Potential pitfalls of crooked‐line seismic reflection surveys

Geophysics ◽  
1996 ◽  
Vol 61 (1) ◽  
pp. 277-281 ◽  
Author(s):  
Jianjun Wu
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Mineral Exploration ◽  
Crystalline Rock ◽  
Complex Nature ◽  
Data Sets ◽  
Implicit Assumption ◽  
Coherent Noise ◽  
Straight Line ◽  
Processing Techniques

During the last few years, the Geological Survey of Canada has pioneered the application of seismic reflection profiling to mineral exploration, in close collaboration with Canadian mining companies and with the Lithoprobe project (e.g., Spencer et al., 1993; Milkereit et al., 1994). Because of the rugged terrain in crystalline rock environments (Dahle et al., 1985; Spencer et al., 1993), vibroseis seismic surveys are frequently conducted along existing roads, resulting in extremely crooked survey profiles. Crooked profiling geometry, coupled with the complex nature of the geological targets, pose special challenges for seismic data processing and interpretation. Many common‐midpoint seismic processing techniques are based on an implicit assumption of a straight‐line survey and are most effective with uniform fold and even offset distribution within common‐midpoint (CMP) gathers. However, with crooked‐line acquisition the CMP gathers are characterized by variable fold and uneven offset distribution. Based on experience with several seismic data sets from mining camps, I have identified two potential pitfalls that stem from acquisition along crooked profiles: (1) seismic transparent zones; and (2) coherent noise. To address these problems, I have critically re‐examined the basic aspects of the CMP processing techniques and have developed robust strategies for dealing with crooked profiles. In this paper, I present a field data example to demonstrate the artifacts and also discuss solutions to eliminate them. Although developed for seismic prospecting in mining camps, the methods presented here are applicable to seismic data acquired in any environment.

scholarly journals Improved Interpretation of Deep Seismic Reflection Data in Areas of Complex Geology Through Integration With Passive Seismic Data Sets

2018 ◽  
Vol 123 (12) ◽  
pp. 10,810-10,830
Author(s):  
Michael Dentith ◽  
Huaiyu Yuan ◽  
Ruth Elaine Murdie ◽  
Perla Pina-Varas ◽  
Simon P. Johnson ◽  
...  
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Data Sets ◽  
Seismic Reflection Data ◽  
Deep Seismic Reflection ◽  
Reflection Data ◽  
Passive Seismic ◽  
Complex Geology

Case Study: Improving the quality of the seismic reflection image for a Fujian mineral exploration data set with offset-domain common-image gathers

Geophysics ◽  
2021 ◽  
pp. 1-45
Author(s):  
Guofeng Liu ◽  
Xiaohong Meng ◽  
Johanes Gedo Sea
Keyword(s):  
Wave Equation ◽  
Image Quality ◽  
Seismic Data ◽  
Seismic Reflection ◽  
Mineral Exploration ◽  
Velocity Model ◽  
Image Point ◽  
Single Shot ◽  
Data Set ◽  
Depth Migration

Seismic reflection is a proven and effective method commonly used during the exploration of deep mineral deposits in Fujian, China. In seismic data processing, rugged depth migration based on wave-equation migration can play a key role in handling surface fluctuations and complex underground structures. Because wave-equation migration in the shot domain cannot output offset-domain common-image gathers in a straightforward way, the use of traditional tools for updating the velocity model and improving image quality can be quite challenging. To overcome this problem, we employed the attribute migration method. This worked by sorting the migrated stack results for every single-shot gather into the offset gathers. The value of the offset that corresponded to each image point was obtained from the ratio of the original migration results to the offset-modulated shot-data migration results. A Gaussian function was proposed to map every image point to a certain range of offsets. This helped improve the signal-to-noise ratio, which was especially important in handing low quality seismic data obtained during mineral exploration. Residual velocity analysis was applied to these gathers to update the velocity model and improve image quality. The offset-domain common-image gathers were also used directly for real mineral exploration seismic data with rugged depth migration. After several iterations of migration and updating the velocity, the proposed procedure achieved an image quality better than the one obtained with the initial velocity model. The results can help with the interpretation of thrust faults and deep deposit exploration.

