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深盆气的最本质特征是盆地中心饱含气。凡煤系发育、构造稳定、埋藏适中、经历过高地温演化阶段的盆地都能形成深盆气。深盆气上倾方向多因致密岩石含水而封闭,孔隙性地层的水封只是个例,它因深盆中仍不断大量供气而存在。深盆气形成于高温高压的环境中,早期地层水因汽化而与甲烷气混溶,一部分随岩性变致密加厚水膜而成为束缚水,导致深盆气盆地内无水层。但在深盆气萎缩阶段,降温降压过程可使蒸汽水“冷凝”形成深盆气中的“酸点”。“酸点”水规模小呈散点状分布,矿化度低于正常地层水矿化度。深盆气因所处演化阶段不同而具有不同的压力特征,既可以是低压的,也可以是高压的。松辽盆地、沁水盆地和西北侏罗系含煤盆地都具有深盆气形成的条件。
The most essential feature of deep basin gas is its full of gas in the center of the basin. Where the coal development, structural stability, buried moderate, experiencing high geothermal evolution stage of the basin can form a deep basin gas. In the deep basin, the upwelling direction is mostly closed due to the water content of dense rocks. The water seal of the porous formation is only an example, because of the large amount of gas still present in the deep basin. Deep basin gas is formed in a high temperature and high pressure environment. Early formation water is miscible with methane gas due to vaporization, and part of it becomes irreducible water due to thickening and thickening of water film with lithology. As a result, there is no water layer in the deep basin gas basin. However, in the stage of deep basin gas atrophy, the process of cooling and depressurization can make the steam water “condensate ” to form “acid point ” in deep basin gas. “Acid point ” small scale water was scattered distribution, salinity is lower than the normal formation water salinity. Deep basin gas has different pressure characteristics due to different stages of evolution, which can be either low pressure or high pressure. Songliao Basin, Qinshui Basin and Northwest Jurassic coal-bearing basins all have the conditions of deep basin gas formation.