Hydrogeomechanical modeling of reservoir by external coupling of specialized computational software and universal CAE Fidesys

We study several algorithms for solving the coupled problem of hydrogeomechanical modeling of fluid filtration in a deformed fractured rock, allowing to describe the mutual influence of filtration and rock deformation processes on the dynamic parameters of the medium: porosity, permeability, rock stiffness and fracture extensions. These algorithms allow solving the problems of choosing the location and drilling trajectory of a well either wellbore stability, ensuring high productivity of the formation due to optimization of the design of hydraulic fracturing and sand control. Together with seismic and reservoir testing data, coupled hydrogeomechanical modeling allows optimizing the tactics and strategy of reservoir development. The disturbance of formation stress-strain state in the near-well zone leads to the development of deformation processes and fracture zones, as well as changes in pore pressure and filtration properties in the reservoir. At the first stage, we verify external and internal iterative external coupling procedures. The specially developed research code was used for internal coupling procedure. For external coupling, a finite element simulator FIDESYS was used which solves numerically the problems of geomechanical stresses and deformation distributions in the rock. We developed the control module to organize the iterative process of geomechanical and hydrodynamic simulators, including reading special simulation data formats, unit conversion, as well as the value fields projection on different model grids.
In this paper, we present the modeling for several problems and discuss the computation results. Effective elastic-strength properties are determined numerically at every mesh node as a result of solving the time consuming spatial elastoplastic problem. Therefore, the reduction in the frequency of data exchange is important in this approach.
One of the goals of this numerical study, related to the above methodology, is to determine the effect of the coupling frequency on the solution. Based on the computation results for the example of the cyclic CO2 injection procedure in the Bazhenov Formation formation (Palyanovo section), only the local production characteristics are sensitive to the coupling frequency. The results obtained in this paper allow us to conclude that the role of geomechanical effects of fractured rock deformations saturated with a fluid is significant for modeling the formation processes.