Swell-noise attenuation: A deep learning approach

2019 ◽  
Vol 38 (12) ◽  
pp. 934-942 ◽  
Author(s):  
Xing Zhao ◽  
Ping Lu ◽  
Yanyan Zhang ◽  
Jianxiong Chen ◽  
Xiaoyang Li
Keyword(s):  
Deep Learning ◽  
Seismic Data ◽  
Learning Model ◽  
Noise Model ◽  
Learning Approach ◽  
Data Sets ◽  
Great Success ◽  
Noise Attenuation ◽  
Coherent Noise ◽  
Deep Learning Model

Noise attenuation for ordinary images using machine learning technology has achieved great success in the computer vision field. However, directly applying these models to seismic data would not be effective since the evaluation criteria from the geophysical domain require a high-quality visualized image and the ability to maintain original seismic signals from the contaminated wavelets. This paper introduces an approach equipped with a specially designed deep learning model that can effectively attenuate swell noise with different intensities and characteristics from shot gathers with a relatively simple workflow applicable to marine seismic data sets. Three significant benefits are introduced from the proposed deep learning model. First, our deep learning model doesn't need to consume a pure swell-noise model. Instead, a contaminated swell-noise model derived from field data sets (which may contain other noises or primary signals) can be used for training. Second, inspired by the conventional algorithm for coherent noise attenuation, our neural network model is designed to learn and detect the swell noise rather than inferring the attenuated seismic data. Third, several comparisons (signal-to-noise ratio, mean squared error, and intensities of residual swell noises) indicate that the deep learning approach has the capability to remove swell noise without harming the primary signals. The proposed deep learning-based approach can be considered as an alternative approach that combines and takes advantage of both the conventional and data-driven method to better serve swell-noise attenuation. The comparable results also indicate that the deep learning method has strong potential to solve other coherent noise-attenuation tasks for seismic data.

Analysis of ground-probing radar data: predictive deconvolution

1991 ◽  
Vol 28 (1) ◽  
pp. 134-139 ◽  
Author(s):  
P. T. Lafleche ◽  
J. P. Todoeschuck ◽  
O. G. Jensen ◽  
A. S. Judge
Keyword(s):  
Ground Penetrating Radar ◽  
Seismic Data ◽  
Prediction Error ◽  
Radar Data ◽  
Digital Data ◽  
Data Sets ◽  
Predictive Deconvolution ◽  
The Common ◽  
Ground Penetrating ◽  
Processing Techniques

Recent advances in ground-probing radar instrumentation have allowed the collection of large volumes of digital data. Such data sets are amenable to modern data-processing techniques both to increase geological resolution and to enhance data presentation. The close similarity between ground-radar data and seismic data suggests that processing techniques that have been used in the seismic industry could be applied to radar data. As an example, a ground probing radar profile is deconvolved using the common prediction-error filter, which assumes a white power spectrum for the reflections, and a filter that assumes a spectrum proportional to spatial frequency. With the prediction-error filter we find three of four buried pipes which are not visible in the undeconvolved section; all four are found with the second filter. Key words: ground-penetrating radar, deconvolution, scaling geology, frozen-core dams, permafrost, containment dams, mill waste, Contwoyto Lake.

scholarly journals Cost-Effective Seismic Exploration: 2D Reflection Imaging at the Kylylahti Massive Sulfide Deposit, Finland

Minerals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 263 ◽  
Author(s):  
Suvi Heinonen ◽  
Michal Malinowski ◽  
Felix Hloušek ◽  
Gardar Gislason ◽  
Stefan Buske ◽  
...  
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Imaging Techniques ◽  
Mineral Exploration ◽  
Massive Sulfide ◽  
Seismic Profile ◽  
Seismic Exploration ◽  
Sulfide Deposit ◽  
Depth Imaging ◽  
Seismic Reflection Profiles

We show that by using an advanced pre-stack depth imaging algorithm it is possible to retrieve meaningful and robust seismic images with sparse shot points, using only 3–4 source points per kilometer along a seismic profile. Our results encourage the use of 2D seismic reflection profiling as a reconnaissance tool for mineral exploration in areas with limited access for active seismic surveys. We used the seismic data acquired within the COGITO-MIN project comprising two approximately 6 km long seismic reflection profiles at the polymetallic Kylylahti massive sulfide mine site in eastern Finland. The 2D seismic data acquisition utilized both Vibroseis and dynamite sources with 20 m spacing and wireless receivers spaced every 10 m. For both source types, the recorded data show clear first breaks over all offsets and reflectors in the raw shot gathers. The Kylylahti area is characterized by folded and faulted, steeply dipping geological contacts and structures. We discuss post-stack and pre-stack data processing and compare time and depth imaging techniques in this geologically complex Precambrian hardrock area. The seismic reflection profiles show prominent reflectors at 4.5–8 km depth utilizing different migration routines. In the shallow subsurface, steep reflectors are imaged, and within and underneath the known Kylylahti ultramafic body reflectivity is prominent but discontinuous.

