多裂缝诱导应力场与簇间距优化

Fractures Induced Stress Field and Inter-cluster Distance Optimization

基于弹性力学基础理论和位移不连续理论,建立了裂缝诱导应力数学模型,同时考虑了井筒内压、原地应力、压裂液渗流效应、岩石温度变化和射孔作用对应力场的影响.以获得最大应力反转区域为优化目标,形成一种新的簇间距优化方法.研究结果表明:诱导应力在最大水平主应力方向和最小水平主应力方向的改变量不同,对最大主应力方向的影响更显著;裂缝间距越小,诱导应力影响越明显,中间裂缝宽度越小.

Staged multi-cluster fracturing technology is the key to the development of unconventional resources technology.The accurate understanding of the stress field change around the wellhole in the fracturing process is of great significance in fracture spacing optimization and reinforcing the effect of reservoir stimulation.Fractures-induced stress mathematical model was established based on the theory of elastic mechanics and displacement discontinuity.The model also takes into the consideration the effect of wellbore pressure,in-situ stress,fracturing fluid seepage effect,thermal stress and perforation upon the stress field so as to find the strongest stress reversal zone as its object for optimization and thus to form a new inter-cluster facture spacing optimization method.The results show that：for induced stress,the number in the direction of maximum horizontal principal stress and minimum horizontal principal stress direction is different and stress change is higher in the direction of maximum horizontal principal stress;the smaller the fracture spacing is,the more obvious the induced stress influence will be,and the smaller of the crack width in the middle becomes.