基于VSP子波谱模拟的谱比法Q值提取及在提高地震分辨率中的应用  

Q Extraction of Spectral Ratio Method based on VSP Wavelet Spectral Simulation and Its Application to Improving Seismic Resolution

作　　者：张在金 Zhang Zaijin(Exploration and Development Research Institute of Daqing Oilfield Co.,Ltd.,Daqing Heilongjiang 163712)

机构地区：[1]中国石油大庆油田有限责任公司勘探开发研究院,黑龙江大庆163712

出　　处：《中外能源》2023年第5期9-14,共6页Sino-Global Energy

摘　　要：地震分辨率一直是地震勘探追求的目标,而地震波的高频成分由于地下介质的吸收衰减损失严重。品质因子Q是表征地下介质对地震波吸收衰减特性的一个重要参量,不仅反映介质的内部本质特征,同时也是油气识别的重要指示因子,因此准确估算Q值对地震资料处理及储层预测具有一定意义。VSP采用井中接收的方式接收地震波,VSP资料中的直达波单程传播,能较好地反映地下介质的吸收作用,与地面地震相比,采用VSP进行Q值提取更为准确。本文在传统谱比法基础上,考虑反射系数及噪声对Q值求取的影响,提出了基于VSP子波谱模拟的谱比法Q值提取方法,采用子波谱模拟的方式消除地层反射系数对ZVSP下行地震子波的影响,在子波谱基础上利用谱比法求取井点处的Q值,然后利用井点处Q值与地层速度的关系外推建立Q场,利用建立的Q场进行驱动地面地震提高分辨率处理。采用此法对含有VSP资料的地震工区进行Q值提取及驱动地面地震提高分辨率处理,效果较好。Seismic resolution has always been the goal of seismic exploration,and the high-frequency components of seismic waves seriously lost due to the attenuation by absorption of underground media.Quality factor Q is an important parameter to characterize the absorption attenuation characteristics of seismic waves for underground media.It not only reflects the internal essential characteristics of media,but also is an important indicator for oil and gas identification.Therefore,accurate estimation of Q value is of certain significance for seismic data processing and reservoir prediction.VSP receives the seismic wave in the well,and the direct wave in the VSP data spreads in one way,which can better reflect the absorption effect of the underground media.Compared with the surface seismic,VSP is more accurate on Q value extraction.Based on traditional spectral ratio method,this paper proposed a spectral ratio method for Q value extraction based on VSP wavelet spectral simulation,which considers the influence of reflection coefficient and noise on the Q value.The wavelet spectral simulation method is used to eliminate the influence of formation reflection coefficient on the downward seismic wavelet of ZVSP,after that,the Q value at the well point is calculated by spectral ratio method based on wavelet spectral,and then the relation between Q value at the well point and formation velocity is used to get Q filed.The Q field is used to drive surface seismic and improve the seismic resolution.This method is applied to Q value extraction for the seismic field with VSP data and improving seismic resolution by surface seismic driving,and good results are achieved.

关 键 词：VSP 子波谱模拟 谱比法 Q值 提高分辨率 

分 类 号：P631.4[天文地球—地质矿产勘探]