Noise types and their attenuation in towed marine seismic: A tutorial

Geophysics ◽  
2020 ◽  
pp. 1-104
Author(s):  
Volodya Hlebnikov ◽  
Thomas Elboth ◽  
Vetle Vinje ◽  
Leiv-J. Gelius
Keyword(s):  
Seismic Data ◽  
Real Data ◽  
Noise Component ◽  
Industry Standard ◽  
Noise Type ◽  
Wide Range ◽  
Different Types ◽  
Seismic Records ◽  
Marine Seismic ◽  
Processing Techniques

The presence of noise in towed marine seismic data is a long-standing problem. The various types of noise present in marine seismic records are never truly random. Instead, seismic noise is more complex and often challenging to attenuate in seismic data processing. Therefore, we examine a wide range of real data examples contaminated by different types of noise including swell noise, seismic interference noise, strumming noise, passing vessel noise, vertical particle velocity noise, streamer hit and fishing gear noise, snapping shrimp noise, spike-like noise, cross-feed noise and streamer mounted devices noise. The noise examples investigated focus only on data acquired with analogue group-forming. Each noise type is classified based on its origin, coherency and frequency content. We then demonstrate how the noise component can be effectively attenuated through industry standard seismic processing techniques. In this tutorial, we avoid presenting the finest details of either the physics of the different types of noise themselves or the noise attenuation algorithms applied. Rather, we focus on presenting the noise problems themselves and show how well the community is able to address such noise. Our aim is that based on the provided insights, the geophysical community will be able to gain an appreciation of some of the most common types of noise encountered in marine towed seismic, in the hope to inspire more researchers to focus their attention on noise problems with greater potential industry impact.

scholarly journals Evaluation of Audio Compression Artifacts

10.14311/906 ◽  
2007 ◽  
Vol 47 (1) ◽  
Author(s):  
M. Herrera Martinez
Keyword(s):  
State Of The Art ◽  
Subjective Evaluation ◽  
Audio Coding ◽  
Coding System ◽  
Audio Compression ◽  
Coding Systems ◽  
Wide Range ◽  
Different Types ◽  
Processing Techniques ◽  
Signal Processing Techniques

This paper deals with subjective evaluation of audio-coding systems. From this evaluation, it is found that, depending on the type of signal and the algorithm of the audio-coding system, different types of audible errors arise. These errors are called coding artifacts. Although three kinds of artifacts are perceivable in the auditory domain, the author proposes that in the coding domain there is only one common cause for the appearance of the artifact, inefficient tracking of transient-stochastic signals. For this purpose, state-of-the art audio coding systems use a wide range of signal processing techniques, including application of the wavelet transform, which is described here. 

Multidimensional de-aliased Cadzow reconstruction of seismic records

Geophysics ◽  
2013 ◽  
Vol 78 (1) ◽  
pp. A1-A5 ◽  
Author(s):  
Mostafa Naghizadeh ◽  
Mauricio Sacchi
Keyword(s):  
Seismic Data ◽  
Interpolation Method ◽  
Hankel Matrix ◽  
Real Data ◽  
Low Frequencies ◽  
Frequency Space ◽  
Reduced Rank ◽  
Seismic Records ◽  
Text Prediction ◽  
Eigen Decomposition

We tested a strategy for beyond-alias interpolation of seismic data using Cadzow reconstruction. The strategy enables Cadzow reconstruction to be used for interpolation of regularly sampled seismic records. First, in the frequency-space ([Formula: see text]) domain, we generated a Hankel matrix from the spatial samples of the low frequencies. To perform interpolation at a given frequency, the spatial samples were interlaced with zero samples and another Hankel matrix was generated from the zero-interlaced data. Next, the rank-reduced eigen-decomposition of the Hankel matrix at low frequencies was used for beyond-alias preconditioning of the Hankel matrix at a given frequency. Finally, antidiagonal averaging of the conditioned Hankel matrix produced the final interpolated data. In addition, the multidimensional extension of the proposed algorithm was explained. The proposed method provides a unifying thread between reduced-rank Cadzow reconstruction and beyond alias [Formula: see text] prediction error interpolation. Synthetic and real data examples were provided to examine the performance of the proposed interpolation method.

scholarly journals Attenuation of long period multiple using F-k filter and surface-related multiple elimination methods on 2D broadband seismic data from Morowali Waters, Sulawesi

2021 ◽  
Vol 944 (1) ◽  
pp. 012005
Author(s):  
G L Situmeang ◽  
H M Manik ◽  
T B Nainggolan ◽  
Susilohadi
Keyword(s):  
Seismic Data ◽  
Seismic Waves ◽  
Frequency Bandwidth ◽  
Long Period ◽  
Time Migration ◽  
Predictive Deconvolution ◽  
Short Period ◽  
Wide Range ◽  
Marine Seismic ◽  
Multiple Elimination

