石油实验地质2025，Vol.47Issue(6)：1316-1328,13.DOI:10.11781/sysydz2025061316
酒泉盆地青西凹陷白垩系页岩油储层特征及含油性评价
Reservoir characteristics and oil-bearing evaluation of Cretaceous shale oil in Qingxi Sag,Jiuquan Basin
摘要
Abstract
A series of fine-grained sediments with mixed origins of mudstone-dolomite and clastic rock are developed in the Cretaceous of Qingxi Sag in the Jiuquan Basin,providing favorable conditions for shale oil enrichment.Samples of different lithofacies were selected as research objects,and a series of analytical tests were conducted,including rock pyrolysis,total organic carbon,X-ray diffraction,scanning electron microscope(SEM)analysis,rock thin section observation,low-temperature nitrogen adsorption,and high-pressure mercury intrusion experi-ments.Through the comprehensive applications of mineral petrology,organic geochemistry,and reservoir physi-cal property analyses,detailed reservoir characterization and oil-bearing evaluation were conducted for shale oil in the sag.The research results showed that:(1)The shale mineral compositions and lithologies in the sag were complex,and the main lithofacies types were dolomitic shale,fine siltstone,gravelly sandstone,and mudstone.The corresponding shale oil types were mixed sedimentation(in a broad sense)and interbedded types.The fine siltstone exhibited the best oil-bearing property,followed by dolomitic shale,and both of them were favorable reservoirs for shale oil.(2)The pore sizes of shale reservoirs were distributed in the range of 10 nm to 100 μm,among which fine siltstone had a relatively uniform pore size distribution,conducive to the enrichment of shale oil.(3)Based on total organic carbon(TOC)content,S1 content,and oil saturation index(OSI),the oil-bearing properties of shale oil were evaluated and classified into ineffective resources,low-efficiency resources,medium-efficiency resources,and high-efficiency resources.(4)Based on shale lithofacies,geochemical characteristics,reservoir physical property characteristics,microscopic pore structure,and oil-bearing characteristics,the shale oil in the sag was divided into Class Ⅰ,Class Ⅱ,and Class Ⅲ sweet spots,in descending order of resource quality.This study clarified the reservoir and oil-bearing characteristics of the shale oil in the Qingxi Sag and cate-gorized shale oil sweet spots,which is of great significance for shale oil exploration in the sag.关键词
页岩油/储集层特征/含油性评价/下沟组/青西凹陷/酒泉盆地Key words
shale oil/reservoir characteristics/oil-bearing evaluation/Xiagou Formation/Qingxi Sag/Jiuquan Basin分类
能源科技引用本文复制引用
李涛,焦文龙,杨克荣,胡鱈茹,宋杰,刘国利,韦德强,刘欣泽..酒泉盆地青西凹陷白垩系页岩油储层特征及含油性评价[J].石油实验地质,2025,47(6):1316-1328,13.基金项目
中国石油油气新能源公司科技项目"中小盆地风险勘探领域和目标研究、工程技术攻关及现场试验"(2023YQX10110)资助. （2023YQX10110）
