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(E32)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E32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69×10^(8)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2460km^(2),指出了下一步勘探的现实领域。
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:①the shale is dominated by carbonate minerals,and the lithology is dominated by laminar dolomite limestone and layered lime dolostone;②the 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;③the 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;④the 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 because①the unique geological characteristics of shale oil in the salinized lake basin are clarified,and the lithologic association
作者
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
GUO Zeqing;LONG Guohui;ZHOU Fei;TANG Li;JIANG Yinghai;BAI Bin;ZHANG Jing;LIU Chang;WANG Yanqing;ZHANG Boce;JIA Shenglong(Research Institute of Petroleum Exploration&Development,PetroChina,Beijing 100083,China;PetroChina Qinghai Oilfield Company,Dunhuang,Gansu 736202,China;China University of Geosciences(Beijing),Beijing 100083,China;PetroChina Hangzhou Research Institute of Geology,Hangzhou,Zhejiang 310023,China)
出处
《地质学报》
EI
CAS
CSCD
北大核心
2023年第7期2425-2444,共20页
Acta Geologica Sinica
基金
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)
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。
关键词
柴西坳陷
咸化湖盆
下干柴沟组上段
页岩油
资源潜力
western Qaidam depression
salinized lake basin
upper member of Lower Ganchaigou Formation
shale oil
resource potential
