北部湾盆地乌石凹陷低阻油层微观成因机理-西南石油大学学报.pdf

西南石油大学学报（自然科学版） 2019 年8 月第41 卷第4 期 Journal of Southwest Petroleum University（Science TechnologyEdition） Vol.41 No. 4 Aug. 2019 DOI ：10.11885/j.issn.1674 5086.2018.05.09.04 文章编号：1674 5086（2019）04 0081 09 中图分类号：TE122 文献标志码：A 北部湾盆地乌石凹陷低阻油层微观成因机理 * 杨毅 ，袁伟，杨冬，谭伟，吴进波 中海石油（中国）有限公司湛江分公司，广东湛江 524057 摘 要：北部湾盆地乌石凹陷古近系流沙港组砂砾岩油藏电阻率差异较大，高、低阻油层并存，流体性质难以识别，给 油田开发带来一定难度。为此，利用测丼、录井、试井、岩芯分析化验等资料，对低阻油层成因机理开展系统深入的剖 析。结果表明，泥浆侵入、导电矿物、地层水矿化度等对电阻率影响较小，高束缚水饱和度是油层电阻率偏低的主要影 响因素。在此认识基础上，通过微观孔隙结构的精细评价，发现低阻油层储集空间为原生粒间孔、次生铸模孔混合孔 隙组合，发育片状、弯片状喉道，排驱压力大，孔喉半径小，孔隙结构复杂是储层高束缚水饱和度的根本原因。 关键词：乌石凹陷；砂砾岩；低阻；束缚水饱和度；孔隙结构 MicroscopicFormationMechanismofLowResistivityOilLayersinthe WushiSagoftheBeibuGulfBasin * YANGYi ,YUANWei,YANGDong,TANWei,WUJinbo CNOOCChinaLimited, Zhanjiang Branch,Zhanjiang,Guangdong524057,China Abstract: The conglomerate sandstone oil reservoir from the Paleogene Liushagang Formation in the Wushi Sag of the Beibu GulfBasinexhibitssignificantresistivitydifferences. Highresistivityandlowresistivityoillayersco-exist;theycanbehardly distinguished based on their fluid properties, leading to difficulties in oil field exploitation. Thus, we conducted in-depth in- vestigation of the formation mechanism of low resistivity oil layers using data from well logging, mud logging, well testing, and core analyses. The results show that mud intrusion, conductive minerals, and mineralization of formation water slightly influence resistivity, while irreducible water saturation is the major factor leading to