基于裂缝形态和产能的水平井分段压裂优化研究

Optimization of Multi-stage Fracturing of Horizontal Wells Based on Fracture Shape and Performance

根据低渗透油藏的特点,基于固体应力平衡和多相流体流动,建立了水平井水力裂缝分段优化的模型。采用有限元模拟和油藏模拟研究了在避免复杂水力裂缝的前提下,水平井水力裂缝优化的影响因素。研究发现,水平井筒与最小水平地应力方位存在夹角时,分段水力裂缝出现弯曲转向,多个弯曲裂缝之间的相互干扰形成复杂的裂缝形态;当水平井筒与最小地应力方位的夹角过大时,尽量增加裂缝分段的距离,以避免相互干扰;油井累积产量随着裂缝间的距离增加而减小;油井累积产量随裂缝长度增加而增加。

Considering characteristics of low-perm reservoirs,an optimization model for multi-stage fracturing of horizontal wells is established,based on solid stress equilibrium and multiphase fluid flow.And finite element method and reservoir simulation are used for specifying factors influencing optimization of multi-stage fracturing,meanwhile avoiding complex fracture shapes.The results indicate that when horizontal wells are not in the direction of the minimum stress,hydraulic fracture will re-orientate,and interference between multiple fractures leads to complicated fractures.In order to avoid interference,to increase distance between multiple fractures is expected,when there is great deviation between horizontal wellbore and the minimum stress.And oil accumulation decreases with distance between fractures,increases with fracture length.