The Geological Factors Affecting The Environmental Impact Of Shale Gas Development In Weiyuan

With the large-scale development of shale gas,the drilling is increasing,the environmental pollution problems in the process of drilling and fracturing are serious.we can Use hydrology,shale gas drilling analysis,mineral petrology,reservoir geology and related theory knowledge to analyze The geological factors of environmental pollution in shale gas drilling in weiyuan.By hydrogeology information collection and analysis on water quality pollution in shale gas,we consider that it has the problem of environmental pollution by drilling fluid and fracturing fluid.Secondly,through the collection and analysis of data,drilling river main layers of drilling fluid leakage are in the xujiahe group,maokou group,qixia group and group of jialing river.According to the drilling data,image and core chip,we think structural fractures and karst development must be The main reason,and we use the formula to prove it.Through the data analysis and sample experiment,it indicates the shale are widely distributed.the TOC content is more than 2 mg/g.The brittleness index is between 30%to 60%,which is liable to fracture.Through brittleness index,the young’s modulus and poisson’s ratio,we Set up three kinds of algorithm of neural network algorithm.It is programmed in MATLAB R2013B to determine network algorithm.The prediction result shows that prediction accuracy of RBF is higher.Such as high shale brittleness index and micro fracture are the main reason of large fracturing scale,and The formed webs can Penetrate the overlying ground.The experimental results show that the fracturing fluid is more easy to seepage and migration under the conditions of low viscosity and high porosity.The development of faults in the area can be a channel of fluid migration and seepage,which will cause environmental pollution.The analysis of water quality and the monitoring of microseismic show that it can lead to fracturing fluid migrates and seepages through cracks and fault when network connect fault.The simulation analysis of the fracturing fluid under the the presence of fault shows that fracturing fluid seepage is more obvious if the leak is closer to the fault.