辽宁大民屯凹陷地热资源形成条件分析

ANALYSIS ON THE FORMING CONDITIONS OF GEOTHERMAL RESOURCES IN DAMINTUN SAG, LIAONING PROVINCE

大民屯凹陷是新生代陆相凹陷盆地,其地层、构造、岩浆岩等地质背景具备传导性地热的良好成矿条件,热源主要为幔源热,储热层为沙河街组砂砾岩层段层状热储,盖层为第四系、新近系馆陶组、明化镇组和部分古近系东营组泥岩段地层.凹陷内基底断层及多期次级断裂形成了地热田良好的导热和导水通道.新近系平均地温梯度2.9℃/100 m,古近系平均地温梯度3.18℃/100 m,一定深度下的地下热水可以达到理想温度,具备地热开发条件.

The Damintun sag is a Cenozoic continental basin, whose geological settings such as stratigraphy, tectonics and magmatic rocks provide good conditions for conductive geotherm. The main heat source is the mantle. The sandy conglomerate layer of Shahejie formation serves as thermal reservoir, covered by Quaternary, Neogene Guantao and Minghuazhen formations and partly Paleogene Dongying formation. The basement faults and multi-staged secondary faults in the sag form good passageways for heat and water in the geothermal field. With Neogene average geothermal gradient of 2.9 ℃/100 m and Paleogene of 3.18 ℃/100 m, the underground hot water in certain depth can reach the expected temperature for exploitation of geotherrn.