Rock deformation models and fluid leak-off in hydraulic fracturing
Rock deformation models and fluid leak-off in hydraulic fracturing
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DOI：
10.1093/gji/ggt199
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发表时间：
2013-09
影响因子：
2.8
通讯作者：
V. Yarushina;D. Bercovici;M. Oristaglio
中科院分区：
文献类型：
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作者：
V. Yarushina;D. Bercovici;M. Oristaglio
摘要 水力压裂期间进入储层岩石的流体损失通过孔隙弹塑性压力扩散方程进行建模，其中总压缩率是流体、岩石和孔隙空间压缩率的总和。模型中包含孔隙压缩性和与孔隙度相关的渗透率会导致泄漏（即排水速率）具有很强的压力依赖性。由于液体侵入而引起的基质扩张导致液体渗漏率更高。本模型适用于天然裂缝和致密气藏，以及机械行为偏离简单弹性定律的松软和固结不良地层。新模型预测，膨胀导致的漏失系数增强，可能有助于解释水力压裂页岩气增产中压裂液回收率较低（通常在 5% 至 50% 之间）的原因。
SUMMARY 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.