库车坳陷北带天然气聚集成藏的关键因素

对比库车坳陷北带不同构造的天然气成藏基本条件,认为气源供给、储集条件、盖层品质、圈闭条件和超压不是天然气成藏的主导因素。烃源岩生排烃期、断裂活动时期和圈闭定型期“三史”匹配表明,不同构造圈闭都有捕获天然气的时机,能否在此时机成藏,关键取决于是否有天然气运移、充注和封盖的条件,而这三个条件能否有利配合,取决于圈闭的完整性和是否发育不切穿区域性盖层的气源断层,这是库车坳陷北带天然气聚集成藏的关键因素。图5表1参12

Key factors of gas accumulation in the north belt of Kuche Depression

The basic conditions of different structure gas accumulation in the north Kuche Depression suggest that the gas supply, reservoir conditions, cap quality, trap qualification and super pressure were not dominant factors of gas accumulation. The periods of hydrocarbon generation and release, period of faults action and trap shaping phase for different structures indicated that all traps had chances to capture oil or gas. Whether gas was accumulated or not during the periods, the key conditions could be gas migration, placement and mothballing. And complication of gas resource faults which not cut through the regional cap-rock is the key factor in the north Kuche Depression.