Case Study 3D example /三维地震研究实例
Combining WesternGeco’s DX-80 vibrator technology with maximum displacement technology (Claudio Bagaini 2008) provides a low-distortion, high-power, broad-bandwidth source output, enhancing the low frequency component of land seismic vibroseis data. The maximum displacement design methodology enables a seismic vibrator to produce more energetic low frequencies than a traditional sweep design approach. High frequencies are progressively absorbed by the earth. In order to achieve resolution at depth, it is important and effective to extend the bandwidth at the low end of the spectrum which results in an improved inversion to acoustic impedance. Inversion requires seismic data with a bandwidth extending down to 0 Hz. By extending the seismic data bandwidth as low as possible before integration of well data, the results of inversion workflows will be improved. The sweep used in this is a broad-bandwidth sweep: 2Hz at -3db to 120Hz (figure 1, left). The low frequency sweep used, enables improved penetration of these low frequencies into the subsurface.
结合WesternGeco公司dx-80型可控震源与极大偏移技术(Claudio Bagaini 2008)提供了一种低失真、大功率、宽带宽的震源输出,可以提高陆地可控震源地震数据的低频分量。极大位移设计方法比传统扫描设计方法使可控震源能够产生更多高能的低频。高频率成分逐渐被地层吸收。为了获得深度分辨率,扩展频谱的低端带宽是非常重要并且有效的，能够改进声阻抗反演。反演工作需要地震资料带宽拓宽到0 赫兹。我们通过将地震数据的带宽扩展至尽可能低在集成井数据前来改善工作流的反演结果。宽带宽的扫描范围在2赫兹3db到120赫兹之间(图1，左)。使用低频范围可以使这些低频更好的穿透到地下。
图1-宽带宽S4勘探振幅谱。1-2Hz范围内的原始单炮集滤波扫描。
Figure 1 (right) demonstrates the associated presence of low frequency direct surface waves in the range of 1–2Hz. Seismic data rich in low-frequency content significantly improves the resolution of deeper targets for structural imaging and data inversion for reservoir properties.
图1(右)展示了1-2赫兹范围内相关的低频地面波。低频含量丰富的地震资料显著提高了更深层目标结构成像和储层属性反演数据的分辨率。
Coherent and Environmental Noise attenuation /相干和环境噪声削弱
图2原始单炮集和消除相干和分散面波后的例子
Seismic imaging of targets in UAE is known to be challenging due to the geological complexity of the near-surface and the various types of associated noise. Visual inspection of the data shows the presence of strong surface waves, dominated by a scattered energy of fundamental mode (Figure 2).
由于近地表地质的复杂性和相关的各种类型的噪声，在阿联酋地震成像的目标是一个巨大挑战。目视检查的数据显示出存在强烈的表面波,基本模式为分散能量控制(图2)。
(来源：金正纵横翻译公司编译)
