PGS LSM for Improving Reservoir Characterization in Salt Provinces

Reservoir targets in the Santos Basin are primarily found in presalt carbonate build-ups underneath layered evaporite sequences, but the geological complexity of both the salt and postsalt sequences adversely affects reservoir characterization.

In this example, PGS LSM was applied to a narrow-azimuth dataset across the Buzios field in the Santos Basin, Brazil. Inputs to the LSM workflow included pre-processed shot gathers, an FWI velocity model and a depth migrated stack, all from a large-scale rejuvenation program, Santos Vision. The objective of LSM was to address presalt imaging limitations, and enhance the resolution of the presalt carbonate build-ups and their associated fault patterns.

In the figure below, PGS LSM shows an uplift over a conventional migration throughout the section with improved resolution and imaging in the postsalt caps and faults, internal salt structures and the reservoir sequence in the presalt. Furthermore, the amplitudes are better balanced in the LSM presalt section, highlighting reservoir potential.

The enhanced image from PGS LSM mitigates the risk associated with reservoir compartmentalization, provides better definition of sweet spots for drilling and allows high-resolution reservoir characterization to accurately predict reservoir properties.

Buzios PGS LSM
Comparison of a standard migration and the enhanced imaging achievable with PGS LSM. The resolution and fault recognition at the presalt reservoir section on the LSM image enables detailed analysis in seismic stratigraphy and reservoir characterization.