Underground Gas Storage Well Test And Reserves Calculation

Natural gas is a source of energy which has been increasingly explored and produced,but there is a disequilibrium between supply and demand.Especially the weather changes would lead to the demand of natural gas fiercely fluctuated.Underground gas storage has big available reserve volume,activity and is easy to construct,which allows to efficiently resolve demand seasonality problems.and as it could be the crucial national energy strategic reserve for our country,so it's really imperative to do some research for underground gas storage.Well test is able to evaluate the injection capacity and productivity of the gas well,aquire the reservoir property parameters,as well as analyze the reservoir capacity of underground gas storage,so this paper mainly apply the well test analysis method to underground gas storage with depleted gas reservoir,and discuss how it's going to work.Because it was most widely distributed,the depleted gas reservoir type of underground gas storage was chose to be the object of study.Based on massive document surveys of it's geological characteristics and it's special injection-production system,I established the flow model in porous media and well testing analysis model for depleted gas reservoir type of underground gas storage.As for deliverability well test,I derivated and solved the flow model in porous media for horizontal well on underground gas storage based on the deliverability binomial equation of vertical well,found that the flowing bottomhole pressure and injection-production rate meet the pressure square binomial relations,made deliverability well analysis for the 4 injection&production wells that constructed on the X gas storage with the measured data of both injection gas process and gas production process,respectively,and acquired the deliverability binomial equation of the corresponding process.To eliminate the influence of the gas storage formation pressure fluctuations,I applied a modified deliverability binomial equation analysis method to these 4 wells,and then proved the modified deliverability binomial equation could be correctly applied to the underground gas storage with depleted gas reservoir by comparing the modified equation and traditional equation.As for the transient pressure testing,I derivated and solved the well testing analysis model for vertical and horizontal well on underground gas storage,made transient pressure testing analysis and the sensitivity analysis of corresponding measured double logarithmic curve for these 4 wells with the measured data of both injection gas process and gas production process,respectively,acquired the parameters such as in-place permeability,measured radius and the formation pressure.As for boundary well test,proved the way of using the boundary response of the transient pressure testing double logarithmic curve to test the closure performance of reservoir is available by analyzing the reaction features of the double logarithmic curve of messured data.As for the reserves calculation,selected the suitable reserves calculation method for gas well on underground gas storage,and then calculated the single well control storage capacity for these 4 wells on X gas storage.