准噶尔盆地重32井区齐古组油藏主控因素

The Dominant Factors of Hydrocarbon Accumulation in Qigu Formation in Zhong32 Wellblock, Junggar Basin

在分析地层、构造、沉积、储层及流体特征基础上,从不整合和断裂两方面对准噶尔盆地重32井区齐古组油藏主控因素进行分析。结果表明:齐古组油藏类型为发育在不整合半风化岩石带内的浅层地层-断块型超稠油油藏,成藏模式为侏罗纪末—白垩纪源外-不整合-断控次生油气藏成藏;不整合-断裂是油气运聚的主要运聚体系;白垩系/侏罗系不整合风化黏土层普遍发育,但其封盖能力差,是稠油形成的重要原因;多期构造运动及断裂-不整合复合输导体系是研究区齐古组稠油油藏形成的主控因素。

Based on the characteristics of strata, tectonics, sedimentary reservoir and fluid characteristics, the dominant factors of the hydrocarbon accumulation in Qigu Formation in Zhong32 wellblock in Junggar Basin are analyzed from the aspects of unconformity and faulty. The results show that Qigu Formation reservoir belongs to the type that would exist in the semi-weathering rock of Cretaceous-Jurassic unconformity in a fault block background. The model of hydrocarbon pool-forming is a secondary reservoir controlled by unconformity-fault, out of the source rock province from the late Jurassic to the Cretaceous unconformity. The unconformity-fault system of migration and accumulation is the primary system in the hydrocarbon migration and accumulation. The long-term weathering and erosion makes the reservoir quality much better. Though the Weathered Clay of Cretaceous-Jurassic unconformity is widespread development in Zhong32 wellblock, its sealing ability is poor, resulting in the leakage of light weight fractions of hydrocarbon and the formation of heavy oil reservoirs. Multistage tectonization and unconformity-fault migration-accumulation system are the main controlling factors for super heavy oil reservoirs in Qigu Formation.