Abstract Wide range frequency bandwidth on seismic data is a necessity due to its close relation to resolution and depth of target. High-frequency seismic waves provide high-resolution imaging that defines thin bed layers in shallow sediment, while low-frequency seismic waves can penetrate into deeper target depth. As a result of broadband seismic technology, its wide range of frequency bandwidth is a suitable geophysical exploration method in the oil and gas industry. A major obstacle that is frequently found in marine seismic data acquisition is the existence of multiples. Short period multiple and reverberation are commonly attenuated by the predictive deconvolution method on prestack data. Advanced methods are needed to suppress long period multiple in marine seismic data. The 2D broadband marine seismic data from deep Morowali Waters, Sulawesi, contains both short and long period multiples. The predictive deconvolution, which is applied to the processing sequences, successfully eliminates short period multiple on prestack data. The combination of F-k filter and Surface Related Multiple Elimination (SRME) methods are successful in attenuating long period multiple of the 2D broadband marine seismic data. The Prestack Time Migration section shows fine resolution of seismic images.

A dictionary learning method for seismic data compression

Geophysics ◽  
2021 ◽  
pp. 1-83
Author(s):  
Mohammed Outhmane Faouzi Zizi ◽  
Pierre Turquais
Keyword(s):  
Data Storage ◽  
Compression Ratio ◽  
Dictionary Learning ◽  
Seismic Data ◽  
Superior Performance ◽  
Seismic Survey ◽  
Learning Method ◽  
Data Set ◽  
Wide Range ◽  
Marine Seismic

For a marine seismic survey, the recorded and processed data size can reach several terabytes. Storing seismic data sets is costly and transferring them between storage devices can be challenging. Dictionary learning has been shown to provide representations with a high level of sparsity. This method stores the shape of the redundant events once, and represents each occurrence of these events with a single sparse coefficient. Therefore, an efficient dictionary learning based compression workflow, which is specifically designed for seismic data, is developed here. This compression method differs from conventional compression methods in three respects: 1) the transform domain is not predefined but data-driven; 2) the redundancy in seismic data is fully exploited by learning small-sized dictionaries from local windows of the seismic shot gathers; 3) two modes are proposed depending on the geophysical application. Based on a test seismic data set, we demonstrate superior performance of the proposed workflow in terms of compression ratio for a wide range of signal-to-residual ratios, compared to standard seismic data methods, such as the zfp software or algorithms from the Seismic Unix package. Using a more realistic data set of marine seismic acquisition, we evaluate the capability of the proposed workflow to preserve the seismic signal for different applications. For applications such as near-real time transmission and long-term data storage, we observe insignificant signal leakage on a 2D line stack when the dictionary learning method reaches a compression ratio of 24.85. For other applications such as visual QC of shot gathers, our method preserves the visual aspect of the data even when a compression ratio of 95 is reached.

scholarly journals Amplitude-Preserved Wave Equation: An Example to Image the Gas Hydrate System

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3700
Author(s):  
Jiachun You ◽  
Sha Song ◽  
Umberta Tinivella ◽  
Michela Giustiniani ◽  
Iván Vargas-Cordero
Keyword(s):  
Wave Equation ◽  
Gas Hydrate ◽  
Seismic Data ◽  
Signal To Noise Ratio ◽  
Matrix Decomposition ◽  
Real Data ◽  
High Signal ◽  
Imaging Result ◽  
Imaging Results ◽  
Seismic Records

Natural gas hydrate is an important energy source. Therefore, it is extremely important to provide a clear imaging profile to determine its distribution for energy exploration. In view of the problems existing in conventional migration methods, e.g., the limited imaging angles, we proposed to utilize an amplitude-preserved one-way wave equation migration based on matrix decomposition to deal with primary and multiple waves. With respect to seismic data gathered at the Chilean continental margin, a conventional processing flow to obtain seismic records with a high signal-to-noise ratio is introduced. Then, the imaging results of the conventional and amplitude-preserved one-way wave equation migration methods based on primary waves are compared, to demonstrate the necessity of implementing amplitude-preserving migration. Moreover, a simple two-layer model is imaged by using primary and multiple waves, which proves the superiority of multiple waves in imaging compared with primary waves and lays the foundation for further application. For the real data, the imaging sections of primary and multiple waves are compared. We found that multiple waves are able to provide a wider imaging illumination while primary waves fail to illuminate, especially for the imaging of bottom simulating reflections (BSRs), because multiple waves have a longer travelling path and carry more information. By imaging the actual seismic data, we can make a conclusion that the imaging result generated by multiple waves can be viewed as a supplementary for the imaging result of primary waves, and it has some guiding values for further hydrate and in general shallow gas exploration.

