中国煤层气采收潜力的研究

RESEARCH ON RECOVERY POTENTIAL OF COALBED METHANE (CBM) IN CHINA

常规煤层气生产量的获取不仅对国家经济可持续发展及能源安全具有重要作用,而且也是CO2注入煤层提高煤层气采收率和CO2埋藏量估算的关键。根据中国煤层气资源丰度、甲烷含气量、煤层渗透率、地层压力和勘探程度因素等,分析得到了中国不同煤层气聚气带生产的校正因子;根据甲烷含量大于4m3/t的1500m以浅煤层气资源量和资源特点,在煤层气平均采收率为30%的基础上,采用对平均采收率校正的方法,对中国4个聚气区和29个聚气带煤层气采用常规生产技术的采收量进行了计算,并结合中国天然气的产量分析了煤层气的生产期。研究表明,在所评价的29个煤层气聚气带中,采用常规煤层气生产技术可以采收33347×108m3煤层气,主要的煤层气生产聚气带为华北区的沁水和华南区的滇东—黔西,分别占可采出煤层气的29.05%和21.80%。按2002年天然气实际生产量和2010年天然气预测产量计算,中国煤层气采用常规煤层生产技术可分别生产103a和40a。

Primary CBM production plays an important role in sustainable growth of national economy and energy security and also the key in estimation of CBM recovery rate by CO_2 injection and CO_2 buried quantity. Discount factors of coalbed methane production in various locations in China were studied according to CBM resources abundance, CBM content, permeability of coal bed, reservoir pressure, exploration maturity, and so forth. The primary CBM recovery quantity of 4 CBM production regions and 29 CBM accumulating zones in China was calculated based on average recovery rate of 30% which is corrected with discount factors obtained considering CMB resources quantity and the characteristics of CBM/coal>4m^3/ton and burial depth<1500m. Furthermore, production cycle of CBM was analyzed according to natural gas production in China. The analysis shows that the primary CBM recovery potential is estimated to be 3334.7 billion m^3 by conventional production techniques, and the main contributors to CBM production are CBM accumulating zone in Qinshui in North China and Eastern Yunnan-Western Guizhou in South China, taking up 29.05% and 21.80% of total CMB production respectively. China's CBM production by conventional approaches could last for 103 years if calculated in accordance with actual natural gas production in 2002, or 40 years in accordance with projected gas production in 2010.