西北沙巴盆地油气地质特征及油气成藏控制因素

以油气地质理论为指导,在构造、沉积地层特征研究的基础上,重点分析了西北沙巴盆地不同构造区烃源岩、储集层、圈闭等油气地质特征,并分析了构造对盆地油气成藏的控制作用。认为该盆地的主要烃源岩是Stage Ⅳ泥/页岩;有利储集层为由Stage ⅣC、Stage ⅣD砂岩组成的上砂岩单元、Stage ⅣA砂岩组成的下砂岩单元以及Stage ⅣC、Stage ⅣD滑塌形成的深水浊积扇;总结出下、上及深水3套储盖组合。盆地各烃源岩、储集层受构造—地貌控制分布于不同的构造区;受不同时期变形作用的影响,盆地各构造区内发育不同类型的圈闭,进而控制了盆地油气藏的形成和分布。

HYDROCARBON GEOLOGY IN NW SABAH BASIN AND CONTROLLING FACTORS ON HYDROCARBON ACCUMULATION

The NW Sabah Basin is one of the major exploration targets in Southeast Asia. With hydrocarbon geological theory as the guide, the distribution and maturity of source rocks, reservoirs, cap rocks and traps in different tectonic zones are studied, and the main controlling factors on hydrocarbon accumulation also discussed in this paper, on the basis of structural and stratigraphic studies. It is proved that the mudstones and shale in the StageⅣ are the main source rocks and the main clastic reservoirs are provided by the Lower Sandstone Unit of Stage ⅣA, the Upper Sandstone Unit of Stage ⅣC and ⅣD, and the turbidites of Stage ⅣC and ⅣD. Three reservoir-seal combinations, i.e. the lower, upper, and deep-water turbidite fan combinations, have been identified, and the lower one is best among the three. Source rocks and reservoirs are distributed in different tectonic areas under the control of tectonics and palaeogeography. Various traps are developed in different tectonic areas by the distinct deformation effect, which controls as well the formation and distribution of oil accumulation in the basin.