莺歌海盆地天然气成藏动力学机制及勘探前景展望

系统地分析了莺歌海盆地天然气成藏动力学机制及主控因素 ,阐释了盆地内异常超压的发育背景及成因 ,指出异常压力是天然气运移的主驱动力 ,而流体压裂则产生了天然气垂向运移输导网络。强调底辟活动是莺歌海盆地天然气成藏与演化的主控因素———底辟活动控制圈闭的形成并为浅部圈闭成藏提供深部烃源 ;底辟的幕式活动控制天然气藏的多次成藏和演化。通过对影响莺歌海盆地天然气勘探各主要因素的分析 ,认为具有构造背景或特殊遮挡条件、成因类型多样的非构造圈闭隐蔽油气藏是莺歌海盆地今后重要的勘探方向。

Gas accumulation mechanism and exploration potential in Yinggehai basin

Based on a systematic analysis of gas accumulation mechanism and its main constraints together with the background and origin of overpressure in Yinggehai basin, it can be shown that the abnormal pressure is the major driver of gas migration, and that the natural hydrofracturing has produced vertical paths for gas migration. It should be emphasized that the episodic diapirism, as the most important constraint to gas accumulation and evolution in the basin, is in control of trap formation, supplies deep hydrocarbon for shallower traps and has influence over gas multiple accumulation and evolution. Therefore, future gas exploration in the basin should be focused on subtle traps with various origins under some special structure background and seal condition.