Home

Seismic

WoodMac: Oil Prices Could Surprise to the Upside with China’s Reopening - 23 March, 2023 07:30 AM

What Soft Skills Should Oil and Gas Workers Possess? - 23 March, 2023 07:30 AM

Discoveries by Equinor and Eni Lead Oil and Gas Stock Roundup - 23 March, 2023 07:30 AM

Atlas Petroleum, Partners Advance Venus Oil Discovery Offshore Equatorial Guinea - 23 March, 2023 07:30 AM

PetroChina Fires Up First Onshore Wind Project to Decarbonize Hydrocarbon Production - 23 March, 2023 07:30 AM

News in Review ...

06 Apr

Low Resistivity Reservoirs: Path to Explore, Discover and Develop Call for Abstracts Expires in 14 days

litutmMedium

View All Deadlines ...

Explorer Geophysical Corner By Rongfeng Zhang,Satinder Chopra

Effective Ways to Eliminate Side-Lobe Effects

It is no secret that geologists do not fully trust all the events shown in pretty seismic pictures.

Added on 01 February, 2014

Bulletin Article

Sequence stratigraphy of the Eocene turbidite reservoirs in Albacora field, Campos Basin, offshore Brazil

This article describes a 250-m (820-ft)-thick upper Eocene deep-water clastic succession. This succession is divided into two reservoir zones: the lower sandstone zone (LSZ) and the upper sandstone zone, separated by a package of pelitic rocks with variable thickness on the order of tens of meters. The application of sequence-stratigraphic methodology allowed the subdivision of this stratigraphic section into third-order systems tracts. The LSZ is characterized by blocky and fining-upward beds on well logs, and includes interbedded shale layers of as much as 10 m (33 ft) thick. This zone reaches a maximum thickness of 150 m (492 ft) and fills a trough at least 4 km (2 mi) wide, underlain by an erosional surface. The lower part of this zone consists of coarse- to medium-grained sandstones with good vertical pressure communication. We interpret this unit as vertically and laterally amalgamated channel-fill deposits of high-density turbidity flows accumulated during late forced regression. The sandstones in the upper part of this trough are dominantly medium to fine grained and display an overall fining-upward trend. We interpret them as laterally amalgamated channel-fill deposits of lower density turbidity flows, relative to the ones in the lower part of the LSZ, accumulated during lowstand to early transgression. The pelitic rocks that separate the two sandstone zones display variable thickness, from 35 to more than 100 m (115–>328 ft), indistinct seismic facies, and no internal markers on well logs, and consist of muddy diamictites with contorted shale rip-up clasts. This section is interpreted as cohesive debris flows and/or mass-transported slumps accumulated during late transgression. The upper sandstone zone displays a weakly defined blocky well-log signature, where the proportion of sand is higher than 80%, and a jagged well-log signature, where the sand proportion is lower than 60%. The high proportions of sand are associated with a channelized geometry that is well delineated on seismic amplitude maps. Several depositional elements are identified within this zone, including leveed channels, crevasse channels, and splays associated with turbidity flows. This package is interpreted as the product of increased terrigenous sediment supply during highstand normal regression.

Added on 31 January, 2014

Bulletin Article

Fault displacement-distance relationships as indicators of contractional fault-related folding style

We present a method of using fault displacement-distance profiles to distinguish fault-bend, shear fault-bend, and fault-propagation folds, and use these insights to guide balanced and retrodeformable interpretations of these structures. We first describe the displacement profiles associated with different end-member fault-related folding models, then provide examples of structures that are consistent with these model-based predictions. Natural examples are imaged in high-resolution two- and three dimensional seismic reflection data sets from the Niger Delta, Sichuan Basin, Sierras Pampeanas, and Cascadia to record variations in displacement with distance updip along faults (termed displacement-distance profiles). Fault-bend folds exhibit constant displacement along fault segments and changes in displacement associated with bends in faults, shear fault-bend folds demonstrate an increase in displacement through the shearing interval, and fault-propagation folds exhibit decreasing displacement toward the fault tip. More complex structures are then investigated using this method, demonstrating that displacement-distance profiles can be used to provide insight into structures that involve multiple fault-related folding processes or have changed kinematic behavior over time. These interpretations are supported by comparison with the kinematics inferred from the geometry of growth strata overlying these structures. Collectively, these analyses illustrate that the displacement-distance approach can provide valuable insights into the styles of fault-related folding.

