Abstract
Full-waveform inversion (FWI) is a powerful technique to obtain high-resolution subsurface models, from seismic data. However, FWI is an ill-posed problem, which means that the solution is not unique, and therefore the expert use of the information is required to mitigate the FWI ill-posedness, especially when wide-aperture seismic acquisitions are considered. In this way, we investigate the multiscale frequency-domain FWI by using a weighting operator according to the distances between each source-receiver pair. In this work, we propose a weighting operator that acts on the data misfit as preconditioning of the objective function that depends on the source-receiver distance (offset) and the frequency used during the inversion. The proposed operator emphasizes information from long offsets, especially at low frequencies, and as a consequence improves the update of deep geological structures. To demonstrate the effectiveness of our proposal, we perform numerical simulations on 2D acoustic Marmousi2 case study, which is widely used in seismic imaging tests, considering three different scenarios. In the first two ones, we have used an acquisition geometry with a maximum offset of 4 and 8 km, respectively. In the last one, we have considered all-offsets. The results show that our proposal outperforms similar strategies, for all scenarios, providing more reliable quantitative subsurface models. In fact, our inversion result has the lowest error and the highest similarity to the true model than similar approaches.
Highlights
An important task at exploration geophysics is the seismic imaging of underground structures such as gas and oil deposits [1, 2]
This paper is organized as follows: First, in Section Methodology, we give a brief overview of full-waveform inversion (FWI) formulation, in which we present in some detail the design of the weighting operator, which is our original contribution
We have presented an efficient strategy to mitigate the FWI non-linearity for wide-aperture seismic data-inversion
Summary
An important task at exploration geophysics is the seismic imaging of underground structures such as gas and oil deposits [1, 2]. A commonly used strategy to reduce the FWI ill-posedness is based on a multiscale approach [19, 20], in which the inversion is carried out sequentially by considering, firstly, the low-frequency-data components and the high-frequencies components In this way, we need to adopt efficient strategies, such as the multiscale approach aforementioned, as well as incorporate as much information as possible in the solution of the inversion problem to steer the inversion towards a reliable seismic image. The new acquisitions geometries allow us to record waveforms with an angular aperture (wider offsets) much larger than a conventional survey [26], which is very important to better illuminating the deeper regions of the medium under study They allow us to evaluate the lower frequencies of the subsurface model [27]. In Section Conclusion, we discuss the gain of our strategy and its potential implications
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
