Numerical Simulation Study On CO₂ Ecbm And Geosequestration Of Deep Buried Area In The Qinshui Basin

Using data of deep and nearby drilling holes,this dissertation studied the geometry features of burial and thickness of coal seam No.3 in Qin County,the target area,and its reservoir parameters,then CO2 ECBM and geosequestration numerical modeling is conducted.Various geological factors of deep coal seam i MPacting the process were discussed,the monte carlo stochastic simulation method is used to obtain statistically in the study area and evaluate the capacity enhancement and sequestration of CO2 effect.The results show that CO2 is hard for geosequestration under the situ permeability condition(0.01 m D).If the permeability value was 0.1m D,daily coalbed methane(CBM)production of displacement should be 624.30 m3,the maximum gas production rate is 1660.4 m3/d.The cumulative gas production volume will reach 33.71×105m3,the maximum injection rate is 4959.5 m3/d,and the cumulative CO2 injection volume is 74.73×105m3;If the permeability value increased to 0.986 m D,the effect of CO2 ECBM and geosequestration is perfect.Coal reservoir thickness of CBM production and CO2 sequestration has obvious positive correlation relationship,with the increase of thickness of coal seam,CO2 sequestration capacity and displacement effect of CBM increased in multiples accordingly.The coal reservoir pressure has a significant negative correlation with the coal bed methane production and carbon dioxide seal stock.With the increase of reservoir pressure,the effect of CO2 storage capacity and displacement of coal bed methane is significantly reduced.Using monte carlo stochastic simulation method,the following statistics are obtained.The expected value of potential coalbed methane recoverable reserves in the region is about 45.62×105m3.The probability of recoverable reserves between 40~90×105m3 is 66.83%.The expected amount of potential CO2 injection is about 89.6×105m3.The probability of potential CO2 injection between 60~120×105m3 is 62.71%.84.5% of the test was not broken in the whole time from the end of the displacement to the cessation of production,and the probability of CO2 breakthrough time between 5760d~6840d is 10.5%.