Using current Embedded Discrete Fracture Models(EDFM) to predict the productivity of fractured wells has some drawbacks, such as not supporting corner grid, low precision in the near wellbore zone, and disregarding th...Using current Embedded Discrete Fracture Models(EDFM) to predict the productivity of fractured wells has some drawbacks, such as not supporting corner grid, low precision in the near wellbore zone, and disregarding the heterogeneity of conductivity brought by non-uniform sand concentration. An EDFM is developed based on the corner grid, which enables high efficient calculation of the transmissibility between the embedded fractures and matrix grids, and calculation of the permeability of each polygon in the embedded fractures by the lattice data of the artificial fracture aperture. On this basis, a coupling method of local grid refinement(LGR) and embedded discrete fracture model is designed, which is verified by comparing the calculation results with the Discrete Fracture Network(DFN) method and fitting the actual production data of the first hydraulically fractured well in Iraq. By using this method and orthogonal experimental design, the optimization of the parameters of the first multi-stage fractured horizontal well in the same block is completed. The results show the proposed method has theoretical and practical significance for improving the adaptability of EDFM and the accuracy of productivity prediction of fractured wells, and enables the coupling of fracture modeling and numerical productivity simulation at reservoir scale.展开更多
励磁模型的准确程度对于电力系统仿真的准确性有显著影响。提出了一种新的、工程中容易实现的方法,即利用非线性直接优化法辨识微分方程形式的励磁模型参数。首先利用Matlab仿真与传统的最小二乘法比较验证算法有效性。然后利用动态信...励磁模型的准确程度对于电力系统仿真的准确性有显著影响。提出了一种新的、工程中容易实现的方法,即利用非线性直接优化法辨识微分方程形式的励磁模型参数。首先利用Matlab仿真与传统的最小二乘法比较验证算法有效性。然后利用动态信号记录装置,根据模型结构获得各个环节的时域内发电机阶跃试验数据,对1台300MW汽轮发电机组的励磁系统分别进行分环节参数辨识和整体辨识。利用电力系统分析综合程序(power system analysis software package,PSASP)的用户自定义模型功能建立励磁模型进行相同的阶跃仿真,结果验证了辨识参数在电力系统仿真中的有效性。展开更多
基金Supported by the China National Science and Technology Major Project (2017ZX05030)
文摘Using current Embedded Discrete Fracture Models(EDFM) to predict the productivity of fractured wells has some drawbacks, such as not supporting corner grid, low precision in the near wellbore zone, and disregarding the heterogeneity of conductivity brought by non-uniform sand concentration. An EDFM is developed based on the corner grid, which enables high efficient calculation of the transmissibility between the embedded fractures and matrix grids, and calculation of the permeability of each polygon in the embedded fractures by the lattice data of the artificial fracture aperture. On this basis, a coupling method of local grid refinement(LGR) and embedded discrete fracture model is designed, which is verified by comparing the calculation results with the Discrete Fracture Network(DFN) method and fitting the actual production data of the first hydraulically fractured well in Iraq. By using this method and orthogonal experimental design, the optimization of the parameters of the first multi-stage fractured horizontal well in the same block is completed. The results show the proposed method has theoretical and practical significance for improving the adaptability of EDFM and the accuracy of productivity prediction of fractured wells, and enables the coupling of fracture modeling and numerical productivity simulation at reservoir scale.
文摘励磁模型的准确程度对于电力系统仿真的准确性有显著影响。提出了一种新的、工程中容易实现的方法,即利用非线性直接优化法辨识微分方程形式的励磁模型参数。首先利用Matlab仿真与传统的最小二乘法比较验证算法有效性。然后利用动态信号记录装置,根据模型结构获得各个环节的时域内发电机阶跃试验数据,对1台300MW汽轮发电机组的励磁系统分别进行分环节参数辨识和整体辨识。利用电力系统分析综合程序(power system analysis software package,PSASP)的用户自定义模型功能建立励磁模型进行相同的阶跃仿真,结果验证了辨识参数在电力系统仿真中的有效性。
