埋藏压实-构造抬升地质过程下储层孔隙回弹的演化过程模型

Sandstone pore rebounding evolution model of a geological process from burial compaction to tectonic uplift

早期埋藏压实、晚期构造抬升是我国多个盆地一种共性的地质演化过程。受此类演化过程的影响，特别是在晚期构造抬升、砂岩孔隙回弹作用下，可形成较优质储层。明确此类储层孔隙、孔径、喉径等参数的演化特征并进行定量评价，对油气勘探具有重要意义。基于成岩物理模拟实验分析，与实际地质研究相结合，认为库车坳陷克拉2气田白垩系储层的孔隙类型、含量变化及演化规律可划分为5个阶段，前3个演化阶段与克拉苏构造带深层相一致，自上新世（5～3Ma）、埋深6000m右始，浅层克拉2井区与深层克深-大北井区的埋藏演化开始分异。之后发生构造抬升作用，可将其划分为早期和晚期两个阶段。构造抬升后发生的“孔隙回弹”作用可使储层剩余的原生孔增加1．0％左右，地层降温卸压作用，可使储层中出现较多的成岩缝。孔隙回弹、成岩缝的出现，促进了次生溶蚀作用发生、储层孔喉分选均一性的增强，进而提高了储集性。

Early shallow buried for a long time, the late quickly buried deep and late tectonic uplift in western foreland basin are common geological evolution process. Affected by such geological evolution process, especially in the late tectonic uplift and sandstone rebounding, a high- quality reservoir can be formed. Clearing this kind of reservoir parameters such as porosity, pore diameter and throat diameter of evolution characteristics and quantitative evaluation, has great significance for oil and gas exploration. Based on analysis of physical simulation of diagenesis experiment, combined with the actual geological research, the reservoir pore types and evolution can be divided into five stages. The first to the three evolution stages is consistent with the deep crassus. Since Pliocene, beginning around 6 000 m depth, the burial evolution that Well Kela 2 and Keshen 2 area began to differentiation. The tectonic uplift effection can be divided into early and late two stages. The sandstone rebounding occurred after tectonic uplift. The sandstone rebounding effect can make the remaining native hole increases by about 1.0%. The sandstone rebounding and secondary dissolution pore can increase the porosity of reservoir. The diagenetic fissure and uniform reservoir pore can improve the reservoir permeability.