石油与天然气地质 ›› 2017, Vol. 38 ›› Issue (6): 1043-1051.doi: 10.11743/ogg20170604

• 油气地质 • 上一篇    下一篇

大港油田上古生界煤系烃源岩地球化学特征与二次成烃

周立宏, 滑双君, 孙超囡, 代昆, 牟智全   

  1. 中国石油 大港油田分公司, 天津 300280
  • 收稿日期:2016-12-26 修回日期:2017-10-11 出版日期:2017-12-28 发布日期:2018-01-08
  • 作者简介:周立宏(1968-),男,教授级高级工程师,油气综合勘探。E-mail:zhoulh@prtrochina.com.cn。
  • 基金资助:
    中国石油重大科技专项(2014E-06-01)。

Geochemical characteristics and secondary hydrocarbon generation of coal-measure source rocks in Upper Paleozoic of Dagang oilfield

Zhou Lihong, Hua Shuangjun, Sun Chaonan, Dai Kun, Mu Zhiquan   

  1. Dagang Oilfield Company, PetroChina, Tianjin 300280, China
  • Received:2016-12-26 Revised:2017-10-11 Online:2017-12-28 Published:2018-01-08

摘要: 大港油田上古生界煤系地层主要分布于中南部,分布面积近10 000 km2。烃源岩包括煤层、碳质泥岩和泥岩3种类型,总厚度100~450 m,纵向上主要分布在太原组和山西组,本溪组少量发育。煤层有机质丰度高,85%以上属于好-极好烃源岩类型,而泥岩丰度各地区之间差异较大。烃源岩显微组分构成中以镜质组含量占优势,50%以上,成熟阶段具有良好的生气条件,同时受成煤环境的影响,主要成煤中心的煤系地层也富含一定的富氢组分,在低熟-成熟阶段具有良好的生油能力。上古生界在地史演化中经历了多期构造活动的改造,煤系源岩也随之经历了两次生烃过程,其中二次生烃范围分布广,资源规模大,是潜山勘探的重要区域。按照构造演化分类,油田内发育4种埋藏史类型,即早埋晚抬型、早抬晚埋型、持续深埋型与稳定埋藏型。除早埋晚抬型之外,其他3类均具有二次生烃条件。经多年的勘探,在二次生烃范围内,相继在孔西“古生中储型”和乌马营潜山、埕海潜山、王官屯潜山“古生古储型”原生油气藏实现了潜山勘探的重大突破。

关键词: 二次生烃, 煤系烃源岩, 原生油气藏, 大港油田

Abstract: Coal-measure formations in the Upper Paleozoic mainly distributes in central-south part of Dagang Oilfield and covers an area of nearly 10 000 km2.Source rocks there consist of coal beds,carbonaceous mudstone and mudrock,and have a gross thickness of 100 to 450 m.Vertically,they distribute mainly in the Taiyuan and Shanxi Formations with some developed in the Benxi Formation.The coal beds are rich in organic matter (more than 85%) and are high to very high quality source rocks,while the organic matter content in mudstone varies greatly from place to place.Vitrinite dominates the maceral of the source rocks with a content of more than 50%,indicating favorable conditions for gas generation during the mature stage of the rocks.Meanwhile,affected by coal-forming environment,the coal-measure strata in the main coal-forming centers are also contain some hydrogen-rich macerals,hinting large oil generation capacity during low maturity to mature stage.The Upper Paleozoic strata experienced multiple phases of tectonic activities,so were the coal-measure source rocks,which went through two stages of hydrocarbon generation.The secondary hydrocarbon generation was cha-racterized by large area and high resource potential and has been the focus of study during the buried hill exploration.Four types of burial history can be recognized in the oilfield based on the tectonic evolution:the early-burial and late-lift type,the early-lift and late-burial type,the continuous deep-burial type and the steady-burial type.Except for the first type,all the other three types possessed favorable conditions for secondary hydrocarbon generation.Years of exploration in the area of secondary hydrocarbon generation yielded primary oil and gas discoveries in buried hills one after another:Kongxi,Wumaying,Chenghai and Wangguantun,to name just a few.

Key words: secondary oil generation, coal-measure source rock, primary oil and gas accumulation, Dagang Oilfield

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