Abstract
Tight sandstone gas has tremendous resource potential and it has become the focus in the area of global unconventional gas exploration. According to the accumulation mechanism controlled by physical property during accumulation process, tight sandstone gas reservoir can be divided into three types: accumulation after the first compaction, compaction after the first accumulation and combination reservoir. Tight sandstone deep basin gas reservoir possesses the characteristics of source-proximal migration, continuous charging and non-darcy flow mechanism. The charging pressure mainly includes overpressure pressure differential and source-reservoir pressure differential. In addition, the gas saturation is commonly controlled by charging pressure, reservoir physical property, heterogeneity and permeability differential. The peculiar gas accumulation mechanism of "dynamic trap" leads to the intermittency of accumulation process and the variation of gas-water distribution. Its enrichment and accumulation require large area source rocks with high abundance ratios, tight heterogeneous reservoir contacting with source rocks closely, regional cap rocks and gentle structure background.
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