四川雅安周公2井地热水环境同位素的初步研究

PRELIMINARY STUDY ON ENVIRONMENTAL ISOTOPES IN HOT MINERAL WATER FROM NO.2 ZHOUGONG WELL IN YA'AN CITY, SICHUAN PROVINCE

四川雅安周公 2井高温热矿水位于井深 180 0m以下 ,为赋存于三叠系雷口波组、嘉陵江组及二叠系茅口组碳酸盐岩地层中的岩溶水 ,盖层为侏罗系及上三叠统的碎屑岩层。初步测试关闭时井下压力 3Mpa ,井口水温达 75℃ ,流量约5 0 0 0t/d。通过对热矿水的14 C及U系法定年及其周围山区地表水氢氧同位素一次性采样及分析 ,研究结果表明 ,周公 2井热矿水系大气降水成因 ,补给区可能为其西部及西南部山区 ,即荥经河、荥河、冷水河以及周公河流域 ,海拔高程大体在15 0 0～ 2 5 0 0m左右。盆地上部主要为第四系—侏罗系赋存于砂砾岩中的孔隙水 ,而盆地深部的热矿水则是山区降水沿断裂裂隙及岩溶管道垂直入渗经深循环至盆地底部 ,两者并无水力联系。

The hot mineral water from No.2 Zhougong Well in Ya'an city, Sichuan Province is located about 1800m deep down the well in karst aquifer that composed of Triassic and Permian carbonate rocks of the Leikoubo Group, Jialingjiang Group (Triassic System) and Maokou Group (Permian System). The over-burden bedrocks of the above-mentioned water-bearing strata are clastic rocks of the Jurassic and the Upper Triassic. When the measure was started and the well was sealed off, the pressure in the well is 3 Mpa, the temperature on the mouth of the well is 75℃, the rate of flow from the well is 5000t/d. Through the measure to the hot mineral water in the well by means of 14 C and U methods, and sampling and analysis to the surface water around the nearby mountains, it is proved that the hot mineral water in No.2 Zhougong well is formed by precipitation, the recharge water probably comes from the mountains to the west and southwest, i.e. the Xingjinghe, Xinghe, Lengshuihe and Zhougonghe river basins, where the altitude is about 1500～2500m above sea level. Water in the upper part of the basin mainly exists in porosities in Quaternary deposit and Jurassic sandstone and conglomerate. But the hot mineral water in the deeper part of the basin comes from the bottom of the basin after deep circulation from precipitation to faults, fractures and karst conduits, and to the bottom in the end. So, there is no hydraulic links between the water in the upper part of the basin and the hot water in the well.