咸化湖盆页岩油地质特征及资源潜力评价方法——以柴西坳陷下干柴沟组上段为例
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本文为国家自然科学基金项目“环青藏高原盆山体系动力学与天然气富集机理”(编号U22B6002)和中国石油天然气股份有限公司重大专项“中国陆相页岩油成藏机理、分布规律与资源潜力研究”(编号2019E- 2601)联合资助的成果


Geological characteristics and resource evaluation method for shale oil in a salinized lake basin: A case study from the upper member of the Lower Ganchaigou Formation in western Qaidam depression
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    摘要:

    柴达木盆地西部坳陷的英雄岭地区古近系下干柴沟组上段(E23)页岩油获勘探重大突破。下干柴沟组上段沉积时期属于典型的咸化湖盆,通过岩芯观察和X射线衍射全岩、地球化学、储层物性分析,发现在此环境下形成的页岩及页岩油具有明显的特性:① 页岩以碳酸盐岩矿物为主,岩性以纹层状云灰岩和层状灰云岩为主;② 烃源岩具有低TOC、高转化率的特点,游离烃含量高,具有明显的石油“超越效应”,而且页岩的含油性和生烃潜量与碳酸盐矿物含量呈正相关性;③ 储层表现为特低孔、特低渗的特点,黏土矿物类型以伊利石和伊蒙混层为主,有利于页岩油的稳产和高产;④ 地层压力系数高,能量充足,原油轻质组分多、气油比高。柴西坳陷E23页岩层系厚度大、面积广,为了评价其资源潜力,将柴西坳陷划分为小梁山、英雄岭、扎哈泉和茫崖4个凹陷,首先应用成因法计算资源量,然后用体积法、容积法和类比法验证其结果的可靠性,最终用德尔菲法确定页岩油总的资源量为69×108 t。本文研究成果具有重要的意义:① 明确了咸化湖盆页岩油独特的地质特征,指出富油层系的岩性组合;② 提出了计算吸附烃的计算公式,提供了一套切实可行的页岩油资源量的评估方法;③ 资源量的落实证实了柴西坳陷具有可观的页岩油资源潜力,坚定了勘探信心;④ 多因素综合划定的I类有利区带面积为2460 km2,指出了下一步勘探的现实领域。

    Abstract:

    Major breakthroughs of shale oil exploration have been made recently in the upper member of the Lower Ganchaigou Formation (E23) of the Paleogene in the Yingxiongling area of the western depression, Qaidam basin. The sedimentary environment of the upper member of the Lower Ganchaigou Formation belongs to a typical saline lake basin. Based on core observation and analysis of X- ray diffraction, whole rock mineral, geochemistry and reservoir physical properties, it is found that the shale and shale oil formed in this environment have the following obvious characteristics: ① the shale is dominated by carbonate minerals, and the lithology is dominated by laminar dolomite limestone and layered lime dolostone; ② the source rock has the characteristics of low TOC and high conversion rate, high free hydrocarbon content and obvious “oil crossover”. Moreover, the oil- bearing property and hydrocarbon generating potential of shale are positively correlated with the carbonate mineral content; ③ the reservoir is characterized by ultra- low porosity and permeability. The clay mineral type is mainly illite and chlorite & illite mixed clay, which is conducive to the stable and high yield of shale oil; ④ the formation pressure coefficient is high, the energy is sufficient, the crude oil has many light components, and the gas oil ratio is high. The E23 shale series in the western Qaidam depression has a large thickness and a wide area. In order to evaluate its resource potential, the western Qaidam depression is divided into four sags, namely, Xiaoliangshan, Yingxiongling, Zhahaquan and Mangya. First, the genetic method is used to calculate the resource quantity, and then the volume method, capacity method and analogy method are used to verify the reliability of the results. Finally, the Delphi method is used to determine the total resource quantity of shale oil as 6.9 billion tons. The research results of this paper are important because ① the unique geological characteristics of shale oil in the salinized lake basin are clarified, and the lithologic association of the rich oil- bearing series is highlighted; ② the calculation formula for calculating adsorbed hydrocarbon is proposed, and a set of practical and feasible evaluation methods for shale oil resources are provided; ③ the estimation of resources confirmed that the western Qaidam depression has considerable shale oil resource potential and strengthened the exploration confidence; ④ the area of type I favorable zones comprehensively determined by multiple factors is 2460 km2, which identifies the practical field of next exploration.

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郭泽清,龙国徽,周飞,唐丽,姜营海,白斌,张静,刘畅,王艳清,张博策,贾生龙.2023.咸化湖盆页岩油地质特征及资源潜力评价方法——以柴西坳陷下干柴沟组上段为例[J].地质学报,97(7):2425-2444.
GUO Zeqing, LONG Guohui, ZHOU Fei, TANG Li, JIANG Yinghai, BAI Bin, ZHANG Jing, LIU Chang, WANG Yanqing, ZHANG Boce, JIA Shenglong.2023. Geological characteristics and resource evaluation method for shale oil in a salinized lake basin: A case study from the upper member of the Lower Ganchaigou Formation in western Qaidam depression[J]. Acta Geologica Sinica,97(7):2425-2444.

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历史
  • 收稿日期:2022-10-14
  • 最后修改日期:2022-12-26
  • 录用日期:2022-12-28
  • 在线发布日期: 2023-07-24