油气地质与采收率2025，Vol.32Issue(6)：42-51,10.DOI:10.13673/j.pgre.202407015
四川盆地南部地区须家河组致密砂岩应力敏感性特征
Stress sensitivity characteristics of tight sandstone of Xujiahe Formation in southern part of Sichuan Basin
摘要
Abstract
Tight sandstone reservoirs have poor physical properties and complex pore structures,so hydraulic fracturing technology is usually used to improve the beneficial development of tight sandstone reservoirs.However,the permeability of tight sandstone shows significant nonlinear characteristics with the change in effective stress,and the TERZAGHI linear effective stress theory is no longer suitable for evaluating the relationship between permeability and effective stress in tight sandstone due to the combined action of the complex fracture network formed after hydraulic fracturing and proppant.In order to determine the effective stress and stress sensitivity of tight sandstone,this paper studies the tight sandstone samples from Xujiahe Formation in the southern part of Sichuan Basin and carries out the stress sensitivity experiments for rock samples with matrix,natural fractures,and artificial fractures under three different confining pressures.The results show that during the aging test of tight sandstone,the permeability damage rates of rock samples with matrix,natural fractures,and artificial fractures without proppant increase successively,and the recovery rates of permeability decrease successively.For rock samples with artificial fractures,the proppant filling effectively increases the permeability,with the maximum permeability achieved at 25%proppant filling,which reduces the permeability damage rate of the rock samples.Compared with those of the rock samples with matrix and natural fractures,the non-linear characteristics of permeability contours of the rock samples with artificial fractures are more obvious.The non-linear effective stress coefficients of the rock samples are calculated by the response-surface model,and the variation range of non-linear effective stress coefficients is the widest in the proppant-filled rock samples with artificial fractures,followed by the rock samples with natural fractures,and the rock samples with the matrix come last.Finally,the effective stress calculated by the non-linear effective stress coefficient produces a good correlation with the permeability.关键词
致密砂岩/人造裂缝/支撑剂/有效应力/渗透率/应力敏感性Key words
tight sandstone/artificial fracture/proppant/effective stress/permeability/stress sensitivity分类
能源科技引用本文复制引用
郑玲丽,王思慧,肖文联,杨玉斌,李沅岷,陈沐遥,陈浩宇..四川盆地南部地区须家河组致密砂岩应力敏感性特征[J].油气地质与采收率,2025,32(6):42-51,10.基金项目
国家自然科学基金项目"致密砂岩气藏岩石非线性有效应力耦合机制研究"(51874248),西南石油大学青年科技创新团队项目"非常规油气渗流物理"(2018CXTD10). （51874248）
