叠前去噪对角道集资料影响的定量评价研究

Quantitative evaluation on the effect of prestack noise attenuation on angle gathers

叠前属性提取和叠前反演处理,需要采用不同角度道集的信息。去除实际资料中所含的面波、随机噪声及相干噪声时或多或少都会影响角道集资料的品质。由于实际资料的复杂性,难以直接定量评价叠前去噪对角道集资料的影响程度,因此建立针对性的理论模型进行了定量研究。研究结果表明,①角道集叠加的抗噪能力要明显好于CMP叠加,对于角度域叠加,资料最低信噪比可达0.5;②相干噪声对角道集的影响程度要小于对CMP道集的影响程度,相干噪声的视速度大,则对叠加效果影响也大,反之则小;③面波能量强、频率低,少量的面波残留也会明显地影响角道集,由于面波主要出现在近偏移距,因此,它对近道的影响要强于远道。

The information of different angles is necessary in the extraction of prestack attributes and prestack inversion.The suppression of surface wave,random noise and coherent noise in actual data will impact the quality of angle gather data more or less.Since actual data is complex,it is difficult to quantitatively evaluate the influence of prestack denoising on angle gather data.Aiming at the problem,a theoretical model was built to carry out quantitative research. The results indicates that①the anti-noise ability of angle domain stacking is much better than that of CMP stacking,moreover, for angle domain stacking,the minimum signal to noise ratio can be up to 0.5;②The effect of coherent noise on angle gather is smaller than that on CMP gather and coherent noise only affects local traces,and the influence will be larger if the apparent velocity of coherent noise is large;③surface wave has strong energy and low frequency and a small amount of residue will affect the angle gather obviously.As surface wave mainly occurs in near offset,which has more influence on near traces.