Research Of Chemical Clogging During Waste Geothermal Water Re-injection Based On Hydrogeochemical Simulation

Either the documentations or reports about clogging mechanism of reinjection tosandstone geothermal reservoir are quite rare, which is still a worldwide problem. In thispaper, we take Xian Yang urban area as the study area, based on field research and sampling,hydrogeochemical simulation methold and indoor experiments were adopted, both the hotwater chemiacal charateristics in the upper part of the well and the geothermal water storageenvoriment below the well were analysed. Through testing and analyzing the elements of thewater, rock, gas, microorganism and precipitation in the geothermal water, the process ofwater-rock-gas interaction in the upper and the bottom part of well, inside and outside of thehot water transportation pipe was much clear, moreover, the dissolution and precipatitioncharacteristics of different mines and its effection to clogging forming are all revealed. Allthese research fruits will supply technology support for preventing and getting rid of thechemical clog in geothermal water reinjection, provide scientific basis for evaluation ofgeothermal water resource sustainable expoitation and utilize.The results of indoor experiments, software simulation and field research all indict thatchemical clog mechanism is complex and is likely be affected by many envorinment factors,of all the factors temperature and PH are the dominant factors which result in chemical clog.The main composition of chemical clog in Xian Yang urban area is possibly Cacilte, whichcould be produced during the processes of geothermal water exploition, transportation andreinjection. Besides, there will be some amorphous silica precipitates as white nasal mucuswhile geothermal water is extracted; many iron scaling formed in the inside and outside of theiron water pipe due to corrosiveness. A little of sufate was found around the expoitation well,it is slight scaling.The study results and parameter of this paper has a positive reference value for the laterresearch of geothermal water reinjection, it will promote the speed of geothermal waterreinjection research.