Spectral structure-oriented filtering of seismic data with self-adaptive paths

Geophysics ◽  
2019 ◽  
Vol 84 (5) ◽  
pp. V271-V280
Author(s):  
Julián L. Gómez ◽  
Danilo R. Velis
Keyword(s):  
Seismic Data ◽  
Random Noise ◽  
Noise Removal ◽  
Quality Data ◽  
Spectral Structure ◽  
Data Sets ◽  
Coherent Noise ◽  
Edge Preserving ◽  
3D Data ◽  
Self Adaptive

We have developed an algorithm to perform structure-oriented filtering (SOF) in 3D seismic data by learning the data structure in the frequency domain. The method, called spectral SOF (SSOF), allows us to enhance the signal structures in the [Formula: see text]-[Formula: see text]-[Formula: see text] domain by running a 1D edge-preserving filter along curvilinear self-adaptive trajectories that connect points of similar characteristics. These self-adaptive paths are given by the eigenvectors of the smoothed structure tensor, which are easily computed using closed-form expressions. SSOF relies on a few parameters that are easily tuned and on simple 1D convolutions for tensor calculation and smoothing. It is able to process a 3D data volume with a 2D strategy using basic 1D edge-preserving filters. In contrast to other SOF techniques, such as anisotropic diffusion, anisotropic smoothing, and plane-wave prediction, SSOF does not require any iterative process to reach the denoised result. We determine the performance of SSOF using three public domain field data sets, which are subsets of the well-known Waipuku, Penobscot, and Teapot surveys. We use the Waipuku subset to indicate the signal preservation of the method in good-quality data when mostly background random noise is present. Then, we use the Penobscot subset to illustrate random noise and footprint signature attenuation, as well as to show how faults and fractures are improved. Finally, we analyze the Teapot stacked and depth-migrated subsets to show random and coherent noise removal, leading to an improvement of the volume structural details and overall lateral continuity. The results indicate that random noise, footprints, and other artifacts can be successfully suppressed, enhancing the delineation of geologic structures and seismic horizons and preserving the original signal bandwidth.

FAULT PLANE RESOLUTION USING THE LOW-FOLD 3D SEISMIC TECHNIQUE OVER WOODADA GAS FIELD, PERTH BASIN, WESTERN AUSTRALIA

1987 ◽  
Vol 27 (1) ◽  
pp. 289
Author(s):  
B.J. Evans ◽  
G.A. Paterson ◽  
S.E. Frey
Keyword(s):  
Western Australia ◽  
Seismic Data ◽  
Joint Venture ◽  
Seismic Survey ◽  
Survey Method ◽  
3D Seismic ◽  
Coherent Noise ◽  
Gas Field ◽  
Single Fold ◽  
Processing Techniques

During August 1984, a conventional 2D seismic line and a single fold 3D seismic survey were recorded over the Woodada Gas Field, North Perth Basin, Western Australia. This survey was a joint venture between the Allied Geophysical Laboratories at the University of Houston and the Exploration Seismology Centre's Field Research Laboratory at the Western Australian Institute of Technology. Previous seismic data were so poor that there was confusion about fault orientation and structure in the survey area. In addition, the fault strike direction and extent were unknown at this location. Consequently, 3D seismic acquisition and processing techniques appeared highly applicable to this geological problem.In general, progressive development of seismic data acquisition methods has been towards higher channel, higher multifold 2D and 3D surveys. However, at the Allied Geophysical Laboratories, processing techniques for single-fold 3D data have been developed using model tank data. This processing technique — LO-FOLD 3D — was used to field trial the method, and to test its ability to define faulting between the gas producing well Indoon 1 and dry step-out well Woodada 9. Previous usage of the single-fold 3D survey method was to delineate reefal structures in the Michigan Basin. Beyond this, no published articles discuss the method.With single-fold data, velocity analysis and coherent noise are a problem. Consequently, 2D bin lines through the 3D volume of data were processed in order to improve the signal to noise ratios. The objective was to delineate the fault orientation in the Carynginia Formation, located between 1.3 and 1.5 seconds. Fault delineation was determined from 2D bin lines and time slices, and is interpreted to run diagonally between the two wells.

