摘要
通过对四川盆地梓潼凹陷烃源岩发育特征及天然气地球化学特征的研究,探讨了该区天然气基本特征及成因类型。研究区烃源岩主要发育于须家河组一段、三段与五段,其中须家河组三段烃源岩厚度最大。烃源岩TOC含量普遍大于1.0%,有机质类型主要为腐殖型,有机质成熟度以成熟、高成熟为主,并已进入大量生烃阶段,生烃强度大于30×108m3/km2,良好的烃源岩条件是研究区天然气聚集成藏的物质基础。研究区干气与湿气同时存在,九龙山、剑门、魏城、白龙场等地区主要为干气,而中坝、老关庙等地区主要为湿气,文兴场、柘坝场、丰谷、绵阳等地区干气与湿气均存在。研究区天然气主要为热成因煤型气,来自该区须家河组烃源岩,仅九龙山地区为油型气,主要来自下伏海相烃源岩。
The characteristics and genetic types of natural gas in the Zitong Sag of the Sichuan Basin have been studied according to the development and geochemical features of source rocks. The hydrocarbon source rocks in the study area mainly located in the first, third and fifth members of the Xujiahe Formation, among which the third member is the thickest. The TOC content of the source rocks is generally greater than 1.0%. Organic matter is of humic type, usually mature or highly mature. A large amount of hydrocarbon has been generated, and the generation intensity is greater than 30×10^9m^3/km^2. Favorable source rock conditions enhance the accumulation of natural gas in the study area. Both dry gas and wet gas have been found. In the Jiulongshan, Jianmen, Weicheng and Bailongchang areas, dry gas is dominant. In the Zhongba and Laoguanmiao areas, wet gas is common. In the Wenxingchang, Zhebachang, Fenggu and Mianyang areas, both dry gas and wet gas exist. The natural gas in the study area is mainly thermogenic coal gas originating from the Xujiahe Formation. Oil type gas exists only in the Jiulongshan area, and is sourced from the underlying marine source rocks. Key words： source rock; geochemical characteristics; gas generation controls ; Xujiahe Formation; Zitong Sag; Sichuan Basin
出处
《石油实验地质》
CAS
CSCD
北大核心
2015年第3期367-373,共7页
Petroleum Geology & Experiment
基金
国家科技重大专项课题(2011ZX05002-004-001)资助
关键词
烃源岩
地球化学特征
天然气成因
须家河组
梓潼凹陷
四川盆地
source rock
geochemical characteristics
gas generation controls
Xujiahe Formation
Zitong Sag
Sichuan Basin
