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In simultaneous source acquisition, seismic data can be recorded with a temporal overlap between the shots. Better sampled data in terms of source spacing, azimuth and/or offset distributions can be obtained in a much more efficient way. These potential benefits can only be realized if the recorded data, with interfering energy from multiple sources, can be handled properly. Common practice is to apply randomized time-delays to the sources during the acquisition of the data. As a result of using randomized firing schemes, coherency measures can be utilized to actively separate the recorded data over the individual sources. In this paper an inversion-based source separation method is utilized to a shallow water data set which may have specific challenges compared to deeper water applications. We will focus a bit more on the randomized firing schemes. It is shown that optimizing these firing schemes, introducing “pseudo randomization”, instead of using random time-delays, can benefit the performance of the source separation.
The separation method is illustrated using a controlled simultaneous source experiment where a shallow water field data set is used to mimic simultaneous recorded data where two sources were located with only a small cross line distance between them (simultaneous FLIP/FLOP acquisition). Results demonstrate that it is advised to utilize “pseudo randomization” of the firing delay-times. The controlled shallow water field data example shows that good separation results are obtained.
For many parts of the year, the weather is poor, and Before acquiring data offshore Suriname in 2016 a survey dramatic eddy currents can prove difficult to cope with assessment was performed to compare various contractor when deploying or towing long streamers.
Seismic interference (SI) still is a considerable problem in marine seismic acquisitions. Looking at the number of marine seismic surveys that are acquired in close vicinity of each other nowadays, seismic interference forces to either acquire surveys in time-sharing mode or apply substantial processing schemes to attenuate the SI-energy afterwards.
Looking at the characteristics and challenges of SI-energy, we see that it is very much related to the deblending challenges faced in simultaneous source acquisitions. Just like the interfering simultaneous sources, which are fired with dithered firing-times, the SI energy show irregular behaviour from shot to shot. Considering the resemblance between the two, it seems natural to treat blending- and SI energy in one and the same algorithm. In this paper it is discussed how an inversion-based source separation method is extended to include SI-energy as well. The extended method is applied to simultaneous long offset (SLO) field data which is contaminated by SI. Good results are obtained for both source separation and SI attenuation.
Simultaneous source acquisition has proven to have significant value in increasing data density, improving acquisition efficiency and reducing cost. Seismic data acquired with simultaneous source acquisition typically goes through a deblending process where it is converted into conventional non-blended data for further processing steps. Despite the progress made in deblending methods, signals can still be misallocated during the deblending process. Inversion-based algorithms use a closed loop in which the data residual is computed iteratively to ensure the complete separation of signals. However, existing algorithms have no or limited ability to reverse signal misallocation. The problem will get worse when we push for higher blending folds and/or better amplitude fidelity. Misallocated signal can contaminate all the other signals within the overlapping recording window. In this paper, I’ll present a method of reversing signal misallocation caused by deblending. A real data test shows signals misallocated/lost during deblending can be recovered effectively. This self-correction mechanism is critical for ensuring the quality separation of blended shots. Presentation Date: Tuesday, October 13, 2020 Session Start Time: 8:30 AM Presentation Time: 10:10 AM Location: 362A Presentation Type: Oral