Numerical Simulation of Sequential and Simultaneous Hydraulic Fracturing

Hydraulic fracturing of horizontal well hydraulic fracturing technology can help develop unconventional geothermal and petroleum resources. Today, industry uses simultaneous and sequential (also known as zipper) fracturing in horizontal petroleum well stimulations. To achieve successful and desired stimulated rock volumes and fracture networks, one must understand the effect of various rock and fluid properties on stimulation to minimize the risk of unwanted fracture geometries. This paper describes the development of a 2D coupled displacement discontinuity numerical model for simulating fracture propagation in simultaneous and sequential hydraulic fracture operations. The sequential fracturing model considers different boundary conditions for the previously created fractures (constant pressure restricting the flow back between stages and proppant-filled). A series of examples are presented to study the effect of fracture spacing to show the importance of spacing optimization. The results show the fracture path is not only affected by fracture spacing but also by the boundary conditions on the previously created fractures.