Quantitative thickness estimates from the spectral response of AVO measurements

Geophysics ◽  
2008 ◽  
Vol 73 (1) ◽  
pp. C1-C6 ◽  
Author(s):  
Ethan J. Nowak ◽  
Herbert W. Swan ◽  
Dave Lane
Keyword(s):  
Frequency Band ◽  
Seismic Data ◽  
Spectral Decomposition ◽  
Spectral Response ◽  
Seismic Survey ◽  
Decomposition Technique ◽  
Target Interval ◽  
Optimization Scheme ◽  
Resolution Limits ◽  
Marine Seismic

This study is motivated by the necessity to quantitatively characterize subtuned reservoirs. The conventional autocorrelation-based spectral-decomposition technique uses frequency notches to calculate vertical traveltime thickness of a layer of dipole reflectivity. Those notches tend to move outside the usable frequency band of the seismic data as the layer exceeds the tuning threshold of the wavelet. Assuming wavelet stationarity and nondipole reflectivity, a similar analysis performed on a crosscorrelation between an intercept and gradient trace extends the resolution limits to one-half the tuning threshold. That is a major improvement; however, many economic reservoirs still do not meet the half-tuning requirement. Such thin reservoirs led to the development of an optimization scheme. This approach, which does not require any wavelet stationarity or reflectivity assumptions, theoretically is not limited by the thickness of the target interval. The optimization scheme was applied successfully to a marine seismic survey in an attempt to estimate the traveltime thickness of a chalk reservoir.

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.

SOME CHARACTERISTICS OF MARINE SPARKER SEISMIC DATA

Geophysics ◽  
1972 ◽  
Vol 37 (3) ◽  
pp. 462-470 ◽  
Author(s):  
F. T. Allen
Keyword(s):  
Seismic Data ◽  
Water Layer ◽  
Seismic Survey ◽  
Multiple Reflections ◽  
Time Profiles ◽  
Survey Technique ◽  
Recording Conditions ◽  
Single Detector ◽  
Marine Seismic ◽  
The Relationship

The marine seismic survey technique of frequent recordings with a single detector group can provide intricate details valuable to relatively shallow investigations. Velocities may be computed from time anomalies, under certain circumstances. The extent of multiple energy response is an indication that the 100,000-joule source is strong enough for the purpose. Recognizable minor details in primary reflections are important clues in identifying related multiple reflections. Bounces off the underside of the water layer are rarely found. The pattern and character of reflections are influenced by recording conditions; thus, the relationship between recorded events and sedimentary beds is not simple. Seismic time profiles frequently give wrong impressions of structural attitudes because of the horizontal‐to‐vertical exaggeration, time anomalies, and multiple reflections, as well as the usual effects of velocity differences. The interpreted cross‐section gives a reasonably correct (even if velocities are assumed) impression of structure; the profile often does not.

scholarly journals Use of spectral decomposition technique for mapping geologic features of ‘Reigh’ field, Onshore Niger Delta

2021 ◽  
Vol 10 (1) ◽  
pp. 1-7
Author(s):  
O.K. Olaleye ◽  
P.A. Enikanselu ◽  
M.A. Ayuk
Keyword(s):  
Seismic Data ◽  
Spectral Decomposition ◽  
Niger Delta ◽  
Thickness Variation ◽  
Decomposition Technique ◽  
Meandering Channel ◽  
Seismic Resolution ◽  
Geological Features ◽  
Bed Thickness ◽  
3D Seismic Data

Spectral Decomposition Technique based on Short-Window Discrete Fourier Transform (SWDFT) was applied to threedimensional (3D) seismic data obtained from ‘Reigh’ field, onshore Niger Delta with a view to enhancing stratigraphic interpretation for geological features which are beyond seismic resolution. Two sands units from the study area were studied to produce spectrally decomposedsurfaces. The result of the study revealed thin bed layer at the centre of the field on sand unit ‘A’. Sand-filled meandering channel wasdetected and highlighted in the northern part of sand unit ‘B’ based on Red-Green-Blue frequency modulation of spectral  decomposition. The study has enhanced geologic understanding of the field by improving thin bed resolution, highlighting geologic features and displaying bed thickness variation of studied sand units in the study area. Keywords: geologic features, Niger Delta, seismic data, spectral decomposition

Spectral-decomposition response to reservoir fluids from a deepwater West Africa reservoir

Geophysics ◽  
2008 ◽  
Vol 73 (6) ◽  
pp. C23-C30 ◽  
Author(s):  
Ganglin Chen ◽  
Gianni Matteucci ◽  
Bill Fahmy ◽  
Chris Finn
Keyword(s):  
West Africa ◽  
Seismic Data ◽  
Spectral Decomposition ◽  
Spectral Response ◽  
Oil Sand ◽  
Low Frequencies ◽  
Amplitude Versus Offset ◽  
Synthetic Modeling ◽  
Seismic Images

