Processing Land Broadband Data: Challenges that Oman Surveys Present and How they are Addressed

Retailleau, M.; Asrag, R. El; Shorter, J.

doi:10.3997/2214-4609.20141699

Cited by 5 publications

(1 citation statement)

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“…8). In the Middle East, most of the sweeps starts now at 1.5 Hz (Mahrooqi et al 2012), and frequencies down to 2-2.5 Hz are preserved in the final image assuming a specific processing by octave is applied (Retailleau, El Asrag and Shorter 2014).…”

Section: Discussion a N D C O N C L U S I O Nmentioning

confidence: 99%

Marine, seabed, and land seismic equipment for broadband acquisition: a review

Mougenot¹

2017

Geophysical Prospecting

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The broadband capabilities of marine, seabed, and land seismic equipment are reviewed with respect to both the source and the receiver sides. In marine acquisition, the main issue at both ends of the spectrum relates to ghosts occurring at the sea surface. Broadband deghosting requires towing at variable depth to introduce notch diversity or using new equipment like multi‐component and/or low‐noise streamers. As a result, a doubling of the bandwidth from about three to six octaves (2.5–200 Hz) has been achieved. Such improvement is not yet observed for seabed surveys in spite of deghosting being a standard process on the receiver side. One issue may be related to the coupling of the particle motion sensor, particularly at high frequencies. For land acquisition, progress came from the vibrators. New shakers and control electronics using broadband sweeps made it possible to add two more octaves to the low‐frequency signal (from 8 to 2 Hz). Whereas conventional 10 Hz geophones are still able to record such low frequencies, 5 Hz high gain geophones or digital accelerometers enhance them to keep the signal above the noise floor. On the high end of the bandwidth, progress is not limited by equipment specifications. Here, the issue is related to a low signal‐to‐noise ratio due to the strong absorption that occurs during signal propagation. To succeed in enlarging the bandwidth, these improved equipment and sweeps must be complemented by a denser spatial sampling of the wavefield by point–source and point–receiver acquisition.

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Section: Discussion a N D C O N C L U S I O Nmentioning

confidence: 99%

Marine, seabed, and land seismic equipment for broadband acquisition: a review

Mougenot¹

2017

Geophysical Prospecting

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Correcting source and receiver scaling for virtual source imaging and monitoring

et al. 2018

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Virtual source redatuming is a data-driven interferometric approach that relies on constructive and destructive interference, and as a result it is quite sensitive to input seismic trace amplitudes. Land surveys are prone to amplitude changes that are unrelated to subsurface geology (source/receiver coupling, etc.). We have determined that such variations may be particularly damaging to construct a virtual-source signal for imaging and seismic monitoring applications, and they need to be correctly compensated before satisfactory images, repeatability, and proper relative amplitudes are achieved. We examine two methods to correct for these variations: a redatuming approach based on multidimensional deconvolution and multisurvey surface-consistent (SC) scaling. Using synthetic data, we discover that the first approach can only balance time-dependent variations between repeat surveys, e.g., compensate for variable shot scaling. In contrast, a multisurvey SC approach can compensate for shot and receiver scaling within each survey and among the surveys. As a result, it eliminates redatuming artifacts, brings repeat surveys to a common amplitude level, while preserving relative amplitudes required for quantitative interpretation of 4D amplitude differences. Applying an SC approach to a land time-lapse field data set with buried receivers from Saudi Arabia, we additionally conclude that separate SC scaling of early arrivals and deep reflections may produce better image and repeatability. This is likely due to the significantly different frequency content of early arrivals and deep reflections.

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