致密砂岩储层构造裂缝形成机制及定量预测研究进展

致密砂岩裂缝性储层已逐渐成为非常规油气资源勘探开发的重点,构造裂缝形成机制研究及定量预测也相应成为热点问题.从构造地质学和地质力学角度对目前的裂缝研究方法进行系统分析,并对含微裂隙的岩石损伤力学实验分析、复合地层本构关系及破裂准则的建立以及不同应力场作用下裂缝参数的定量表征方法进行详细对比后认为,裂缝的产生、裂缝的位置和方向以及裂缝参数的量化是实现裂缝准确预测的关键.今后裂缝研究的发展方向主要有3个,即基于构造地质学和岩石损伤力学的宏观野外观察和微观室内试验相结合研究裂缝形成机制,考虑多重影响因素并基于能量转换理论的复合岩石破裂准则建立,基于精细构造地质模型的有限元数值模拟实现各期应力场作用下裂缝参数的三维定量表征.

RESEARCH PROGRESS ON MECHANISM AND QUANTATIVE PREDICTION OF STRUCTURAL FRACTURES IN TIGHT-SAND RESERVOIRS

As fractured tight-sand reservoirs was thought to be an important type for exploration and production of unconventional oil and gas resources at present, understanding mechanism of structural fracture networks in reservoirs accordingly is thought to be the research focus. From sides of structural geology and rock mechanics to make comprehensive analysis, such as comparisons of rock damage mechanics experiments, constitutive relation of composite formation and its failure criteria, and quantitative method for predicting fracture distribution, it is shown that generation, location, orientation of fractures and quantification are the keys to predict fracture networks. Then it is shown that there exist three main directions for fracture research, including fracture mechanism study using structural geology, damage mechanics and laboratory experiments, composite rock failure criterion based on energy conservation law considering multiple factors, and fracture parameters of three- dimensional quantitative characterization using finite element numerical method based on fine structure model.