We study the spectral-decomposition response to reservoir fluids from a deepwater West Africa reservoir through a systematic modeling approach. Our workflow starts from selecting the seismic data (far-angle seismic images) that show more pronounced fluid effect based on amplitude-versus-offset (AVO) analysis. Synthetic seismic forward modeling performed at the control well established the quality of the seismic well tie. Reservoir wedge modeling, spectral decomposition of the field and synthetic seismic data, and theoretical analyses were conducted to understand the spectral-decomposition responses. The reservoir fluid type is a main factor controlling the spectral response. For this deepwater reservoir, the amplitude contrast between oil sand and brine sand is higher at low frequencies [Formula: see text]. In addition, synthetic modeling can help identify the possible frequency band where the amplitude contrast between hydrocarbon sand and brine sand is higher. When properly included in a comprehensive direct-hydrocarbon-indicator (DHI)–AVO evaluation, spectral decomposition can enhance the identification of hydrocarbons.

scholarly journals Facies models of hydrocarbon-bearing formations of Podneytinskiy reservoir at Bovanenkovskoye and Kharasaveyskoye fields

2021 ◽  
Vol 6 (4) ◽  
pp. 43-53
Author(s):  
Oksana A. Popova ◽  
Oleg O. Uraev
Keyword(s):  
Seismic Data ◽  
Development Planning ◽  
Seismic Survey ◽  
Target Interval ◽  
Tidal Channels ◽  
Reservoir Properties ◽  
The Core ◽  
Reservoir Architecture ◽  
Geological Features ◽  
Quantitative Characteristics

Background. Significant part of hydrocarbons at Bovanenkovskoye and Kharasaveyskoye fields are contained in Podneytinskiy reservoir, and study of geological features of its productive strata is important for development planning for the fields in a whole. Aim. The paper reflects the results of integrating well and seismic data to characterize the formations of Podneytinskiy reservoir at Bovanenkovskoye and Kharasaveyskoye fields. Materials and methods. As part of the study, sedimentological description of core was analyzed, the core, well logging and seismic survey information were assessed, and the facies schemes were prepared. Results. As a result of the work, the reservoir architecture features and the distribution of reservoir properties of the target interval were revealed. It has been established that the considered formations of Podneytinskiy reservoir can be divided into two parts, the lower one is represented by deposits of predominantly deltaic origin, and the upper one is of continental and subcontinental genesis. The sedimentary conditions of rocks influenced the complexity of their architecture, so, in the formations referred to the lower part of the studied interval, the reservoirs, as a rule, are laterally continuous, in contrast to the deposits of the upper part of the section, which are typically characterized by extremely high lateral heterogeneity. Depositional conditions also influenced the reservoir properties of productive sediments. As a result of the work, it was revealed that the reservoirs of better quality are formed in fluvial and tidal channels, distributary channels and proximal parts of deltas, they have higher reservoir properties, are characterized by thicker sandstone interlayers and lower portion of carbonated interlayers in comparison with reservoirs formed in other conditions. Conclusions. The article provides quantitative characteristics of reservoir properties depending on sedimentary conditions. The results obtained form the basis for creation of geological models of Bovanenkovskoye and Kharasaveyskoye fields.

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

PROCESSING AND IMAGING OF MARINE SEISMIC DATA FROM THE JEQUITINHONHA BASIN (BAHIA, BRAZIL)

2016 ◽  
Vol 33 (3) ◽  
Author(s):  
Lourenildo W.B. Leite ◽  
J. Mann ◽  
Wildney W.S. Vieira
Keyword(s):  
Seismic Data ◽  
Sedimentary Basins ◽  
Study Results ◽  
Marine Seismic ◽  
Present Case Study

ABSTRACT. The present case study results from a consistent processing and imaging of marine seismic data from a set collected over sedimentary basins of the East Brazilian Atlantic. Our general aim is... RESUMO. O presente artigo resulta de um processamento e imageamento consistentes de dados sísmicos marinhos de levantamento realizado em bacias sedimentares do Atlântico do Nordeste...

HORIZON SLICE OF BANDWIDTH-ENHANCED SEISMIC DATA FOR THIN BEDS AUTOTRACKED FROM SPECTRAL DECOMPOSITION

2017 ◽  
Author(s):  
Hyeonju Kim ◽  
◽  
Gwang H. Lee ◽  
Han-J. Kim ◽  
John D. Pigott
Keyword(s):  
Seismic Data ◽  
Spectral Decomposition
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