Bulletin Article
In this study, seismic models and a Starfak and Tiger Shoal fields data set in the Gulf of Mexico Basin are used to investigate uncertainties caused by the frequency dependence of seismic data and solutions for avoiding pitfalls in seismic-stratigraphic and facies interpretation. Seismic amplitude and instantaneous attributes, along with stratigraphic interpretation of these attributes, are controlled by seismic interference, or tuning, between thin geologic units. Seismic-tuning effects include thickness tuning and frequency tuning, which cause nonlinear variations of reflection amplitude and instantaneous seismic attributes with thickness and/or data frequency. Seismic modeling shows that, whereas thickness tuning determines seismic-interference patterns and, therefore, occurrence of seismic events and seismic facies in layered rock, frequency tuning may further influence the nature of the correlation of seismic data and geologic time and modify seismic facies. Frequency dependence offers a new dimension of seismic data, which has not been fully used in seismic interpretation of geology.
Field-data examples demonstrate that a stratigraphic formation is typically composed of lithofacies of varying thicknesses, and a broadband, stacked seismic data set is not necessarily optimal for stratigraphic and facies interpretation. Although it is difficult to predict correct frequency components for interpretation of not-yet-known geologic targets, local geologic models and well data can be used to optimize the frequency components of seismic data to a certain degree and intentionally modify seismic-interference patterns and seismic facies for better seismic interpretation of geologic surfaces, sediment-dispersal patterns, geomorphology, and sequence stratigraphy.
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American Association of Petroleum Geologists (AAPG)
Added on 31 January, 2013
Explorer Geophysical Corner
By Satinder Chopra,Supratik Sarkar
While seismic processing shops usually are the “professionals” when it comes to velocity analysis, the interpreter may have greater insight into the cause of the poor data quality.
American Association of Petroleum Geologists (AAPG)
Added on 01 January, 2013
Bulletin Article
We reviewed the tectonostratigraphic evolution of the Jurassic–Cenozoic collision between the North American and the Caribbean plate using more than 30,000 km (18,641 mi) of regional two-dimensional (2-D) academic seismic lines and Deep Sea Drilling Project wells of Leg 77. The main objective is to perform one-dimensional subsidence analysis and 2-D flexural modeling to better understand how the Caribbean collision may have controlled the stratigraphic evolution of the offshore Cuba region.
Five main tectonic phases previously proposed were recognized: (1) Late Triassic–Jurassic rifting between South and North America that led to the formation of the proto-Caribbean plate; this event is interpreted as half grabens controlled by fault family 1 as the east-northeast–south-southwest–striking faults; (2) Middle–Late Jurassic anticlockwise rotation of the Yucatan block and formation of the Gulf of Mexico; this event resulted in north-northwest–south-southeast–striking faults of fault family 2 controlling half-graben structures; (3) Early Cretaceous passive margin development characterized by carbonate sedimentation; sedimentation was controlled by normal subsidence and eustatic changes, and because of high eustatic seas during the Late Cretaceous, the carbonate platform drowned; (4) Late Cretaceous–Paleogene collision between the Caribbean plate, resulting in the Cuban fold and thrust belt province, the foreland basin province, and the platform margin province; the platform margin province represents the submerged paleoforebulge, which was formed as a flexural response to the tectonic load of the Great Arc of the Caribbean during initial Late Cretaceous–Paleocene collision and foreland basin development that was subsequently submerged during the Eocene to the present water depths as the arc tectonic load reached the maximum collision; and (5) Late Cenozoic large deep-sea erosional features and constructional sediment drifts related to the formation of the Oligocene–Holocene Loop Current–Gulf Stream that flows from the northern Caribbean into the Straits of Florida and to the north Atlantic.
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American Association of Petroleum Geologists (AAPG)
Added on 31 December, 2012
Explorer Historical Highlights
By Phil Richards
Some bold and creative geologists, full of the entrepreneur spirit, helped turn the Falkland Islands into a success story.
American Association of Petroleum Geologists (AAPG)
Added on 01 December, 2012
Explorer Geophysical Corner
By Ritesh Sharma,Satinder Chopra
This month’s column deals with quantifying facies variation.
American Association of Petroleum Geologists (AAPG)
Added on 01 December, 2012
Explorer Emphasis Article
By Louise Durham
It’s all about staying on target: Technological advances are helping to make geosteering an increasingly valuable tool for geologists involved in horizontal wells.
American Association of Petroleum Geologists (AAPG)
Added on 01 December, 2012
Explorer Emphasis Article
By David Brown
A new well in Oklahoma may be the most historic and geologically interesting project in the entire country – and for a bonus, it may involve a new helium province.
American Association of Petroleum Geologists (AAPG)
Added on 01 December, 2012
Explorer Geophysical Corner
By Satinder Chopra
This month’s column deals with seismic waveforms and facies classification.
American Association of Petroleum Geologists (AAPG)
Added on 01 November, 2012
Explorer Emphasis Article
By Ken Milam
Crews face a number of challenges in acquiring 3-D seismic in the Arctic. Fortunately, there are a number of solutions, too.
American Association of Petroleum Geologists (AAPG)
Added on 01 November, 2012
Explorer Emphasis Article
By Ken Milam
The North Sea is one place where new approaches to older challenges are constantly sought. The new technique called “frequency blend” applies color to help visualize frequency bands and is working well in the Barents Sea.
American Association of Petroleum Geologists (AAPG)
Added on 01 November, 2012