地质科技通报2025，Vol.44Issue(5)：40-52,13.DOI:10.19509/j.cnki.dzkq.tb20240099
塔里木盆地顺北地区奥陶系天然气地球化学与成因
Geochemistry and origin of Ordovician natural gas in Shunbei area of Tarim Basin
摘要
Abstract
[Objective]Petroleum breakthroughs in the strike-slip fault zones of the northeastern Shunbei area in the last decades reveled the spatial variation in petroleum accumulation types and phase patterns,including the oil accumulation on the north,condensate gas accumulation on the south,and dry gas accumulation on the east.Therefore,to further advance ultra-deep petroleum exploration,it is crucial to reveal the genesis mechanism,source,and thermal maturation of the natural gas from the perspective of overall petroleum distribution.[Methods]This study systematically collected gas samples from various fault zones in the Shunbei area in order to analyze the geochemical characteristics of natural gas and reveal its generation mechanism or thermal evolution process.[Results]The results indicate that the natural gas in the Shunbei area was minimally affected by TSR even though some parts of the fault zones showed strong modification of thermal-chemical sulfate reduction(TSR).The natural gases in the No.1 fault zone and in the northern and middle sections of the No.5 fault zone are primarily crude oil-associated gases generated by primary kerogen cracking.In contrast,the natural gases in the southern section of the No.5 and No.4 fault zones were mainly the mixture of early kerogen cracking gas(oil-associated gas)and late crude oil cracking gas.The natural gas in the Shunbei No.12 fault zone originated from deeper,high-temperature crude oil cracking gas,which occurred at the wet gas stage.The natural gases in the study area predominantly came from the source rocks of the Lower Cambrian Yurtus Formation,and the parent material of these gases is characterized by benthic algae or a mixture of benthic and planktonic algae.Finally,a regression equation for thermal maturity calculation based on the carbon isotope of methane was established for the hydrocarbon generation process in the source rocks of the Yurtus Formation.[Conclusion]The research findings provide important insights into the origin,source,and thermal maturity of ultra-deep gas,offering valuable references for future studies on hydrocarbon generation in the Shunbei area.关键词
顺托果勒低隆起/原油裂解/天然气/热成熟度/玉尔吐斯组/顺北地区Key words
Shuntuoguole Lower Uplift/oil cracking/natural gas/thermal maturity/Yurtus Formation/Shunbei area分类
天文与地球科学引用本文复制引用
曹自成,云露,平宏伟,李海英,耿锋,韩俊,黄诚,毛庆言,丁勇..塔里木盆地顺北地区奥陶系天然气地球化学与成因[J].地质科技通报,2025,44(5):40-52,13.基金项目
国家自然科学基金项目(42072176 （）
42272169) （）
国家科技重大专项"塔里木盆地深层超深层碳酸盐岩油气藏高效勘探开发技术与集成示范项目"(2025ZD1402301) （2025ZD1402301）
