东海盆地丽水凹陷油气成藏组合与模式

ASSEMBLAGES AND PATTERNS OF FORMING OIL AND GAS RESERVOIRS IN LISHUI SEG OF EAST CHINA SEA BASIN

异常压力与油气的运聚、成藏和分布有密切关系。东海盆地丽水凹陷具有非常明显的异常压力现象。通过分析异常高压的分布特征 ,讨论了异常高压与油气成藏的关系 ,并总结出研究区内与异常高压有关的成藏组合和模式。研究结果表明 ,丽水凹陷异常压力属于顶封滞排型异常压力系统 ,超压带压力梯度明显不一致 ,纵向上超压带可划分为封隔层超压带、压力过渡带和超高压带等三个异常压力带。根据油气分布及成藏特征可分为封隔层内油气成藏模式 。

Abnormal formation pressure is closely related to the migration, accumulation and distribution of oil and gas and abnormal pressure phenomenon is very obvious in Lishui Seg. Through analyzing the characteristics of abnormally high formation pressure distribution, the relation between abnormally high formation pressure and reservoir formation is discussed and the assemblages and patterns of reservoir formation related to abnormally high formation pressures in the region are summarized in the paper. In light of the research results it is indicated that the abnormal formation pressure in Lishui Seg belongs to a top-sealed and stagnantly expelling abnormal pressure system; the pressure gradients in the overpressure zone are obviously different from each other; and the overpressure zone may be vertically divided into three abnormal formation pressure zones, i.e. confining-bed overpressure zone, pressure transitional zone and superhigh pressure zone, etc. According to oil and gas distribution and the characteristics of forming oil and gas reservoirs, three reservoir formation patterns may be classified in the region, i.e. reservoir formation in the confining bed, reservoir formation above the confining bed and reservoir formation below the confining bed in the abnormal pressure system.