Study Of Renewal And The Recharge Question Of Geothermal Waters In The Guanzhong Basin

This article take the geothermal water in the Guanzhong basin as the object of study, using the environment isotope and the hydrogeochemistry method to analyse the source of supply, the environmental occurrence and the cyclical pattern of the geothermal water in the Guanzhong basin, and then deduce the possibility of renewal of the geothermal water in different regions of the Guanzhong basin qualitatively; built model by using the tritium isotope in the geothermal water to calculate the age of geothermal water that contains the tritium value and analysed the possibility of renewal of the geothermal water in the Guanzhong basin combined with CFC data of hot well bore and the quantitative analysis of the ¹⁴C's age. Dividing the possibility of renewal of the geothermal water in the Guanzhong basin initially by the combination of qualitative method and quantitative method.And discuss the related issues of recharge of geothermal water in the Guanzhong basin based on the study of the possibility of renewal.The distributed characteristic of geothermal water's isotope in the Guanzhong basin is: The sampling point of basin peripheral geothermal water spread along the line of atmospheric precipitation essentially, theδ¹⁸O isotope of the sampling point of geothermal water in deep part of Xianyang, Xi'an which lies in the middle of the Guanzhong basin deviated the line of atmospheric precipitation obviously, which occurredδ¹⁸O drift , the conformation ofδD in the coincident point of the drifting line of geothermal water in Xi'an and the atmospheric precipitation is according with that of the geothermal water in Qinling mountain, the conformation ofδD in the coincident point of the drifting line of geothermal water in Xianyang and the atmospheric precipitation is according with that of the geothermal water in the northern part of Shaanxi. This indicated that the geothermal water in the southern part of basin (Qinling moutain) and the northern part of basin is supplied by the modernistic atmospheric precipitation or the mixture of modernistic and ancient atmospheric precipitation, the supplies source before the drifting of geothermal water in Xi'an might be the atmospheric precipitation of the forepart on Qinling moutain, the supplies source before the drifting of geothermal water in Xianyang might be the atmospheric precipitation of the Beishan moutain or karstificated water in the northern part of Shaanxi. To analysis the environmental occurrence and the cyclical pattern of the geothermal water according to the isogram of theδ¹⁸O,δD value, the distributed characteristic of ¹⁴C's age and the hydrochemical characteristic that indicated that the more near the central part of basin, the more close the environmental occurrence of geothermal water is, the more deeper the geothermal water is buried and the possibility of renewal of the geothermal water is weaker. Using the index-piston model to calculate the average age of mixed water of the sampling point of geothermal water that contains the tritium, to divide the possibility of renewal of the geothermal water in the Guanzhong basin into four kinds:intense renewable,renewable,renewal weak and non-renewable,combined with CFC, the age of ¹⁴C and the characteristic of isotope. The recharge is one of the effective methods to solve the renewal of the geothermal water in the Guanzhong basin, which could deal with the geothermal waste liquids, recover the thermogenic ability of thermic storage, fill up the geothermal water and relieve the descent of water lever to maintain the sustainable development of the geothermal water in the Guanzhong basin.As we can see from the possibility of renewal, the recharge of the geothermal water in the Guanzhong basin is easy in the peripheral part of basin and is difficult in the central part of basin, which means the recharge ratio is low in the peripheral part of basin although the thermic storage is buried deeply, the hydraulic pressure is great and the solid of the thermic storage pressure is fine,it's facile to block up during the recharge process. But the recharge well would be set up near the break area of the central part of basin, using the recharge method of vacuous inflating, strengthening the recharge experiment, on guard against the problems that are easily to occur during the recharge process of the Guanzhong basin highly and take the corresponding measures immediately can also accomplish the recharge to maintain the sustainable development of the geothermal water in the Guanzhong basin.