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- Volume 28, Issue 9, 2010
First Break - Volume 28, Issue 9, 2010
Volume 28, Issue 9, 2010
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News Feature: Why untenable US natural gas boom may soon need wellhead price-floor regulation for industry survival
More LessIn one of his occasional contributions on oil and gas strategy challenges, Ruud Weijermars discusses concerns about the sustainability of the US natural gas business model and suggests that wellhead price-floor regulation may be the solution.
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Technical Feature: Performance assessment and applications of boom-mounted airborne magnetic and electromagnetic systems
Authors W.E. Doll, T.J. Gamey, L.P. Beard, D.T. Bell, J.R. Sheehan, J. Norton and J.S. HolladayWilliam E. Doll, T.J. Gamey, L.P. Beard, D.T. Bell, J.R. Sheehan, J. Norton and J.S. Holladay report that airborne geophysical methods for investigating the near surface, particularly for identifying unexploded ordnance (UXO), have improved dramatically in recent years and suggest many environmental and engineering applications could also benefit from the emerging technology.
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Comparison of Q estimation using data from conventional hydrophone and dual-sensor streamer acquisitions
Authors M. Deighton and A. VignerMatt Deighton and Alan Vigner, Petroleum Geo-Services, discuss the estimation of Q using different spectral ratio methodologies with data from different towed streamer technologies, and show that the increased useable bandwidth from dual-sensor streamers and careful choice of reference wavelet measurably improve the result.
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Lows and highs: using low frequencies and improved velocity tools to image complex ridges and basement highs in the Faroe-Shetland Basin
Authors A. Hardwick, T. Travis, S. Stokes and M. HartAnthony Hardwick, Tom Travis, Simon Stokes and Matthew Hart describe three seismic reprocessing strategies in the time domain for two regional long offset 2D surveys in the Faroe-Shetland Basin which combine to provide a dramatic improvement in the interpretability of the sub-basalt image in the dataset.
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Modelling azimuthal NMO in laterally heterogeneous HTI media
By E. JennerEdward Jenner, ION Geophysical, expands previous work on how lateral velocity heterogeneity in the overburden could explain apparent azimuthal NMO at a target horizon on field data. Here, modelling studies show, among other things, that lateral variations in anisotropy are well resolved and do not distort the inverted interval anisotropy in deeper target layers if the vertical velocity is laterally homogeneous.
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Adaptive attenuation of surface-wave noise
Authors D. Le Meur, N. Benjamin, L. Twigger, K. Garceran, L. Delmas and G. PoulainA new method developed to deal with the issue of surface waves is described by David Le Meur, Nigel Benjamin, Luke Twigger, Katia Garceran, Laurie Delmas and Guillaume Poulain of CGGVeritas. Although originally conceived for land seismic data in the Middle East and North Africa, the authors suggest that the method may have much wider application.
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Building geologically plausible anisotropic models using well data and horizon-guided interpolation
Authors O. Zdraveva, A. Bakulin and Liu Y.In a Gulf of Mexico case study Olga Zdraveva, Andrey Bakulin and Yangjun (Kevin) Liu show that derivation of anisotropy parameters from multiple wells and a horizon-guided approach to their interpolation can deliver more geologically plausible velocity models for imaging seismic data compared to a conventional approach that assumes a single smooth anisotropy profile hang off a shallow horizon.
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Multi-point geostatistics – an introductory overview
More LessMulti-point geostatistics is an algorithm which complements the traditional variogram driven cell-based and object modelling approaches to facies modelling. It is situated somewhere between the two, being a cell-based approach, but because it uses estimates of the multi-variate distribution instead of the simple bi-variate distributions that are available to variogramdriven algorithms, it is capable of capturing geometries that are more similar to those available with object modelling. This paper introduces and reviews the merits and weaknesses of this new method, particularly with regard to its ability to provide additional control in conditioning to secondary data such as may be provided from seismic data.
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Role of fine-scale layering and grain alignment in the electrical anisotropy of marine sediments
More LessElectrical resistivities of seafloor sediments determined by controlled source electromagnetic (CSEM) surveys have been found to be significantly greater than those measured by electrical well logging, in some instances by a ratio of as much as 5:1. Because borehole logging techniques invariably measure electrical resistivity using currents circulating in horizontal planes and CSEM surveys are sensitive to the currents circulating in vertical planes, a possible cause of this discrepancy is strong electrical anisotropy of the sediments. We have examined electrical log data from vertical exploration and appraisal wells and deviated production wells in the North Sea. By correlating the same sedimentary units between wells, we are able to compare resistivities measured at different borehole inclination angles. As the inclination angle changes, the amount of vertical and horizontal resistivity contributing to the resistivity changes. Hence we can estimate the electrical anisotropy in the sediments. Results indicate that anisotropy ratios of 1:5 and greater are present within the shale-dominated units. We show that fine-scale horizontal layering can make only a relatively small contribution to this anisotropy, but that a model of horizontal alignment of highly oblate spheroidal grains can account for most or all of it.
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Volumes & issues
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Volume 42 (2024)
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Volume 41 (2023)
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Volume 40 (2022)
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Volume 39 (2021)
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Volume 38 (2020)
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Volume 37 (2019)
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Volume 36 (2018)
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Volume 35 (2017)
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Volume 34 (2016)
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Volume 33 (2015)
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Volume 32 (2014)
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Volume 31 (2013)
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Volume 30 (2012)
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Volume 29 (2011)
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Volume 28 (2010)
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Volume 27 (2009)
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Volume 26 (2008)
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Volume 25 (2007)
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Volume 24 (2006)
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Volume 23 (2005)
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Volume 22 (2004)
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Volume 21 (2003)
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Volume 20 (2002)
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Volume 19 (2001)
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Volume 18 (2000)
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Volume 17 (1999)
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Volume 16 (1998)
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Volume 15 (1997)
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Volume 14 (1996)
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Volume 13 (1995)
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Volume 12 (1994)
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Volume 11 (1993)
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Volume 10 (1992)
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Volume 9 (1991)
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Volume 8 (1990)
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Volume 7 (1989)
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Volume 6 (1988)
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Volume 5 (1987)
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Volume 4 (1986)
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Volume 3 (1985)
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Volume 2 (1984)
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Volume 1 (1983)