Hydraulic fracturing process by using a modified two-dimensional particle flow code - method and validation

Abstract

Hydraulic fracturing had been proved as a very useful tool for unconventional oil and gas development, where the fracturing fluid is injected into tight reservoirs under high pressure to enhance the permeability of rock mass. Although hydraulic fracturing theory, numerical modelling, and laboratory experiments develops fast, knowledge is still limited when the geological conditions are complex. This paper presents a numerical method - particle flow code (PFC) - and validates its power for hydraulic fracturing modelling in complex conditions. Firstly, the bonded particle method (BPM) and fluid-mechanical coupling mechanism are introduced; secondly, Darcy's flow in circular particles is simulated; thirdly, a series of numerical simulations is carried out to validate its suitability for hydraulic fracturing modelling; finally, the laminated reservoir will be modelled by BPM. The modelling results show good agreement with classical analytical solution and laboratory test results, which demonstrates that the BPM is a useful and strong tool for understanding the fracturing behaviour of reservoir rocks.