12 December 2019
Full Waveform Inversion (FWI) is the state of the art in building high-resolution Earth models for seismic imaging and interpretation. It is the buzz technology that has circulated in the industry over the past few years, with contractors presenting increasingly higher frequency results as a demonstration of compute prowess and their technology advantage.
FWI is an iterative tomographic technique, driven directly by differences between the true seismic data and synthetic data modelled with the current best estimate of the Earth model. All modelling is performed using an accurate solution of the two-way wave equation, leading to much greater resolution in the inverted model than can be achieved through conventional ray-based tomographic methods.
FWI has the potential to deliver fantastic results, as shown in the GIF above, but also needs to be tempered with a few notes of caution. The sensitivity of the technique to the accuracy of its principle ingredients; the starting model, the recorded (and prepared) fielddata and a suitable source wavelet, means that when unchecked, the technique can lock into local minima and deliver a cycle-skipped result. With any inversion, careful consideration of the singly inverted attribute needs to be considered, with anisotropic, attenuative and elastic effects needing to be understood. A full grasp of the available constraint data (well logs, depthing control/calibration, geological input) is important in this regard.
Shearwater’s FWI is fully integrated into the Reveal platform allowing integration of FWI into a range of Shearwater’s Processing & Imaging services, whether onboard, in-office or in the Cloud. We are excited to present more examples of Shearwater’s FWI capabilities in the coming months.
Example shown uses original fielddata from Geoscience Australia. This compares the initial VP model to an FWI sweeping to 30Hz.