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

Key words: 
• low porosity and low permeability /
• tight sandstone reservoir /
• accumulation process /
• deep basin gas /
• accumulation mechanism

Abstract: 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.