论文标题

使用具有粗糙接触变形的集成LSM-DFN方案的自然裂缝储层的弹性特性

Elastic characteristics for naturally-fractured reservoirs using an integrated LSM-DFN scheme with rough contact deformation

论文作者

Liu, Ning

论文摘要

裂纹微地形和摩擦学特性对破裂岩石的弹性特征产生了重要影响。数值模拟作为此问题的有希望的方法仍然面临一些挑战。随着计算机和计算技术的快速开发,具有理想特性的基于离散的数值方法已经越来越开发,但是很少有尝试考虑晶格类型模型中粒子表面粗糙度的尝试。为此,通过耦合修改的LSM和DFN建模来开发一个集成的数值计算粗略接触变形,以预测现实露头的有效机械性能。引入平滑的关节逻辑以考虑裂缝表面处的接触和滑动行为,并通过对粗糙接触变形估算正常力 - 位置的修改接触关系。为岩石基质和粗糙断裂表面开发和使用改进的本构定律,并在修改后的LSM中实施。 DFN提出的复杂断裂网络将根据梯度霍夫变换算法自动提取。这个开发的框架通过经典的等效中等理论验证。它表明该模型可用于模拟自然裂纹的培养基,并定量研究断裂属性和微尺度表面粗糙度对压缩机制的影响。

Crack micro-geometries and tribological properties pose an important impact on the elastic characteristics of fractured rocks. Numerical simulation as a promising way for this issue still faces some challenges. With the rapid development of computers and computational techniques, discrete-based numerical approaches with desirable properties have been increasingly developed, but few attempts to consider the particle surface roughness in a lattice type model. For this purpose, an integrated numerical scheme accounting rough contact deformation is developed by coupling modified LSM and DFN modeling for predicting the effective mechanical properties of a realistic outcrop. Smooth joint logic is introduced to consider contact and slip behaviors at fracture surfaces and a modified contact relation to estimating the normal force-displacement from rough contact deformation. Improved constitutive laws are developed and employed for rock matrix and rough fracture surface and implemented in the modified LSM. Complex fracture networks presented by DFNs are automatically extracted based on the gradient Hough transform algorithm. This developed framework is validated by classic equivalent medium theories. It shows the model could be used to emulate naturally-fractured media and to quantitatively investigate the effects of fracture attributes and micro-scale surface roughness on the compression mechanism.

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