晋东南山西组主煤层热演化生烃史及热源分析  

A ANALYSIS TO THE HISTORY OF THERMAL EVOLUTION HYDROCARBON-GENERATING AND THE HEAT SOURCE ABOUT MAIN SEAM OF SHANXI FORMATION IN SOUTHEASTERN SHANXI PROVINCE

作　　者：曾勇[1] 范炳恒[1] 刘洪林[1] 王纯信[2] 

机构地区：[1]中国矿业大学 [2]山西晋城矿务局

出　　处：《地质科学》1999年第1期90-98,共9页Chinese Journal of Geology(Scientia Geologica Sinica)

摘　　要：以晋城矿区山西组主煤层为代表，利用时间－温度指示法、有机质变质程度法、挥发分产率法对该煤层煤化作用历史进行了定量分析，指出其埋藏历史经历了４个发展阶段：（１）Ｐ１—Ｔ３的快速沉降阶段，平均沉降速度达９４ｍ／Ｍａ；（２）Ｊ１的逐渐抬升阶段，抬升幅度大于７５０ｍ；（３）Ｊ２的缓慢沉降阶段，平均沉降速率为１０ｍ／Ｍａ；（４）Ｊ３—现代的再次回返阶段。主煤层热演化主要发生在埋藏历史的第１阶段和第４阶段的Ｊ３—Ｋ时期，前者为深成变质作用，主要生成湿气且难于保存；后者为异常高热古地温场所致，促使主煤层出现二次生烃作用，为裂解气阶段，主要生成干气，易于保存。最后指出晚中生代异常高温古地温场是由于上地幔顶界面隆起、地壳变薄、岩浆作用加剧、热流值增高所致。Taking the main seam (seam № 3)of Shanxi formation in Jincheng Mining district as research target,the authors have made the quantitative analysis to the coalification history of the seam using TTI method,LOM method and Z value method, and point out that the burying of the main seam underwent four developing stages.That is: 1. P 1—T 3—called quick subsidence stage, mean subsidence velocity reaching to 94 m/Ma. 2. J 1 ——gradual uplift stage, the greatest uplift extent being more than 750 m. 3. J 2 ——slow subsidence stage, mean subsidence velocity being 10m/Ma . 4. J 3—Present——re inversion stage. The thermal evolution (maturation)of the main seam mainly took place during the 1st stage and the J 3—K period of 4st stage. In the 1st stage , the seam underwent the plutonic metamorphism and mainly generated the wet gas,but it is very difficult for the wet gas to be preserved. In the J 3—K period, the thermal evolution of the main seam is resulted from the anomaly high hot paleogeothermics field.This field caused the main seam to generate hydrocarbon again (secondary hydrocarbon generatoin). In this stage, the main seam mainly generated dry gas,which can be preserved easily . In the later part of this paper, the authors have analysized the geologic settings from which the anomaly high-hot paleogeothermics field in Late Mesozoic is resulted, and thought that in that time,the top of upper mantle uplifting,the earth crust thining locally, the magmatism strenthening and the thermal current value increasing resulted in the formation of the anomaly high-hot paleogeothermics field. Meanwhile, the authors point out that the uplift of upper mantle was related to the upwelling and radiation of hot plume belong to plume tectonics.

关 键 词：山西组 煤层 生烃史 热幔柱 煤矿床 油气成因 

分 类 号：P618.130.1[天文地球—矿床学] P618.114[天文地球—地质学]