›› 2016, Vol. 37 ›› Issue (3): 1-1.doi: 10.7657/XJPG20160315

• 论文 •    

煤层气开采过程中的逸散

朱苏阳,李传亮,杜志敏,李泽沛,彭小龙   

  1. (西南石油大学 油气藏地质及开发工程国家重点实验室,成都 610599)
  • 出版日期:2019-01-01 发布日期:1905-07-14

Escaping Loss of CoalBed Methane during Production

ZHU Suyang,LI Chuanliang,DU Zhimin,LI Zepei,PENG Xiaolong   

  1. (State Key Laboratory of Oil and Gas Reservoir Geology and ExploitationSouthwest Petroleum University,Chengdu, Sichuan 610500, China)
  • Online:2019-01-01 Published:1905-07-14

摘要: 分析煤层气的赋存方式、成藏过程以及开采过程中的逸散问题,通过定义逸散速度比与逸散距离比,提出了判断煤层气在开采过程中是否发生逸散的条件,模拟计算了开采过程中的煤层气逸散量及其分布情况,同时研究了围岩渗透率、煤层的初始含气量以及气井产量对煤层气逸散量的影响。若煤层气逸散距离比大于逸散速度比的最大值,则可以认为煤层气无法发生逸散。实例计算表明,距离井筒越远越容易发生逸散;开采过程中煤层气的逸散可以损失10%~15%储量,超过占储量10%的煤层气是在开采初期逸散的。高含气量和低含气量的煤层气在开采过程中的逸散量较少,而中等含气量的煤层气逸散较多。减少开采过程中煤层气逸散量的关键是在煤层中快速建立生产压差,实现开发初期的快速生产。

Abstract: This paper analyzes coal?bed methane (CBM) preservation, accumulation and the escaping loss during production, presents several factors to identify coalbed methane escaping loss by defining 2 parameters?escaping velocity ratio and escaping distance ratio. Then the escaping loss volume and distribution of CBM escaping are calculated by simulation. Meanwhile, the impact of surrounding rock permeability, initial entrapped gas volume in coal beds and gas production on CBM escaping loss volume are studied. If CBM escaping distance ratio is larger than the maximum CBM escaping velocity ratio, it is considered that CBM will not escape from coal beds. Case calculation shows that the escaping loss is likely to occur in the areas far from wellbores and 10%~15% of CBM reserves will be lost during production, and more than 10% of CBM reserves escapes during the early production stage. Relative low loss commonly occurs in the coal?beds with high and low CBM content, however, the coal?beds with intermediate CBM content may suffer relative high losses. Therefore, the key to reducing CBM escaping loss is to establish producing pressure?drop quickly in coal beds to realize rapid production at the early stage

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