Empirical observations relating near‐surface magnetic anomalies to high‐frequency seismic data and Landsat data in eastern Sheridan County, Montana

Geophysics ◽  
1991 ◽  
Vol 56 (10) ◽  
pp. 1553-1570 ◽  
Author(s):  
John A. Andrew ◽  
Duncan M. Edwards ◽  
Robert J. Graf ◽  
Richard J. Wold
Keyword(s):  
Seismic Data ◽  
Magnetic Anomalies ◽  
Oil Fields ◽  
Data Types ◽  
Seismic Line ◽  
Near Surface ◽  
The North ◽  
Basement Faults ◽  
Magnetic Basement ◽  
Seismic Sections

Our empirical synergistic correlations of aeromagnetic and seismic data and a Landsat lineament interpretation revealed lineations on the magnetic map that have expression on seismic sections. We observed a conjugate set of northwest‐southeast and northeast‐southwest trending magnetic lineaments (zones which offset and truncate near‐surface magnetic anomalies). We believe these OZs (offset zones) represent lateral faults in a wrench‐fault system. Lateral offsets appear to be 100s of meters to a few kilometers (fractions of a mile to a few miles). We observed a direct correlation between OZs and vertical faults in seismic data. Faults on seismic sections extend from near the surface to near the seismic basement. The faults are most pronounced in the Upper Cretaceous reflectors and seem to disappear with depth. Fault throws are inconsistent (reversing throw across faults). OZs trend northeast‐southwest in the north half of the study area and both northeast‐southwest and northwest‐southeast in the south half. The OZ direction of northeast‐southwest in the north half of the survey is confirmed with seismic data. The northwest‐southeast seismic line contains numerous faults and the northeast‐southwest seismic line contains few faults. Most northeast‐southwest faults do not appear to reach seismic basement and are not seen in an interpretation of the magnetic basement. In two cases, northwest‐southeast OZs and correlative Landsat lineaments coincide with mapped magnetic basement faults. These magnetic basement faults can be seen in seismic data too. Faults trending northwest‐southeast may represent Precambrian faults reactivated during the Laramide Orogeny. Movement along these faults possibly generated the northeast‐southwest faults. Most oil fields have an associated near‐surface magnetic anomaly. Other near‐surface magnetic anomalies occur over obvious, untested (in 1985), seismic character or amplitude anomalies in seismic events which correlate with producing intervals in the oil fields. This synergistic correlation is the most important single observation from our study. Different data types and interpretation techniques identified the same geologic trends and prospective geographical areas. This fundamentally important information is often lost in bickering over which filter or processing technique to use or in arguments over which data type is “more important” than others. Further, if the synergistic correlation of data types were not done, the importance of the anomalous features in each individual data type may not have been recognized.

Conversaziones, 1971

1971 ◽  
Vol 26 (2) ◽  
pp. 125-133
Keyword(s):  
North Sea ◽  
Oil Fields ◽  
Scale Model ◽  
British Petroleum ◽  
The North ◽  
Company Limited ◽  
The North Sea ◽  
Seismic Sections ◽  
Petroleum Company ◽  
Gas Fields

CONVERSAZIONES were held this year on 6 May and 24 June. At the first conversazione twenty-four exhibits and a film were shown. Dr P. E. Kent, F.R.S., and Mr P. J. Walmsley of The British Petroleum Company Limited arranged an exhibit demonstrating the latest progress in the exploration for hydrocarbons in the North Sea. The established gas fields and the recently discovered oil fields were shown on maps together with sections which illustrated their structure. Seismic sections and geological interpretations were exhibited to show the type of information being obtained in the North Sea and the structural complexities which arise. A scale model of one of the semi-submersible drilling outfits used in North Sea exploration was on display together with a sample of British North Sea oil.

Synergistic interpretation of near‐surface magnetic anomalies and high‐frequency seismic data: Northeastern Montana

1986 ◽  
Author(s):  
John A. Andrew ◽  
Richard J. Wold ◽  
Robert J. Graf ◽  
Douglas P. O'Brien
Keyword(s):  
Seismic Data ◽  
High Frequency ◽  
Magnetic Anomalies ◽  
Near Surface

Revitalizing seismic data with new imaging solutions to positively impact field development

2019 ◽  
Vol 38 (1) ◽  
pp. 20-26
Author(s):  
Gareth Venfield ◽  
Michael Townsend ◽  
Paul Cattermole ◽  
Tony Martin ◽  
Stuart Fairhead
Keyword(s):  
Seismic Data ◽  
Model Building ◽  
Large Population ◽  
Waveform Inversion ◽  
Structural Complexity ◽  
Velocity Model ◽  
Near Surface ◽  
Field Development ◽  
The North ◽  
The Right

