深层优质碎屑岩储层全生命周期分析方法论

A full-life-cycle research methodology of deep high-quality clastic rock reservoirs

油气勘探领域的深层是指沉积盆地中埋深在3 500~4 500 m及以深的地层。在含油气盆地的深层碎屑岩储层中,优质储层是重要的勘探目标。优质储层具有大量孔隙,其形成与沙或砂岩的沉积条件、埋藏方式、区域温压场、膏盐岩效应等多种因素有关。通过系统研究全球不同区域不同时代不同类型深层碎屑岩储层,提出优质深层碎屑岩储层的全生命周期研究方法,即从储层形成演变的全部时间出发,将深部储层的形成过程划分为早期剥蚀搬运沉积阶段、中期埋藏阶段、中期或/和晚期改造阶段,从全生命周期的尺度分阶段综合分析深层碎屑岩储层的形成及演化过程,推演在地质历史时期中的优质储层演化时序及发育阶段、分布位置。

Deeply buried hydrocarbon reservoirs are those located in the depth of 3 500 to 4 500 m interval or ever deeper. The high quality reservoirs that have anomalously high porosity(AHP) are important exploration targets for deeply buried clastic hydrocarbon accumulations. The generation and preservation of AHP is related to a number of factors, such as depositional environment, burial process, regional temperature-pressure conditions and gypsum-salt effects. A full-life-cycle research methodology of AHP in deeply buried clastic reservoirs is proposed in this paper, after comprehensive studies on varied deeply buried clastic reservoirs from vast number of regions with different geological times both at home and abroad. Based on the spatial and temporal evolution of reservoir formation, AHP process can be divided into several stages, including provenance rock weathering, clastic material transportation and deposition in the early stage, then burial and transformation processes in the middle and late stages. The evolution process of AHP during its full geological history is analyzed and high quality reservoir locations are predicted.