塔里木盆地库车坳陷克深大气田深层天然气成藏地球化学特征  

Geochemical characteristics of deep-seated natural gas accumulation of the Keshen large gas field in the Kuqa Depression,Tarim Basin

作　　者：魏强 李贤庆[1,2] 孙可欣[1,2] 李瑾[3] 肖中尧[4] 梁万乐[1,2] 张亚超 Wei Qiang;Li Xian-qing;Sun Ke-xin;Li Jin;Xiao Zhong-yao;Liang Wan-le;Zhang Ya-chao

机构地区：[1]中国矿业大学(北京)煤炭资源与安全开采国家重点实验室,北京100083 [2]中国矿业大学(北京)地球科学与测绘工程学院,北京100083 [3]中国石油勘探开发研究院天然气地质研究所,河北廊坊065007 [4]中国石油塔里木油田分公司勘探开发研究院,新疆库尔勒841000

出　　处：《天然气地球科学》2019年第6期897-907,共11页Natural Gas Geoscience

基　　金：国家科技重大专项课题(编号:2016ZX05007-003);国家自然科学基金项目(编号:U1810201);中央高校基本科研业务费专项资金项目(编号:2010YM01)联合资助

摘　　要：利用天然气组分定量、稳定碳同位素组成、流体包裹体显微测温和生烃动力学实验数据,对塔里木盆地库车坳陷克深大气田深层天然气的地球化学特征及成因、储层流体包裹体特征与均一温度、油气充注时间及成藏过程进行研究.结果表明:库车坳陷克深大气田深层天然气以烷烃气为主,甲烷含量占87.30%~98.33%,重烃(C2+)含量占0~0.66%,干燥系数达0.99%~1.0%;δ^13 C1值、δ^13C2值分别为-29.3‰^-26.4‰、-21.4‰^-16.1‰,属于过成熟的煤成气.克深大气田白垩系巴什基奇克组储层发育2期烃类包裹体:第Ⅰ期为发蓝白色荧光的液态烃包裹体,指示早期轻质油充注;第Ⅱ期为无荧光的气态烃包裹体,与其共生的盐水包裹体均一温度为145~160℃,为晚期天然气充注.克深大气田主要经历了库车组沉积期末(约2.5 Ma)以来的天然气大量充注,气源主要来自克深井区和拜城凹陷生气中心的侏罗系煤系烃源岩,为深埋快速生烃、强源储压差作用下晚期聚集成藏.The geochemical characteristics and genesis of deep-seated natural gas,type features and homogenization temperature of fluid inclusions,charge time of hydrocarbon and accumulation process of the Keshen large gas field in the Kuqa Depression,Tarim Basin were studied,by using the data of the quantification of gas components,carbon isotope compositions,micro temperature measurement of fluid inclusion,and hydrocarbon generation kinetics.The results show that deep-seated natural gas in the Keshen large gas field is dominated by alkanes,of which methane accounts for 87.30%-98.33%,the C2+ content is 0%-0.66%,and the dryness coefficient is 0.99%-1.0%.The δ13C1 and δ13C2 values are from-29.3‰to-26.4‰ and from -21.4‰ to -16.1‰,respectively,indicative of the over mature coal-derived gas.There are two episodes of hydrocarbon inclusions in the Cretaceous Bashijiqike Formation reservoirs in the Keshen large gas field.The first phase inclusion is liquid inclusion with blue-white fluorescence color,which means that the early light oil was charged.The second phase inclusion is gas inclusion with non-fluorescence color.The homogenization temperature of aqueous inclusion symbiosis with gas inclusion is 145-160℃,which indicates that the late gas was charged.The Keshen large gas field has experienced large-scale natural gas charging history since the Late Kuche Formation sedimentary period(about 2.5 Ma).Natural gas in the Keshen large gas field is mainly originated from Jurassic coal-bearing source rocks in the Keshen well area and center of Baicheng Sag,which is the late accumulation under the actions of rapid hydrocarbon-generation in the deepburied strata and strong pressure difference gradient of resource-reservoir.

关 键 词：库车坳陷 克深大气田 天然气成因 流体包裹体 生烃动力学 成藏过程 

分 类 号：TE122.1[石油与天然气工程—油气勘探]