塔里木盆地塔中隆起天然气地球化学特征及成因类型  

Organic geochemical characteristics and genetic type of natural gas in the Tazhong uplift,Tarim basin

作　　者：史江龙 李剑[1,2,3] 李志生[2,3] 祁青山 郝爱胜[2,3] 

机构地区：[1]中国科学院大学渗流流体力学研究所,河北廊坊065007 [2]中国石油勘探开发研究院廊坊分院,河北廊坊065007 [3]中国石油天然气集团公司天然气成藏与开发重点实验室,河北廊坊065007 [4]中国石油青海油田勘探开发研究院,甘肃敦煌736202

出　　处：《东北石油大学学报》2016年第4期19-25,共7页Journal of Northeast Petroleum University

基　　金：国家科技重大专项(2011ZX05007)

摘　　要：统计塔里木盆地塔中隆起400余个天然气气样组分和稳定碳同位素,分析塔中隆起不同构造单元天然气地球化学特征及成因类型。结果表明:(1)塔中隆起天然气为典型的油型气,主要以烃类为主,非烃气体含量差异显著,表现为塔中Ⅰ号断裂带CO2含量(体积分数)相对较高,N2含量相对较低;塔中10号构造带和塔中主垒带天然气CO2含量相对较低,N2含量明显偏高。(2)塔中Ⅰ号断裂带天然气为原油裂解气和干酪根裂解气的混合气,天然气处于高成熟—过成熟阶段,主要来源于寒武系烃源岩;塔中Ⅹ号构造带天然气处于成熟阶段,为中—上奥陶统烃源岩的干酪根裂解气;中央断垒带天然气处于成熟—过成熟阶段,来源为寒武系—下奥陶统和中—上奥陶统烃源岩的混合气。(3)塔中隆起天然气为热解成因气,δ13C1主要介于-50‰^-38‰,仅部分原油伴生气δ13 C1小于-50‰。(4)塔中隆起天然气主体为正碳同位素序列,由于同源不同期气或同型不同源气的混合使得部分天然气的碳同位素序列发生局部倒转。该研究为塔中隆起油气勘探提供依据。To systematically understand the geochemical characteristics and genetic type of natural gases in the Tazhong uplift,through the statistics of gas components and carbon isotope of more than 400 natural gas samples,the characteristics and genetic types of natural gases in different geotectonic units were analyzed and discussed.The results show that:(1)The natural gases of the Tazhong uplift are mainly composed of hydrocarbon gases and the differences of contents in non-hydrocarbon gases are remarkable.The Tazhong No.1fault belt of natural gases has a high content of CO_2 and N_2content is relatively low,while the natural gases of 10 th structure of Tazhong and Tazhong horst zone have a relatively low content of CO_2 and N_2content is obviously high.(2)The natural gases in Tazhong No.1fault belt are mixed gases of oil cracking gas and kerogen cracking gas coming from Cambrian source rock at the high to overmatured stage.The natural gases in the 10 th structure of Tazhong are kerogen cracking gas coming from the middle-upper Ordovician source rock at the middle matured stage.The natural gases of Tazhong horst zone are mixed gases of Ordovician-lower Ordovician and middle-upper Ordovician source rock at the stage of high to over maturity.(3)The natural gases in the Tazhong uplift are thermogenic gas,and the value ofδ13C1is mainly between-50‰^-38‰,except for some oil associated gases are less than-50‰.(4)The carbon isotope order of the natural gases in the Tazhong uplift are mainly normal order,while some mixed gases from the same source rock with different maturities or mixed gases form the same type source rocks have partially reversed carbon isotope orders.

关 键 词：塔中隆起 天然气 组分 碳同位素 成因类型 塔里木盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]