Impact Assessment Of Gas Field Development On Groundwater Environment

During the exploitation of gas fields,there are some stages may cause pollution in groundwater.Such as the mud leak of drilling and the reinjection of gas flied effluent.Because of the large area,the long-time exploitation of the gas field may have a serious impact on the local environment.This paper takes the gas field in Erdos as the research object.According to the regional survey about water quality and the analysis about technologies,stages of pollution discharge and main pollutants during the exploitation of gas field.We have gotten the local present situation of groundwater and the main factors that may affect the location groundwater.Based on the investigation of geological structure and hydrogeology,we construct the groundwater numerical model of flow and solute transport.And use it to evaluate the influence of mud leakage and reinjection on groundwater during the exploitation of gas field.It shows that the groundwater quality in the local area is good.Through the analysis of the impact of pollutants on groundwater during drilling,a large amount of drilling wastes invades the aquifer.The casing damage will increase the concentration of pollutants in the groundwater near the well,and is easy to cause serious pollution.During the reinjection of sewage,the rupture on well pipe will lead to a large area of groundwater pollution.If there is a large penetrating crack or "skylight" at the Jurassic aquifer,the wastewater will enter the Cretaceous aquifer through the shortcut,resulting in a large area of groundwater pollution.Therefore,during the exploration of the reinjection well,it is necessary to do a good choice in the site selection,and strengthen the management of the reinjection well during reinjection.