Paper Summary
Continental shelf slopes are associated with deep erosional canyons that in general form perpendicular to depth contours, but we acquire strike of the water bottom in order to minimise HSE risk from streamert angles and maximise coverage. This choice results in poor sampling of the complex multiples and rapid lateral near surface velocity changes, leading to many scales of distortion in the seismic image. We developed enhancements to 3D surface related multiple elimination (SRME) that combine the kinematics of 3D SRME and high resolution radon transforms to improve the subtraction of multiples. The increased signal to noise in conjunction with iterative wavelet shift tomography and pre-stack depth migration improves the imaging of potential exploration targets. Examples of using these techniques are shown from the processing of 31,000 sq.km 3D seismic over continental shelf slopes in Tanzania, Kenya and Uruguay.