Shifted-elliptical nonstretch moveout correction of wide-angle seismic data in the τ-p domain, using an example from the Faeroe-Shetland Basin

We developed a method of moveout correction in the [Formula: see text] domain to tackle some of the problems associated with processing wide-angle seismic reflection data, including residual moveout and normal-moveout stretching. We evaluated the concept of the shifted ellipse in the [Formula: see text] domain as an alternative to the well-known concept of the shifted hyperbola in the [Formula: see text] domain. We used this shifted-ellipse concept to address the problem of residual moveout caused by vertical heterogeneity in the subsurface. We also addressed the stretching problem associated with dynamic corrections by combining selected strips from a set of constant-moveout stacks generated using a shifted-ellipse equation. Application of this method to a wide-angle data set from the Faeroe-Shetland Basin provided an enhanced image of the subbasalt structure.

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Reducing source‐generated noise in shallow seismic data using linear and hyperbolic τ‐p transformations

Geophysics ◽

10.1190/1.1487106 ◽

2001 ◽

Vol 66 (5) ◽

pp. 1612-1621 ◽

Cited By ~ 20

Author(s):

Roman Spitzer ◽

Frank O. Nitsche ◽

Alan G. Green

Keyword(s):

Seismic Reflection ◽

Guided Waves ◽

Relative Strength ◽

Data Set ◽

Processing Scheme ◽

Seismic Reflection Data ◽

Northern Switzerland ◽

Reflection Data ◽

Shallow Seismic ◽

P Domain

High‐resolution seismic reflection data recorded at many locations on the earth are plagued by the overwhelming effects of direct, refracted, guided, and surface waves. These different components of source‐generated noise may completely mask reflections at traveltimes <∼50–100 ms. Conventional processing methods that include the time‐consuming application of mute functions may lead to the misprocessing of source‐generated noise (especially guided waves) as reflected events and/or the unintentional removal of important shallow reflections. We introduce a combined linear and hyperbolic τ‐p processing scheme that results in the effective separation of reflections from source‐generated noise. After applying linear moveout terms that adjust the direct, refracted, and guided arrivals to appear horizontal to subhorizontal, the reduced traveltime shot gathers are transformed into the linear τ‐p domain. It is then straightforward to design a single τ‐p filter that eliminates most of the source‐generated noise throughout the entire data set. Following inverse linear τ‐p transformation and removal of the linear moveout terms, the filtered shot gathers contain reflections and residual elements of the source‐generated noise. Because summing along hyperbolas favors reflections, transforming the filtered shot gathers into the hyperbolic τ‐p domain leads to significant enhancements in the S/N ratio. A simple rescaling of data values in the hyperbolic τ‐p domain, which results in the loss of true amplitude information, increases further the relative strength of the reflected signals. Finally, inverse hyperbolic transformation yields shot gathers dominated by reflections. In tests of the combined τ‐p processing scheme on a synthetic shot gather and on a complete shallow seismic reflection data set recorded in northern Switzerland, significant improvements in the quality of reflections in the prestacked data and on a fully processed section are readily apparent. According to the results of these tests, the new scheme works well for reflections originating from flat and dipping horizons.

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

Journal of Geophysical Research Solid Earth ◽

10.1029/2018jb015795 ◽

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

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Shallow seismic reflection study of a glaciated valley

Geophysics ◽

10.1190/1.1444441 ◽

1998 ◽

Vol 63 (4) ◽

pp. 1395-1407 ◽

Cited By ~ 49

Author(s):

Frank Büker ◽

Alan G. Green ◽

Heinrich Horstmeyer

Keyword(s):

