物探在共和盆地干热岩勘查与开发中的应用与成果

Application and achievements of geophysical prospecting in exploration and development of hot dry rocks in Gonghe basin

针对共和盆地深部地质结构、开发场地干热岩储层特征不清晰,高温测井仪器有待攻关,干热岩测井标准规范有待建立等问题,开展了大地电磁测深与地球物理测井工作。地面物探工作以三维电磁探测技术为主,面积性覆盖整个共和盆地东部地区;开发场地测井工作以井温测井和成像测井为主,收集分析了全部干热岩钻井测井资料。通过本项目的实施,基本查明岩石物性特征,建立了开发场地地层物性柱;评价了干热岩储层物性特征,支撑干热岩开发试采;获取了共和盆地三维电性模型,基本查明主要地层结构和构造格架,编制了基岩界面埋深等值线图;基本查明共和盆地及周边电性结构与深部低阻体,刻画了共和盆地断裂几何特征、青藏高原东北缘缩短变形模式,圈定2处干热岩有利区;研发了耐高温井温测井仪器,编制了《干热岩测井规范》。以上成果为共和盆地干热岩资源调查与勘查试采示范提供了有力支撑。

In order to solve the problems of the deep geological structure of the Gonghe basin,which is characterized as the unclear characteristics of the hot dry rock reservoir in the development site,the need to develop high-temperature logging instruments,and the establishment of the specifications for hot dry rock well logging,the magnetotelluric sounding and geophysical logging work were carried out.The ground geophysical exploration work is mainly based on three-dimensional electromagnetic detection technology,which covers the entire eastern part of the Gonghe basin.The logging work at the development site is mainly based on well temperature logging and imaging logging,and all the hot dry rock drilling logging data have been collected and analyzed.Through the implementation of this project,the petrophysical properties have been basically identified.As a result,a stratigraphic physical property column of the development site has been established.The physical properties of hot dry rock reservoirs were evaluated to support the development and trial production of hot dry rock.The main stratigraphic structure and structural framework were basically identified.A three-dimensional geological structure model of the Gonghe basin was constructed.And a contour map of the bedrock interface buried depth was compiled.The electrical structures and deep low-resistance bodies of Gonghe basin and its surrounding areas were basically identified,with the features of the geometrical characteristics of the faults,the shortening deformation model of the northeastern margin of the Qinghai-Tibet plateau were delineated,and finally two favorable areas for hot dry rocks were delineated.High-temperature-resistant temperature measurement instruments were developed."Specifications for hot dry rock well logging"were compiled.The above results provide a strong supporting for the investigation,exploration,test-mining and demonstration of hot dry rock resources in the Gonghe basin.