东海盆地西湖凹陷原油地化特征及来源分析

Geochemical characteristics and source of crude oil in Xihu Sag, East China Sea Shelf Basin

曹倩 宋在超 周小进 梁世友 王岭

CAO Qian SONG Zaichao ZHOU Xiaojin LIANG Shiyou WANG Ling

1. 中国石化 石油勘探开发研究院 无锡石油地质研究所, 江苏 无锡 214126; 2. 中国石化 上海海洋油气分公司研究院, 上海 200120

1. Wuxi Research Institute of Petroleum Geology, SINOPEC, Wuxi, Jiangsu 214126, China; 2. Research Institute of Shanghai Marine Petroleum Branch, SINOPEC, Shanghai 200120, China

将地化、地质分析相结合，分析了东海陆架盆地西湖凹陷中央背斜带、三潭深凹和保俶斜坡原油的地化特征，进行了油源对比，并梳理了油气成藏过程。不同构造带原油成熟度、母质来源及成藏过程存在差异：西湖凹陷原油成熟度分布在成熟-高成熟范围，中央背斜带以成熟原油为主，三潭深凹和保俶斜坡原油在成熟-高成熟范围均有分布。油源对比结果显示，中央背斜带花港组原油的源岩以花港组泥质烃源岩为主；三潭深凹花港组原油的源岩以平湖组和花港组泥质烃源岩为主；保俶斜坡平湖组原油源岩以平湖组煤系烃源岩为主；保俶斜坡宝石组原油的源岩以宝石组泥质烃源岩为主。西湖凹陷原油普遍具有"蒸发分馏、气洗分馏"的成藏机制，以保俶斜坡原油最为典型。

The geochemical characteristics of oil in the Central Anticline, Santan Sag and Baochu Slope were determined, and the oil source correlation and the process of oil accumulation were analyzed based on geological and geochemical analyses. There are differences in crude oil maturity, parent material source and accumulation process in different tectonic zones. The crude oil in the Xihu Sag is distributed in the mature or high maturity range. The Central Anticline is dominated by mature crude oil, and that in the Santan Sag and Baochu Slope is in the mature or high maturity range. The oil source correlation results show that the crude oil in the Huagang Formation mainly sourced from the argillaceous source rocks in the Huagang Formation in the Central Anticline, and the argillaceous source rocks in the Pinghu and Huagang formations in the Santan Sag. The crude oil in the Pinghu Formation on the Baochu Slope mainly originated from the coal-series source rocks in the Pinghu Formation, while those in the Baoshi Formation mainly sourced from the argillaceous source rocks in the Baoshi Formation. The crude oil in the Xihu Sag generally has the accumulation mechanism of “evaporative fractionation and gas-washing fractionation”, and those on the Baochu Slope are the most typical.

中国石化上海海洋油气分公司科研项目"东海西湖凹陷中央背斜带成藏主控因素研究"（34000000-12-ZC0613-0004）资助。

https://doi.org/10.11781/sysydz201902251