叠前衰减补偿时间偏移及GPU实现  

Attenuation compensation in prestack time migration and its GPU implementation

作　　者：吴吉忠 左虎[1] WU Jizhong;ZUO Hu(Jidong Oilfield Company, PetroChina, Tangshan, Hebei 063004, China)

机构地区：[1]中国石油冀东油田公司,河北唐山063004

出　　处：《石油地球物理勘探》2019年第1期84-92,I0004,共10页Oil Geophysical Prospecting

基　　金：国家科技重大专项"南堡凹陷油气富集规律与增储领域"(2016ZX05006-006)资助

摘　　要：地下介质的黏滞特性会导致地震波能量耗散、相位畸变,地震剖面分辨率降低。为此,发展了一种偏移方法,可以在叠前偏移中沿波场传播路径补偿黏滞介质的吸收效应,提高地震分辨率。在Q场建模方面,通过VSP测井资料与地面反射地震资料联合应用求取品质因子Q值,并依据衰减合成地震记录与井旁地震道的匹配情况判断Q值是否合理;在压制偏移噪声方面,采用倾角域变偏移孔径的实现方式,通过孔径的自适应改变,有效压制偏移噪声;在提高计算效率方面,采用GPU加速策略,有效解决频率域衰减补偿叠前时间偏移计算效率低的问题。模拟与实际数据处理结果表明,叠前衰减补偿时间偏移在提高地震资料分辨率的同时,能较好保持地震剖面的信噪比与波组关系,在衰减强烈且信噪比较低地区有广阔的应用前景。The intrinsic absorption in subsurface media causes dissipation of seismic energy, thus decreases the amplitude and modifies the phase, and gives worse data resolution. We propose a prestack time migration in this paper, which compensates the attenuation along the seismic wave propagating path and enhance the resolution. For Q estimation, we calculate Q value with the joint use of VSP and seismic data. In general, we judge a right Q value based on visco-acoustic seismic synthetic seismogram and seismic traces at the well. For noise elimination, we use adaptive aperture according to dip angles, which can effectively remove migration noise. To improve computation efficiency, we adopt GPU calculating scheme. Model and real data results demonstrate that the proposed approach can not only compensate seismic energy but also improve data resolution.

关 键 词：品质因子 叠前时间偏移 衰减 自适应偏移孔径 

分 类 号：P631[天文地球—地质矿产勘探]