LITHOPROBE seismic reflection imaging of Rocky Mountain structures east of Canal Flats, British Columbia

1988 ◽  
Vol 25 (9) ◽  
pp. 1339-1348 ◽  
Author(s):  
David W. S. Eaton ◽  
Frederick A. Cook
Keyword(s):  
British Columbia ◽  
Seismic Data ◽  
Seismic Reflection ◽  
Rocky Mountain ◽  
Normal Fault ◽  
Seismic Reflection Data ◽  
Middle Cambrian ◽  
Reflection Data ◽  
Processing Techniques ◽  
Surface Geology

LITHROPROBE seismic reflection data, coupled with information from industry seismic data and surface geology, image the thin-skinned structures of the western Rocky Mountains from the Main Ranges to the Rocky Mountain Trench near Canal Flats, British Columbia. Reprocessing of the LITHOPROBE seismic reflection line was conducted to improve resolution of upper-crustal features. Careful application of "conventional" processing techniques significantly improved the coherence of reflections from the first 6 s. A spatial semblance filter was applied to further enhance coherent signal, and residual-statics corrections were applied by cross correlation of unstacked data with semblance-filtered pilot traces.A near-basement reflection zone arising from Middle Cambrian strata is visible on an industry reflection profile at an approximate depth of 8 km beneath the Main Ranges. A similar reflection zone is imaged on the LITHOPROBE data at a depth of 11 km bsl but is interpreted as arising from Proterozoic strata. The autochthonous crystalline basement is interpreted as being below these layers and dipping about 2 °to the west. Geometric evidence is visible for several major thrust ramps involving the basal décollement and for an intermediate-level décollement that loses displacement into folds within the Porcupine Creek Anticlinorium. Reflections related to the Gypsum fault, the Redwall thrust, and the Lussier River normal fault are also imaged.

scholarly journals Integrated magnetotelluric and seismic investigation of Cenozoic graben structure near Obrzycko, Poland

2021 ◽  
Author(s):  
Adam Cygal ◽  
Michał Stefaniuk ◽  
Anna Kret
Keyword(s):  
Seismic Data ◽  
Geophysical Methods ◽  
Geological Structure ◽  
Data Sets ◽  
Low Velocity ◽  
Shallow Subsurface ◽  
Geophysical Model ◽  
Novel Approach ◽  
Loose Deposits ◽  
Static Corrections

AbstractThis article presents the results of an integrated interpretation of measurements made using Audio-Magnetotellurics and Seismic Reflection geophysical methods. The obtained results were used to build an integrated geophysical model of shallow subsurface cover consisting of Cenozoic deposits, which then formed the basis for a detailed lithological and tectonic interpretation of deeper Mesozoic sediments. Such shallow covers, consisting mainly of glacial Pleistocene deposits, are typical for central and northern Poland. This investigation concentrated on delineating the accurate geometry of Obrzycko Cenozoic graben structure filled with loose deposits, as it was of great importance to the acquisition, processing and interpretation of seismic data that was to reveal the tectonic structure of the Cretaceous and Jurassic sediments which underly the study area. Previously, some problems with estimation of seismic static corrections over similar grabens filled with more recent, low-velocity deposits were encountered. Therefore, a novel approach to estimating the exact thickness of such shallow cover consisting of low-velocity deposits was applied in the presented investigation. The study shows that some alternative geophysical data sets (such as magnetotellurics) can be used to significantly improve the imaging of geological structure in areas where seismic data are very distorted or too noisy to be used alone

Seismic reflection test on the granite of the Skye Tertiary igneous centre

1992 ◽  
Vol 129 (5) ◽  
pp. 633-636 ◽  
Author(s):  
N. R. Goulty ◽  
M. Leggett ◽  
T. Douglas ◽  
C. H. Emeleus
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Intrusive Complex ◽  
Gravity Modelling ◽  
Test Location ◽  
Basic Rocks

AbstractWe have conducted a seismic reflection test over a short profile on the granite of the Skye Tertiary central intrusive complex. From previous gravity modelling work it had been inferred that the granite is approximately 1.5 km thick and overlies basic rocks. The seismic data indicate that the granite is at least 2 km thick at the test location. Reflection events of alternating polarity between depths of 2.1 and 2.4 km suggest that basic and acidic sheets are interlayered at the base of the granitic mass.

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