Lattice Simulation of Fracture Propagation in the Bakken Formation

Horizontal well drilling and hydraulic fracturing have been widely applied to enhance the shale oil production in the Bakken Formation. Previous research for Bakken Formation primarily focused on reservoir characterization, hydraulic fracturing treatments, and well completion design. However, few studies have been done on the simulation of hydraulic fracture propagation under real Bakken Formation's mechanical properties and field stresses. The objective of this study was to investigate numerically the effects of the in-situ stresses and formation properties on the geometry and pressure of hydraulic fracture. A fully coupled lattice model, based on the distinct element method (DEM) and synthetic rock mass (SRM), was used for the simulations. XSite, a new, lattice-based software by Itasca was used in this study. The model input data was taken from 1D mechanical earth models (MEM) built and the results of lab test on 240 core samples acquired from eight wells drilled into Upper, Lower and Middle Bakken. The results indicated that the hydraulic fracture which is initiated at the center of the Middle Bakken Formation can penetrate into both the Upper and Lower Bakken formations due to the high Young's modulus of both formations. Sensitivity analyses of the formation properties and in-situ stresses on hydraulic fracture propagation were carried out.