Added on 31 January, 2014

Explorer Geophysical Corner By Rongfeng Zhang

Finding the Value in Spectral Decomposition

When we see a rainbow, it is visually appealing – and the natural tendency is to appreciate its aesthetic qualities rather than study it on an analytical basis, as frequency sub-bands decomposed from white light.

Added on 01 January, 2014

Explorer Emphasis Article By Louise Durham

3-D Symposium Hits Its 20-Year Milestone

The RMAG/DGS 3-D Seismic Symposium on Feb. 14 will be the 20th anniversary of the annual forum and will feature 3-D seismic sage Alistair Brown as keynote speaker.

Added on 01 January, 2014

Explorer Emphasis Article By Louise Durham

3-D Seismic Drives Geosteering Advances

New geosteering tools are helping to drive eye-raising crude oil production levels in the Bakken shale play.

Added on 01 January, 2014

Bulletin Article

Acoustic nonlinear full-waveform inversion on an outcrop-based detailed geological and petrophysical model (Book Cliffs, Utah)

Analog outcrops are commonly used to develop predictive reservoir models and provide quantitative parameters that describe the architecture and facies distribution of sedimentary deposits at a subseismic scale, all of which aids exploration and production strategies. The focus of this study is to create a detailed geological model that contains realistic reservoir parameters and to apply nonlinear acoustic full-waveform prestack seismic inversion to this model to investigate whether this information can be recovered and to examine which geological features can be resolved by this process. Outcrop data from the fluviodeltaic sequence of the Book Cliffs (Utah) are used for the geological and petrophysical two-dimensional model. Eight depositional environments are populated with average petrophysical reservoir properties adopted from a North Sea field. These units are termed lithotypes here. Synthetic acoustic prestack seismic data are then generated with the help of an algorithm that includes all internal multiples and transmission effects. A nonlinear acoustic full-waveform inversion is then applied to the synthetic data, and two media parameters, compressibility (inversely related to the square of the compressional wave velocity vP) and bulk density, ρ, are recovered at a resolution higher than the shortest wavelength in the data. This is possible because the inversion exploits the nonlinear nature of the relationship between the recorded data and the medium contrast properties. In conventional linear inversion, these details remain masked by the noise caused by the nonlinear effects in the data. Random noise added to the data is rejected by the nonlinear inversion, contributing to improved spatial resolution. The results show that the eight lithotypes can be successfully recovered at a subseismic scale and with a low degree of processing artifacts. This technique can provide a useful basis for more accurate reservoir modeling and field development planning, allowing targeting of smaller reservoir units such as distributary channels and lower shoreface sands.

Added on 31 December, 2013

Bulletin Article

Quantifying Cretaceous–Cenozoic exhumation in the Otway Basin, southeastern Australia, using sonic transit time data: Implications for conventional and unconventional hydrocarbon prospectivity

