复杂孔隙结构储层地震岩石物理分析及应用

Seismic Rock Physical Analysis of Complex Porous Reservoir and Its Application

致密砂岩、碳酸盐岩气藏等多以低孔低渗储层为主,孔隙成因和类型复杂多样,孔隙度及渗透率对地震弹性模量和速度产生重要影响,为含气性预测带来很大困难。针对低孔低渗复杂孔隙介质,借助孔隙结构表征及地震岩石物理分析,评价孔隙结构的复杂性及孔隙流体分布的非均匀性对地震波速度的影响,揭示低孔低渗储层中地震波速度随物性、含流体性的变化规律。修正White模型描述低孔低渗储层地震频段纵波速度随含气饱和度的变化规律,建立低孔低渗储层含气饱和度定量预测模板,推动地震定量解释技术研发。研究成果在四川盆地须家河组致密砂岩气层含气饱和度地震定量预测应用中取得了良好效果。

Most of the tight sandstone and carbonate rock gas reservoirs are mainly low-porosity and low-permeability reservoirs with a variety of complex porous genesis and types. The porosity and permeability have an important influence on the seismic elastic modulus and velocity, making gas detection very difficult. To focus on the low porosity and low permeability complex pore media, the integrated evaluation of porous structure and seismic rock physical analysis can be used to evaluate how the complexity of porous structure and heterogeneity of porous fluid distribution influence seismic wave velocity, thus unveiling the law that seismic wave velocity changes with the physical properties and fluid properties. The White model is modified to represents the relationship between compressional wave velocity and gas saturation and establish the quantitative prediction template of gas saturation of low-porosity and low-permeability reservoir in order to promote seismic quantitative interpretation technological research and development. Good results were achieved when the research results were used to make seismic quantitative prediction of gas saturation in the tight sandstone gas reservoir of Xujiahe Formation in Sichuan Basin, SW China.