Simulation of simultaneous propagation of multiple hydraulic fractures in horizontal wells

Abstract

The multi-stage hydraulic fracturing technology is widely used in horizontal wells for the economical production of fossil fuels. This technology can reduce the operational costs by simultaneously creating multiple hydraulic fractures, however production log data demonstrate its failure in generating effective hydraulic fractures from a portion of perforation clusters. In order to promote a more uniform fracture growth, we present a numerical model as a tool to investigate the simultaneous propagation of multiple hydraulic fractures in horizontal wells. The model captures related physical processes by coupling elastic deformation of rock, stress interaction among fractures, fluid flow in fractures and flow distribution into different fractures. We simulate the growth of multiple hydraulic fractures in numerical cases to investigate the competition process in hydraulic fractures. Numerical results indicate that some measures such as increasing perforation friction and utilizing the inter-well stress interference can promote the uniform growth of multiple hydraulic fractures. We also investigate these optimization measures and their limitation in engineering practice. Although some factors in practice, such as unpredictable near-wellbore tortuosity pressure drops, hinder the optimization of uniform growth, the above-mentioned measures are still proposed to partially mitigate the non-uniformity.