- Home
- A-Z Publications
- First Break
- Previous Issues
- Volume 19, Issue 4, 2001
First Break - Volume 19, Issue 4, 2001
Volume 19, Issue 4, 2001
-
-
Web-based technology and business developments
Authors A. McBarnet, J. Hesthammer, S. Hesthammer, S.E. Johansen and B.M. SaetherSome say that the E&P industry was late into e-technology and commerce. But that is all changing now. We have a profile of B2B portal IndigoPool.com, reports on different company experiences with e-technology and communications plus a major article on the value of e-learning for the geoscience and engineering community. The articles collected here are: -'Bringing you the dot.com with a mission to succeed in the E&P business!', by Andrew McBarnet. -'Preparing for e-learning in petroleum geoscience', by Jonny Hesthammer, Steinar Hesthammer, Stale Emil Johansen and Bjørn Saether. -'Pilot your processing and reservoir projects powered by CGG'. -'How PGS Seres brought minds together with Intranet'.
-
-
-
Investigation of ground roll over loess-covered areas of Hungary
By O. AdámIn the past, the biggest problem in land-seismic surveying was ground roll. In certain areas these surface waves made successful seismic investigation impossible, while in other areas they led to a decrease in quality, to greater or lesser extent. Understandably, studies on ground roll occupied an important role in the literature during the 1950s and 1960s (refer in particular to Dobrin 1951; Dobrin et al. 1954; Howell & Bundenstein 1955; Hagedorn 1962; White & Sengbush 1963). This situation changed drastically with the computer revolution, enabling a revision of both field and data processing techniques. The introduction of different seismic sources, geophone groups consisting of a large number of geophones, the application of a wide variety of digital frequency and twodimensional filters fitting to the local conditions, have displaced the topic of ground roll from the leading edge of seismic research. After two decades, Anstey's (1986) paper Whatever happened to ground roll? initiated a new wave of interest in the topic. Although his paper deals with the design of geophone groups as the main weapon against ground roll, most of the subsequent papers focus on 'How ground roll can be used' rather than 'How to get rid of ground roll'. From my own point of view, bearing in mind my own concern with ground roll (¡d·m 1954, 1969), different questions arose, e.g. 'Do we really know the real nature of ground roll?', or 'What possibilities do the latest computer techniques offer in the field of ground roll investigation? To study these questions, a series of experiments were carried out at ELGI thanks to the financial backing of the Hungarian Scientific Research Fund (OTKA No. T 015 5850 and 046415).
-
-
-
Benefits of pre-stack time migration in model building: a case history in the South Caspian Sea
Authors E. Robein and C. HanitzschThe South Caspian Sea (Fig. 1) was only recently opened for exploration to western companies. The number of offshore wells drilled in the past has been limited. The seismic response in the area is generally good, but the geology may be locally complicated. In particular, the presence of undercompacted overpressured shale layers has been reported. Reliable pieces of information relevant to the geophysicist, such as sonic logs or check shot surveys are sparse. Consequently, one often has to rely on seismic data, and more precisely on stacking velocities to estimate the velocities needed for imaging (migration) or for time-to-depth conversion later in the processing-interpretation process. Unfortunately, stacking velocities often diverge dramatically from the needed geological 'propagation' velocities. The many reasons for this are well known and have been documented for a long time in the seismic literature (Al Chalabi 1994). The South Caspian Sea is no exception, to the rule and strong stacking velocity 'anomalies' were noticed over most of the structures as soon as the first speculative surveys were made available in the area.
-
-
-
Anisotropy detection by tomography and polarization analysis in a 3D three-component VSP
Authors G. Rossi, A. Vesnaver and S.A. PetersenVertical Seismic Profiles (VSP) allow borehole information (e.g. well logs and geological ties) to be extended to the surrounding space. Well logs span only one dimension i.e. depth along the well itself, but with a very high resolution. Conversely, conventional surface seismic data provides information with a lower resolution, but with a much wider 2D or 3D extent. Matching of events in the VSP and the surface seismic increases the physical and geological consistency of the Earth model we can build in depth. Depth is the natural dimension for VSP data, while surface seismic provides a reflectivity image of the Earth in the time domain. The velocity of seismic waves connects the two worlds. Seismic tomography estimates a 2D or 3D velocity field by jointly inverting different wave types, i.e. diret, reflected and refracted arrivals. It provides a macro-model for the velocity field that is consistent with the resolution of the available signal, without assuming simple shapes for the interfaces or smooth velocities. Thus, it can bridge both the gap between the time and depth domains, and also between data with different resolution scales: almost 100 m for seismic waves, and about 1 m for sonic logs.
-
Volumes & issues
-
Volume 42 (2024)
-
Volume 41 (2023)
-
Volume 40 (2022)
-
Volume 39 (2021)
-
Volume 38 (2020)
-
Volume 37 (2019)
-
Volume 36 (2018)
-
Volume 35 (2017)
-
Volume 34 (2016)
-
Volume 33 (2015)
-
Volume 32 (2014)
-
Volume 31 (2013)
-
Volume 30 (2012)
-
Volume 29 (2011)
-
Volume 28 (2010)
-
Volume 27 (2009)
-
Volume 26 (2008)
-
Volume 25 (2007)
-
Volume 24 (2006)
-
Volume 23 (2005)
-
Volume 22 (2004)
-
Volume 21 (2003)
-
Volume 20 (2002)
-
Volume 19 (2001)
-
Volume 18 (2000)
-
Volume 17 (1999)
-
Volume 16 (1998)
-
Volume 15 (1997)
-
Volume 14 (1996)
-
Volume 13 (1995)
-
Volume 12 (1994)
-
Volume 11 (1993)
-
Volume 10 (1992)
-
Volume 9 (1991)
-
Volume 8 (1990)
-
Volume 7 (1989)
-
Volume 6 (1988)
-
Volume 5 (1987)
-
Volume 4 (1986)
-
Volume 3 (1985)
-
Volume 2 (1984)
-
Volume 1 (1983)