SN油田重复压裂技术界限研究

重复压裂是提高低渗透油田采出程度非常有效的技术措施。基于SN油田裂缝诱导应力场和生产诱导应力场模拟计算，结合最小主应力原理确定重复压裂裂缝延伸方位与原裂缝方位偏转一定角度。根据正交设计分析，应用压裂生产动态模拟器分析地层压力、当前含水状况、储层渗透率、储层孔隙度、压裂规模和导流能力对重复压裂效果的影响；以NPV作为评价重复压裂效果的准则，进而确定SN油田重复压裂最佳时机：有效厚度大于5m、压力系数大于0.5，有效渗透率大于1.0×10^-3μm²、含水饱和度不大于60%。考虑到井网配合条件，重复压裂裂缝长度应控制在90～120m、砂比>30%。应用效果良好。

RE FRACTURING TECHNOLOGY CONDITIONS IN SN OILFIELD

Re fracturing is an important stimulation for low permeability reservoir. stress field induced by existed fractures and oil production in SN Oilfield is simulated in this paper, it is proven that the azimuth of new fractures created by refracturing will be different from that of existed fractures on the base of principle of minimum principal stress. Then, according to theory of orthogonal design, simulator of fractured well production performance is used to analyze such factors affecting the oil production as formation pressure, current water cut, permeability and porosity, fracturing scale and conductivity on re fracturing effect, depending on the NPV criteria, conditions of refracturing are determined, moreover, the best time of re fracturing of SN oilfield is determined, effective thickness greater than 5m, pressure coefficient greater than 0.5，permeability greater than 1.0×10^-3μm², current water cut less than 60%。Fracture length should be controlled within 90~120m and sand ratio at 30% application effect is good.