摘要
准噶尔盆地西北缘乌—夏地区目前已经发现了多个与不整合相关的地层油气藏,分析这些不整合在油气成藏过程中的作用具有重要意义。基于三维地质模型和剥蚀厚度分析,恢复了研究区不整合的形成和埋藏史,并进行了成藏动力学的三维模拟。结果表明:乌—夏地区的三套烃源岩分别在不同的地质时期达到成熟并排烃。佳木河组烃源岩在中晚二叠世成熟,风城组烃源岩在晚三叠世开始成熟,下乌尔禾组烃源岩则在侏罗纪末开始生烃。不整合输导的模拟表明,靠近烃源岩层的不整合在油气运移中的贡献远大于远离烃源岩层的不整合,油气在不整合中沿着风化淋滤带和底砾岩层中微构造的脊部运移,形成优势运移通道。风化淋滤带中的油气横向运移距离短于底砾岩层中油气的横向运移距离。同一不整合中,油气容易在风化粘土层薄弱环节突破,进行窜层运移。不整合不但是油气输导体系,也是油气聚集的场所。
Many stratigraphic reservoirs with unconformity have been found in Wuxia area of the northwestern edge of Junggar Basin. It is important to study the role of the unconformity in the process of hydrocarbon accumulation. On the basis of 3D geological model and analysis of Erosion Thickness,the formation of unconformity and burial history of this area were studied,and the 3D dynamic system was simulated. Simulations show that the three sets of source rock reach maturity and expulse hydrocarbon at different ages in Wuxia area. The source rocks in Jiamuhe formation reach maturity at middle Permian and Late Permian Epoch. The source rocks in Fengcheng formation reach maturity at Late Traissic Epoch. The source rocks in Lower Wu’erhe Formation begin to generate hydrocarbon at Jurassic Period. The unconformity conduit simulation shows that the role of unconformity near the source rock is more important than that far from the source rock in the process of hydrocarbon accumulation,and that oil and gas migrate along the ridge in the weathering-cracked loess horizon and basal conglomerate. It is the predominant pathways for oil and gas migration. The lateral migration distance in along the ridge in the weathering-cracked loess horizon is shorter than that in basal conglomerate. Oil and gas mostly break through thin clay area and migrate to near horizon in the same unconformity. Unconformity is not only the hydrocarbon passage systems but also the oil and gas accumulation place. The distribution of Oil and gas pool is relevant to the block of the unconformity. The Oil and gas pool distribute at the block of unconformity.
出处
《西南石油大学学报（自然科学版）》
CAS
CSCD
北大核心
2011年第4期13-19,185,共7页
Journal of Southwest Petroleum University(Science & Technology Edition)
基金
国家重大科技专项"岩性地层油气藏成藏规律
关键技术及目标评价"项目(2008ZX05001)
山东省自然科学基金项目(ZR2010DQ004)
关键词
成藏模拟
不整合结构体
成藏动力学
油气运聚史
准噶尔盆地
hydrocarbon accumulation simulation
unconformity structure
dynamic system
migration and accumulation history
Junggar Basin
