我国东部沉积盆地中深部高温地热系统形成机制-以大庆徐家围子地区为例

With the drastic reduction of the fossil energy and the increasingly prominent environmental issues, renewable energies have been gradually appearing on the energy scene. The geothermal resource is the most realistic and competitive renewable energy and its development and utilization are increasingly getting the attention of the international community. China, rich in geothermal resources, is good at direct utilization while weak in the exploitation. This is mainly because high-temperature geothermal resources with outcrops are distributed in the remote Yunnan-Tibet zone, which is very scarce. Meanwhile, most discoveries from medium-shallow parts of sedimentary basins, which are distributed in a large area, are low-temperature geothermal resources and few researches are on their medium-deep parts. Due to severe energy shortages of eastern China, this project is aimed at the key scientific problem that whether or not medium-deep parts of sedimentary basins in eastern China can form high-temperature geothermal systems. In the project, the research area is Xujiaweizi in Daqing, with higher geothermal field. By using exploration data of gas from deep zone in Daqing Oilfield, it depicts the variation of the geothermal field in three-dimensional space in detail and interprets deep geological structures such as discordogenic faults, basement fractures, the low-velocity-and-high-conductive layer, heat flow diapir body, etc. Through analyzing the abiogenetic gas in the deep layers, it demonstrates the migration and accumulation mechanism of deep heat flow and has confirmed the existence of high-temperature geothermal systems in deep layers, which reveals the formation mechanisms, distribution rules and distribution patterns. All of these lay a solid scientific foundation for the improvement of sedimentary basin geothermal theory, creating of medium-deep geothermal energy demonstration bases and the selection of EGS test site.

随着化石能源的急剧减少和环境问题日益突出，新能源逐渐登上能源舞台。地热是新能源中最现实和最具有竞争力的一种可再生能源，其开发利用受到国际社会的日益关注。我国地热资源丰富，虽是直接利用的大国，但却是开发的弱国，主要是因为有露头的高温地热资源处于滇藏一带，稀少且地域偏僻，大面积分布的沉积盆地中浅部发现都是低温地热资源，而中深部研究薄弱。因我国东部能源短缺严重，所以本项目针对我国东部沉积盆地中深部能否形成高温地热系统这一关键科学问题，选择地热场较高的大庆徐家围子为研究靶区，利用大庆油田深层天然气探测数据，详细刻画地热场在三维空间变化规律、解译深大断裂、基底断裂、低速高导体、热流底辟体等深部地质结构和对深部无机成因天然气分析，诠释深部热流运聚机理，确认中深部高温地热系统的存在，揭示其形成机制、分布规律和分布模式，为完善沉积盆地地热理论、创建中深部地热利用示范基地和EGS试验场址选择奠定科学科学基础

地热是新能源家族中最现实和最有竞争力的一种可再生能源，在推动节能减排、减少环境污染方面具有有非常大的优势，广受国际社会重视。我国地热资源利用的量非常大，但是利用的效益低。主要的根源在于我国发现的高温地热资源比较少，尤其是东部大面积分布的沉积盆地中没有找到有效的高温地热资源。因此，该项目针对我国东部沉积盆地中深部能否形成高温地热系统这一关键科学问题，选择地热场较高的大庆徐家围子地区为研究工区，通过较系统岩石热物性测试，结合深部油田探井和生产井的试油试气数据，建立了深部地层温度预测方法，精细刻画了深部地温场，确定了地层温度变化规律；通过解译深部地学断面、地震剖面，分析了靶区深大断裂、低速高导体、热流底辟体等深部地质结构特征及形成机制。分析研究了深部地质流体特征和成因模式。在此基础上通过多场对比耦合分析，确定了深部热区形成机制和主控因素，建立了靶区深部地热系统模型。在此基础上对松辽等东部沉积盆地地质特征进行了深入剖析，论述了沉积盆地深部地热资源分布规律，为完善沉积盆地地热理论、创建中深部地热利用示范基地和EGS试验场址选择奠定了坚实的科学基础。