史南区块沙三中亚段4砂组储层精细刻画

Fine Reservoir Characterization of 4;Sand Group in Middle of Sha3 Memberin Shinan Block

史南区块沙三中亚段浊积岩储层具有十分复杂的岩性构成、波阻抗特征,常规地震属性分析无法满足该类岩性储层识别和预测。从测井资料入手,在地层对比、精细构造解释等工作的基础上,开展史南区块沙三中亚段4砂组储层发育及展布特征探究。结果表明:史南地区沙三中亚段4砂组地层垂直物源方向变化不大,平行物源方向地层从东向西逐渐变薄;针对4砂组浊积岩岩性复杂、分布广泛、埋深大、厚度薄的特点,通过优选敏感曲线、优选反演方案,确定波形指示反演,开展全区砂体识别,可以有效识别砂体厚度>5m的砂体,极大提高纵向识别精度和横向延展精度,反演结果符合沉积规律,并得到钻井验证;最终结合4砂组反演属性及预测砂厚平面图分析,认为工区砂厚中心主要集中在中部,通过对单套油砂进行精细刻画,西部主要为水层,东部油层上部发育一套薄水层,隔夹层仅1m,封堵效果较差,且东部水体逐步增加,为下一步勘探目标的部署起到积极的作用。

The turbidite reservoir of the middle of third member of Shahejie Formation in Shinan block has very complicated lithological composition and wave impedance characteristics.Conventional seismic attribute analysis cannot satisfy the identification and prediction of this type of lithological reservoir.Starting with log-ging data,the reservoir development and distribution characteristics of the 4;sand group in the middle of Sha3 Member in Shinan block are studied on the basis of stratigraphic correlation and fine structure inter-pretation.The results show that the 4;sand group in the middle of Sha3 Member in Shinan block in the direction of being vertical to the provenance does not change much,and that in the direction of being parallel to the provenance gradually becomes thinner from east to west.In view of the characteristics of complex lithology,wide distribution,deep burial depth and thin thickness of the turbidite in the 4;sand group,the waveform indication inversion is determined and the sand body is identified in the whole area after the sen-sitive curve and inversion plan is optimized.The sand bodies with the thickness of more than 5 m can be ef-fectively identified,and the accuracy of longitudinal identification and lateral extension are greatly improved.The inversion results conform to the sedimentary law and have been verified by drilling.Finally according to analysis on the 4;sand group inversion attributes and the predicted sand thickness plan,it suggests that the center of sand thickness in the study area is mainly concentrated in the center.Fine description on a single set of oil sand shows that the western part is mainly water layers,and a set of thin water layers develops at the upper part of the eastern oil layers with only 1 m interlayer,which has poor plugging.The eastern water body is gradually increasing,which will play a positive role in the deployment of the next exploration target.