scholarly journals GPR-based Detection of Voids and Evaluation of Grouting Under Semi-rigid Basement

2018 ◽  
Author(s):  
Jiaqi Zheng
Keyword(s):  
Theoretical Analysis ◽  
Data Processing ◽  
Least Squares Method ◽  
Fdtd Method ◽  
Real Data ◽  
Rigid Base ◽  
The Road ◽  
Image Characteristics ◽  
Different Types ◽  
Processing Techniques

The void underneath semi-rigid base is a common defect in roads. There are some difficulties in the detection and repair for this kind of hidden damage, as well as in the evaluation of the effects of grouting treatment. For the detection and maintenance of roads, it is essential to study the detection and judging for voids underneath base and the evaluation of the spread of grout. Through theoretical analysis, numerical simulation and analysis of real data, this research generated the characteristics of under-base voids of different types and dimensions on GPR images, proposed the detecting and dimension-measuring methods for under-base voids, and studied the process and effects of data analysis techniques. (1) The characteristics of under-base voids of different types (air-filled, water-filled or grout-treated) and dimensions (height and horizontal dimensions), on A-scan and B-scan GPR image respectively, were analyzed theoretically. The gprMax software which is based on the FDTD method was employed to simulate the transmission of GPR wave within the road structure, which certified the conclusion of theoretical analysis of the image characteristics of voids. In addition, the influence of antenna frequency on the detection for voids are also analyzed.(2) Approaches for detecting voids and for estimating its height were studied, focusing on voids with a height ranging from 0.01m to 0.3m. The Least Squares Method of System Identification and the Tikhonov Regularized Deconvolution were both successfully applied to the detection and dimension estimation of air-filled voids, and their application conditions were discussed. As for water-filled and grout-treated voids, the reflection-amplitude-based dielectric constant method was used for void detection.(3) The approach for estimating the horizontal dimension of voids was studied, focusing on voids with a length ranging from 0.04m to 0.52m. According to the simulating results of air-filled voids, the estimation index was selected, and the linear calculation formula for length of voids was generated by regression analysis. (4) The data processing process was discussed. Also, the effects of different data processing techniques were studied in terms of noise filtering and attenuation compensation, and their influence on the image characteristics was also discussed.

scholarly journals Estimating shallow shear velocities with marine multicomponent seismic data

Geophysics ◽  
2002 ◽  
Vol 67 (6) ◽  
pp. 1991-2004 ◽  
Author(s):  
Michael H. Ritzwoller ◽  
Anatoli L. Levshin
Keyword(s):  
Seismic Data ◽  
Guided Waves ◽  
Oil And Gas ◽  
Real Data ◽  
Shear Velocity ◽  
Dispersive Waves ◽  
Sea Floor ◽  
Interface Waves ◽  
Uncertainty Estimates ◽  
Marine Seismic

Accurate models of shear velocities in the shallow subsurface (<300 m depth beneath the sea floor) would help to focus images of structural discontinuities constructed, for example, with P to S converted phases in marine environments. Although multicomponent marine seismic data hold a wealth of information about shear velocities from the sea floor to depths of hundreds of meters, this information remains largely unexploited in oil and gas exploration. We present a method, called the multiwave inversion (MWI) method, designed to use a wide variety of information in marine seismic data. As presented here, MWI jointly uses the observed traveltimes of P and S refracted waves, the group and phase velocities of fundamental mode and first overtone interface waves, and the group velocities of guided waves to infer shear velocities and Vp/Vs ratios. We show how to obtain measurements of the traveltimes of these diverse and, in some cases, dispersive waves and how they are used in the MWI method to estimate shallow shear velocities. We illuminate the method with synthetic and real multicomponent marine data and apply MWI to some real data to obtain a model of Vs with uncertainty estimates to a depth of 225 m and Vp/Vs to about 100‐m depth. We conclude by discussing the design of offshore surveys necessary to provide information about shallow shear‐velocity structures, with particular emphasis on the height of the acoustic source above the sea floor.

Formation geological depth image according to refraction and reflection marine seismic data

2017 ◽  
Vol 39 (6) ◽  
pp. 106-121
Author(s):  
A. O. Verpahovskaya ◽  
V. N. Pilipenko ◽  
Е. V. Pylypenko
Keyword(s):  
Seismic Data ◽  
Depth Image ◽  
Marine Seismic
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