Seismic Reflection ◽

High Amplitude ◽

Data Sets ◽

Seismic Section ◽

Data Set ◽

Seismic Reflection Data ◽

Northern Switzerland ◽

Reflection Data ◽

Shallow Seismic ◽

Glaciated Valley

Shallow seismic reflection data were recorded along two long (>1.6 km) intersecting profiles in the glaciated Suhre Valley of northern Switzerland. Appropriate choice of source and receiver parameters resulted in a high‐fold (36–48) data set with common midpoints every 1.25 m. As for many shallow seismic reflection data sets, upper portions of the shot gathers were contaminated with high‐amplitude, source‐generated noise (e.g., direct, refracted, guided, surface, and airwaves). Spectral balancing was effective in significantly increasing the strength of the reflected signals relative to the source‐generated noise, and application of carefully selected top mutes ensured guided phases were not misprocessed and misinterpreted as reflections. Resultant processed sections were characterized by distributions of distinct seismic reflection patterns or facies that were bounded by quasi‐continuous reflection zones. The uppermost reflection zone at 20 to 50 ms (∼15 to ∼40 m depth) originated from a boundary between glaciolacustrine clays/silts and underlying glacial sands/gravels (till) deposits. Of particular importance was the discovery that the deepest part of the valley floor appeared on the seismic section at traveltimes >180 ms (∼200 m), approximately twice as deep as expected. Constrained by information from boreholes adjacent to the profiles, the various seismic units were interpreted in terms of unconsolidated glacial, glaciofluvial, and glaciolacustrine sediments deposited during two principal phases of glaciation (Riss at >100 000 and Würm at ∼18 000 years before present).

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Late Cretaceous – Cenozoic history of the transition zone between the East European Craton and the Paleozoic Platform, Polish sector of the Baltic Sea, revealed by new offshore regional seismic reflection data (BALTEC project)

10.5194/egusphere-egu21-13383 ◽

2021 ◽

Author(s):

Piotr Krzywiec ◽

Łukasz Słonka ◽

Quang Nguyen ◽

Michał Malinowski ◽

Mateusz Kufrasa ◽

...

Keyword(s):

High Resolution ◽

Late Cretaceous ◽

Seismic Data ◽

Seismic Reflection ◽

Upper Cretaceous ◽

Seismic Reflection Data ◽

East European ◽

Reflection Data ◽

Multichannel Seismic Reflection ◽

Multichannel Seismic Reflection Data

<p>In 2016, approximately 850 km of high-resolution multichannel seismic reflection data of the BALTEC survey have been acquired offshore Poland within the transition zone between the East European Craton and the Paleozoic Platform. Data processing, focused on removal of multiples, strongly overprinting geological information at shallower intervals, included SRME, TAU-P domain deconvolution, high resolution parabolic Radon demultiple and SWDM (Shallow Water De-Multiple). Entire dataset was Kirchhoff pre-stack time migrated. Additionally, legacy shallow high-resolution multichannel seismic reflection data acquired in this zone in 1997 was also used. All this data provided new information on various aspects of the Phanerozoic evolution of this area, including Late Cretaceous to Cenozoic tectonics and sedimentation. This phase of geological evolution could be until now hardly resolved by analysis of industry seismic data as, due to limited shallow seismic imaging and very strong overprint of multiples, essentially no information could have been retrieved from this data for first 200-300 m. Western part of the BALTEC dataset is located above the offshore segment of the Mid-Polish Swell (MPS) &#8211; large anticlinorium formed due to inversion of the axial part of the Polish Basin. BALTEC seismic data proved that Late Cretaceous inversion of the Koszalin &#8211; Chojnice fault zone located along the NE border of the MPS was thick-skinned in nature and was associated with substantial syn-inversion sedimentation. Subtle thickness variations and progressive unconformities imaged by BALTEC seismic data within the Upper Cretaceous succession in vicinity of the Kamie&#324;-Adler and the Trzebiat&#243;w fault zones located within the MPS documented complex interplay of Late Cretaceous basin inversion, erosion and re-deposition. Precambrian basement of the Eastern, cratonic part of the study area is overlain by Cambro-Silurian sedimentary cover. It is dissected by a system of steep, mostly reverse faults rooted in most cases in the deep basement. This fault system has been regarded so far as having been formed mostly in Paleozoic times, due to the Caledonian orogeny. As a consequence, Upper Cretaceous succession, locally present in this area, has been vaguely defined as a post-tectonic cover, locally onlapping uplifted Paleozoic blocks. New seismic data, because of its reliable imaging of the shallowest substratum, confirmed that at least some of these deeply-rooted faults were active as a reverse faults in latest Cretaceous &#8211; earliest Paleogene. Consequently, it can be unequivocally proved that large offshore blocks of Silurian and older rocks presently located directly beneath the Cenozoic veneer must have been at least partly covered by the Upper Cretaceous succession; then, they were uplifted during the widespread inversion that affected most of Europe. Ensuing regional erosion might have at least partly provided sediments that formed Upper Cretaceous progradational wedges recently imaged within the onshore Baltic Basin by high-end PolandSPAN regional seismic data. New seismic data imaged also Paleogene and younger post-inversion cover. All these results prove that Late Cretaceous tectonics substantially affected large areas located much farther towards the East than previously assumed.</p><p>This study was funded by the Polish National Science Centre (NCN) grant no UMO-2017/27/B/ST10/02316.</p>

