西北低阶煤中生物成因煤层气的成藏模拟实验

以往经验认为,具有商业价值的煤层气资源主要存在于中煤阶的煤层中,煤阶太低,一般含气量不高,不具有勘探价值.但是近几年来发现美国的粉河和澳大利亚的苏拉特等低煤阶盆地煤层厚度大,渗透率高,资源丰度大,含气饱和度高,可获得商业性的气流.从其气体的成因来看,其中有很大一部分是生物成因的煤层气.通过本次采用FY-Ⅱ型煤层气成藏模拟装置和西北低煤阶含煤盆地的煤岩样品开展了低煤阶生物成因的煤层气成藏模拟,从实验角度证明了中国西北地区虽然煤层煤阶较低,热成因气较少,但是却存在着具有商业价值的二次生物成因的甲烷气,再加上含煤层系众多,煤层厚度大,资源丰度极高,仍具有巨大的勘探潜力.

SIMULATION EXPERIMENT OF BIOGENIC GAS IN NORTHWEST CHINA

In the past time, it is believed that commercial coalbed methane gas exists only in medium-high rank coal and low rank coal is not worth of exploration with its low gas reserves. But the cognition has changed now, some coalbed methane gas fields have already been found in low rank coal basin, such as Powder River basin and Surat basin. In these basins, the thickness of coalbed is big and the gas saturation is high, it is favorable to coalbed methane enrichment. From the character of coalbed methane, we can find that coalbed methane was mainly composed of biogenic gas. In this paper, we carry out our coalbed methane enrichment experiments using low rank coal sampled from the Northwest china. Our experiment results testify that the existence of commercial biogenic gas in northwest coal basin is really possible and it is favorable for exploration in basins with high coalbed-thickness and high resource concentration.