Evaluating, planning, and forecasting are integral parts of asset development and continue throughout the life cycle of a producing field. The right decisions are required to lower risk and maximize economic recovery in challenging environments. The Claymore Complex is located in the North Sea and was discovered in 1977. A number of geologic challenges affect the imaging and hence field development including a system of shallow interweaving Quaternary channels, numerous high-contrast layers of varying composition, overburden structural complexity, and a sequence of tilted fault blocks containing the main reservoir systems. Historically, seismic processing over the area has not fully solved these challenges, resulting in significant imaging uncertainty. The Claymore Complex has an abundance of data including a large population of well information and interpretation. As part of a data revitalization process, geostatistical integration of these auxiliary data into a velocity model building sequence using full-waveform inversion and wavelet shift tomography enabled the generation of an accurate high-resolution velocity model. Access to a recent 3D survey acquired obliquely to existing data improved subsurface illumination for both the model building and imaging phases. Near-surface imaging effects and their impact on reservoir positioning and clarity were improved using the upgraded velocity model and dual-azimuth data. Shallow imaging challenges were mitigated by utilizing the additional illumination and angular diversity contained within the multiple reverberations. The revitalization of the Claymore area seismic data has challenged the current understanding of the geologic framework. Confidence has been improved by solving depth conversion problems and increasing the understanding of fault positioning and reservoir connectivity, which are invaluable for future field development.

Ghosting and marine signature deconvolution: A prerequisite for detailed seismic interpretation

Geophysics ◽  
1983 ◽  
Vol 48 (11) ◽  
pp. 1468-1485 ◽  
Author(s):  
Dushan B. Jovanovich ◽  
Roger D. Sumner ◽  
Sharon L. Akins‐Easterlin
Keyword(s):  
Gulf Coast ◽  
Seismic Line ◽  
Near Surface ◽  
Seismic Wavelet ◽  
Phase Errors ◽  
Air Gun ◽  
Statistical Hypotheses ◽  
Seismic Sections ◽  
Sonic Logs ◽  
Zero Phase

Detailed lithologic interpretation of seismic sections and/or pseudo‐sonic logs generated from seismic data requires that the seismic trace can be modeled as a reflection series convolved with a zero‐phase broadband wavelet. Ghosting and marine signature deconvolution processing is a prerequisite for assuring that the seismic wavelet on a marine CDP section will be zero phase. A deterministic approach to deconvolution is centered around the concept of abandoning the purely statistical method of wavelet estimation and actually measuring the seismic wavelet. A proper signature recording for marine data is, therefore, a crucial component of deterministic deconvolution. Another important element in the deterministic deconvolution sequence is the application of a deghosting filter to remove near‐surface reflections. Proper application of a deghosting filter significantly improves the correlation between log synthetics and the seismic trace. It has been found that statistical deconvolution schemes, because of the number of statistical hypotheses required to produce a deconvolution filter, produce residual wavelets that are highly variable in character and whose average phases cover the entire phase spectrum, modulo 2π. Examples of a Gulf Coast marine line which was shot with Aquapulse™, air gun, and Maxipulse™ sources by the RV Hollis Hedberg are presented to demonstrate the differences between statistical and deterministic deconvolution processing sequences. It will be shown, using sonic logs from wells adjacent to the seismic line, that the deterministic deconvolution sections for all three sources are close to zero phase while the statistical deconvolution sections have residual average phase errors between 180 and 270 degrees. The deterministic deconvolution sections have a high degree of correlation among themselves and to the wells adjacent to the line, while the statistical deconvolution sections correlate poorly to each other and to the wells. Synthetic seismograms and their impedance logs, and the seismic sections and their corresponding pseudo‐sonic logs, are used to demonstrate how deconvolution influences lithologic interpretation. ™Western Geophysics Co.

scholarly journals The nature of regional magnetic anomalies in the northeast of the Barents-Kara continental margin based on the results of seismic data interpretation

2021 ◽  
Vol 11 (2) ◽  
pp. 195-204
Author(s):  
E.V. Shipilov ◽  
◽  
L.I. Lobkovsky ◽  
S.I. Shkarubo ◽  
◽  
...  
Keyword(s):  
Arctic Basin ◽  
Data Interpretation ◽  
Magnetic Anomalies ◽  
The Arctic ◽  
The North ◽  
Franz Josef Land ◽  
Seismic Reflection Method ◽  
Anna Trough ◽  
Seismic Sections ◽  
Severnaya Zemlya

