煤层中埋藏CO_2量的计算方法

Calculation Method of Carbon Dioxide's Storage in Coalbed

CO2注入油气藏、煤层等地质体既有助于油气采收,也可以成为处理CO2的重要方法。计算CO2的储存量,可以根据其在地质体中的不同存在相态分别计算,这样既能确定地质体总的存储能力,也可以确定各存储机制的贡献。根据相态的不同把CO2在煤层中的储存量分成吸附、游离和溶解3部分计算,并考虑了压力上升引起的孔隙膨胀、存储空间增加。计算结果表明,随着注入压力的上升,吸附量、气态量、溶解量和膨胀增量都在增加。气态量、溶解量和膨胀增量所占百分数也在增加,吸附量能占到总量的90%左右。

The injection of CO2 into geologic bodies, such as oil reservoirs and coalbed, can enhance the recovery of oil and gas, also has the potential of storing large volumes of CO2. The storage of CO2 can be acquired by calculating carbon dioxide＇s volume by its different phases in the geologic bodies. Thus, the specific contribution of each phase can also be gained with the total storage ability of geologic body. The storage of CO2 in coal seam is divided into absorpton, free and dissolved three parts according to each of its phases. The increase of storage capacity led by the increase of pressure, the expansion of pores, is also considered. According to the calculation, the amounts of gaseous amount, amount of dissolved and incremental expansion led by inflation are all increased in pace with the increase of injection pressure, so are the percentages of the last three parts. The fraction of absorbed CO2 can be as high as 90%.