High‐resolution 3-D seismic survey over a coal mine reserve area in the U.S.—A case study

Geophysics ◽  
2000 ◽  
Vol 65 (3) ◽  
pp. 712-718 ◽  
Author(s):  
Lawrence M. Gochioco

A high‐resolution three‐dimensional (3-D) seismic survey was conducted in advance of coal mine development in the Illinois basin in May 1989 to better define a geologic structure with the potential to adversely affect longwall mining conditions. The 3-D seismic data indicate that an abrupt change in seam elevation, or roll, encountered near the northern property line trends south into the reserve area and then turns southeast. A personal computer‐based workstation was used to integrate borehole and seismic data for modeling in which 3-D block diagrams of the calculated seam elevations were generated. The block diagrams show a steep slope on the west flank of the roll that gradually decreases as the roll turns to the southeast. The survey also reveals a geologic structure beneath the roll at an estimated depth of 46–62 m. Horizontal time‐slice sections of this feature suggest the presence of a paleochannel that meanders on a similar course as the roll, which apparently was connected to a larger paleochannel system. A Conoco high‐frequency vibroseis unit was successfully used as the seismic source to generate the high frequencies necessary to detect and resolve the thin coal beds.

Geophysics ◽  
1989 ◽  
Vol 54 (12) ◽  
pp. 1521-1527 ◽  
Author(s):  
Lawrence M. Gochioco ◽  
Steven A. Cotten

A high‐resolution seismic reflection technique was used to locate faults in coal seams that were not visible on the surface and could only be observed in underground coal mines. An 8‐gauge buffalo gun, built by the research and development department of Consolidation Coal Company, was used as the seismic source. The coal seam at a depth of 700 ft produces a reflection with a predominant frequency of about 125 Hz. The high‐resolution seismic data permitted faults with vertical displacements of the same magnitude as the seam thickness to be detected at depths of several hundred feet beneath the surface. Several faults were detected and interpreted from the seismic sections, and the magnitudes of their displacement were estimated by matching the recorded seismic data to synthetic seismic data. Subsequent underground mine development in the study area confirmed two interpreted faults and their estimated displacements. Mining engineers were able to use the information provided by the seismic survey to plan an entry system through the fault zone so that less rock needed to be mined, resulting in a safer and more productive mine.


2020 ◽  
Author(s):  
Young Jun Kim ◽  
Snons Cheong ◽  
Deniz Cukur ◽  
Dong-Geun Yoo

<p>In marine seismic surveys, various acquisition systems are used depending on the survey purpose, target depth, survey environment, and conditions. A 3D survey of oil and/or gas exploration, for instance, require large-capacity air-gun arrays and six or more streamers with a minimum length of 6 km. In contrast, a high-resolution seismic survey for the shallow-water geological research and engineering needs a small capacity source such as air-gun, sparker, and boomer, deployed with a single-channel or multi-channel (24-channel) streamers. The main purpose of our seismic survey was to investigate the Quaternary geology and stratigraphy of offshore, Korea. Because the Quaternary is the most recent geological period, our target depth was very shallow at about 50 m below the sea-bottom. We used a high-frequency seismic source including a sparker of 2,000 J capacity or a 60 in<sup>3</sup> mini GI-gun and an eight-channel streamer with a 3.125 m group interval or a single-channel streamer that included 96 elements. To compare the resolution of seismic data according to the seismic source, a boomer or sparker systems were used with the single-channel streamer on a small survey ship. The seismic data processing was performed at the Korea Institute of Geoscience and Mineral Resources (KIGAM) with ProMAX, and the data processing and resolution of each survey were compared based on their acquisition systems.</p>


Geophysics ◽  
1989 ◽  
Vol 54 (2) ◽  
pp. 267-270
Author(s):  
Donald S. Stone

As a happy owner of the popular SEG monographs by Tucker and Yorston (1973) and Tucker (1982), the appearance of Tucker (1988) as the leadoff article in the June, 1988 issue of Geophysics caught my attention, and I began reading with high expectations. Admitting that the paper was chiefly about the philosophy and mechanics of contouring seismic data, I nevertheless found it disappointing, primarily because in describing his unique seismic contouring skill, Tucker never mentions migration or its importance in the conversion of raw seismic times to three‐dimensional (3-D) geologic structure. Also, many of the statements in his paper can be challenged on the grounds of imprecision or omission in terms of real structural interpretation.


