Fracture Network Model And Water Curtain Optimization Evaluation Of Underground Oil Storage Caverns

Petroleum is the lifeblood of a country's economic development.Sustainable and stable oil supply can ensure the sustainable development of economy and society.China's economy is in a period of rapid development with the increasing demand for oil.Establishing and improving the oil reserve system is a guarantee to meet domestic oil supply and respond to emergencies.Underground water sealed oil storage cavern is the best choice for oil reserves with the advantage of high security,large inventory,saving land,saving investment etc.It is necessary and urgent to carry out large-scale promotion and application in China's energy reserve strategy.As an important part of underground water sealed oil storage cavern,the water curtain system provides high underground water pressure and groundwater recharge through the surrounding rock fracture,which ensures the sealing of oil storage cavern.The key of underground petroleum storage caverns construction and operation is to analyze the influence of surrounding rock fissures on oil storage caverns of seepage field,and to optimize the design of water curtain system to ensure cavern sealing.Therefore,it is of great engineering significance and scientific value to study the fracture network modeling and the water sealing performance of oil storage caverns.According to the Qingdao Huangdao underground water sealed oil storage caverns project,this research numerical simulation combined with theoretical analysis,the fracture network model based on Monte Carlo method was established,and the influence of fracture network on seepage field of surrounding rock was studied,and the optimum design of the parameters and arrangement of the curtain wall was carried out based on 3D model.The main contents are as follows:(1)The common probability distribution of fracture geometry parameters was summarized.The fracture network model based on Monte Carlo method was established,which programed in MATLAB,and the effective analysis area of the model was analyzed.(2)By changing the geometric parameters of the fracture network,the fracture network models were simulated,and the influence of the geometric parameters on the permeability of the fracture network model was analyzed.(3)The calculation method of equivalent permeability tensor of fracture network model was deduced and programed.The fracture network model of Huangdao underground cavern was established,and the REV and equivalent permeability tensor were obtained.(4)In the background of the Huangdao underground water sealed oil storage caverns project,the change of the underground cavern inflow,Darcy velocity and pressure distribution was analyzed,and the influence of distance,angle,pressure,length of the water curtain hole for sealing effect was studied.(5)The 3D models of underground water sealed oil storage caverns were established,and the influence of different fracture surface parameters on the sealing effect of oil storage cavern is analyzed.(6)The 2D models of principal permeability directions were established,and cavern water seal effect with three water curtain hole layouts in different principal permeability directions model was analyzed,and the suitable condition of different water curtain hole arrangement was carried out.