柴北缘东坪地区深层含油气系统油气运聚成藏规律
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摘要
近年来,柴达木盆地边缘大型构造-岩性复合油气藏具有良好的勘探前景,近期勘探实践表明,柴北缘东坪地区深层发育基岩风化壳和路乐河组底砾岩两大含油气系统。通过综合分析两大含油气系统中烃源供给子系统、储盖组合子系统、油气运聚子系统的地质特征,同时利用东坪地区虚拟井地层埋藏史、生烃史模拟结果,分析了油气运聚成藏规律,建立了路乐河组和基岩风化壳两套含油气系统成藏模式。结果表明,相邻的坪东凹陷和昆特依凹陷侏罗系地层是两套含油气系统的主要供烃中心,连片的厚层砂体、区域性不整合面是油气横向运移的重要通道。围绕侏罗系大型生烃凹陷,立足阿尔金山前古构造(古斜坡),寻找大型煤型气田是东坪地区实现突破的勘探新思路。喜山期活跃的深大断裂为油气的纵向输导提供了通道,在古隆起和古斜坡背景下形成了以构造-岩性复合圈闭和地层岩性圈闭为主要类型的天然气聚集区,沿油气运移通道分布的复合圈闭是东坪地区下步勘探的有利方向。
In recent years,large-scale structural-lithologic hydrocarbon reservoirs at the margin of the Qaidam Basin has good exploration prospect.Recent exploration practices have shown that two major petroliferous sys-tems of the bedrock weathering crust and the Lulehe Formation conglomerate deeply developed in Dongping area at the northern margin of the Qaidam Basin.Geological characteristics of the hydrocarbon source supply subsystem,reservoir-cap combination subsystem,and oil-gas migration and accumulation subsystem in two major petroliferous systems were analyzed comprehensively.Based on the simulation results of the burial history and hydrocarbon generation history of the virtual well strata in the Dongping area,the oil and gas migration and accumulation law was analyzed.Accumulation models of these two petroliferous systems were proposed.The results show that the Jurassic strata in the adjacent Pingdong and Kunteyi Sag are the main hydrocarbon supply centers of the two petroliferous systems.The contiguous thick sand body and regional unconformity sur-face are the important pathways for the lateral migration of oil and gas.The breakthrough of the development in Dongping area focuses on looking for large-scale coal-related gas fields based on Altyn piedmont pale-ostructure(palaeoslope) around the Jurassic large-scale hydrocarbon-generation sag.The active deep faults in the Himalayan period provide a channel for the longitudinal transport of oil and gas,tectonic-lithologic complex traps and stratigraphic lithologic traps and other types of natural gas accumulation areas were formed under the background of the paleo-uplift and the ancient slope.The complex traps distributed along the oil and gas migration pathway are favorable directions for the next exploration in Dongping area.
In recent years,large-scale structural-lithologic hydrocarbon reservoirs at the margin of the Qaidam Basin has good exploration prospect.Recent exploration practices have shown that two major petroliferous sys-tems of the bedrock weathering crust and the Lulehe Formation conglomerate deeply developed in Dongping area at the northern margin of the Qaidam Basin.Geological characteristics of the hydrocarbon source supply subsystem,reservoir-cap combination subsystem,and oil-gas migration and accumulation subsystem in two major petroliferous systems were analyzed comprehensively.Based on the simulation results of the burial history and hydrocarbon generation history of the virtual well strata in the Dongping area,the oil and gas migration and accumulation law was analyzed.Accumulation models of these two petroliferous systems were proposed.The results show that the Jurassic strata in the adjacent Pingdong and Kunteyi Sag are the main hydrocarbon supply centers of the two petroliferous systems.The contiguous thick sand body and regional unconformity sur-face are the important pathways for the lateral migration of oil and gas.The breakthrough of the development in Dongping area focuses on looking for large-scale coal-related gas fields based on Altyn piedmont pale-ostructure(palaeoslope) around the Jurassic large-scale hydrocarbon-generation sag.The active deep faults in the Himalayan period provide a channel for the longitudinal transport of oil and gas,tectonic-lithologic complex traps and stratigraphic lithologic traps and other types of natural gas accumulation areas were formed under the background of the paleo-uplift and the ancient slope.The complex traps distributed along the oil and gas migration pathway are favorable directions for the next exploration in Dongping area.
引文
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[2]景琛,王兆兵,张德龙.利用流体包裹体确定成藏期研究进展[J].中外能源,2018,23(11):48-54.
[3]刘静江,刘池洋,王震亮.从含油气系统到成藏油气系统研究新动向[J].地质论评,2008,54(6):801-806.
[4]张景茹,何家雄,龚晓峰,等.南海北部湾盆地福山凹陷含油气系统与油气运聚成藏规律[J].海洋地质前沿,2011,28(1):30-37.
[5]王永卓,孙德君,徐景祯.柴达木盆地北缘地区含油气系统划分与成藏历史分析[J].石油学报,2003,24(5):21-25.
[6]关德范,徐旭辉,李志明,等.烃源岩生排烃理论研究与泥页岩油气[J].中外能源,2012,17(0):40-52.
[7]张敏,尹成明,陈琰.柴达木盆地北缘含油气系统与油气勘探方向[J].沉积学报,2005,23(1):143-149.