石油与天然气地质 ›› 2004, Vol. 25 ›› Issue (3): 288-293.doi: 10.11743/ogg20040310

• 油气地质 • 上一篇    下一篇

酒西坳陷青南次凹烃源岩的热演化及生烃史

高波1, 程克明2, 张大江2, 涂建琪2, 胡咏2, 杨智明3   

  1. 1. 中国石化石油勘探开发研究院,北京 100083;
    2. 中国石油石油勘探开发研究院,北京 100083;
    3. 中国石油玉门油田分公司石油勘探开发研究院,甘肃玉门 735200
  • 收稿日期:2004-04-02 出版日期:2004-06-25 发布日期:2012-01-16

Analysis of thermal evolution and hydrocarbon-generating history of source rocks in Qingnan sub-sag in Jiuxi depression

Gao Bo1, Cheng Keming2, Zhang Dajiang2, Tu Jianqi2, Hu Yong2, Yang Zhiming3   

  1. 1. Exploration & Production Research Institute, SINOPEC, Beijing;
    2. Petroleum Exploration & Development Research Institute, PetroChina, Beijing;
    3. Petroleum Exploration & Development Research Institute, Yumen Oilfield Company, PetroChina, Yumen, Gansu
  • Received:2004-04-02 Online:2004-06-25 Published:2012-01-16

PDF (PC)

567

被引次数

34

摘要：

应用可溶有机质演化、岩石热解、生物标志物参数和镜质体反射率等方法对酒西坳陷青南次凹下白垩统烃源岩热演化史的研究表明:次凹的生油门限深度为4000～4100m,中沟组绝大部分现处于未成熟阶段,中沟组底部和下沟组上部处于低成熟阶段,下沟组下部和赤金堡组上部处于生烃的成熟阶段,赤金堡组下部则处于湿气-凝析油阶段。应用EasyRo(%)数值模拟软件对青南次凹地热史的研究表明,白垩纪与第三纪的古地温梯度分别为30℃/km和29℃/km。烃源岩生烃史具有如下特点:(1)青南次凹下白垩统烃源岩不存在二次生烃作用,其主要生油阶段为晚第三纪—第四纪;(2)下沟组下部和赤金堡组上部的烃源岩经历了油气大量生成的成熟阶段,是油气生成的主力烃源岩;(3)下沟组上部和中沟组的烃源岩层,有机质的热演化程度较低,对生烃的贡献不大;(4)赤金堡组底部的岩层热演化程度较高,但由于是一套较粗的碎屑岩,有机质丰度较低,生烃能力比较有限。

关键词: 青南次凹, 烃源岩, 热演化程度, 生烃史

Abstract:

Thermal evolution of Lower Cretaceous source rocks in Qingnan sub-sag in Jiuxi depression is studied by using several methods including evolution of soluble organic matter, rock pyrolysis, biomarker parameters and vitrinite reflectance. It is revealed that the depth of oil threshold ranges from 4000 to 4100m in the sub-sag. Most of Zhonggou Formation is in immature stage, the bottom of Zhonggou Formation and the upper Xiagou Formation are in low-mature stage, the lower Xiagou Formation and the upper Chijinpu Formation are in mature stage, and the lower Chijinpu Formation is in wet gas-condensate generating stage. Study of geothermal history in Qingnan sub-sag with the Easy-Ro(%) numerical modeling software shows that the Cretaceous and Tertiary palaeo-geothermal gradients are 30℃/km and 29℃/km,respectively.Hydrocarbon generating history of the source rocks has the following characteristics:(1)the Lower Cretaceous source rocks in Qingnan sub-sag have not experienced secondary hydrocarbon generation and the main oil-generating period is from Neogene to Quaternary;(2)the source rocks in lower Xiagou Formation and the upper Chijinpu Formation are in mature stage with large amount of hydrocarbon generation,i.e.they are the main source rocks;(3)source rocks in the upper Xiagou Formation and Zhonggou Formation make little contribution to hydrocarbon generation, due to the low thermal evolution of organic matter;(4)although rocks at the bottom of Chijinpu Formation have experienced relatively high thermal evolution, they have limited hydrocarbon generating capacity, as they are mainly composed of coarse clastic rocks with low abundance of organic matter.

Key words: Qingnan sub-sag, source rocks, thermal evolution, hydrocarbon-generating history

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