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Migration with reduced artifacts from internal multiple reflections

Geophysics ◽

10.1190/geo2019-0780.1 ◽

2020 ◽

Vol 85 (4) ◽

pp. A25-A29

Author(s):

Lele Zhang

Keyword(s):

Seismic Reflection ◽

Computational Cost ◽

Data Sets ◽

Square Root ◽

Multiple Reflections ◽

Data Set ◽

Seismic Reflection Data ◽

Reflection Data ◽

Recent Developments ◽

Multiple Elimination

Migration of seismic reflection data leads to artifacts due to the presence of internal multiple reflections. Recent developments have shown that these artifacts can be avoided using Marchenko redatuming or Marchenko multiple elimination. These are powerful concepts, but their implementation comes at a considerable computational cost. We have derived a scheme to image the subsurface of the medium with significantly reduced computational cost and artifacts. This scheme is based on the projected Marchenko equations. The measured reflection response is required as input, and a data set with primary reflections and nonphysical primary reflections is created. Original and retrieved data sets are migrated, and the migration images are multiplied with each other, after which the square root is taken to give the artifact-reduced image. We showed the underlying theory and introduced the effectiveness of this scheme with a 2D numerical example.

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Monte Carlo reservoir analysis combining seismic reflection data and informed priors

Geophysics ◽

10.1190/geo2014-0052.1 ◽

2015 ◽

Vol 80 (1) ◽

pp. R31-R41 ◽

Cited By ~ 24

Author(s):

Andrea Zunino ◽

Klaus Mosegaard ◽

Katrine Lange ◽

Yulia Melnikova ◽

Thomas Mejer Hansen

Keyword(s):

Monte Carlo ◽

Seismic Data ◽

Seismic Reflection ◽

Probabilistic Approach ◽

Multiple Point ◽

Petroleum Reservoir ◽

Inversion Algorithm ◽

Reservoir Properties ◽

Seismic Reflection Data ◽

Reflection Data

Determination of a petroleum reservoir structure and rock bulk properties relies extensively on inference from reflection seismology. However, classic deterministic methods to invert seismic data for reservoir properties suffer from some limitations, among which are the difficulty of handling complex, possibly nonlinear forward models, and the lack of robust uncertainty estimations. To overcome these limitations, we studied a methodology to invert seismic reflection data in the framework of the probabilistic approach to inverse problems, using a Markov chain Monte Carlo (McMC) algorithm with the goal to directly infer the rock facies and porosity of a target reservoir zone. We thus combined a rock-physics model with seismic data in a single inversion algorithm. For large data sets, the McMC method may become computationally impractical, so we relied on multiple-point-based a priori information to quantify geologically plausible models. We tested this methodology on a synthetic reservoir model. The solution of the inverse problem was then represented by a collection of facies and porosity reservoir models, which were samples of the posterior distribution. The final product included probability maps of the reservoir properties in obtained by performing statistical analysis on the collection of solutions.

