D气田CO_2成因及分布浅析

ORIGIN AND DISTRIBUTION OF CO_2 IN D GASFIELD

在D气田开发过程中,出现了高烃井和高CO2井并存的现象,同时在开发初期为高烃的井也有部分开始向高CO2井转化的趋势。根据气田现有资料,查阅大量相关文献,结合前人所作的相关模拟实验及成果,进行综合研究和分析判断,指出CO2来自有机成因和深部壳源碳酸盐高温热分解无机成因,具有纵向上CO2和CH4气体存在重力差异分布、平面上CO2含量呈北高南低分区分块且沿断裂附近含量高的特点。推断在高CO2井区距离断裂带较远部位,仍有局部高烃井存在的极大可能性,建议在后续评价中对该区进行钻探验证。

During the development of D gasfield,there appeared a situation of high- hydrocarbon wells coexisting with high CO_2 ones.Meanwhile,some of the former,which formed at the early stage of development,began to transform into the latter.On the basis of the field data,related literature,simulation experiments and their achievements,this paper points out that CO2 has organic and inorganic(deep crust source carbonate high-temperature pyrolysis)origins.Longitudinally,there exists gravitational differential distribution between CO_2 and CH_4.On a plane,the content of CO_2 is higher in the north and lower in the south,and high along faults.Therefore,it is really possible to find high- hydrocarbon wells in the area of high CO_2 wells far away from fault zone.