“MULLOCK” is an innovative approach to multiple attenuation that does not require velocity discrimination to separate primaries from multiples. Much of the residual multiple energy in CDP gathers occurs where the velocity contrast between primaries and multiples is small and SRME has proved ineffective at modelling the peg-leg multiples.. .

Spectrum’s proprietary “MULLOCK” technique analyses the data in an entirely different way, based on eigenvector matrices. This requires some dip discrimination and has proved very powerful and cost-effective.

MULLOCK attenuates peg leg multiples on stacks or common offset planes. The target multiple is interpreted and flattened before being decomposed to eigen-images. Then a limited range of eigen-images are selected for reconstruction before the flattening is reversed. The main assumption is that after flattening the multiples are represented by the dominant eigen-images, which can be omitted from the reconstruction.


Example 1: Before and After Application of MULLOCK


Example 2: Before and After Application of MULLOCK