We use a novel meshing routine to build a coupled flow-geomechanical model of injection and production in a caprock-reservoir-basement system with two conjugate curved faults that resemble a horst-graben or a synthetic-antithetic fault structure. The routine provides the 3D coordinates of each corner in the grid in a CMG grid file format. Our workflow enables us to represent the two faults as 3D objects to which we assign actual physical properties and dimensions of the faults. This is highly advantageous because traditional structured grids cannot represent curved faults, connected faults, or fault intersections without sacrificing either their geometry or their hydromechanical properties. Sacrificing the curved geometry of faults results in a loss of accuracy in computing the induced stresses in the basement region, which is known to host most of the recorded induced seismic events in US. The generated grid was used in a poro-elastoplastic simulation to examine stress changes resulting after production from a reservoir located in the hanging wall block (graben) region bounded by the two conjugate faults. The change in pore pressure due to production causes changes in both the total stress and the effective stress in the reservoir and the basement. The evolution of the shear and effective normal stresses on the faults may induce fault failure and slip depending on the fault rheology and friction parameters.
Number of Pages
Gringarten, E. J., Arpat, G. B., Haouesse, M. A., Dutranois, A., Deny, L., Jayr, S., … Nghiem, L. X. (2008, January 1). New Grids for Robust Reservoir Modeling. Society of Petroleum Engineers.
Gringarten, E. J., Haouesse, M. A., Arpat, G. B., & Nghiem, L. X. (2009, January 1). Advantages of Using Vertical Stair Step Faults in Reservoir Grids for Flow Simulation. Society of Petroleum Engineers
Computer Modelling Group LTD. (2016). Advanced Processes & Thermal Reservoir Simulator: User Guide. Calgary, Canada
Peter O. Gold, Eric Cowgill, Oliver Kreylos, Ryan D. Gold; A terrestrial lidar-based workflow for determining three–dimensional slip vectors and associated uncertainties. Geosphere ; 8 (2): 431–442.
Bubshait, A. A., Aminzadeh, F., & Jha, B. (2018, April 22). An Integrated Framework of Stress Inversion and Coupled Flow and Geomechanical Simulation for 4D Stress Mapping. Society of Petroleum Engineers.
Looking for more?
Some of the OnePetro partner societies have developed subject- specific wikis that may help.