Formation condition, distribution law and exploration potential of far-source secondary oil and gas reservoirs

TAO Shizhen; LI Jianzhong; LIU Shaobo; BAI Bin; ZHENG Min; WEI Yanzhao; CAO Zhenglin; HAN Wenxue; MA Weijiao; LIU Haitao; YANG Fan; LIU Wei; GU Zhidong; WU Yinye; TAO Xiaowan

Abstract：It is a strategic choice to find the efficient and high quality oil-gas reserves and reduce the exploration cost under the background of low oil prices.Based on independent research,tracing analysis of oil-gas exploration and production,development trend of global oil-gas exploration practice,we analyzed the geological characteristics,reservoir forming conditions,resource potential,distribution law and exploration prospect of oil and gas reservoirs.In the course of study,we mainly focused on the formation and distribution of high quality resources of fault basin,depression basin,foreland basin and craton basin including Songliao basin,Bohai Bay basin,Ordos basin,Junggar basin,Tarim basin,Qaidam basin.Meanwhile,we also studied five middle and small basins including Jiuquan basin,Jianghan basin,South basin and 68 far-source secondary oil and gas reservoirs.We have made clear that secondary oil and gasreservoirs are shallow buried,with good physical properties,high productivity,rapid construc-tion capacity and high producing degree,and they are an important area of low cost and highbenefit exploration and development in the near future.Four favorable geological conditions forfar-source secondary oil and gas reservoirs were analyzed and results show that the secondaryreservoirs have the characteristics of wide distribution,large scale and good prospects for ex-ploration.It is confirmed that shallow layers in Junggar basin,Jurassic formations in Ordosbasin,middle and east of Tarim basin,Neogene formations in Bohai Bay basin and Heidimiaooil layer of Songliao basin are favorable accumulation areas of large far-source secondary oil andgas reservoirs.The uplift area,the slope belt and the late complex fault zone are the enrichedzones of far-source secondary oil and gas reservoirs.The types of oil and gas reservoirs aremainly lithologic stratigraphic reservoirs and low amplitude structural reservoirs.The resultsof this paper can provide reference for the research on far-source secondary oil and gas re-sources and the low cost and high benefit exploration and development.