克拉苏冲断带深层碎屑岩有效储层物性下限及控制因素

Lower Physical Property Limit and Controlling Factors on Deep Effective Clastic Reservoirs in Kelasu Structure Zone

库车坳陷克拉苏冲断带深层白垩系碎屑岩储层为研究区内一套优质储层和主要产层,埋深2 300~7 900m,取心偏少,有效储层分布预测难度大。综合运用岩心、储层实验分析和测井、压汞、试油等资料,分别利用分布函数曲线法、含水饱和度上限值法、最小有效孔喉半径法及排驱压力法,求取了白垩系巴什基奇克组储层不同深度下有效储层的物性下限,并运用回归分析方法求取了物性下限与深度之间的函数方程,实现了物性下限与深度的动态拟合。结果表明：研究区内有效储层孔隙度下限取2.63%,有效储层埋深下限预测达8 320m;而理论上,克拉苏冲断带有效储层孔隙度下限可达1.69%,埋深下限可达9860m,勘探前景非常广阔。本文在物性下限研究的基础上,结合岩性特征、埋深、地层压力及成岩作用特征探讨了深层有效储层发育的控制因素。储层质量差异主要受控于储层的埋深、溶蚀作用及构造破裂作用。

The Cretaceous Bashijiqike Formation is a high-quality sandstone reservoir and a primary oil/gas-producing bed in Kelasu structure zone.As its burial depth is between 2 300 mto 7 900 m,and cores are relatively limited,and the prediction of effective reservoirs is considerably difficult.Based onthe comprehensive application of the core,well logging data,mercury injection data,and oil production test,the lower physical property limit of deep clastic reservoirs in Kelasu structure zone is determined by the distribution function curve method,the upper limit of water saturation method,the lowest effective pore throat radius method,and the entry pressure method.The functional equation between lower physical property limit and depth is obtained.The lower porosity limit of effective reservoirs is 2.63%.The lower burial depth limit of effective reservoirs is predicted to be about 8 320 m,which indicates a bright exploration prospect.The lower porosity limit and the lower burial depth limit would be 1.69%and 9 860 min theory.On the basis of the research of lower physical property limit,combining the analysis of the sedimentary characteristics, buried depth, reservoir pressure, and diagenesis characteristics of Bashijiqike Formation sandbodies,the controlling factors of effective reservoirs are discussed.The main controlling factors of the effective reservoir include buried depth,dissolution and fissure.