山前复杂岩性油气藏地震储层预测与应用——以塔里木盆地乌什凹陷神木地区为例

Seismic reservoir prediction and application of Piedmont complex lithologic reservoir——case study of Shenmu area of Wushi sag in Tarim Basin

山前地区储层预测面临的主要困难是地震资料品质差、目的层岩性变化快且岩石物理规律不清。将叠前同时反演技术、岩石物理建模技术及岩相概率分析进行有机结合,首次联合应用到塔里木盆地乌什凹陷神木区块。通过岩石物理建模,弄清了该区舒善河组泥岩、砾岩、砂岩的岩石物理规律;通过地震CRP道集优化处理、井震精细标定、建立复杂低频模型,利用叠前同时反演准确求取了舒善河组地层的弹性信息;在岩石物理的指导下,通过贝叶斯模糊判别方法进行岩性的定量解释和不确定性估算,将反演得到的弹性属性体转化为孔隙砂岩概率体。利用岩性概率体完成了舒善河组孔隙砂岩储层的精细雕刻,预测出了神木2井区舒善河组储层主要为一北东向展布的河道砂体。研究成果为下一步井位部署提供了依据。

The main difficulty in reservoir prediction in piedmont area is that the quality of seismic data is poor,the lithology of the target layer changes rapidly and the petrophysical laws are unclear.The lithofacies probability analysis is integrated with simultaneous inversion,petrophysical modeling to apply to the Shenmu Block of Wushi Depression in Tarim Basin.The petrophysical laws of mudstone,conglomerate and sandstone in Shushanhe Formation of the area are clarified by petrophysical modeling.The complex low-frequency model is established by seismic CRP gathers optimization processing and fine calibration of well seismics to obtain the elasticity information of the Shushanhe Formation.Under the guidance of the rock physics,the Bayesian fuzzy discriminant method is used to quantitatively explain the lithology and estimate the uncertainty.The elastic property obtained by inversion is transformed into the probability body of the pore sandstone.Then the probability body is used to complete the fine carving of the pore sandstone reservoir in Shushanhe Formation.It is predicted that the reservoir of Shushanhe Formation in Shenmu2Block is river sand body with a north-east distribution.The results of this research provide the basis for further location of wells.