北部湾盆地涠西南凹陷流沙港组页岩油赋存空间多尺度表征及可动性评价  

Shale Oil Mobility Evaluation and Multi-Scale Characterization of Oil Occurrence Space of Liushagang Formation in Weixinan Sag, Beibuwan Basin

作　　者：范彩伟 游君君 周刚 Fan Caiwei;You Junjun;Zhou Gang(Zhanjiang Branch,CNOOC Limited Company,Zhanjiang 524057,China)

机构地区：[1]中海石油(中国)有限公司湛江分公司,广东湛江524057

出　　处：《地球科学》2025年第1期127-143,共17页Earth Science

基　　金：中国海洋石油集团有限公司资助项目(No.KJZH-2023-2106);中海石油(中国)有限公司湛江分公司资助项目(No.SCKY-2022-ZJ-15)。

摘　　要：为了明确北部湾盆地涠西南凹陷流沙港组页岩油赋存空间及可动性特征,采用岩石薄片鉴定、荧光观测、扫描电镜、氮气吸附、高压压汞、数字岩心分析、核磁共振、多温阶热解等实验技术,对涠西南凹陷流沙港组不同类型页岩油的储层孔隙结构、页岩油赋存空间及可动性特征进行定性分析和定量表征.结果表明:(1)基质型页岩油储层主要发育纳米级的有机孔、黄铁矿晶间孔、黏土矿物粒间孔、以及层理缝、有机质粒缘收缩缝;基质型页岩油主要赋存在孔喉半径小于10 nm的储集空间内.纹层型页岩除了发育纳米-微米级的有机孔、晶间孔及微裂缝外,还发育粒间孔、粒内孔等;纹层型页岩油主要赋存在孔喉半径为10~50 nm之间的储集空间内.夹层型页岩主要发育纳米-微米级的晶间孔、粒间孔、粒内孔及溶蚀孔等;夹层型页岩油主要赋存在孔喉半径介于100~1 000 nm的储集空间内.(2)不同类型页岩油可动性差异明显,其中夹层型页岩油可动性最好,最大可动油含量为22.78~42.63 mg/g,平均32.71 mg/g,可动油比例高达80%以上;纹层型页岩油可动性次之,最大可动油含量为1.78~16.35 mg/g,平均10.88 mg/g,可动油比例在60%左右;基质型页岩油可动油含量和可动油比例最小.(3)有机质丰度与成熟度、储层物性及矿物组成等共同控制了页岩油的可动性;当R_o为1.0%左右,TOC介于1.5%~4%之间,页岩储层可动油最为富集;另外,储层孔喉半径越大、物性越好、脆性矿物含量越高、黏土矿物含量越低,页岩油可动性越好.基于上述研究成果,夹层型页岩具有较大的赋存空间及较好的可动性,是涠西南凹陷页岩油勘探的首选类型,并推动海上页岩油钻探获得重大突破.In order to clarify the occurrence space and mobility characteristics of shale oil in the Liushagang Formation of the Weixinan Sag in Beibuwan Basin,comprehensive experimental techniques such as thin section identification,fluorescence observation,scanning electron microscopy,nitrogen adsorption,high-pressure mercury injection,digital core analysis,nuclear magnetic resonance,and multi-temperature pyrolysis were utilized to qualitatively and quantitatively investigate the pore structure,occurrence space,and mobility characteristics of different types of shale oil reservoirs in the Liushagang Formation of the Weixinan Sag.Results show that:(1)matrix-type shales mainly contain nanoscale pores in organic matter,intergranular pores in pyrite,interparticle pores in clay minerals,fractures at bedding interface,as well as shrinkage fractures on the edge of organic matter particles.Oil in the matrix-type shales mainly stores in pores with pore throat radius less than 10 nm.In addition to organic pores,intergranular pores and microfractures,there are intergranular and intragranular pores developed in laminated shale oil reservoirs.Oil in the laminated shales mainly stores in pore spaces with pore throat radius between 10 nm and 50 nm.The"sandwiched"shales mainly contain intergranular pores,intergranular pores,intraparticle pores,and dissolution-related pores at the nanometer to micrometer scale.Oil in the"sandwiched"shales mainly exists in pore spaces with pore throat radius ranging from 100 to 1000 nm.(2)There are significant differences in the oil mobility of different types of shales.Among them,the"sandwiched"shales have the best mobility.The maximum movable oil content of the"sandwiched"shales is between 22.78 and 42.63 mg/g(averaging 32.71 mg/g),and the movable oil proportion is higher than 80%.The second is the laminated shales,with the maximum movable oil content of 1.78-16.35 mg/g(averaging 10.88 mg/g),and the movable oil proportion of about 60%.The matrix-type shales have the lowest movable oil content and movable

关 键 词：页岩油 赋存空间 可动性 可动油含量 涠西南凹陷 北部湾盆地 石油地质学 

分 类 号：P618.13[天文地球—矿床学]