鹤岗盆地煤层气赋存特征及勘探开发潜力

鹤岗盆地煤层气勘探程度很低，目前仅有3口煤层气参数井，对该区开展煤层气勘探开发潜力的评价工作具有重要意义。为此，从区域构造特征、含煤地层特征、储层特征（煤层埋深、煤层厚度、煤岩特征、煤变质程度、煤层气含气量）3个方面入手，分析了该区煤层气的赋存特征。结果显示：主要含煤地层为白垩系城子河组，含煤40余层，可采或局部可采36层，煤层累计厚度为30~70 m，主力煤层为15^#、18^#煤层，单层厚度超过10 m；煤质主要以气煤为主，受岩浆岩作用，煤变质程度由南往北逐渐增高。煤层气资源量预测结果表明：该区煤层气资源量主要分布在1 500 m以浅的范围内，煤炭储量有48.12×10⁸ t，煤层气资源量为496.4×10⁸ m³。其中南山-新一矿为鹤岗矿区的主要含气区，含气量介于7～16 m^3/t，煤层气资源量为352.4×10⁸ m³，占总资源量的70%，说明该区具有良好的勘探开发潜力。

Occurrence and resource potential of coalbed methane in the Hegang Basin

Coalbed methane (CBM) gas exploration is poor in the Hegang Basin where there are only 3 CBM parameter wells at present, thus resource potential evaluation is of great significance. The CBM occurrence in this basin is analyzed in respect of regional structures, coal bearing formations and CBM reservoirs including burial depth and thickness of coal layer, petrologic features and metamorphic grade of coal, as well as gas content. The main coal bearing formation is the Cretaceous Chengzihe Formation with over 40 coal layers, of which 36 layers are recoverable or partly recoverable. The gross thickness of coal layers is in the range of 30~70 m. The major coal layers are No. 15 and 18 layers with a single layer thickness of over 10 m. The coals are dominated by gas coal and the metamorphic grade increases progressively from the south to the north due to igneous intrusion. The prediction of CBM resource volume in this basin shows that the coal reserves are up to 4.812 billion tons, while CBM mainly occurs in coal layers shallower than 1500 m with a cumulative CBM resource volume being 49.64 bcm. Among the five CBM blocks in this basin, the Nanshan Xinyi Block is the major one with gas content of 7~16 m3/t and resource volume of 35.24 bcm which accounts for 70% of the total.