松辽盆地南部长岭断陷高含CO_2气藏成藏机制分析

Study on the Pool-forming Mechanism of High Content CO_2 Gas Pools in Changling Fault-depression,South Songliao Basin

通过对松辽盆地南部长岭断陷典型高含CO2气藏的解剖,对比分析了长深1、长深2、长深4、长深6、长深7等高含CO2气藏的气体成因、分布特征及其差异,指出基底大断裂的活动特征决定了幔源CO2和烃类气成藏条件的相对好坏,从而决定了气藏中CO2的含量及含CO2天然气的赋存层位,建立了长岭断陷高含CO2气藏运聚成藏模式,合理解释了长岭断陷含CO2天然气的勘探现状和复杂分布问题,为CO2和烃类气的钻前预测提供了理论依据。

Based on the dissections of the typical high content CO2 gas pools in Changling fault-depression, south Songliao basin,a comparative analysis was taken on the genesis,distribution characteristics and their differences of the gases of Changshen 1,2,4,6,7 high content CO2 gas pools in deep layer. Results showed that the type of basement faults determined the relative good or bad conditions for mantle-derived CO2 and hydrocarbon gas accumulations,which further determined the CO2 content in gas pools and the accumulation layer of CO2-containing gas. The model of gas migration and accumulation in Changling fault-depression was established,which reasonably explains the gas exploration status and complex distribution problems. What＇s more,it provides a theoretical basis for prediction of CO2 and hydrocarbon gas before drilling.