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Shallow 3D seismic-reflection imaging of fracture zones in crystalline rock

Geophysics ◽

10.1190/1.2787336 ◽

2007 ◽

Vol 72 (6) ◽

pp. B149-B160 ◽

Cited By ~ 24

Author(s):

Cedric Schmelzbach ◽

Heinrich Horstmeyer ◽

Christopher Juhlin

Keyword(s):

Seismic Reflection ◽

Crystalline Rock ◽

Three Dimensions ◽

Disposal Site ◽

3D Seismic ◽

Fracture Zones ◽

Data Set ◽

Seismic Reflection Data ◽

Reflection Data ◽

Receiver Array

A limited 3D seismic-reflection data set was used to map fracture zones in crystalline rock for a nuclear waste disposal site study. Seismic-reflection data simultaneously recorded along two roughly perpendicular profiles (1850 and [Formula: see text] long) and with a [Formula: see text] receiver array centered at the intersection of the lines sampled a [Formula: see text] area in three dimensions. High levels of source-generated noise required a processing sequence involving surface-consistent deconvolution, which effectively increased the strength of reflected signals, and a linear [Formula: see text] filtering scheme to suppress any remaining direct [Formula: see text]-wave energy. A flexible-binning scheme significantly balanced and increased the CMP fold, but the offset and azimuth distributions remain irregular; a wide azimuth range and offsets [Formula: see text] are concentrated in the center of the survey area although long offsets [Formula: see text] are only found at the edges of the site. Three-dimensional dip moveout and 3D poststack migration were necessary to image events with conflicting dips up to about 40°. Despite the irregular acquisition geometry and the high level of source-generated noise, we obtained images rich in structural detail. Seven continuous to semicontinuous reflection events were traced through the final data volume to a maximum depth of around [Formula: see text]. Previous 2D seismic-reflection studies and borehole data indicate that fracture zones are the most likely cause of the reflections.

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Minimizing field operations in shallow 3‐D seismic reflection surveying

Geophysics ◽

10.1190/1.1487118 ◽

2001 ◽

Vol 66 (6) ◽

pp. 1761-1773 ◽

Cited By ~ 11

Author(s):

Roman Spitzer ◽

Alan G. Green ◽

Frank O. Nitsche

Keyword(s):

Seismic Reflection ◽

Cost Effective ◽

Unconsolidated Sediments ◽

Data Set ◽

Seismic Reflection Data ◽

Northern Switzerland ◽

Shallow Subsurface ◽

Reflection Data ◽

Effective Manner ◽

Original Survey

By appropriately decimating a comprehensive shallow 3‐D seismic reflection data set recorded across unconsolidated sediments in northern Switzerland, we have investigated the potential and limitations of four different source‐receiver acquisition patterns. For the original survey, more than 12 000 shots and 18 000 receivers deployed on a [Formula: see text] grid resulted in common midpoint (CMP) data with an average fold of ∼40 across a [Formula: see text] area. A principal goal of our investigation was to determine an acquisition strategy capable of producing reliable subsurface images in a more efficient and cost‐effective manner. Field efforts for the four tested acquisition strategies were approximately 50%, 50%, 25%, and 20% of the original effort. All four data subsets were subjected to a common processing sequence. Static corrections, top‐mute functions, and stacking velocities were estimated individually for each subset. Because shallow reflections were difficult to discern on shot and CMP gathers generated with the lowest density acquisition pattern (20% field effort) such that dependable top‐mute functions could not be estimated, data resulting from this acquisition pattern were not processed to completion. Of the three fully processed data subsets, two (50% field effort and 25% field effort) yielded 3‐D migrated images comparable to that derived from the entire data set, whereas the third (50% field effort) resulted in good‐quality images only in the shallow subsurface because of a lack of far‐offset data. On the basis of these results, we concluded that all geological objectives associated with our particular study site, which included mapping complex lithological units and their intervening shallow dipping boundaries, would have been achieved by conducting a 3‐D seismic reflection survey that was 75% less expensive than the original one.

