An embedded fracture modeling framework for simulation of hydraulic fracturing and shear stimulation
An embedded fracture modeling framework for simulation of hydraulic fracturing and shear stimulation
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DOI：
10.1007/s10596-015-9543-2
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发表时间：
2016-02
影响因子：
2.5
通讯作者：
J. Norbeck;M. McClure;J. Lo;R. Horne
中科院分区：
文献类型：
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作者：
J. Norbeck;M. McClure;J. Lo;R. Horne
描述了一种能够计算流体流动、地质力学和岩石破坏耦合过程的数值模拟框架，该框架可应用于与储层增产有关的一般工程问题，包括水力压裂和剪切增产。该数值公式采用嵌入式裂缝建模方法，在计算复杂度和效率方面优于传统方法。具体而言，嵌入式裂缝建模策略避免了通常要求裂缝域离散化符合裂缝周围岩石体积离散化的要求。当流体在两个域之间交换时，通过耦合项保证质量守恒，该耦合项在控制质量平衡方程中作为简单源项出现。通过这种方式，当新的拉伸裂缝在力学作用下成核并扩展时，与引入新的裂缝控制体积相关的数值复杂性在很大程度上被抵消了。此外，独立离散裂缝和围岩体积的能力提供了为每个域单独选择可接受的离散化水平的自由。通过三个数值实例来证明嵌入裂缝模型在流体流动、机械变形和岩石破坏等问题中的应用。数值算例结果表明，嵌入裂缝模型能够准确反映新裂缝在储层中扩展和裂缝剪切破坏过程中储层渗透率的复杂非线性演化过程。
A numerical modeling framework is described that is able to calculate the coupled processes of fluid flow, geomechanics, and rock failure for application to general engineering problems related to reservoir stimulation, including hydraulic fracturing and shear stimulation. The numerical formulation employs the use of an embedded fracture modeling approach, which provides several advantages over more traditional methods in terms of computational complexity and efficiency. Specifically, the embedded fracture modeling strategy avoids the usual requirement that the discretization of the fracture domain conforms to the discretization of the rock volume surrounding the fractures. As fluid is exchanged between the two domains, conservation of mass is guaranteed through a coupling term that appears as a simple source term in the governing mass balance equations. In this manner, as new tensile fractures nucleate and propagate subject to mechanical effects, numerical complexities associated with the introduction of new fracture control volumes are largely negated. In addition, the ability to discretize the fractures and surrounding rock volume independently provides the freedom to choose an acceptable level of discretization for each domain separately. Three numerical examples were performed to demonstrate the utility of the embedded fracture model for application to problems involving fluid flow, mechanical deformation, and rock failure. The results of the numerical examples confirm that the embedded fracture model was able to capture accurately the complex and nonlinear evolution of reservoir permeability as new fractures propagate through the reservoir and as fractures fail in shear.