新疆塔什库尔干谷地地热资源研究进展

Progress in research on the geothermal resources in Taxkorgan Valley,Xinjiang

归纳了新疆塔什库尔干谷地地热地质条件,分析了区内地质构造、地温分布、地热流体化学及同位素特征,研究了地热形成机理,计算了曲曼地热田的地热资源量和可开采量。结果表明:研究区地热资源受断裂构造控制;地温变化与盖层、完整基岩、断裂带(热储)表现出明显的一致性,目前实测最高热储温度为161℃,深部热储计算温度可达222~268℃,地温梯度最高为149.20℃/100 m;地热流体具有深循环特征,与浅表冷水的水化学和同位素特征具有明显的差异;地热流体来源于大气降水,在断裂及裂隙内储存、运移、富集,在侵入岩体放射性生热和结晶余热的热量供应下,地下流体不断与围岩进行热量及物质交换,在热储围岩和盖层中,热量以传导方式为主,在热储内,热量以对流方式为主;曲曼地热田储存的热量为55.919×10^(11)MJ,地热流体可开采量约为12593 m^3/d,产能(热能)约为77.9 MW。因此认为,塔什库尔干谷地热储埋藏深度浅,易开采,具有可观的直接和间接经济价值。

Geothermal geological condition of Xinjiang Taxkorgan Valley was summarized in this paper.The geological structures,geothermal distribution,chemical and isotopic characteristics of geothermal fluid were analyzed.The author also investigated the geothermal formation mechanism,and calculated the geothermal resources and exploitable quantity.The results show that the geothermal resources in the study area are controlled by faults,and the ground temperature changes are obviously consistent with those of caprock,intact bedrock and fault zone(geothermal reservoir).The maximum temperature of measured thermal reservoir is 161℃now,and the calculated temperature of deep geothermal reservoir can reach 222~268℃.Besides,the maximum geothermal gradient is 149.20℃/100 m.The geothermal fluid is characterized by deep circulation,which is obviously different from shallow water in hydrochemistry and isotopic characteristics.Geothermal fluid is derived from meteoric water and is stored,transported and enriched in fractures and fissures.With the heat supply of radioactive heat and crystallization heat of intrusive rock,the underground fluid continuously exchanges heat and substance with the wall rock.In the wall rock and cover layer of thermal reservoir,heat exchange is mainly in the mode of conduction,and in the heat storage reservoir,heat is mainly in the mode of convection.The stored heat in the geothermal field is 55.919×10 11 MJ,and the exploitable quantity of geothermal fluid is 12 593 m 3/d,with the heat energy productivity of 77.9 MW.The thermal reservoir of Taxkorgan Valley has shallow buried depth and is easy to be exploited,which has considerable direct and indirect economic value.