A new method for calculating dynamic reserves of interconnected gas wells in abnormally high pressure gas reservoirs
The conventional method can not accurately calculate the dynamic reserves of each well,when there is interwell interference in gas reservoir.In view of the objective phenomenon that rock compressibility changes with formation pressure exhaustion and dynamic reserve calculation process involves complex parameters,this paper analyzes the variation law of rock cumulative compressibility by using gas reservoir engineering theory,optimization deviation factor and bottom hole pressure conversion method,and reference to core experimental data.The dimensionless mass balance equation of pressure and production is presented,and a new method for evaluating the total dynamic reserves of interference well groups is formed.The results show that:l)The calculation method based on Gray model should be used to calculate the bottom hole pressure of water-producing gas wells in high-pressure gas reservoirs,and the error of the calculation result is less than 2％;2)Compared with the conventional mass balance equation in dimensional form,the dimensionless pressure and dimensionless cumulative gas production equation proposed takes into account the compression coefficient of variable rock and describes the theoretical gas well production dynamics under different water invasion degrees.The water invasion characteristic value of the target abnormal high-pressure gas reservoir parameter is determined to be 0.7 by fitting the actual data;3)Compared with the conventional method,the accuracy of dynamic reserves calculated by the new method is improved by 14％.The new reserve calculation method has been successfully applied to interference well groups of gas reservoirs with abnormal high pressure and water,which can guide the further efficient development of gas reservoirs.
high pressure gas reservoirmulti-well interferenceparameter selectionmass balancereserve estimate
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