Comprehensive Identification Method Of Gas Channeling In Flue Gas Flooding

The water flooding and water channeling in the middle and lower high permeability layers are more serious after water flooding in X fault biock reservoir,so gas flooding can improve the development effect.The development of fire drive in the adjacent block produced a lot of exhaust gas,namely flue gas.In order to reduce the impact of this part of flue gas emission on atmosphere and environment,and at the same time apply to underground crude oil displacement,flue gas displacement is used for development in fault block X.However,the gas channeling problem seriously restricts the development effect of flue gas drive.In order to ensure the implementation effect of EOR,it is necessary to establish the identification technology of gas channeling in the flue gas drive.This paper firstly studies the mechanism and law of flue gas flooding gas channeling based on the numerical simulation.The gas channeling mechanism lies in the gravity override caused by the difference of gas oil density and the viscosity fingering caused by the difference of gas oil viscosity;Sedimentary rhythm determines whether reservoir heterogeneity intensifies or inhibits gas channeling and reservoir heterogeneity determines the degree of intensification or inhibition.For positive rhyming and compound rhyming reservoirs,gas gradually moves to the middle and upper part and generally does not form gas channeling channels.For an antimetrical reservoir,gas is pushed along the hyperpermeable layer,forming a gas channeling channel at the top.On the basis of understanding the mechanism and law of flue gas channeling,a method of gas channeling degree identification is established by three-level comprehensive fuzzy evaluation.According to the correlation of injection-production dynamics and production logging data,a method for determining the direction of gas channeling is established.Based on the analysis of the shape characteristics of the gas channel,the calculation model of the size of the gas channel is established according to the theory of seepage mechanics and the gravity override mechanism.Using VB language,the identification system software of flue gas flooding gas channel is programmed,including gas channeling degree identification module,gas channeling direction identification module and gas channel scale calculation and blocking agent dosage design module.Finally,based on the analysis of the water flooding channeling channel in the early stage of X block reservoir,the gas channel identification technology of flue gas flooding was used to calculate the gas channeling degree,gas channeling direction and gas channel volume of the target block,and the sealing channeling layer selection and blocking agent dosage were designed.The identification results can provide theoretical basis and technical support for gas channeling plugging.