不同成因类型致密砂岩气成藏过程及机理研究进展

根据前人大量的研究成果,总结了致密砂岩气成藏过程和机理的研究进展。根据成因将其分为致密常规、致密深盆和致密复合砂岩气藏。致密深盆气和常规致密气成藏过程分别为:储层致密化→气体充注→聚集成藏、烃源岩生排烃→运聚成藏→储层致密化→构造改善。而致密常规和深盆砂岩气在构造叠合作用下则形成致密复合砂岩气藏。常规油气藏的背斜、断层、水动力等封闭机理适用于常规致密砂岩气藏。致密深盆砂岩气成藏机理包括水体封闭、上浮受阻、侧向断层-垂向页岩封闭、地层-成岩作用复合封闭、动态平衡圈闭和驱动压差等成藏封闭机理。其中,学者们较为公认的是动态平衡封闭机理。这种机理实质上为力学平衡与物质平衡共同作用下的动态圈闭系统,但仍存在某些方面的不确定性。所以为了更清晰地认识与研究不同地区致密砂岩气成藏机制,结合实际地质演化的特殊性进行综合判断将为其勘探开发提供一定的理论依据与指导。

A Review of the Accumulation Process and Formation Mechanism about Different Genetic Types of Tight-Gas Sandstone Reservoir

According to a large number of previous studies, we summarized the research progress of tight sandstone gas reservoir formation process and mechanism. Under its genetic classification, it was divided into conventional tight sandstone reservoir, deep basin tight sandstone reservoir and composite tight sandstone reservoir by its genetic classification. Their accumulation process was hydrocarbon generation → accumulation → densified → structure improved, densified → gas charge → accumulation and conventional reservoir→ densified →deep basin tight sandstone reservoir → accumulation compounded, respectively. Currently the conventional tight sandstone reservoir accumulation mechanism had been studied deeply. But the deep basin accumulation mechanism was studied at all the time. As we have known, it contained the following six general mechanism, water block, lack of buoyancy, fault block, straitigraphic-diagenetic, driving pressure differential and dynamic balance. Although among them the dynamic balance was widespread accepted, it all had deficiencies. So, considering the practical situation of geology is very important. And then we can understand and research different areas of tight sandstone gas reservoirs clearly to provide theoretical guidance for its exploration and development.