Rock deformation models and fluid leak-off in hydraulic fracturing

作者：Viktoriya M. Yarushina, David Bercovici, Michael L. Oristaglio · 发表于：Geophysical Journal International · 年份：2013 · DOI：10.1093/gji/ggt199 · 被引用次数：115 · 研究领域：Hydraulic Fracturing and Reservoir Analysis、Seismic Imaging and Inversion Techniques、Drilling and Well Engineering

Fluid loss into reservoir rocks during hydraulic fracturing is modelled via a poro-elastoplastic pressure diffusion equation in which the total compressibility is a sum of fluid, rock and pore space compressibilities. Inclusion of pore compressibility and porosity-dependent permeability in the model leads to a strong pressure dependence of leak-off (i.e. drainage rate). Dilation of the matrix due to fluid invasion causes higher rates of fluid leak-off. The present model is appropriate for naturally fractured and tight gas reservoirs as well as for soft and poorly consolidated formations whose mechanical behaviour departs from simple elastic laws. Enhancement of the leak-off coefficient by dilation, predicted by the new model, may help explain the low percentage recovery of fracturing fluid (usually between 5 and 50 per cent) in shale gas stimulation by hydraulic fracturing.