受挤压状态分为完全弹性变形、弹塑性变形和完全塑性变形3个阶段,并且假设弹塑性变形阶段光滑且连续地衔接其他2种变形。为了更好地描述衔接过程,采用了样板函数,连接完全弹性变形和完全塑性变形状态方程,进而得出微凸体受挤压而压缩整个过程的数学模型。随后,引入当前关于概率分布的理论,合理优化出因为表面的微凸体受压缩而导致裂缝闭合的状态模型。最后,使用新模型模拟出裂缝闭合量随各项参数的变化,并与已有的完全弹性模型、完全塑性模型进行对比。结果表明,新模型中裂缝闭合量随各参数的变化介于完全弹性模型和完全塑性模型之间,裂缝受到有效应力而闭合的状态也更加符合预期,可以合理地体现裂缝逐渐闭合的状态。
[Abstract]:A new fracture closure model based on microstructure is proposed by using elastoplastic theory.In the new model, firstly, by using the classical contact mechanics theory, the extrusion state of the micro-convex body on the crack surface is divided into three stages: complete elastic deformation, elastic-plastic deformation and complete plastic deformation.It is also assumed that the elastic-plastic deformation stage is smooth and connected continuously with the other two kinds of deformation.In order to better describe the connection process, a template function is used to connect the state equations of complete elastic deformation and complete plastic deformation, and then the mathematical model of the whole process of extrusion and compression of the micro-convex body is obtained.Then, the current theory of probability distribution is introduced to optimize the state model of crack closure due to the compression of the surface microconvex body.Finally, the new model is used to simulate the variation of crack closure with various parameters, and compared with the existing complete elastic model and complete plastic model.The results show that the crack closure in the new model varies with each parameter between the complete elastic model and the complete plastic model, and the state of crack closing due to effective stress is more in line with the expectation.The state of gradual closure of cracks can be reasonably reflected.
【作者单位】：中国石油大学(北京)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;
【基金】：国家自然科学基金项目“硬脆/塑性泥页岩微裂缝产生的岩石物理学机制基础研究”(41572130)
【分类号】：TE311

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