Coalbed methane reservoir is a pressure sealreservoir and its production characteristic is different from that of conventional natural gas.
煤层气是一种压力封闭型气藏，其生产特征不同于常规天然气。
2
The watertight seal of Changzhuang reservoir spillway tunnel is irregular and ageing, having caused severe leakage.
常庄水库泄洪洞伸缩缝极不规则且止水均已老化，渗漏严重。
3
The essential elements are source rock, reservoir rock, seal rock and overburden rock, and the processes include trap formation and the generation-migration-accumulation of petroleum.