论文详情
对4组深层致密砂岩样品进行不同围压条件下的声学测试,利用Biot相洽原理及微分等效介质原理对岩石裂隙密度ε及孔隙纵横比α进行了反演。将2种方法相结合探讨了不同围压条件下岩石中孔裂隙形态演化及分布规律,避免了单一方法研究的不足。研究结果表明,ε随围压增加而减小,α随围压增加而增大。由于不同砂岩内部结构及性质的不同,内部裂隙具有不同的应力敏感性。分选性较差的砂岩应力敏感性强,裂隙维持张开所能承受的应力较低;分选性较好的砂岩应力敏感性较弱,裂隙维持张开所能承受的应力较高。探讨了所定义转折压力与岩石样品物性间的关系,结果表明,两者具有非常好的正相关性。
we carry out acoustic test on four groups of deep tight sandstone samples under different confining pressures,inverse the rock fracture density (ε) and pore aspect ratio (α) using Biot-consistent principle and differential effective media theory.By combining the two methods,we can identify the rock pore/fissure morphology evolution and distribution under different confining pressure conditions.It can overcome the deficiency using a single method.The results show that the fracture density decreases while the pore aspect ratio increases along with the increasing confining pressure,which is mainly due to the closure of fractures in high stress environment.Because the internal structure and properties of sandstone is different,there’s different stress sensitivity for internal fractures.The stress sensitivity of poor sorting sandstone of A group and D group is strong,the stress that fracture maintains open is low;the stress sensitivity of good sorting sandstone of B group and C group is weak,the stress that fracture maintains open is high.Discussion on the relationship of defined twist pressure and rock physical properties show a very good positive correlation between them.
国家自然科学基金面上项目(41372139,41072098)和国家科技重大专项(2016ZX05046-003-001,2011ZX05018-001-002,2011ZX05033-004)联合资助。