2006 ◽  
Vol 46 (1) ◽  
pp. 101 ◽  
Author(s):  
K.J. Bennett ◽  
M.R. Bussell

The newly acquired 3,590 km2 Demeter 3D high resolution seismic survey covers most of the North West Shelf Venture (NWSV) area; a prolific hydrocarbon province with ultimate recoverable reserves of greater than 30 Tcf gas and 1.5 billion bbls of oil and natural gas liquids. The exploration and development of this area has evolved in parallel with the advent of new technologies, maturing into the present phase of revitalised development and exploration based on the Demeter 3D.The NWSV is entering a period of growing gas market demand and infrastructure expansion, combined with a more diverse and mature supply portfolio of offshore fields. A sequence of satellite fields will require optimised development over the next 5–10 years, with a large number of wells to be drilled.The NWSV area is acknowledged to be a complex seismic environment that, until recently, was imaged by a patchwork of eight vintage (1981–98) 3D seismic surveys, each acquired with different parameters. With most of the clearly defined structural highs drilled, exploration success in recent years has been modest. This is due primarily to severe seismic multiple contamination masking the more subtle and deeper exploration prospects. The poor quality and low resolution of vintage seismic data has also impeded reservoir characterisation and sub-surface modelling. These sub-surface uncertainties, together with the large planned expenditure associated with forthcoming development, justified the need for the Demeter leading edge 3D seismic acquisition and processing techniques to underpin field development planning and reserves evaluations.The objective of the Demeter 3D survey was to re-image the NWSV area with a single acquisition and processing sequence to reduce multiple contamination and improve imaging of intra-reservoir architecture. Single source (133 nominal fold), shallow solid streamer acquisition combined with five stages of demultiple and detailed velocity analysis are considered key components of Demeter.The final Demeter volumes were delivered early 2005 and already some benefits of the higher resolution data have been realised, exemplified in the following:Successful drilling of development wells on the Wanaea, Lambert and Hermes oil fields and identification of further opportunities on Wanaea-Cossack and Lambert- Hermes;Dramatic improvements in seismic data quality observed at the giant Perseus gas field helping define seven development well locations;Considerably improved definition of fluvial channel architecture in the south of the Goodwyn gas field allowing for improved well placement and understanding of reservoir distribution;Identification of new exploration prospects and reevaluation of the existing prospect portfolio. Although the Demeter data set has given significant bandwidth needed for this revitalised phase of exploration and development, there remain areas that still suffer from poor seismic imaging, providing challenges for the future application of new technologies.


Geophysics ◽  
1991 ◽  
Vol 56 (12) ◽  
pp. 2036-2047 ◽  
Author(s):  
G. L. Kinsland ◽  
J. A. McDonald ◽  
G. H. F. Gardner

A thin sand has been successfully imaged at great depth using a carefully designed, high‐resolution, three‐dimensional (3-D), seismic survey. The area of the survey was along a portion of the boundary between northeastern Vermilion Parish and southern Lafayette Parish about twelve miles south of Lafayette, Louisiana. Surface terrain was typically flat farmland at the southern edge of the Pleistocene Prairie Terrace and was ideal for this type of high‐resolution survey. The greatest elevation difference between any two source or receiver locations was about 6 ft (1.8 m). The target for this survey was the Cib jeff sand at a depth of about 13,400 ft (4084 m). The Cib jeff sand is within massive shales and is within a geopressured zone. Relative isolation of the Cib jeff sand by the surrounding shales makes the sand a good candidate for seismic imaging. After some preliminary field tests a survey was designed which used the crossed‐array method in which the source and receiver lines are at some angle to one another, usually orthogonal. Data were collected using a 1024-channel recording system with vibrators as sources. Receiver arrays were not used as it was possible to sweep with frequencies outside the frequency range of the ground roll. A total of [Formula: see text] seismic traces was collected. Many tests were also carried out in the processing of these data and it was found that large variations of offsets in the data volume resulted in deterioration in the quality of stacked data due to nonhyperbolic moveout. The migrated data volume was restricted to traces with less than 7500 ft (2286 m) source‐to‐receiver offset, and to the time window containing the Cib jeff sand, namely from 2.5 to 5.0 s. The Cib jeff sand was successfully imaged and the migrated data volume was interpreted using paper sections. As one would expect, the interpretation based on the total volume is more complex than the interpretation using available conventional two‐dimensional (2-D) lines. In particular the fault pattern interpretation based on 2-D seismic data and well logs is believed to be in error. The western bounding fault is placed further west and other faults were delineated through the reservoir when the interpretation was based on the total 3-D volume. Overall, we believe that this reservoir was mapped with more control than was possible with 2-D data.


