| Abstract Submission No. | ABS-4.1-0156 |
| Title of Abstract | Velocity Prediction Using Integrated Rock Physics Modeling of Fracture Networks |
| Authors | Souvik Patra*, Prof. Saurabh Datta Gupta |
| Organisation | Indian Institute of Technology (Indian School of Mines) Dhanbad |
| Address | Diamond Hostel, IIT (ISM) Dhanbad Dhanbad, Jharkhand, India Pincode: 826004 E-mail: 23mc0096@iitism.ac.in |
| Country | India |
| Presentation | Poster |
| Abstract | The increasing urgency for sustainable and clean energy resources has bolstered interest in Hot Dry Rock (HDR) geothermal systems, which are characterized by low-porosity crystalline rocks where reservoir performance relies heavily on fracture networks. Conventional reservoir characterization approaches have limited capability in directly quantifying fracture density, orientation, and complex connectivity, especially in deep-seated, fluid-deficient HDR systems. This study aims to enhance the prediction of velocities in HDR geothermal reservoirs by integrating well log with advanced rock physics modeling frameworks that explicitly account for mineral composition, pore structure, and fracture-induced anisotropy. The modeling workflow employs a combination of the differential Kuster-Toksz theory and the Differential Effective Medium (DEM) approach to simulate the elastic moduli of mixed mineral hosts with vugs, interparticle pores, and varied pore aspect ratios. For anisotropic effects caused by fracture alignment and orientation, Hudson¿s crack model and Thomsen¿s anisotropy theory are used to predict the directional dependence of P- and S-wave velocities by incorporating fracture dip, aspect ratio, and volume fraction as independent parameters. Fluid substitution effects on elastic velocities under in situ reservoir conditions are modeled using the anisotropic extension of Gassmann¿s equation. Simulation results demonstrate that pore aspect ratio and porosity are primary controls on elastic velocities, with low aspect ratio (crack-like) pores exerting a pronounced impact. Fracture porosity and dip emerge as key factors, particularly above threshold values, dictating the anisotropic response of P- and S-wave velocities, and accurately reproducing observed log data and seismic signatures in fractured HDR systems. This integrative rock physics modeling methodology provides a robust and quantitative means to estimate subsurface velocity fields, consequently facilitating improved fracture characterization, fluid detection, and reservoir evaluation, thereby reducing exploration risk and supporting the advancement of geothermal energy extraction from Hot Dry Rocks. |
| Keywords | Velocity Prediction, Rock Physics Modeling, Differential Kuster-Toksz Model, Differential Effective Medium (DEM) |