Numerical Simulation and Characteristic Analysis of Top-Casing Electric Source Imaging for Monitoring Proppant-Containing Hydraulic Fractures

Summary Geometric parameters evaluation of hydraulic fractures plays a vital role in improving production from unconventional shale oil reservoirs. Borehole resistivity measurement exhibits promising potential for characterizing hydraulic fractures. However, accurately monitoring fracture orientation in steel-cased boreholes poses a significant challenge. The top-casing electric source method is a subsurface imaging technique that has emerged as a focal point of research in recent years. Our aim with this study is to test the practicality of using top-casing electric source technology to locate and detect hydraulic fractures. A 3D finite element algorithm is used to conduct a numerical simulation of top-casing electric source detection of hydraulic fractures. The simulation investigates the relationships between the geometric parameters of both fractures and boreholes and the measurement signals. Two case studies are analyzed to evaluate the efficacy of the proposed method in complex underground conditions. Numerical results demonstrate that measurement signals are sensitive to a fracture’s morphology. This method is suitable for characterizing fractures with a half-length exceeding 50 m. In terms of borehole configuration, it is crucial to maintain the lateral segment either horizontally or with a slight upward tilt. Furthermore, this approach shows exceptional effectiveness, even in complex situations that involve multistage fracturing and multiple boreholes. Our findings contribute to the development of a galvanic measurement survey to enhance the effectiveness of hydraulic fracture monitoring.