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- Volume 19, Issue 3, 2001
First Break - Volume 19, Issue 3, 2001
Volume 19, Issue 3, 2001
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Understanding the fundamentals of 3D seismic survey design
More LessGijs Vermeer, long-time authority on the theory of seismic acquisition techniques originally with Shell (1967-97) and now with his own consulting company 3DSymSam, provides a summary of his recent research work extracted from his newly completed PhD thesis which he publicly 'defended' last month at TU Delft, The Netherlands.
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When 'oil in the well, gas in the stove' may no longer hold true
By F. di CesareIn this provocative article, Franco di Cesare, a petroleum consultant and past President of the EAGE, argues that the way we perceive oil and gas is due for a change
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Land seismic surveys and technology
Time to give land seismic the benefit of the doubt? According to one well known industry commentator, land seismic is 'difficult, dangerous, expensive, slow, environmentally challenging, needs too many people, offers low data quality compared with marine, and uses time-warped equipment stuck in a time warp'. It's a view shared by many oil companies who feel frustrated by the lack of innovation. But is it fair? In our Special Topic, we look at a number of companies which in one way or another are addressing the issues which continue to dog land seismic operations.
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Understanding land telemetry cable testing and save money
By R. BridglandData transmission problems in modern land acquisition systems have heightened contractors' awareness of telemetric cable quality. With many of these problems attributable to cables and connectors, comprehensive testing of these components has become essential, not only to comply with client specifications, but more fundamentally, to ensure reliable data acquisition. Because crew down-time caused by cable faults has become a major factor in the cost of acquiring seismic data, this issue should be of interest to the wider geophysical community. A better understanding of a cable's numerous electrical parameters and a professional approach to cable testing can save money at four distinct operational levels. The man laying out the line wants to know if the cable will work today. He needs a quick, simple test routine and a fast 'one button' operation. A bad cable can be taken off the line before it is deployed and sent to the repair shop. Patrick Burger (1999) emphasized the operational difficulties in laying out heavy multichannel cables, particularly in jungle or mountainous regions. He showed how these difficulties translate directly into financial cost - a cost doubled, it might be added, if the cable later proves faulty and has to be substituted.
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Imaging of complex fault-fold structures in a mountainous setting
Authors M.G. Kirtland Grech, D. A. Spratt and D.C. LawtonIn areas of complex structural geology, with folds, thrusts and imbricate structures which are typical of many mountain belts around the world, the assumption that the common midpoint (CMP) stack represents a zero-offset section is no longer valid. This is attributed to the strong lateral changes in velocity and coincident events that have different stacking velocities. Similar problems are also encountered in areas of salt mobilization and extensional faulting (Fagin 1991). Under such circumstances, migration after stack will no longer produce a true image of the subsurface, and depth or time migration before stack becomes necessary (Yilmaz 1987; Gray 1998). Furthermore, the conventional assumptions of elevation static corrections are often violated in areas with large topographic variations which are typical of fold-thrust belts. In such environments, pre-stack migration from topography is found to produce the best images of steeply dipping, shallow reflectors (e.g. Gray & Marfurt 1995; Lines et al. 1996; Wu et al. 1998). The objectives of this paper are to demonstrate which migration algorithms perform best for imaging these complex fault-fold environments, evaluate the sensitivity of different migrations to variations in the velocity model, examine the effect of rugged topography on the migration result and to determine which structural styles are likely to be the most difficult to image. This knowledge is of importance to the petroleum industry, as many hydrocarbon traps occur in complex fold-thrust environments.
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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)