An Integrated Geology-Engineering Approach to Duvernay Shale Gas Development: From Geological Modeling to Reservoir Simulation

Abstract

Abstract Unconventional shale resources are widely distributed in the Western Canadian Sedimentary Basin and have great potential for development. However, due to the complex distribution of shale sweet spots and the high drilling and fracturing costs of horizontal wells, the petroleum industry faces great challenges in the efficient and economic development of shale resources. This paper proposes an integrated geological-engineering method to characterize the Duvernay shale reservoir near the Fox Creek region. First, reservoir petrophysics is characterized based on core experiments. Second, based on geomechanical experiments and acoustic logging, we characterize elastic parameters and in-situ stress tensors to establish a geomechanical model. Next, focal mechanisms of microseismicity are employed to identify large-scale natural fractures and faults. Then, based on the aforementioned models, as well as the perforation and treatment data, the propagation of full 3D hydraulic fracture networks for horizontal wells is simulated to construct the unconventional fracture model (UFM) via Petrel Kinetix. Finally, numerical simulations of horizontal wells are conducted, which are further corroborated by the production performance of fractured wells. It is found that the core analysis of the key well suggests that reservoir porosity, permeability, and gas saturation are averaged to be 5.3% and 404 nD, respectively. The rock mechanical parameters, including Poisson's ratio, and Young's modulus, are derived from the triaxial compression tests, with both average values of 0.21 and 36.2 GPa, respectively. The natural fractures in the examined region have been demonstrated to be governed by two-period tectonic activities and hence developed with mean dip azimuths of NE21° and SE111°, respectively. Real-time fracturing parameters of four horizontal wells are used to simulate the complex propagation of hydraulic fracture networks, considering the reservoir heterogeneity and stress shadows among different stages. Numerical simulations of well production are conducted based on the geological and geomechanical models. The agreement between simulation results and production performance reaches more than 90%, indicating the effectiveness of this integrated method for shale gas development. This work provides a solid foundation for site selection and fracturing job size optimization of new horizontal wells in the future.