A standard quantitative calibration procedure for marine seismic sources

Geophysics ◽  
1985 ◽  
Vol 50 (10) ◽  
pp. 1525-1532 ◽  
Author(s):  
J. R. Fricke ◽  
J. M. Davis ◽  
D. H. Reed
Keyword(s):  
Energy Flux ◽  
Spectral Characteristics ◽  
Seismic Energy ◽  
Seismic Source ◽  
Calibration Procedure ◽  
National Standards ◽  
Computer Algorithms ◽  
Source Evaluation ◽  
Transient Nature ◽  
Marine Seismic

Marine source evaluation has traditionally been a subjective and qualitative study. This is particularly true in the case of source spectral characteristics. As a result, source evaluation, development, and array design based on seismic energy over a specified frequency band have been impossible. Further, the transient nature of source wavelets lends itseft to energy analysis rather than the traditional relative power analysis. The methodology required to achieve a calibrated quantitative estimate of marine seismic source energy is detailed here. The procedure involves two steps. First, a calibrated high‐fidelity measurement of the source signature is required; and second, an analysis of the signatures by a suite of computer algorithms designed to extract quantified measures of amplitude and energy is necessary. Results of the analysis include a time‐domain signature calibrated in American National Standards Institute (ANSI) units of pressure and a frequency domain spectrum calibrated in ANSI units of energy flux. These results provide figures of merit for evaluation of individual source characteristics (e.g., energy flux over seismic bandwidth, and total source energy). Additionally, the results provide data for a quantitative comparison of any two or more sources. Illustrative examples of source studies are included.

Compact sleeve‐gun source arrays

Geophysics ◽  
1991 ◽  
Vol 56 (3) ◽  
pp. 402-407 ◽  
Author(s):  
P. M. Fontana ◽  
T.‐A. Haugland
Keyword(s):  
Small Volume ◽  
Spectral Characteristics ◽  
Seismic Source ◽  
Pulse Amplitude ◽  
Operational Efficiency ◽  
Far Field ◽  
Air Compressor ◽  
Air Gun ◽  
Marine Seismic

Data derived from far‐field signature measurements have inspired several guidelines for using clustered sleeve guns effectively in tuned marine seismic source arrays. Primarily, these data show that for a given volume the signature produced by a cluster of sleeve guns has a comparable bubble period, increased primary amplitude, and reduced bubble‐pulse amplitude compared to the signature of a single gun. These results agree with those reported for clusters of conventional air guns. However, when the data are analyzed in terms of acoustic and operational efficiency, we find that for array elements with volumes greater than [Formula: see text] two‐gun clusters are more desirable than equivalent volume clusters of several small volume guns. For array elements with volumes up to [Formula: see text], the data show no significant advantages for using clusters instead of single guns. These guidelines have led to the design of sleeve‐gun arrays that produce signatures with temporal and spectral characteristics equal to or exceeding those produced by conventional air‐gun arrays incorporating almost twice the total gun volume. Moreover, these new arrays operate with a total number of individual guns comparable to conventional arrays, thus improving the performance of source arrays on small survey vessels without having to increase air compressor capacity or ancillary source equipment.

Coherent noise in marine seismic data

Geophysics ◽  
1983 ◽  
Vol 48 (7) ◽  
pp. 854-886 ◽  
Author(s):  
Ken Larner ◽  
Ron Chambers ◽  
Mai Yang ◽  
Walt Lynn ◽  
Willon Wai
Keyword(s):  
Seismic Data ◽  
Noise Suppression ◽  
Seismic Source ◽  
Coherent Noise ◽  
Critical Data ◽  
Predictive Deconvolution ◽  
Scattered Energy ◽  
Marine Seismic ◽  
The Many ◽  
Water Bottom

Despite significant advances in marine streamer design, seismic data are often plagued by coherent noise having approximately linear moveout across stacked sections. With an understanding of the characteristics that distinguish such noise from signal, we can decide which noise‐suppression techniques to use and at what stages to apply them in acquisition and processing. Three general mechanisms that might produce such noise patterns on stacked sections are examined: direct and trapped waves that propagate outward from the seismic source, cable motion caused by the tugging action of the boat and tail buoy, and scattered energy from irregularities in the water bottom and sub‐bottom. Depending upon the mechanism, entirely different noise patterns can be observed on shot profiles and common‐midpoint (CMP) gathers; these patterns can be diagnostic of the dominant mechanism in a given set of data. Field data from Canada and Alaska suggest that the dominant noise is from waves scattered within the shallow sub‐buttom. This type of noise, while not obvious on the shot records, is actually enhanced by CMP stacking. Moreover, this noise is not confined to marine data; it can be as strong as surface wave noise on stacked land seismic data as well. Of the many processing tools available, moveout filtering is best for suppressing the noise while preserving signal. Since the scattered noise does not exhibit a linear moveout pattern on CMP‐sorted gathers, moveout filtering must be applied either to traces within shot records and common‐receiver gathers or to stacked traces. Our data example demonstrates that although it is more costly, moveout filtering of the unstacked data is particularly effective because it conditions the data for the critical data‐dependent processing steps of predictive deconvolution and velocity analysis.

