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Application of Full Waveform Inversion and Q-Tomography for Earth Model Building: Shallow Water, Shallow Gas Case Study
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, APGCE 2015, Oct 2015, Volume 2015, p.1 - 5
Abstract
Summary
Imaging below shallow gas bodies is one geophysical challenge encountered in offshore Southeast Asia basins. There are two key components in addressing this challenge: 1) the derivation of an accurate, high-resolution, geologically consistent velocity model and 2) compensating for absorption of the seismic signal as it propagates through the gas bodies.
An accurate Earth model in the overburden will not only improve imaging in the shallow section but will also facilitate subsequent model building and improve deeper reservoir-level imaging. Full-waveform inversion (FWI) velocity model building operates in the data domain and presents the capability of creating a high-resolution velocity model through a wavefield-consistent solution.
Q tomography and Q imaging address the Earth’s attenuation effects by first deriving a spatially and temporally variant 3D interval 1/Q model using ray-based reflection tomography techniques and then incorporating this model within a migration operator.
In this study, we present the application of FWI and Q tomography to a shallow-water, shallow-gas dataset from offshore Southeast Asia. We demonstrate the successful ability of FWI and Q tomography to resolve the low P-wave velocities and high attenuation of shallow gas bodies and subsequently compensate for the complex kinematics and absorption during depth migration.
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