中国CO_2煤层储存容量初步评价

PRELIMINARY ESTIMATION OF CO2 STORAGE CAPACITY OF COALBEDS IN CHINA

地下储存是降低大气中CO2含量以缓解温室效应的有效措施之一。其中煤层储存可有效地减少CO2排放量,同时增加煤层气可开采量,降低CO2地下储存的成本。煤层储存CO2是将CO2吸附在煤基质中,具有安全可靠的特点。中国煤层分布广泛,煤炭资源储量丰富,是CO2地下储存的首选措施。根据中国煤炭和煤层气勘探资料,不同性质煤的储量分布及CO2与CH4置换比例,对中国主要含煤层气区深度300～1500m范围内的煤层CO2储存潜力进行初步评价。结果表明,利用注CO2增采煤层气技术可使中国总的煤层气可采量达1.632×1012m3,可储存约120.78×108tCO2,相当于2002年全国CO2排放量的3.6倍。

Geological storage is an effective means of reducing anthropogenic atmospheric emission of CO2 to alleviate the worsening global climate change. CO2 storage in coalbeds can effectively reduce the emission of CO2, and at the same time, it can enhance the recovery of coalbed methane to reduce the cost of CO2 geological storage. The CO2 molecules are absorbed on the surface of coal matrix and the methane molecules can be releasedwhen CO2 is injected into the coalbeds. The absorbed CO2 on coal matrix can be kept stably in coalbeds forgeologic time. There is a huge storage capacity for CO2 in coalbeds in China for the wide distribution and abundant resources of coal. Putting CO2 into coalbeds should be the prior choice for its security and safety.According to the latest prospecting data of coal and coalbed methane resources in China and the replacement ratio between CO2 and CH4 in the coal with different ranks, it is estimated that the CO2 storage can be performed from depth of 300 m to 1 500 m in the main coalbed methane basins in China. The total recoverable coalbed methane resources will approach to 1.632×10^12 m^3 if the CO2-enhanced coalbed methane recovery（CO2-ECBM） technology is utilized, and the CO2 storage capacity in coalbeds is about 120.78×10^8t, which is about 3.6 times as the total CO2 emission of China in 2002.