基于低频伴影和波阻抗反演的礁滩相储层预测

Prediction of reef-flat facies reservoirs based on low-frequency shadow and wave impedance inversion

(成都理工大学“油气藏地质及开发工程”国家重点实验室,四川成都610059)

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China

基于小波变换的谱分解原理的低频伴影与储层中流体有密切关系,可以作为流体识别的重要标志,确定储层在横向上的展布,但难以有效识别其顶底界限。波阻抗反演技术可以利用测井纵向分辨率高的优点,很好地分辨储层的顶底界限。综合利用这两种方法可以更好地预测储层,精细刻画储层范围。川东北地区发育礁滩相储层,此类储层埋藏深、油气分布不均匀。该区礁滩相储层预测及研究结果表明,利用低频伴影的不同频率切片和单频剖面可以预测储层的横向展布范围,波阻抗反演剖面可以预测储层纵向分布范围,综合这两种方法可以精细刻画储层在横向和纵向上的分布及油气富集的位置和范围,提高了储层预测精度。

Low-frequency shadow based on spectral decomposition theory of wavelet transform is closely related to fluid of reservoir,which can be used as an important indicator for fluid identification and determines the lateral distribution of reservoir,but the top and bottom boundaries of reservoir are difficult to effectively identify .Wave impedance inversion,which uses the advantages of high vertical resolution in logging data,can well distinguish the top and bottom boundaries of reservoir.Combination of these two methods can better predict reservoir and finely characterize reservoir range.In northeast Sichuan Basin,reef-flat facies reservoirs are developed with the characteristics of deep buried and uneven distribution of oil and gas.The reservoir prediction result in the region shows that the lateral distribution of reservoirs can be predicted by the slices of different frequencies and profile of single frequency obtained by low-frequency shadow,and the vertical distribution of reservoirs can be predicted by wave impedance inversion profile.The above methods can be used together to finely characterize the lateral and vertical distribution of reservoir and oil/gas concentrating position and range,as well as enhance the accuracy of reservoir prediction.