Explorer Geophysical Corner

Coherence and curvature are iconic attributes now commonly available on most interpretation workstations that help characterize small- and large-scale faults, large fractures, pinch-outs, buried channels, reef edges and unconformities. The quality of both these attributes, among other factors, relies on accurate estimates of volumetric dip. Coherence, amplitude gradients and GLCM texture attributes should be computed along structural dip, while curvature is computed from volumetric estimates of structural dip. Due to differences in both resolution and sensitivity to coherent noise, different frequency components might exhibit different dip. Such awareness has led to the development of multispectral coherence that makes use of summation of covariance matrices of individual spectral components, rather than just the covariance matrix computed from broadband seismic data.

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American Association of Petroleum Geologists (AAPG)
Explorer Article

Some 257 people gathered at the beautiful new Hilton Hotel in Port Moresby, Papua New Guinea in the last week of February 2020 to attend the first AAPG/EAGE Papua New Guinea Petroleum Geoscience Conference and Exhibition. The theme for the conference was, “PNG’s Oil and Gas Industry Maturing Through Exploration Development and Production.”

American Association of Petroleum Geologists (AAPG)
Explorer Geophysical Corner

The interactive visualization of seismic attributes makes an effective use of color. Any color can be represented in RGB color space, which forms the working model for computer and television monitors. Normally, humans do not think of any color as a mixture of these three colors, but often refer to colors being more- or less-saturated, having different tones, or even one color being brighter than the other. Thus, besides the 3-D RGB color space, other more intuitive 3-D color models such as HSV and HSL have also been developed, with the application of the latter model for co-visualizing two or three different seismic attributes.

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American Association of Petroleum Geologists (AAPG)
Explorer Geophysical Corner

Shale resource plays are associated with low permeability, so hydraulic fracturing is required for their stimulation and production. In order to enhance the flow of fluids with hydraulic fracturing, it is vital to understand the stress field distribution. The efficiency and effectiveness of a hydraulic fracture stimulation are predicated on adequate horizontal well placement in the subsurface. For that purpose, the horizontal wells are usually drilled in the direction of minimal horizontal stress so that hydraulic fracturing takes place in the direction of maximal stress that ensures better reservoir contact and production, which also depends on how a complex fracture network is created by induced fractures.

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American Association of Petroleum Geologists (AAPG)
Explorer Geophysical Corner

The bandwidth of a signal is a measure of the breadth of its spectrum, often expressed as the distance measured in Hertz between the half-power points of a smooth spectrum. Bandwidth is the best measure of resolution. Although first introduced to the seismic community in the 1970s, only a limited number of published papers show the value of this attribute. In this column, we show the value of bandwidth when applied to data from the Utica area of Eastern Ohio, United States and from the Gulf of Mexico.

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American Association of Petroleum Geologists (AAPG)
Explorer Foundation Update

A new named grant honoring the memory of an AAPG Honorary member – a pioneer and giant in the world of geological-geophysical integration – has been established by the AAPG Foundation. The R. Randy Ray Memorial Named Grant, intended to support students in petroleum geology, honors a geologist who was hailed during his career as being “a tireless volunteer,” praised for his efforts to advance integrated geoscience knowledge and training, and honored for having a “vision energized by optimism and enthusiasm.”

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American Association of Petroleum Geologists (AAPG)
Explorer Geophysical Corner

With the advent of 3-D seismic technology and its remarkable spatial resolving power, mass transport deposits are better defined in terms of their full areal extent and their morphologic features in areas affected by slope failure. Though mass movements have been extensively studied within the Permian Basin, little work has been published on the nature of these MTDs and their related geomorphological expression on seismic. The goal of this study is to understand sediment flow and delineate the anatomy of the MTD that was deposited 275 million years ago in the Midland Basin. This feature was deposited in the Upper Leonard interval which overlies the Upper Spraberry formation.

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American Association of Petroleum Geologists (AAPG)
Explorer Geophysical Corner

Seismic attributes help enhance the subtle subsurface geologic detail that might be difficult and time consuming to decipher from 3-D seismic amplitude data. Beginning with the simple computation of envelope, phase and frequency attributes in the 1970s, several dozen seismic attributes are generated these days containing disparate types of information. To bring together all this information and produce an accurate subsurface model, the multiple attributes need to be carefully visualized and displayed, and thus has become an important interpretation tool for seismic interpreters.

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American Association of Petroleum Geologists (AAPG)
Learn! Blog

Geologists are using many new technologies to combine surface, subsurface, and geochemical and thereby improve subsurface modeling, potentially leading to new understanding and dramatic new discoveries. Welcome to an interview with Jon Blickwede, who is currently combining in-depth field and subsurface knowledge with new 3D digital surface mapping. Jon also serves on the technical committee for AAPG’s Hedberg Research Conference on the Geology and Hydrocarbon Potential of the Circum Gulf of Mexico Pre-Salt Section, 4 – 6 of February in Mexico City.

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American Association of Petroleum Geologists (AAPG)
Explorer Article

Five internationally acclaimed geoscientists have been named for this season’s AAPG Distinguished Lecture program, the Association’s flagship offering of cutting-edge geoscience excellence that once again will be accessible to everyone, everywhere, at any time.

American Association of Petroleum Geologists (AAPG)
VG Abstract

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!

American Association of Petroleum Geologists (AAPG)
DL Abstract

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.

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Request a visit from Jacob Covault!

American Association of Petroleum Geologists (AAPG)
DL Abstract

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.

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Request a visit from Frank Peel!

American Association of Petroleum Geologists (AAPG)

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