华北陆块南部下寒武统海相泥质烃源岩的发现对天然气勘探的意义  

Discovery of Marine Muddy Hydrocarbon Source Rocks in the Southern Margin of the North China Block and Its Significance for Gas Exploration

作　　者：戴金星[1] 刘德良[2] 曹高社[2] 

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国科学技术大学石油与天然气研究中心地球与空间科学学院,合肥230026

出　　处：《地质论评》2003年第3期322-329,共8页Geological Review

基　　金：国家重点基础研究规划专题(编号2001CB209132);"十五"科技攻关项目(编号010201-6-j-2)

摘　　要：在华北陆块南部发现的下寒武统海相泥质烃源岩,有机碳含量平均高达11.2％;干酪根碳同位素等多项分析表明,生源为低等生物菌藻类,属Ⅰ型有机质类型;R_o(2％～3.5％)与t_(max)(500～600C)反映的成熟度已进入过成熟早期乃至晚期阶段,但仍处于生气高峰期内。对我国下寒武统烃源岩综合对比表明,华北陆块南缘下寒武统烃源岩同塔里木陆块和扬子陆块相当层位的烃源岩具有显著的相似性。综合分析认为,华北陆块南缘下寒武统烃源岩具有形成深源气、裂解气和保留早期气的现实性。该套烃源岩的发现,为我国油气勘探提出了新观念——注重海相地层、新层位——寒武系、新领域——在华北陆块周缘寻找以石炭系为主储层的和田河式气藏、以震旦系为主储层的威远式气藏。Marine muddy hydrocarbon source rocks of the lower Cambrian have been discovered in the southern part of the North China block. The rocks have an average organic carbon content as high as 11. 2%. A combined analysis including the carbon isotope ratio of the kerogen indicates that the biogenic sources are bacteria and algae, belonging to the I-type organic matter. As revealed by Ro(2%-3. 5%) and tmax(600-500℃), the area has reached an overmature stage, but still in the peak stage of gas formation. A comprehensive comparison of the lower Cambrian hydrocarbon source rocks in China reveals that the hydrocarbon source rocks in the southern part of the North China block bear remarkable similarity with those of corresponding horizons in the Yangtze and Tarim blocks. According to the above analysis, there is the possibility that the lower Cambrian hydrocarbon source rocks in the North China block may form deep-sourced gas, pyrolytical gas while maintaining the early-stage gas. The discovery of this suite of hydrocarbon source rocks puts forward a new idea for oil and gas exploration of China, i.e., we should pay attention to marine strata, new horizons-the Cambrian, and new fields of exploration-searching in the periphery of the North China block for Ordos-type gas fields in which the reservoirs are mainly of the Ordovician, the Hotanhe-type gas fields dominated by Cambrian reservoirs, and the Weiyuan-type gas fields mainly with Sinian reservoirs.

关 键 词：华北陆块 干酪根 下寒武统 烃源岩 有机碳 成熟度 深源气 裂解气 天然气勘探 

分 类 号：P618.13[天文地球—矿床学]