塔里木盆地阿克库勒凸起于奇探区三叠系油气成藏条件与成藏模式

OIL & GAS ACCUMULATION CONDITIONS AND MODELS IN THE TRIASSIC CLASOLITES OF YUQI BLOCK IN AKEKULE ARCH,TARIM BASIN

塔里木盆地阿克库勒凸起北部于奇探区是塔河油区外围重要的油气探区。以成盆、成烃和成藏理论为指导,应用盆地分析、储层预测、荧光薄片及流体包裹体分析等技术,综合研究了于奇探区哈拉哈塘组和阿克库勒组碎屑岩的油气成藏条件,建立了油气成藏演化模式。结果表明,区内油源主要来自阿克库勒凸起南部寒武系—下奥陶统烃源岩,油源较充足,具有一定的资源潜力;储集层类型以孔隙型为主,为大容积、中等—高渗透性储层,有利的储层分布区位于YQ 3—YQ 4—LX 4—LX 2井区一带;盖层封盖能力好,最有利的保存条件分布区位于于奇探区南部;圈闭类型主要为低幅度的构造圈闭和岩性圈闭;至少发生了3次油气注入成藏期,即燕山期、喜山早期和喜山晚期,油气分布主要受低幅度背斜和断层所控制;成藏模式为它源—双向排烃—多期次生成藏或古生新储—双向排烃—多期次生成藏,成藏演化经历了2个阶段。

Yuqi block in the north of the Akekule arch, Tarim basin is an important oil ＆ gas exploration area in the Tahe Oilfield. Under the guidance of the theories of basin evolution, hydrocarbon generation, and oil ＆ gas accumulation, the oil ＆ gas accumulating conditions in the clasolites of the Triassic Akekule and Halahatang formations in the Yuqi block were discussed, and oil ＆ gas accumulation models were established according to the techniques of basin analysis, reservoir prediction, fluorescence thin section and fluid inclusion. The result shows that the oil ~ gas in the Yuqi block was derived from the Cambrian to lower Ordovician source rocks in the south of the Akekule arch; and the Akekule and Halahatang formations in the Yuqi block has definite resources potential. The clasolites reservoirs types are porosity, with high porosity, and permeability ranging from intermediate to high. The favorable reservoirs is located in the wells of YQ3, YQ4, LX4 and LX2. The mudstone as seal rock in the Triassic Akekule and Halahatang formations is valid. The profitable preservation region is located in the south of the Yuqi block. The trap types are low scope tectonic traps and lithological traps. The oil ＆ gas distribution is controlled by faults and low scope anticlines. There are three times of oil/gas charges, i.e. , Yanshanian, early Himalayan and late Himalayan. The oil ＆ gas accumulation model in the Yuqi block is outward source-bidirectional hydrocarbon expulsion multi-stage accumulation or hydrocarbon sourced from the old rocks and preserved in the young rocks-bidirectional hydrocarbon expulsion-multistage accumulation with two-stage evolution. This model will provide a theoretical fundament for the next exploration in the Yuqi block and its vicinities.