In prospective basins affected by exhumation, uncertainty commonly exists regarding the maximum burial depths of source, reservoir, and seal horizons. One such basin is the Otway Basin, an important gas province in southeastern Australia, which has witnessed several exhumation events. Here, we present estimates of net exhumation magnitudes for 110 onshore and offshore petroleum wells based on the sonic transit time analyses of Lower Cretaceous fluvial shales. Our results show significant post-Albian net exhumation in the eastern onshore Otway Basin (1500 m [4920 ft]) and a generally minor net exhumation (200 m [655 ft]) elsewhere in the Otway Basin, consistent with estimates based on thermal history data. The distribution of net exhumation magnitudes in relation to mid-Cretaceous and Neogene compressional structures indicates that exhumation was dominantly controlled by short-wavelength basin inversion driven by plate-boundary forces. Deeper burial coupled with high geothermal gradients in the onshore eastern Otway Basin and along the northern basin margin during the early Cretaceous have rendered Lower Cretaceous source rocks mostly overmature, with any remaining hydrocarbons from the initial charge likely to be trapped in tightly compacted reservoirs and/or secondary (fracture-related) porosity. However, the embrittlement of these reservoirs during their deeper burial may present opportunities for the development of low-permeability plays through hydraulic fracturing where smectite clay minerals are illitized. Source rocks at near-maximum burial at present day are at temperatures suitable for gas generation, with key controls on prospectivity in these areas including the sealing potential of faulted traps and the relationship between charge and trap development.

Added on 31 December, 2013

Explorer Geophysical Corner By Kurt Marfurt,Satinder Chopra

Spectral Decomposition's Analytical Value

Stratigraphers use seismic data in two major ways.

Added on 01 December, 2013

Explorer Emphasis Article By David Brown

Seismic While Drilling Moves Closer to Reality

The ability to see ahead of the drillbit while drilling, in real time, helps the driller avoid hazards, increase drilling efficiency and improve well results. Successful SWD captures seismic data without interrupting drilling operations, saving money and reducing risk.

Added on 01 December, 2013

VG Abstract By Juan I. Soto

Salt versus Shales in Continental Margins and Orogens

In comparison with the known boundary conditions that promote salt deformation and flow in sedimentary basins, the processes involved with the mobilization of clay-rich detrital sediments are far less well established. This talk will use seismic examples in different tectonic settings to document the variety of shale geometries that can be formed under brittle and ductile deformations.

Request a visit from Juan I. Soto!

Added on 26 June, 2019

DL Abstract By Frank Peel

A Lost World Rediscovered: 3D Seismic Data Reveal Spectacular Images of a Jurassic Landscape on the Eve of Louann Salt Deposition in the Gulf of Mexico, with Implications for Salt Deposition

Around 170 million years ago, the Gulf of Mexico basin flooded catastrophically, and the pre-existing landscape, which had been a very rugged, arid, semi-desert world, was drowned beneath an inland sea of salt water. The drowned landscape was then buried under kilometers of salt, perfectly preserving the older topography. Now, with high-quality 3D seismic data, the salt appears as a transparent layer, and the details of the drowned world can be seen in exquisite detail, providing a unique snapshot of the world on the eve of the flooding event. We can map out hills and valleys, and a system of river gullies and a large, meandering river system. These rivers in turn fed into a deep central lake, whose surface was about 750m below global sea level. This new knowledge also reveals how the Louann Salt was deposited. In contrast to published models, the salt was deposited in a deep water, hypersaline sea. We can estimate the rate of deposition, and it was very fast; we believe that the entire thickness of several kilometers of salt was laid down in a few tens of thousands of years, making it possibly the fastest sustained deposition seen so far in the geological record.

Request a visit from Frank Peel!

Added on 16 November, 2022

DL Abstract By Jacob Covault

Submarine-Channel Evolution From Seismic Stratigraphy & Numerical Models: Patterns and Predictions Revisited

Three-dimensional (3D) seismic-reflection surveys provide one of the most important data types for understanding subsurface depositional systems. Quantitative analysis is commonly restricted to geophysical interpretation of elastic properties of rocks in the subsurface. Wide availability of 3D seismic-reflection data and integration provide opportunities for quantitative analysis of subsurface stratigraphic sequences. Here, we integrate traditional seismic-stratigraphic interpretation with quantitative geomorphologic analysis and numerical modeling to explore new insights into submarine-channel evolution.

Request a visit from Jacob Covault!

Added on 20 July, 2022

Seismic

Related Interests

See Also ...

STAY CONNECTED: