Efficient Beam Velocity Model Building with Tomography Designed to Accept 3d Residuals Aligning Depth Offset Gathers

This novel Velocity Model Building (VMB) system addresses issues of Economics, Turn-Around-Time, Quality, Resolution, Stability and Ease-of-Use.

Seismic data is decomposed into wavelets, each with important, invariant attributes, particularly traveltime and dip at source and receiver locations. This wavelet representation is independent of the VM and provides the input to all subsequent PreSDM, VMB and quality control (QC) operations.

Ray tracing through a VM provides a mapping of each wavelet to its migrated spatial location and is very efficient for generating PreSDM common image point gathers (CIP) for VMB QC. The method enables the rapid estimation of a 3D spatial shift for each wavelet that produces high quality alignment of the CIP offset gathers. An efficient consistent tomography module inverts these 3D residuals into a high resolution, stable update to the current VM. The steps in this paragraph are iterated.

Workflows exploit the power of these already efficient individual processes, facilitate visualization of the QC products, ease the burden on data processing personnel, and provide rapid, flexible VMB. Examples illustrate the quality of this system.