多子波分解技术在大庆长垣南薄互层砂岩预测中的应用

Application of the Multi-Wavelet Decomposition Technique in Prediction of the thin-interbedded Sand Reservoir in Changyuan Area of Daqing Oilfield

大庆长垣南部扶余油层是薄互层地质条件,据统计单层砂岩厚度小于5m,其中F1油层组中由于T2低频强反射干扰作用,使得本身平面展布规模较小的薄互层砂体更难识别。应用多子波分解与重构技术,对叠后地震数据进行基于多子波理论的道分解,可以得到具有不同形态特征的某种子波记录的线性相加。利用地层变化有一定连续性这一特点,假设一定范围内,具有相同岩性的地层中其地球物理响应相似,由已知钻井信息选取与砂岩相关的子波进行重构得到新的突显砂岩弱化非砂岩信息的数据,或者在重构的基础上进一步提取地震分量,优选出对砂岩解释更有效的地震分量或其组合,来开展砂岩预测。这样可有效的提取强背景下的砂岩弱反射信息,砂岩预测符合率较常规振幅属性提高了15个百分点以上。

Changyuan Fuyu oil layers in south Daqing are thin-interbed geologic conditions, which sandstone thickness of a single layer is less than 5m according to the statistics of data, wherein the F1 formation in the strong reflection interference effect due to T2 low frequency,which makes the thin interbedded sand itself the planar distribution of smaller more difficult to identify. Application of multi wavelet decomposition and reconstruction technique and the decomposition of the seismic trace based on multi wavelet theory, can be obtainedwith different morphological characteristics of a seed wave recording linear additive. Base on the formation change has the character of continuity, assuming a certain range, with the same lithology strata in the geophysical responses are similar, known by the drilling information selection of wavelet that sandstone is related with are reconstructed to obtain new data of prominence sandstone and weakening non sandstone information, or in the basis of reconstruction to further extract seismic component, to select seismic component more effective in the interpretation or the combination of sandstone and to carry out sandstone prediction. So it can effectively extract reflection information in the strong background, sandstone prediction coincidence rate compared with the conventional amplitude property increased by more than 15 percentage points.