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3D Velocity Model Building via Simultaneous Joint Inversion of 2D Seismic and 3D Gravity Datasets
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 78th EAGE Conference and Exhibition 2016, May 2016, Volume 2016, p.1 - 5
Abstract
In 2D seismic surveying the geology is often under-sampled in space. The geologic structures change in space more rapidly than what the grid sampling can capture.
In modeling, tomography is used to infer perturbations in the ray trajectory and time, in order to update the velocity of the time reflections. To obtain a reliable solution, it is essential to provide the inverse solver with the most uniform information distribution in terms of areal coverage, offset and azimuth of propagation.
The SJI methodology enables building a single 3D velocity model inferred by the simultaneous use of multiple 2D seismic lines of varying orientations and of a 3D non-seismic (potential field or EM) measurement. 2D seismic lines are gridded in a single 3D volume and inverted jointly with either 3D gravity or 3D EM data. While these 3D non-seismic measurements operate on their own properties for minimizing their own data misfit, the similarity criterion regularizes the 3D structure to the velocity property operated by the seismic data.
This enables an advanced imaging for the 2D seismic lines. In particular, the estimation of a correct 3D tilt angle from the model enables the application of tilted-transverse isotropic (TTI) ray-tracing technology for tomography and migration.