Successfully creating multiple hydraulic fractures in horizontal wells is critical for unconventional gas production economically. However, it will not be possible to fully optimize multiple fracture stimulations until accurate methods are available to directly predict fracture geometry.
In this paper, a novel Fracture Propagation Model (FPM) is developed to simulate multiple hydraulic fracture propagation simultaneously in a stage of the horizontal wellbore. This model couples fracture deformation with fluid flow in the fractures and the horizontal wellbore. The displacement discontinuity method is used to describe the geometry of multiple fractures, considering mechanical interaction between the fractures. Fluid flow and pressure drop in the fractures are determined by the Hagen Poiseuille law. Friction pressure drop in the wellbore and perforation zones is taken into account by applying Kirchoff's first and second laws. The fluid flow rates and pressure compatibility are maintained between the wellbore and the multiple fractures by using Newton's numerical method. The model accurately predicts multiple fracture geometry and computed non-planar fracture trajectories. Shear stress distributions indicate areas likely to have induced micro-seismicity.
The simulation results of FPM can serve as guidance for shale gas simulation and multiple fracture treatments. Also, the results from the model highlight conditions under which restricted width occurs that could lead to proppant screenout. This wok can help operators to design multiple fractures to enhance recovery in unconventional gas reservoirs.