呼和拗陷浅层气特征及成藏地质条件

The feature and accumlative geologic conditions about shallow gas in Huhe Depression

目的探究呼和拗陷第四系更新统、第三系上新统浅层气的成气原因,查明该区成藏地质因素。方法气样组分分析、烃源岩地球化学分析、钻井岩心与岩石薄片(铸体)鉴定、粒度分析和录井资料。结果呼和拗陷浅层气为生物成因气;目的层系为第三系上新统、第四系更新统,该区具备生物气成藏地质条件:有机质丰度高,生气能力强,干酪根类型好;储层孔、渗性能普遍好;芒硝层、腐植土大面积稳定分布,为区域性盖层;地层序列与岩性组合为生物气藏形成了有利的生、储、盖空间配置。结论通过以上研究,得出浅层气聚集的有利部位是次级拗陷之间的相对隆起区。

Aim To explore the shallow gas about pleistocene and pliocene strata in Huhe Depression and research, the gas genetic type and accumulation geological factors. Methods The composition of shallow gas and geo-chemical characteristics of source rock were tested. The samples of granularity was analyzed and the slice of drill core was identified as well. Results It has the geological conditions of biological gas reservoirs ： organic matter abundance is high, gas generating capacity is good, Porosity and permeability is of superiority. Type of pore structure is mainly primary pore. The thickness of Glauber is salt, distributing widely and steadily, which can form favourable traps, ranged from 4 m to 34 m,and the main type of gas reservoirs belongs to alternate auto-storing gas derivation. Conclusion With the above research, it has indicated that the favourable exploration targets for shallow gas lies in ridgy areas relatively between two sub-depressions.