【摘要】 传统的品质因子Q值估算方法通常是基于VSP资料或者叠加的地面地震资料,在薄互层存在的情况下,它们难以提取地震子波及有效地分离固有衰减和散射衰减。为了获得更可靠的地震波衰减图像,研究采用了一种基于Walkaway井地联合地震资料的波形反演来求取Q值的方法。通过理论模型的数值计算分析,探讨了初始模型厚度、Q值及噪声对反演结果的影响。合成的Walkaway井地联合地震资料的衰减估计结果表明,波形反演的Q值估算方法充分利用了各种波的运动学和动力学信息,避免了初至拾取和波场分离等处理困难,并能减小可能的人为误差,提高计算的精度。将该方法用于某油田的高分辨Walkaway井地联合地震资料Q值估计,结果表明,介质品质因子Q与介质性质和孔隙流体有良好的对应关系。更多还原

【Abstract】 Traditional Q estimation methods were generally based on VSP data or stacked surface seismic data. They are incapable of extracting wavelets and distinguishing the inherent attenuation from the scattering attenuation in the presence of thin interbeds. To obtain a more reliable Q image, a waveform inversion method was developed for estimating Q from the walkaway VSP and surface seismic data. By calculation with theoretical model, the effects of thickness and Q value of the initial mode, as well as the noise on the inversion results were discussed. Theoretical modeling indicates that the waveform inversion for Q estimation can avoid the difficulties in first break pickup and wave field separation by fully utilizing the kinematic and dynamic information of seismic waves. It can also reduce the possible artificial errors, and improve calculation accuracy. The method is used in a certain oil field for estimating the Q from the walkaway VSP and surface seismic data, the result shows that the quality factor Q corresponds well with petrophysics characters of reservoirs.更多还原