Based on the interpretation of seismic sections via seismic reflection method, the lines of which intersect the positive magnetic anomalies in the St. Anna Trough and on the North Kara Shelf, the authors have substantiated the position of the Early Cretaceous dike belt in the north of the Barents-Kara platform for the first time. They traced the belt from the arch-block elevation of arch. Franz Josef Land, which belongs to the Svalbard platе through the Saint Anna Trough and further into the Kara platе to arch. Severnaya Zemlya. The distinguished dyke belt has discordant relationships with the structural-tectonic plan of the region under consideration. The authors illustrate the manifestations of dyke magmatism in the marked tectonic elements in seismic sections, and conclude that the dyke belt relates to the formation of the structural system of the Arctic basin.

The SEAM Barrett model: strengths and weaknesses

Geophysics ◽  
2021 ◽  
pp. 1-31
Author(s):  
Heloise Lynn ◽  
Colin M. Sayers ◽  
Benjamin Roure
Keyword(s):  
Seismic Data ◽  
Fractured Reservoirs ◽  
Unconventional Reservoirs ◽  
Velocity Variation ◽  
Permian Basin ◽  
Amplitude Variation ◽  
Near Surface ◽  
Reflection Seismic ◽  
The North ◽  
Shale Reservoirs

The SEAM Barrett model was designed to model typical land basins found in the North American mid-continent that host unconventional reservoirs, such as fractured shale reservoirs. This model was used recently in several studies to assess whether shale bodies could be resolved using azimuthal 3D P-P reflection seismic data. In one study it was claimed that near-surface complexity prevents the identification of the shale bodies using azimuthal analysis and concluded that VVAz (Velocity Variation with Azimuth) and AVAz (Amplitude Variation with Azimuth) are not worth running in the Permian basin. However, another study by different authors applied a different seismic processing sequence to successfully resolve the reservoir geobodies and showed promising AVAz and VVAz results. This paper focuses on the SEAM Barrett model itself. Despite some advantages, the limitations of the Barrett model prevent conclusions to be drawn about the usefulness of VVAz and AVAz to characterize fractured reservoirs in other situations, such as the Permian Basin.

Seismic images of the Grenville Orogen in Ontario

1994 ◽  
Vol 31 (2) ◽  
pp. 293-307 ◽  
Author(s):  
D. J. White ◽  
R. M. Easton ◽  
N. G. Culshaw ◽  
B. Milkereit ◽  
D. A. Forsyth ◽  
...  
Keyword(s):  
Shear Zone ◽  
Seismic Data ◽  
Lower Crust ◽  
Wide Band ◽  
The South ◽  
Tectonic Zone ◽  
Seismic Reflection Data ◽  
Near Surface ◽  
Crustal Shortening ◽  
The North

In 1990, Lithoprobe acquired 240 km of seismic-reflection data across parts of the Central Gneiss Belt (CGB) and the Central Metasedimentary Belt (CMB) within the western Grenville Province of southern Ontario. Interpretation of these data in conjunction with geological constraints provided by bedrock mapping supports a model of northwest-directed thrusting and crustal shortening for the Grenville Orogen. Within the CGB, the Parry Sound shear zone is imaged as a 3 km wide zone of reflections dipping southeastward at 20–25° and soling at depths < 7 km in the north and < 3 km in the south beneath Parry Sound domain. Parry Sound domain and the immediately adjacent domains are underlain by a gently southeast-dipping reflective zone at 4.5–12.0 km depth interpreted as a detachment surface, likely associated with the central Britt shear zone. This zone may have accommodated northwesterly transport of Parry Sound, southern Britt, and northwestern Rosseau domains over Britt domain during Grenvillian thrusting.Within the CMB, the seismic data indicate that crustal shortening and imbrication have not been confined to domain and terrane boundaries, as presently defined. A 6 km wide band of reflections dips south at ~20° from the surface within Bancroft terrane, soling into a mid-crustal décollement beneath Elzevir terrane. Beneath and to the north of this planar reflective zone is a complex pattern of strong, south-dipping (10–40°) reflections that extends from the near surface to the lower crust above a less reflective wedge-shaped zone. The zone of complex reflectivity projects updip to the CMB boundary zone and into the CGB; together with the linear band of reflections affiliated with Bancroft terrane, they form the tectonized boundary between the CGB and the CMB. To the south of the linear reflective zone, prominent reflective packages are restricted to the middle and upper crust. The generally nonreflective uppermost crust beneath Elzevir terrane is underlain by a series of gently southeast-dipping, antiformal reflections that appear to sole into the mid-crustal décollement beneath Mazinaw terrane. These observations suggest that the collision between the CMB and the CGB resulted in a sequence of relatively thin (15–20 km thick) allochthonous terranes within the CMB being transported along a regional décollement and thrust northwestward over footwall rocks of the CGB along a penetratively deformed tectonic zone, while a lower crustal wedge may have delaminated the CMB lower crust. Crustal thickness where defined by the seismic data is 42.0–43.5 km in both the CGB and the CMB.