2019 ◽  
Vol 56 (5) ◽  
pp. 569-583 ◽  
Author(s):  
Gilles Bellefleur ◽  
Saeid Cheraghi ◽  
Alireza Malehmir

We reprocessed legacy three-dimensional (3D) seismic data from the Halfmile Lake and Brunswick areas, both of which were acquired for mineral exploration in the Bathurst Mining Camp, New Brunswick. Each 3D seismic survey was acquired over known volcanogenic massive sulphide deposits and covered areas with strong mineral potential. Most improvements resulted from a reduction of coherent and random noise on prestack gathers and from an improved velocity model, combined with re-imaging with dip moveout corrections and poststack migration or prestack time migration. At Halfmile Lake, the new imaging results show the Deep zone and a possible extension of the sulphide mineralization at greater depth. True amplitude processing has shown that this anomaly has strong amplitudes and is offset from the Deep zone by a shallowly dipping fault (<15°). With the clearer geological context provided by our results, this anomaly, which appears as a stand-alone anomaly on an original image obtained by Noranda Exploration Ltd., becomes a defendable exploration target. Nonorthogonal acquisition geometry and receiver patches of the Brunswick No. 6 3D seismic survey generated artefacts after dip moveout processing that reduced the overall quality of the seismic volumes. By using a filtering approach based on the application of a weighted Laplacian-Gaussian filter in the Kx–Ky domain, we reduced the noise and improved the continuity of reflections. We also imaged the short and flat reflections observed previously only in the shallow part of prestack time migrated data. These short reflections appear as diffractions on the filtered stacked section with dip moveout corrections, indicating that they originate from small geological bodies or discontinuities in the subsurface.


1978 ◽  
Vol 18 (1) ◽  
pp. 116
Author(s):  
E. G. Selby

There are many limitations in the ultimate accuracy of a conventional two dimensional seismic survey. One of the most important of these is that, in general, a prospect is not a two dimensional model but a three dimensional one. For a complete interpretation of a prospect area the final result should be a migrated time or depth map. With limited sampling (a seismic grid typically consists of loops with dimensions at least 1 km by 1 km) it is necessary to interpolate grid points to allow map migration and this method has inherent inaccuracies.The three dimensional seismic exploration technique is designed to provide a sufficiently close sampled grid of seismic traces, typically with a line and depth point spacing as close as 50-100 m, to allow the seismic data itself to be migrated three dimensionally. This allows the interpreter to work with migrated seismic sections and to contour directly the migrated map.Several techniques exist to allow practical and economic collection of seismic data to provide this close sampling. These techniques can be adapted to various terrain and cultural conditions.The main advantages of three dimensional data collection are correct imaging of the seismic information giving true vertical reflection time sections and improved signal-to-noise ratio due to the increased fold inherent in the three dimensional migration process. The additional advantage to the interpreter is that the data has a sampling which gives a line intersection at each depth point in the prospect.


Author(s):  
Christian Marcussen ◽  
James A. Chalmers ◽  
Holger Lykke Andersen ◽  
Rasmus Rasmussen ◽  
Trine Dahl-Jensen

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Marcussen, C., Chalmers, J. A., Lykke Andersen, H., Rasmussen, R., & Dahl-Jensen, T. (2001). Acquisition of high-resolution multichannel seismic data in the offshore part of the Nuussuaq Basin, central West Greenland. Geology of Greenland Survey Bulletin, 189, 34-40. https://doi.org/10.34194/ggub.v189.5195 _______________ A high-resolution multichannel seismic survey (project NuussuaqSeis 2000) was carried out from 18 July to 2 August 2000 in the offshore part of the Nuussuaq Basin, central West Greenland using the Danish research vessel R/V Dana with seismic equipment from the Geological Institute, Aarhus University, Denmark. Funding for the project was provided by the Danish Energy Research Programme, the Bureau of Minerals and Petroleum, Nuuk, Greenland, the Geological Institute of Aarhus University and the Geological Survey of Denmark and Greenland (GEUS). After completion of the NuussuaqSeis 2000 project, R/V Dana was used for a three-day coring project in Disko Bugt (see Kuijpers et al. 2001, this volume) before the ship returned to Denmark.


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