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Instantaneous spectral bandwidth and dominant frequency with applications to seismic reflection data

Geophysics ◽

10.1190/1.1443425 ◽

1993 ◽

Vol 58 (3) ◽

pp. 419-428 ◽

Cited By ~ 106

Author(s):

Arthur E. Barnes

Keyword(s):

Instantaneous Frequency ◽

Seismic Data ◽

Seismic Reflection ◽

Power Spectra ◽

Dominant Frequency ◽

Center Frequency ◽

Spectral Bandwidth ◽

Instantaneous Amplitude ◽

Seismic Reflection Data ◽

Reflection Data

Fourier power spectra are often usefully characterized by average measures. In reflection seismology, the important average measures are center frequency, spectral bandwidth, and dominant frequency. These quantities have definitions familiar from probability theory: center frequency is the spectral mean, spectral bandwidth is the standard deviation about that mean, and dominant frequency is the square root of the second moment, which serves as an estimate of the zero‐crossing frequency. These measures suggest counterparts defined with instantaneous power spectra in place of Fourier power spectra, so that they are instantaneous in time though they represent averages in frequency. Intuitively reasonable requirements yield specific forms for these instantaneous quantities that can be computed with familiar complex seismic trace attributes. Instantaneous center frequency is just instantaneous frequency. Instantaneous bandwidth is the absolute value of the derivative of the instantaneous amplitude divided by the instantaneous amplitude. Instantaneous dominant frequency is the square root of the sum of the squares of the instantaneous frequency and instantaneous bandwidth. Instantaneous bandwidth and dominant frequency find employment as additional complex seismic trace attributes in the detailed study of seismic data. Instantaneous bandwidth is observed to be nearly always less than instantaneous frequency; the points where it is larger may mark the onset of distinct wavelets. These attributes, together with instantaneous frequency, are perhaps, of greater use in revealing the time‐varying spectral properties of seismic data. They can help in the search for low frequency shadows or in the analysis of frequency change due to effects of data processing. Instantaneous bandwidth and dominant frequency complement instantaneous frequency and should find wide application in the analysis of seismic reflection data.

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Structural Interpretation of Yamama and Naokelekan Formations in Tuba Oil Field Using 2D Seismic Data

Iraqi Geological Journal ◽

10.46717/igj.54.2b.5ms-2021-08-25 ◽

2021 ◽

Vol 54 (2B) ◽

pp. 55-64

Author(s):

Belal M. Odeh

Keyword(s):

Seismic Data ◽

Seismic Reflection ◽

Synthetic Seismogram ◽

Oil Field ◽

Well Log ◽

Seismic Reflection Data ◽

Depth Maps ◽

Reflection Data ◽

Interpretation Process ◽

Southern Iraq

This research includes structure interpretation of the Yamama Formation (Lower Cretaceous) and the Naokelekan Formation (Jurassic) using 2D seismic reflection data of the Tuba oil field region, Basrah, southern Iraq. The two reflectors (Yamama and Naokelekan) were defined and picked as peak and tough depending on the 2D seismic reflection interpretation process, based on the synthetic seismogram and well log data. In order to obtain structural settings, these horizons were followed over all the regions. Two-way travel-time maps, depth maps, and velocity maps have been produced for top Yamama and top Naokelekan formations. The study concluded that certain longitudinal enclosures reflect anticlines in the east and west of the study area representing Zubair and Rumaila fold confined between them a fold consist of two domes represents Tuba fold with the same trending of Zubair and Rumaila structures. The study confirmed the importance of this field as a reservoir of the accumulation of hydrocarbons.

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