中国东部CO_2气地球化学特征及其气藏分布  

Geochemical characteristics of CO_2 gases in eastern China and the distribution patterns of their accumulations

作　　者：廖凤蓉 吴小奇[1] 黄士鹏[1] 

机构地区：[1]中国石油勘探开发研究院,北京100083

出　　处：《岩石学报》2012年第3期939-948,共10页Acta Petrologica Sinica

基　　金：中国石油勘探开发研究院石油科技中青年创新基金资助

摘　　要：中国东部CO2气田(藏)发育广泛,分布复杂。本文对中国东部松辽、渤海湾、苏北、三水、东海、珠江口、莺琼、北部湾等盆地和内蒙古商都地区以及部分现代构造岩浆活动区CO2气田(藏)和气苗中CO2的地球化学特征进行了分析和研究,探讨了中国东部CO2气的成因、来源及分布。中国东部CO2气的含量主要分布区间为0～10%,其次为90%～100%,呈现典型的U字型。δ13CCO2值则呈现典型的单峰式分布,峰值区间为-6‰～-4‰。CO2含量、δ13CCO2值和R/Ra值综合表明,中国东部高含CO2气以幔源无机成因为主,混有部分有机成因气和(或)壳源无机气。中国东部已发现的36个无机成因CO2气田(藏)在空间分布上与新近纪及第四纪北西西向玄武岩活动带展布一致,深大断裂和岩浆活动是无机成因CO2富集、运移和分布最重要、最直接的两大主控因素。CO2 gas accumulations are distributed widely and complexly in eastern China.This study focuses on the origin and distribution of CO2 gases in eastern China based on the geochemical analyses of samples from some basins in the eastern China,such as Songliao,Bohai Bay,Subei,Sanshui,East China Sea,Pearl River Mouth,Yinggehai-Qingdongnan and Beibuwan,as well as Shangdu area in Inner Mongolia and some modern tectonomagmatic activity regions.The distribution pattern of CO2 contents in natural gases is similar to the typical ＂U＂ type.The CO2 contents mainly range from 0～10%,and secondarily 90%～100%.The δ13CCO2 values show a notable unimodal distribution,with the peak interval ranging from-6‰～-4‰.Combined analyses of CO2 contents,δ13CCO2 values and R/Ra values indicate that high-content CO2 in gases is dominated by mantle-derived abiogenic gases and mixed with some biogenic and crust-derived abiogenic ones.The distribution of 36 CO2 gas accumulations is in accordance with the Neogene-Quaternary north-northwest-trending basalt belts in eastern China.The deep faults and magmatism are the most important and direct controlling factors on the accumulation,migration and distribution of abiogenic CO2 gases.

关 键 词：CO2 无机成因气 碳、氦同位素 玄武岩带 分布 

分 类 号：P618.13[天文地球—矿床学]