The impact of field-survey characteristics on surface-related multiple attenuation

Field-survey characteristics can have an important impact on the quality of multiples predicted by surface-related multiple elimination (SRME) algorithms. This paperexamines the effects of three particular characteristics: in-line spatial sampling, source stability, and cable feathering. Inadequate spatial sampling causes aliasing artefacts. These can be reduced by f-k filtering at the expense of limiting the bandwidth in the predicted multiples. Source-signature variations create artefacts in predicted multiples due to spatial discontinuities. Variations from a well-behaved airgun array produced artefacts having an rms amplitude about 26 dB below the rms amplitude of multiples predicted with no variations. Cable feathering has a large impact on the timingerrors in multiples predicted by 2D SRME when it is applied in areas having cross dip. All these problems can be reduced by a combination of better survey design, use of advanced data-acquisition technologies, and additional data-processing steps.