新乡一机井热异常特征及其成因研究

The features and cause of hot anomaly in a well in Xinxiang,Henan province

位于新乡市区的一机井反复出现水温异常偏高现象 ,水温高达 40～ 5 0℃。经过一系列的现场测试和调查发现 ,机井下部水温正常 ,水温波动仅位于上部 10～ 35m的深度范围内。根据异常特征和水中溶解气体的气相色谱分析结果 ,可以初步断定此热异常不是由构造活动引起。为了真正搞清热异常的具体成因 ,应用数字滤波和相关分析等数理方法对观测数据作进一步的处理分析 ,认为此热异常是由于机井长期抽取地下水 ,潜水泵所在部位的地下水流通过中细砂强透水层的渗流 ,与附近另一深井的热水贯通 ,成类似“管涌”的渗透破坏 ,从而导致水温升高。

A high temperature water is found in a well in Xinxiang, Henan Province. The temperature of the water may rise to 40～250℃. By the approach of a series of site tests and investigation, it is discovered that the water temperature at the lower of the well is in normal, the temperature fluctuation only lies in the depth range of 10～35m. Based on the features of hot anomaly and the result of color spectrum analysis of dissolved gas, it may be preliminarily concluded that the hot anomaly is not resulted from structure activities. To find the real cause of the hot anomaly, some data reduction methods of digital filtering and corelation analysis are used for data processing.Long term groundwater abstraction accelerates the percolation from phreatic aquifer consisting of medium small grain sand.Further more. the subsurface flow near the pump is gradually mixed with the flow of another hot well and the hot anomaly therein occcurs.