储层的地震低频响应及识别

Seismic low frequency response of reservoir and its recognition.

常规地震资料处理中把大地看成是完全弹性介质,实际上,地层岩石孔隙中常常含有流体(油、气、水),当地震波在其中传播时要发生与频率相关的能量衰减和相位畸变,且高频成分的衰减、散射和弥散远高于低频成分。地层介质对地震波的这种选频吸收作用使得在地震波的低频成分中保留了更为丰富的反映介质性质的信息。为此,开展了储层的地震低频响应研究。首先将Korneev等提出的一维弥散粘滞型波动方程拓展为二维形式,推导出二维形式下波动方程的解;然后设计了二维透镜体储层模型,采用二维弥散粘滞型波动方程通过相位移加插值方法进行了数值模拟。数值模拟结果与实验室物理模拟结果类似,从理论上证实了含流体储层存在低频高能量现象(低频伴影)。

In conventional seismic data processing,the earth is regarded as prefectly elastic medium.However,the pores of stratum rock of- ten contain fluid (oil,gas,water).So,when the seismic wave propa- gates in it,there are energy attenuation and phase distortion related to frequency.Moreover,the attenuation,scattering,and dispersion of high-frequency components are far higher than that of low-fre- quency components.The frequency selecting absorbing effect of stratum medium on seismic wave keeps more information of medi- um characteristics in the low-frequency components.Aiming at this problem,we studied the seismic low frequency response of reser- voir.Firstly,the 1-D viscous-diffusive wave equation proposed by Korneev was spread to 2-D,and the solution of wave equation in 2- D form was reduced.Then,a 2-D lens reservoir model was designed and 2-D viscous-diffusive wave equation was adopted for numerical simulation through phase shift and interpolation method.The nu- merical simulation results are similar to that of experimental physi- cal simulation,which theoretically proved low-frequency high-energy phenomenon (low frequency shadow) existing in fluid-filled reservoir.