Integrated Subsalt Velocity Model Building in the Central Gulf of Mexico
An integrated workflow was devised to build a velocity model over 2,000 Outer Continental Shelf blocks in the central of Gulf of Mexico utilizing velocity information from more than 300 wells, guided by regional a stratigraphic framework, and constrained with a rock physics model. The model was further validated through iterations of 5D subsalt tomography. The resultant earth model is consistent with the velocity trends at well locations, honors wide-azimuth and full-azimuth seismic data, and obeys the law of rock physics. It can be used as a benchmark earth model in the central Gulf of Mexico for exploration and appraisal applications.
Construction of the earth model involves six steps: (1) stratigraphic framework construction based on regional seismic interpretation that ties to the available wells; (2) para-sequence definition within each stratigraphic unit; (3) rock physics template generation at each well location; (4) low-frequency velocity trend generation through upscaling sonic velocity or check shots at well location; (5) geostatistical velocity population in 3D; and (6) 5D subsalt tomography.
The final earth model was used in prestack depth migration of wide-azimuth and full-azimuth seismic data, yielding a superb result. Many real data examples from the central of Gulf of Mexico will be shown in the presentation.
AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016