摘要
鄂博梁构造带各构造均钻有以古近系—新近系为目的层的探井,但含气丰度很低,一直未能实现勘探的实际突破,同时限于侏罗系烃源岩层埋深较大,成藏富集规律认识不清。近年来随着勘探程度的不断提高,多口探井钻达侏罗系地层,为进一步深入研究奠定了基础。通过对鄂博梁构造带烃源岩、天然气地球化学特征以及运聚条件的详细分析,开展了成藏条件的综合研究。结果表明:处于边缘地区的牛东鼻隆—鄂博梁Ⅰ号构造有机质丰度不高、成熟度很低,不具备大规模形成天然气的烃源岩条件。目前已发现的天然气为高成熟、过成熟的煤型气,来自凹陷中心形成的高成熟烃源岩,侏罗系顶面广泛分布的不整合与沟通源岩的断层是主要的输导途径。鄂博梁构造带进一步的勘探工作应选择凹陷中心烃源岩成熟度高的地区,目的层应尽可能贴近源岩。该研究成果为鄂博梁构造带进一步勘探指出了有利勘探地区。
Exploration wells have been drilled in each structure of Eboliang structural belt with Paleogene and Neogene as the target layer,but the gas abundance is very low,so actual exploration breakthrough has not been achieved.At the same time,due to the large buried depth of Jurassic source rocks,the accumulation and enrichment rules are not clear.In recent years,with the continuous improvement of exploration degree,many exploration wells have been drilled to Jurassic,which lays a foundation for further study.Based on the analysis of hydrocarbon source rocks,geochemical characteristics of natural gas and migration and accumulation conditions of Eboliang structural belt,a comprehensive study on hydrocarbon accumulation conditions was carried out.The results show that the organic matter abundance is not high and the maturity is very low in Niudong nose-shaped uplift and Eboliang No.1 structure,so they do not have the source rock conditions for large-scale natural gas formation.At present,the discovered natural gas is highly mature and over mature coal type gas,which comes from the highly mature source rocks formed in the center of the depression.The unconformities widely developed on the top of Jurassic and the faults connecting the source rocks are the main transport channels.The area with high maturity of source rock in the center of depression should be selected for the next exploration in Eboliang structural belt,and the target layer should be as close as possible to the source rocks.The research results indicate favorable exploration areas for further exploration in Eboliang structural belt.
作者
孔红喜
王远飞
周飞
朱军
陈阳阳
宋德康
KONG Hongxi;WANG Yuanfei;ZHOU Fei;ZHU Jun;CHEN Yangyang;SONG Dekang(Research Institute of Exploration and Development,PetroChina Qinghai Oilfield Company,Dunhuang 736202,Gansu,China)
出处
《岩性油气藏》
CSCD
北大核心
2021年第1期175-185,共11页
Lithologic Reservoirs
基金
国家油气专项“岩性地层油气藏区带、圈闭有效性评价预测技术”(编号:2017ZX05001-003)
国家科技重大专项“柴达木复杂构造区油气成藏、关键勘探技术与新领域目标优选”(编号:2016ZX05003006)
中国石油重大科技专项“柴达木盆地建设高原大油气田勘探开发关键技术研究与应用”(编号:2016E-0102)联合资助。
关键词
烃源岩
天然气组分
甲烷碳同位素
输导条件
成藏模式
勘探方向
鄂博梁构造带
柴达木盆地
source rocks
natural gas components
carbon isotope of methane
transport conditions
accumulation model
exploration direction
Eboliang structure belt
Qaidam Basin
