Using Embedded Discrete Fracture Model (EDFM) in numerical simulation of complex hydraulic fracture networks calibrated by microseismic monitoring data
Using Embedded Discrete Fracture Model (EDFM) in numerical simulation of complex hydraulic fracture networks calibrated by microseismic monitoring data
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DOI：
10.1016/j.jngse.2018.04.019
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发表时间：
2018-07
影响因子：
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通讯作者：
M. Shakiba;J. S. A. C. Filho;K. Sepehrnoori
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文献类型：
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作者：
M. Shakiba;J. S. A. C. Filho;K. Sepehrnoori
非常规页岩和致密储层的水力刺激通常会产生复杂的诱导裂缝网络，这需要进行全面的表征以成功开采和开发。过去十年中应用于水力压裂成像的主要技术之一是微震监测，它分析水力增产期间记录的地震信息以定位岩石变形。然后使用微震数据解释的结果来生成和校准水力裂缝网络的模型。然而，由于裂缝模型的复杂性和油藏模拟器的缺陷，这些复杂裂缝网络的直接应用受到了很大的限制。相反，过度简化的模型用于评估水力压裂处理的效率。这样的评估技术，没有进一步的建模和模拟的油气生产和压力排水，不能代表一个准确的视图的连通性和复杂性的裂缝system.In本文中，我们提出了一个嵌入式离散裂缝模型（EDFM）在数值模拟的现实几何形状的裂缝。利用EDFM，每个断裂平面嵌入计算矩阵网格内，并通过单元边界离散化。我们已经在德克萨斯大学奥斯汀分校（UT）内部油藏模拟器UTCOMP中实施了EDFM。我们讨论了使用非相邻连接的实现方法。使用开发的模拟器，我们研究了天然气生产从实际的微震监测数据校准的水力压裂网络。我们研究了裂缝网络几何形状对这些水力刺激的整体性能的影响。模拟结果表明，井处理的效率主要由水力裂缝的互连性和裂缝网络内的导流能力分布控制。对于一个给定的微震云，通过改变校准模型中的连接程度，观察到了广泛的生产响应。此外，该研究表明，考虑到地震变形（如拉伸开口）的作用，显着增加了累积产量预测。忽略这些裂缝的影响可能导致低估最终采收率。
Hydraulic stimulation of unconventional shale and tight reservoirs often creates a complex induced fracture network, which requires a comprehensive characterization for successful exploitation and development. One of the major technologies applied over the past decade to image hydraulic fractures is microseismic monitoring, which analyzes seismic information recorded during hydraulic stimulation to locate the rock deformation. Results of the microseismic data interpretation are then used to generate and calibrate a model of the hydraulic fracture network. However, because of the complexity of the fracture model and the shortcomings of reservoir simulators, direct application of these complex fracture networks has been very limited. Instead, oversimplified models are used to assess the efficiency of the hydraulic fracturing treatment. Such assessment techniques, without further modeling and simulation of hydrocarbon production and pressure drainage, fail to represent an accurate view of the connectivity and complexity of the fracture system.In this paper, we present the application of an Embedded Discrete Fracture Model (EDFM) in numerical simulation of realistic geometry of fractures. With EDFM, each fracture plane is embedded inside the computational matrix grid and is discretized by cell boundaries. We have implemented EDFM in The University of Texas at Austin (UT) in-house reservoir simulator UTCOMP. We discuss the implementation approach using non-neighboring connections. Using the developed simulator, we studied gas production from hydraulic fracture networks calibrated from actual microseismic monitoring data. We investigated the impact of fracture network geometry on the overall performance of these hydraulic stimulations.Simulation results indicate that the efficiency of well treatment is primarily controlled by the interconnectivity of hydraulic fractures and the distribution of conductivity within the fracture network. For a given microseismic cloud, a wide range of production responses was observed by changing the degree of connectivity in the calibrated model. Moreover, the study showed that taking into account the role of aseismic deformations (such as tensile openings) significantly increased cumulative production forecasts. Neglecting the effect of these fractures may lead to underestimation of ultimate recovery.