烃源岩中甲基菲的分布及对成熟度参数的影响

DISTRIBUTION OF METHYL PHENANTHRENE IN SEDIMENTS AND ITS IMPACTING ON MATURITY PARAMETERS

宋长玉 金洪蕊 刘璇 王忠

Song Changyu Jin Hongrui Liu Xuan Wang Zhong

中国石油化工股份有限公司, 胜利油田分公司, 地质科学研究院, 山东, 东营, 257015

Institute of Geological Science, Shengli Oilfield Company, SINOPEC, Dongying, Shandong 257015, China

通过对渤海湾盆地济阳坳陷部分煤样及渤南洼陷不同沉积环境烃源岩中甲基菲分布特征的分析,认为沉积环境及生源对甲基菲的分布具有较大的影响。渤南洼陷以低等水生生物为主要生源的湖相沉积中,9-甲基菲丰度大于1-甲基菲;咸水澙湖环境下的烃源岩中3-甲基菲和2-甲基菲相对丰度增加,其甲基菲指数也偏大;形成于淡水—微咸水湖相沉积环境的烃源岩,甲基菲指数偏低。在半咸水—咸水还原环境的富含菌类和藻类等低等生物的煤中,易于生成9-甲基菲,而在弱氧化—弱还原沉积环境且以高等植物为主要生源的煤中,1-甲基菲较9-甲基菲丰富。利用甲基菲指数评价有机质成熟度时应考虑生源不同所造成的差别。

In this paper,the distribution features of methyl phenanthrene from some coals in Jiyang Depression and some hydrocarbon source rocks in Bonan Sag were analyzed.The results show that the sedimentary environment and the biologic source have a great influence on the distribution of methyl phenanthrene.In Bonan Sag,the 9-methyl phenanthrene is more abundant than 1-methyl phenanthrene in the lake facies sediments with lower hydrobios being the dominant species.The relative abundances of 3-methyl phenanthrene and 2-methyl phenanthrene increase in the hydrocarbon source rock under the salt lagoon environment and the methyl phenanthrene index is on the high side.But the index is on the low side in the fresh-brackish lake facies sediments.In the coals in Jiyang Depression,the 9-methyl phenanthrene is liable to form in the salty reducing environment with aboundant bacteria and alga,while 1-methyl phenanthrene is more abundant than 9-methyl phenanthrene in the weak oxidizing environment with higher plants being dominant species.The difference causing by biologic source should be considered in utilizing methyl phenanthrene index for evaluating maturity of organics.

https://doi.org/10.11781/sysydz200702183