Some notes on air-gun development as a marine seismic source

2009 ◽  
Vol 28 (11) ◽  
pp. 1334-1335 ◽  
Author(s):  
Ben F. Giles
Keyword(s):  
Seismic Source ◽  
Air Gun ◽  
Marine Seismic

Design of Near-orthogonal Air-gun Sequences for Marine Seismic Source Encoding

2016 ◽  
Author(s):  
M.B. Mueller ◽  
D.F. Halliday ◽  
D.J. van Manen ◽  
J.O.A. Robertsson
Keyword(s):  
Seismic Source ◽  
Air Gun ◽  
Marine Seismic ◽  
Source Encoding

Source location with cross-coherence migration

Geophysics ◽  
2020 ◽  
Vol 85 (4) ◽  
pp. KS127-KS138 ◽  
Author(s):  
Yujin Liu ◽  
Yue Ma ◽  
Yi Luo
Keyword(s):  
Field Data ◽  
Random Noise ◽  
Synthetic Data ◽  
Seismic Energy ◽  
Seismic Source ◽  
Spectral Amplitude ◽  
Multiple Sources ◽  
Passive Seismic ◽  
Similar Images ◽  
Resolution Property

Locating microseismic source positions using seismic energy emitted from hydraulic fracturing is essential for choosing optimal fracking parameters and maximizing the fracturing effects in hydrocarbon exploitation. Interferometric crosscorrelation migration (ICCM) and zero-lag autocorrelation of time-reversal imaging (ATRI) are two important passive seismic source locating approaches that are proposed independently and seem to be substantially different. We have proven that these two methods are theoretically identical and produce very similar images. Moreover, we have developed cross-coherence that uses normalization by the spectral amplitude of each of the traces, rather than crosscorrelation or deconvolution, to improve the ICCM and ATRI methods. The adopted method enhances the spatial resolution of the source images and is particularly effective in the presence of highly variable and strong additive random noise. Synthetic and field data tests verify the equivalence of the conventional ICCM and ATRI and the equivalence of their improved versions. Compared with crosscorrelation- and deconvolution-based source locating methods, our approach shows a high-resolution property and antinoise capability in numerical tests using synthetic data with single and multiple sources, as well as field data.

Marine Seismic Source Characterization Using Fiber Optic Sensors

2019 ◽  
Author(s):  
Ezzedeen Alfataierge ◽  
Nikolay Dyaur ◽  
Li Chang ◽  
Robert R. Stewart
Keyword(s):  
Fiber Optic ◽  
Seismic Source ◽  
Fiber Optic Sensors ◽  
Source Characterization ◽  
Marine Seismic

Seismic source decomposition

Geophysics ◽  
1983 ◽  
Vol 48 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Paul L. Stoffa ◽  
Anton Ziolkowski
Keyword(s):  
Point Source ◽  
Spectral Characteristics ◽  
Patent Application ◽  
Power Spectra ◽  
Seismic Source ◽  
Three Dimensions ◽  
Far Field ◽  
Air Gun ◽  
Power Spectral ◽  
Directional Characteristics

We exploit the differences that exist between the radiation fields of a point source and an array to design a time‐separated marine seismic source array with desired power spectral and directional characteristics, whose far‐field time signature is known precisely from measurements. The desired power spectral characteristics are created by firing a predetermined series of point source units sequentially, such that their time signatures do not overlap. The effective power spectrum of the whole series of time‐distributed signatures can be made to approximate the sum of the power spectra of the individual signatures and can, therefore, be designed to suit the desired application by the appropriate choice of source units. The desired directional characteristics of the array can be created by arranging the source unit separations such that each source unit reaches the desired spatial position at the prescribed firing instant. The key to the subsequent processing of the recorded data is to measure the pressure wave generated by each point source unit with a hydrophone placed close by, but in the linear radiation field. The position of this hydrophone relative to the source unit must be known accurately in all three dimensions. The depths of the source units and their relative spatial positions at the instants of firing must also all be known. From these measurements the far‐field signature of the sequence in any azimuth can be deduced, and the impulse response of the earth can be recovered by dividing the Fourier frequency spectrum of the recorded reflection data by that of the measured source unit sequence. This process is completely deterministic in nature and depends primarily upon our ability to monitor accurately the far‐field signature of each source unit. Field results from an initial evaluation of this method indicate that this measurement can be readily accomplished. The success of this technique is then ultimately dependent on the signal to noise ratio. [This method is the subject of a patent application.] We stress that, since the signature is known, we are not obliged to make any assumptions about the phase. In particular, we do not need to make the minimum‐phase assumption. We are therefore free to choose our parameters to optimize our desired power spectral and directional characteristics with complete disregard for the conventional requirement that the signature of an air gun source have a high primary‐to‐bubble ratio.

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