【摘要】 根据鄂尔多斯盆地下石盒子组致密砂岩在地层条件和不同流体相态下(干燥与水饱和)岩石纵波速度、横波速度、密度、模量等岩心测试数据,统计分析了岩石弹性参数的变化规律。结果表明,岩石碎屑都比较纯净、颗粒之间呈接触胶结,造成致密砂岩密度与速度的变化关系不同于高孔渗砂岩;孔隙度降低造成致密砂岩的横波速度与纵波速度的斜率明显变小;岩石孔隙度增加10%,引起纵波和横波速度降低分别约17%和21%,而泥质含量增加10%,引起纵波和横波速度降低分别约6%和9%;孔隙度大于5%的干砂岩体积模量与剪切模量在数值上接近,相对误差不超过5%。这些规律的认识有助于指导低孔隙度储层预测和地震资料的岩石物理解释。更多还原

【Abstract】 Variation rules of elastic properties of tight sands in the lower Shihezi Formation of the Ordos Basin were discussed based on in-situ measurement data of longitudinal velocity,transversal velocity,density and modulus of rocks under conditions of different formation pressures and pore fluid phases(dryness and water saturation).The result shows that rock detritus are relatively pure and characterized by contact cement among grains,the variation relationship between density and velocity of tight sands is different from that of highly porous and permeable sands.Porosity reduction may result in a significant decrease of the slope between longitudinal velocity and transversal velocity of tight sands.When porosity increases by 10%,longitudinal and transversal velocities will decrease by about 17% and 21%,respectively,whereas longitudinal and transversal velocities will decrease about 6% and 9%,respectively when shale content increases by 10%.As for dry sands with porosity greater than 5%,the bulk modulus is similar in value to the shear modulus and the proportional error is less than 5%.These conclusions are of help for predictions of low-porosity reservoirs and petrophysical interpretations of seismic data.更多还原