胜北洼陷岩性油气藏成藏条件特殊性分析

充分认识含油气洼陷的基本石油地质条件是开展油气勘探的前提,而认识油气成藏的特殊性是寻找油气勘探切入点的关键。胜北洼陷岩性圈闭组成要素的复杂性和岩性油气藏成藏地质背景的特殊性主要表现在:1盆地性质、构造特征的特殊性――吐哈盆地表现为窄而长的多旋回叠合盆地;2洼陷沉积体系的特殊性――南北双向短物源沉积体系分布格局;3岩性油气藏成藏地质背景的特殊性――下生上储式生储组合和南斜坡的构造斜坡带;4岩性油气藏成藏圈闭的特殊性――缺乏沟通油源断裂、侧向封堵断裂的必要配置;5岩性油气藏赋存的特殊性――成带分布的岩性圈闭含油气面积小、砂体薄、单层圈闭储量规模较小。根据对这些特殊性的综合分析认为,胜北洼陷中浅层岩性油气藏勘探应依附于一定的构造背景展开;处于南北物源交汇区的胜北构造南翼是岩性圈闭发育和岩性油气藏勘探的有利地区。

THE PARTICULARITY ANALYSIS OF STRATIGRAPHY RESERVOIRS IN SHENGBEI DEPRESSION

The basic petroleum geological condition analysis is the premise for oil-gas exploration, but the particularity analysis is the key point for finding the most effective cut-in way for oil-gas exploration. The particularity of subtle traps formation and subtle reservoirs mainly show in the following points: the property of Tuha basin and structure characteristics- a long and narrow multi-recycle stacked basin; sedimentary system-two directions (north and south) short sediment sources sedimentary systems; the geological background of subtle reservoir-lower generation and upper reservoir, structural slope character of south slope; subtle traps for oil-gas occurring-fault connected with source rock and lateral fault must be existing; subtle reservoir-space accumulated with oil-gas of subtle traps are small, sandstones for oil-gas reservoir are thin and reserves of single trap are small. According the conditions mentioned above, the subtle reservoirs exploration of Shengbei depression must be clinging to stated structural background, and the south wing of Shengbei structural zone, a crossover region of north and south sediment sources, is an available area for subtle traps developing and subtle reservoirs exploration.