scholarly journals Using Chaos and Ant Track Attributes to Recognize The Faulting Systems and Subtle Faults of a Jurassic - Cretaceous Sedimentary Packages in Merjan_West Kifl Oil Fields - Central Iraq

2019 ◽  
pp. 1350-1361
Author(s):  
Mohammed Sadi Fadhil ◽  
Ali M. Al-Rahim
Keyword(s):  
Gravitational Collapse ◽  
Seismic Data ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Three Dimensional ◽  
Lower Jurassic ◽  
Passive Margin ◽  
Oil Fields ◽  
Normal Faults ◽  
Seismic Sections

Study of three dimensional seismic data of Merjan area-central Iraq has shown that the Jurassic – Cretaceous succession is affected by faulting system. Seven major normal faults were identified and mapped. Synthetic traces have been calculated by using sonic and density log data of the well Me-1.Two exploration wells were drilled in the area Me-1 and Wkf-1 wells, the distance between them is 15.82 km. Discussion about the effect of this system on the sedimentary package has been presented. The tight faults that couldn’t be distinguished it on seismic sections were determined using seismic attributes. They have different strike and limited in their vertical and horizontal extension. They are system facilitates the movement or migration of the fluid across the stratigraphic column in the study area. Faulting framework can be divided into two groups: the first affects the Jurassic and lower Cretaceous rocks and the second effect the upper Cretaceous and lower Tertiary rocks. The first group is associated with the post rift thermal sag, passive margin progradation and gravitational collapse (lower Jurassic – upper Cretaceous (Turonian) 022 – 93 Ma); approximately Sargelue – NahrUmr depositional time. The second group is few and is associated with the rifting creating the Euphrates graben (Late Turonian – Maastrichtian 90 – 70 Ma) approximately Tanuma shale / Sadi – Shiranish) depositional time.

Crustal structure of the London–Brabant Massif, southern North Sea

1993 ◽  
Vol 130 (5) ◽  
pp. 569-574 ◽  
Author(s):  
Richard Rijkers ◽  
Ed Duin ◽  
Michiel Dusar ◽  
Vital Langenaeker
Keyword(s):  
North Sea ◽  
The West ◽  
Seismic Line ◽  
Southern Limit ◽  
Northern Margin ◽  
Southern North Sea ◽  
The North ◽  
Seismic Sections ◽  
Fault Belt ◽  
Lower Crustal

AbstractIn 1991 a deep seismic line, MPNI-9101, was acquired in the southern North Sea. The line runs from the Mesozoic Broad Fourteens Basin in the north, across the West Netherlands Basin, onto the London–Brabant Massif in the south. The London–Brabant Massif is a WNW–ESE trending stable structure located beneath southeastern England, the southern North Sea and Belgium. The London–Brabant Massif represents the most easterly part of the Anglo-Brabant Massif. At the northern margin of the London-Brabant Massif, Devonian and Carboniferous siliciclastic and carbonate rocks onlap the massif. Farther south, shallow parts of the seismic line in the vicinity of the axial zone of the London–Brabant Massif are almost completely devoid of primary reflections. This zone is composed of strongly folded Lower Palaeozoic sedimentary units which have been mapped in the onshore part of Belgium. Numerous seismic reflection multiples from the base of the Cretaceous are observed on this part of the section. The southern limit of the zone is very abrupt and may correspond to a fault belt delimiting an area of magmatic rocks known in the onshore part of Belgium. Unusually the deeper parts of the seismic line show a strongly reflective lower crust beneath the London-Brabant, a phenomenon which has not been observed on other deep seismic sections across the massif. Two-way travel times to the base of the lower crustal reflective zone (corresponding to the Moho), increase from 10 seconds beneath the West Netherlands Basin in the north to 12 seconds beneath the London–Brabant Massif, suggesting a thickening of the crust.

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