FWI-guided Q Tomography and Q-PSDM for Imaging in the Presence of Complex Gas Clouds: Case Study from Offshore Malaysia
X. Wu, J. Zhou, K. Teng, Y. Xie, F. Lefeuvre, I. Anstey and L. Sirgue
Event name: EAGE Workshop on Seismic Attenuation
Session: Estimation from Field Data: Surface Seismic
Publication date: 28 October 2013
Info: Extended abstract, PDF ( 748.12Kb )
Price: € 20
The presence of gas clouds has long been recognized as a significant problem in the seismic data processing. To compensate the phase, frequency and amplitude loss due to the gas absorption in the QPSDM migration, both the geometry and the Quality Factor values within these anomalous attenuation regions need to be accurately estimated. In recent years, Ray-based Q tomography has been successfully applied to field data to estimate the anomalous Q model. However, when the distribution of the gas charged sand bodies gets more complex, Q tomography itself often fails to provide necessary resolution to generate a geological plausible absorption model. Joint inversion for velocity and Q with visco-acoustic full waveform inversion has attracted a lot of interest from the industry; however, it remains a very challenging topic as the joint inversion for both Vp and Q is an ill-posed problem, as they are coupled. In this paper, we propose a new approach which uses the highly detailed velocity information from the 3D frequency domain FWI to guide the Q tomography inversion. We demonstrate with a production example offshore Malaysia that our method can effectively reconstruct the Q model and improve the seismic imaging in the presence of complex gas clouds.