海相碳酸盐岩烃源岩生排烃能力研究

Study on capability of hydrocarbon generation and expulsion from marine carbonate source rocks

秦建中 刘宝泉 郑伦举 张渠

Qin Jianzhong Liu Baoquan Zheng Lunju Zhang Qu

在5000余块海相不同类型烃源岩样品的精细筛选和比较的基础上,选取了青藏高原侏罗系、冀北上元古界、云南禄劝泥盆系等34个样品进行了人工加水热压模拟实验。综合研究认为,海相烃源岩中碳酸盐岩相对泥页岩对干酪根生排烃具有较强的催化作用,可使生排总油高峰温度前移,更容易形成未熟-低熟稠油,排油效率增大,总产气、CO和H产率增高,总油、气携油、残留油、烃气及总烃产率也相对有所增加。这与α-碳原子形成自由基的催化反应、碳酸盐岩干酪根中浮游藻类含量相对较高以及碳酸盐对有机质及烃类的吸附作用弱有关。但是,含钙泥页岩(碳酸盐含量为5%～25%)总油等烃类产率相对最高。它主要多为封闭强还原环境下形成的富烃含钙页岩,干酪根类型好,有机质丰度高。

Based on selection and comparison of 5000 marine source rock samples of various types,34 samples acquired from Jurassic in Qinghai-Tibet plateau,Upper Proterozoic in northern Hebei province and Devonian in Luquan of Yunnan province have been selected for artificially watering,heating and pressurizing simulation experiment.Comprehensive study shows that the marine carbonate rock has relatively higher accelerating effect on hydrocarbon generation from kerogen and expulsion in comparison with marine mudstone and shale,lowers the temperature of peaks of total oil generation and expulsion,and easily forms immature-low-mature heavy oil,resulting in increasing oil expulsion efficiency,and enlarging yields of total gas,CO,H,total oil,oil carried by gas,residual oil,hydrocarbon gas and total hydrocarbons.All these are related to the catalytic reaction of α-carbon atom forming free radical,the relatively high content of planktonic algae in kerogens of carbonate rocks,and the weak adsorption of carbonate rock to organic matter and hydrocarbons.However,calcareous mudstone and shale,with carbonate content in the range of 5%-25%,relatively have the highest yields of hydrocarbons including total oil.They are mainly formed in closed and strong reduction environments and have good kerogen type and high abundance of organic matter.

10.11743/ogg20060309