摘要
海相碎屑岩油藏内部常发育不同程度的白云化隔夹层,影响油气水系统的识别及开发策略的制定,同时也严重影响后期进一步提高采收率。综合识别白云化隔夹层的特征,阐明不同程度白云化砂岩机理,刻画白云化砂岩展布特征,对海相碎屑岩油藏的高效开发具有重要的现实意义,同时对于丰富白云化成因机理具有一定的理论意义。选取中东地区典型海相碎屑岩油藏UK,综合应用测井、岩心分析及生产动态资料,系统开展不同程度白云化隔夹层岩石分类、识别、形成机理及展布特征研究。结果表明:①海相碎屑岩油藏岩性除纯砂岩和泥岩外,不同程度白云化隔夹层岩性主要为含云质砂岩、白云质砂岩、砂质白云岩和含砂白云岩,其中白云质砂岩和含砂白云岩是常见的两种类型;②建立了不同程度白云化隔夹层岩性的定性及测井定量识别模板,随着白云化程度的不断增强,岩心在常光下表现为逐渐变亮,同时自然伽马、密度及电阻率呈逐渐增大的特征;③原始地下富镁卤水及泥岩压实水为主要的离子来源,物性较好的砂体及不整合面为主要的流体运移通道,储层物性差异导致孔隙流体与颗粒接触(水岩接触反应)时间的差异最终导致不同程度的白云化作用;④刻画了不同级次白云化隔夹层的展布,宏观层次白云化隔夹层易于发生在海平面上升半旋回及下降半旋回的中期,中观层次易于发生在河道顶部、侧翼及河口坝底部物性较差的部位,微观层次易于发生在孔喉连通不畅的区域。
The dolomitic barriers and baffles with different degrees ofdolomitization are developed in marine clastic reservoirs,which will influence the water/oil/gas system identification and also seriously affect the further enhancement of oil recovery.The identification,formation mechanism analysis and distribution characterization ofdolomitic barriers and baffles are important for the efficient development ofthe marine clastic reservoirs and can shed light on the mechanism ofdolomitization.Typical clastic reservoirUpper Kirkuk(UK)Formation in the Middle East is taken as an example.Logging,core analysis,and dynamic production data are adopted to systematically study the classification,identification,formation mechanism,and distribution characteristics ofthe dolomitic barriers and baffles in the marine clastic reservoirs.The researchresults are as follows.①Exceptforthe pure sand and mudstones in the marine clastic reservoirs,the lithology of dolomitic barriers and baffles is dolomite bearing sandstones,dolomitic sandstones,sandy dolomites,and sand bearing dolomites.The dolomitic sandstones and sand bearing dolomites are the main lithology.②The qualitative and quantitative criteriawere made to identify different degrees ofdolomitization.With the increase in the degree ofdolomitization,the core appears to gradually brighten under normal light.The gamma,density,and resistivity values increase with the degree of dolomitization.③The original underground magnesium-rich brine and mudstone compaction waters are the main ion sources.Pure sands with good physical properties and unconformities are main fluid migration channels.The difference in the physical properties ofthe reservoir leads to that in the contact time between the pore fluid and the particles(water-rock contactreaction),which ultimately results in different degrees ofdolomitization.@The distribution of dolomitic barriers and baffles is characterized in difierent levels.At the macro-level,the dolomitic barriers and baffles tend to occur in the middle p
作者
秦国省
王友净
吕洲
兰宇坤
QIN Guosheng;WANG Youjing;Lü Zhou;LAN Yukun(PetroChina Research Institute of Petroleum Exploration&Development,Beijing City,100083,China)
出处
《油气地质与采收率》
CAS
CSCD
北大核心
2023年第3期1-10,共10页
Petroleum Geology and Recovery Efficiency
关键词
海相碎屑岩油藏
白云化机理
识别标准
展布特征
UpperKirkuk组
marine clastic reservoir
dolomitic mechanism
identification criterion
distribution characteristics
Upper Kirkuk Fonnation
