呼和湖凹陷是海拉尔盆地中一个重要的二级凹陷,其中存在2套主力烃源岩系(大磨拐河组和南屯组),均含有煤层,且煤层生烃条件优越,可以作为煤成气的有效源岩。基于对该凹陷中煤系源岩综合评价,笔者采用三维建模与构造模拟系统(TSM)对该凹陷进行盆地模拟,计算出了该区煤系源岩的生气潜量。研究表明,呼和湖凹陷中部和南部的煤层分布比较广泛,平均厚度为120m左右;煤系源岩干酪根类型主要为Ⅲ型,属于倾气型烃源岩;该凹陷以未成熟-低成熟阶段的煤系源岩为主,Ro大部分在0.3%~0.9%;凹陷煤成气总量为1.6897×10^12m^3,具有很好的勘探开发前景。
Huhehu depression is one of the important secondary sags in Hailar Basin,and there exist in this depression two sets of coal-bearing source rocks,namely Damoguaihe Formation and Nantun Formation,which have excellent hydrocarbon-generating conditions and can be regarded as effective coal measure source rocks.Based on a comprehensive evaluation of coal measure source rocks in this depression,the authors calculated the amount of gas generated by the coal measure source rocks by using the approach of basin modeling with the three-dimensional modeling and simulation system.The results show that the coal in the middle and south parts of this depression covers a large area,and the thickness of the coal seam is around 120 meters on average;the kerogen of coal measure source rocks is mainly of type Ⅲ,belonging to gas inclining source rocks;the maturity of the source rocks is mainly at the immature-low mature stage,with Ro mostly between 0.3% and 0.9%.The total amount of coal-formed gas generated is 1.6897×10^12 m^3 in this depression,which is very favorable for exploration and development.