数值分析

模拟水压致裂的另一种二维FDEM-flow方法

展开
  • 中国地质大学 工程学院,湖北 武汉 430074
严成增,男,1986年生,博士,特任教授,主要从事有限元-离散元耦合及多物理场耦合的相关研究

收稿日期: 2015-09-28

  网络出版日期: 2018-06-05

基金资助

国家自然科学基金青年项目(No.11602006);北京市自然科学基金青年项目(No.1174012);朝阳区博士后科研活动经费资助(No.2016ZZ-01-08)。

A new two-dimensional FDEM-flow method for simulating hydraulic fracturing

Expand
  • Engineering Faculty, China University of Geosciences, Wuhan, Hubei 430074, China

Received date: 2015-09-28

  Online published: 2018-06-05

Supported by

This work has been supported by the Natural Basic Research Program of China (11602006), the Beijing Natural Science Foundation (1174012) and Chaoyang District Postdoctoral Science Foundation funded project (2016ZZ-01-08).

摘要

可考虑岩石本身渗透性的FDEM-flow方法充分利用原FEMDEM中节理单元和三角形单元独特的拓扑连接关系,将节理单元作为流体流动的天然通道,基于立方定律来表征流体在岩石本身及裂隙中的流动,而岩石本身渗透性则通过标定合适节理单元张开度来表征。用一个含解析解自由面稳态渗流算例初步验证了本文渗流算法及标定岩石本身渗透率方法的正确性。最后计算了一个水力压裂算例,验证了该FDEM-flow方法可同时考虑岩石本身的渗透性和裂隙的渗透性,用简单的纯裂隙渗流完成了对复杂问题的处理。研究结果表明:修改后的FDEM-flow方法能够很好地再现压裂过程中流体压力的分布及裂隙的扩展,可简洁地求解水力压裂这一复杂力学的问题,适用范围更广。为模拟页岩气开采、干热岩地热获取中的水力压裂问题提供新的求解工具。

本文引用格式

严成增 . 模拟水压致裂的另一种二维FDEM-flow方法[J]. 岩土力学, 2017 , 38(6) : 1789 -1796 . DOI: 10.16285/j.rsm.2017.06.029

Abstract

In this study, a new FDEM-flow method is developed by considering the permeability of rock matrix, and it fully utilises the unique topological connection between joint elements and triangular elements in the original combined finite-discrete element method (FDEM). First, the joint elements were used as a natural channel for fluid flow, and the fluid flow in rock matrix and fissures were characterized by fluid flow in joint elements based on the cubic law. While the permeability of rock matrix was determined by calibrating the appropriate aperture of the joint element. Then, a numerical example of the free surface steady flow with the analytical solution was employed to validate the proposed seepage algorithm and the calibration method for rock matrix permeability. Finally, a hydraulic fracturing example was conducted to demonstrate that the permeability of rock matrix and fracture was considered simultaneously in the modified FDEM-flow method. Moreover, by using simple pure fracture seepage this method solved the complex issues of hydraulic fracturing. Therefore, the application scope of the new FDEM-flow method is broader than that of the original FDEM-flow method. This method provides a new solve tool for simulating hydraulic fracturing in shale gas exploration and geothermal exploration in hot dry rock.
文章导航

/