天然气分步捕获原理及在成藏研究中的作用

天然气生成具有阶段性,不同演化阶段形成的天然气的地球化学性质不同。构造的演化与圈闭的形成具有阶段性,因此不同阶段形成的圈闭可捕获不同演化阶段的天然气。源岩早期生成的天然气及形成的气藏可能由于后期构造活动遭散失或转移,使一些圈闭只能捕获源岩晚期生成的天然气,即圈闭对天然气的捕获具有阶段性,属于部分捕获而非连续捕获(或聚集)过程。介绍了天然气分步捕获的原理,并结合塔里木盆地塔北地区天然气地球化学特征,讨论了天然气分步捕获原理在成藏研究中的作用。

THE MECHANISM OF NATURAL GAS FRACTION ENTRAPMENT AND ROLE IN STUDY ON NATURAL GAS RESERVOIRS FORMATION

Because of the episode of natural gas generation and structure evolution, the natural gas formed at different stages is different from each other in geochemical properties, natural gas generated from source rock at different evolution stage may be entrapped by trap formed at different geology phase. Natural gas or gas reservoirs formed at early stage may get lost or transferred due to late structure evolution, trap formed lately could only entrap natural gas generated from source rock at late stage, i.e., natural gas are entrapped by traps at different stages. The mechanism of natural gas fraction entrapment is introduced in the paper. According to natural gas geochemical properties of gas reservoirs from Tabei area in Tarim basin, authors explain the mechanism of natural gas fraction entrapment and its role in study on natural gas reservoir formation.