基于压缩感知的地震频带拓宽方法——以珠江口盆地东部惠州地区为例  

Method for Seismic Frequency Band Widening Based on Compressed Sensing——A Case Study of Huizhou Area in Eastern Pearl River Mouth Basin

作　　者：朱焱辉 Zhu Yanhui(Shenzhen Branch of CNOOC China Limited,Shenzhen Guangdong 518054)

机构地区：[1]中海石油(中国)有限公司深圳分公司,广东深圳518054

出　　处：《中外能源》2023年第6期44-52,共9页Sino-Global Energy

基　　金：中国海洋石油集团公司“十四五”重大项目“南海深水区油气勘探开发关键技术”之课题4:深水中深层地球物理关键技术研究(编号:KJGG-2022-0104)。

摘　　要：常规海上地震资料频带较窄,普遍缺失8Hz以下和60Hz以上频带的信息,导致钻前储层预测结果与实际钻井吻合度较低,严重影响了储层预测的精度和钻井成功率。在假设短时窗内的地震波形具有平稳信号特征的基础上,利用傅里叶变换和反射系数奇偶分解方法,推导出L1范数约束条件下的反射系数反演目标函数。采用压缩感知原理和坐标轴下降算法对目标函数进行求解。对求解出的反射系数序列再褶积一宽频带通子波,滤除甚低频和过高频带的虚假信息,从而实现了地震资料频带的拓宽。理论模型测试和实际资料处理结果表明,相对于传统的反Q滤波,在不降低地震资料信噪比,保持原始地震波组和能量关系基本不变的条件下,基于压缩感知的地震频带拓宽方法能够最大程度地拓宽地震资料的有效频带,充分挖掘地震资料的有效信息,获得相对可靠的高分辨率地震数据。Conventional offshore seismic data have a narrow frequency band and generally miss the information of frequency band below 8Hz and above 60Hz,which results in a low degree of agreement between predrilling reservoir prediction results and actual drilling,and seriously affects the accuracy of reservoir prediction and drilling success rate.Based on the assumption that the seismic waveform in a short-time window has the characteristics of stationary signal,the objective function of reflection coefficient inversion under the constraint of L1 norm is derived by using Fourier transform and reflection coefficient odd-even decomposition method.The objective function is solved by compressed sensing principle and coordinate descent algorithm.The reflection-coefficient sequence is then convolved into a wide band pass wavelet to filter out the false information in very low frequency and much high frequency band,thus realizing the widening of frequency band of seismic data.The results of theoretical model testing and actual data processing show that,compared with the traditional inverse Q filter,the seismic frequency band widening method based on compressed sensing can widen the effective band of seismic data to the maximum extent and fully excavate the effective information of seismic data under the condition that the signal-to-noise ratio of seismic data is not reduced and the relationship between the original seismic wave group and energy is basically unchanged.Relatively reliable high-resolution seismic data are obtained.

关 键 词：压缩感知 坐标轴下降算法 地震频带拓宽 反射系数 反演 信噪比 

分 类 号：P631.4[天文地球—地质矿产勘探]