ALFT is a multidimensional seismic data regularization module.

ALFT, or, Antileakage Fourier Transform based data regularization uses an inversion technique where plane waves are modeled one at a time from the strongest to the weakest. These modeled plane waves are then subtracted from the input trace location (irregular) and added to a regular output trace location until the residual is very small.  The regularization is multidimensional. ALFT offers highly efficient 3D (cdpx, cdpy, time),  4D (cdpx, cdpy, time, offsetradial), and 5D (cdpx, cdpy, time, offsetx, offsety or cdpx, cdpy, time, azimuth, offsetradial) data regularization algorithms.

 

 

The image examples are courtesy of TGS’s East Flemish Pass 3D survey in offshore Canada. The before regularization images show the usual lack of full coverage in near offsets due to cable spread. The images after regularization show that the 4D ALFT regularization is able to fill in those missing data with very good fidelity.

 

Xu, Sheng, Yu Zhang, Don L. Pham, Gilles Lambar 2004, On the orthogonality of antileakage Fourier transform based seismic trace interpolation: 74th Annual International Meeting, SEG, Expanded Abstracts, 2013-2016.

Xu, Sheng, Yu Zhang, Don Pham, Gilles Lambaré, 2005, Antileakage Fourier transform for seismic data regularization: GEOPHYSICS, 70, No. 4, V87-V95.

Xu, Sheng, Y. Zhang, and G. Lambare, 2010, Antileakage Fourier transform for seismic data regularization in higher dimensions: Geophysics, 75, no. 6, WB113-WB120.

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Time Slice at 2500 ms : After 4D Data Regularization 250 m offset bin
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Time Slice at 2500 ms : Before 4D Data Regularization 250 m offset bin

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after 4D
Time Slice at 2500 ms : After 4D Data Regularization 450 m offset bin
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