地热系统类型划分与主控因素分析

摘要

In accordance with previous studies and for the betterment of geothermal resource exploration and development,a geothermal system is defined here as a relatively independent heat-source-centered geological unit which contains geological ingredients and effects needed for generating,migrating and gathering geothermal resources,i.e.,a system that constitutes a functional unit of geothermal aggregation.According to tectonic settings,geothermal systems can be divided into two types:the rifted mountain (type Ⅰ) and sedimentary basin (type Ⅱ) types,which then can be subdivided into the rifted mountain magmmorigin,rifted mountain non-magma-origin,sedimentary basin magma-origin and sedimentary basin non-magma-origin types.Based on these divisions,the above four types of geothermal systems are further classified as hydrothermal and non-hydrothermal depending on the form of geothermal storage.In geothermal resource development,plentiful heat source is the foundation for all geothermal systems.For hydrothermal types,water supply and fracture development predominate the formation of a rifted mountain hydrothermal system,whereas ample high-quality geothermal reservoir at an appropriate burial depth controls the formation of a sedimentary basin hydrothermal system.In non-hydrothermal systems that favor the development of an EGS project,formation key factors are the natural permeable reservoir and advantageous cap rocks.%为了更好地进行地热开发利用,该文在前人研究基础上,将地热系统定义为一个相对独立的地质单元,以热源为中心,包含热生成运移—聚集所需要的地质要素和地质作用,这些要素和作用组成了能形成热能聚集的功能单元.根据地质构造背景,地热系统可分为隆起山地型地热系统(Ⅰ型)和沉积盆地型地热系统(Ⅱ型)两大类.根据热源类型,地热系统可细分为隆起山地岩浆型地热系统(Ⅰ1型)、隆起山地非岩浆型地热系统(Ⅰ2型)、沉积盆地岩浆型地热系统(Ⅱ1型)、沉积盆地非岩浆型地热系统(Ⅱ2型)4亚类.根据热的赋存方式,上述4亚类地热系统可进一步细分为隆起山地岩浆水热型地热系统、隆起山地岩浆干热型地热系统等8种类型.充足的热源是一切地热系统形成的基础.充足的水源补给和断裂发育是隆起山地水热型地热系统形成的主控因素,一定埋深的大规模优质储层是沉积盆地水热型地热系统形成的主控因素.埋藏较浅的高渗透性储层及较好的盖层,是干热型地热系统形成的主控因素.