- Home
- Conferences
- Conference Proceedings
- Conferences
60th EAGE Conference and Exhibition
- Conference date: 08 Jun 1998 - 12 Jun 1998
- Location: Leipzig, Germany
- ISBN: 978-90-73781-09-2
- Published: 08 June 1998
151 - 200 of 489 results
-
-
Implications of 4D Signal Detection for Seismic Data Processing
Authors R. G. Williams and R. GoodchildThe use of 4D or time Lapse seismic surveys for measurement of changes within reservoirs caused by production of hydrocarbons requires accurate, high resolution and reliable seismic imaging.
-
-
-
Compensating for Variations in Geophone Coupling of OBC Data
By J. E. GaiserFor both marine and land data inconsistent coupling of the three geophone components can prevent a proper combination for vector wavefield processing. On the ocean bottom it is more difficult than on land to plant geophones effectively, and it is expensive to bury cables or plant them with robotic devices to ensure good coupling.
-
-
-
Gravity Model of the Hekery Rive-Fuzuli-Carli-Maraza Azerbaijan Profile
Authors F. Kadirov and N. AskerhanovaAzerbaijan is placed on Tavro-Caucasus Geosynclinal in Alpine-Indonesia geotectonic belt. There exist geotectonic elements of Megaanticlinorium of Great Caucasus, Kur Basin, Megaanticlinorium of Small Caucasus and South Caspian Basin in Tavro-Caucasus Geosynclinal.
-
-
-
3D Volumic and Gravity Modelling Applied to Cadomian Terranes (Northern French Brittany) and Argentat Fault Area (French Massif Central)
By A. GuillenGeological bodies are naturally complex because they result from a succession of events that have led to their present morphologies. In order to understand them, maps, sections, drillings, seismic profiles are commonly used to reconstruct their geometry. These informations are generally represented apart from each other on separate media. In that case, relationship between the data are often difficult to understand. Moreover, geometrical incoherences are not easy to detect. Three dimensional modelling is an essential tool to merge all the 1D and 2D geometrical data in a unique 3D spats. Then, a 3D model can be constructed to represent the geometry of the whole study area.
-
-
-
Full Tensor Gradient Data Plus 3D Seismic Equals Better Resolution
By J. PrutzmanWith drilling occurring in water depths of 1,000 to 1,500 meters, reducing risks with new technology is critical to the economic succes of future fields. Since full Censor gravity gradient data is becoming available, a test project was designed over the well-imaged subsalt Gemini Field, Mississippi Canyon, Gulf of Mexico.
-
-
-
Man Made Gravity Anomalies in Lignite Mining
By H. LindnerChanges in the gravity field due to technical modifications of the water level were first proven by torsion balance measurements carried out by Alfred Schleusener in 1935.
-
-
-
A Field Experiment of Micro-Gravity Survey for very Shallow Subsurface Investigations
More LessThe authors have developed the micro gravity method, which is based on μGal-order gravity measurements, for the shallow subsurface mapping in engineering and environmental applications (Nozaki and Kanemori, 1996). The experiment shown in this paper was conducted to examine the applicability of the micro-gravity method we developed to very shallow subsurface investigations down to around ten meters in depth.
-
-
-
Levelling Marine Potential Field and Bathymetry Data - a New Approach
More LessThe levelling of marine potential field and bathmetry data has been a difficult and often time consuming problem. As part of the Australian Geological Survey Organisation's (AGSO) Timor Sea Project, a major upgrade of the marine ship-track potential field and bathymetry data which have been acquired on the north-west Australian margin since 1963 has been undertaken. AGSO and Desmond Fitzgerald and Associates have developed new techniques for correcting crossover and other errors in these data, thereby enabling the production of high quality images for interpretation.
-
-
-
Compilation of Gravity and Aeromagnetic Data of Thuringia and their Importance to the Regional Geology
Authors K. Seidel, R. M. Scheibe, J. Zenk and I. PustalIn connection with the formation of the new federal states in Eastern Germany after the reunification in 1990, the production of general geological maps of the new federal states became important.
-
-
-
Strike, Dip and Depth from Magnetic Anomalies - an Analytical Signal Technique
Authors M. Bastani and L. B. PedersenWe have recently (Pedersen & Bastani) introduced a method to estimate the dip angle of dyke like structures using a thin sheet model and an analytical signal approach. The method has been further developed so that it becomes possible to estimate depth to the top and strike of such magnetic structures.
-
-
-
High Resolution Imaging of Fractures Using a Borehole Sonic as a Downhole Sreamer
Authors K. Dodds, R. Coates, C. Esmersoy and M. KaneTraditional borehole sonic measurements identify arrival of the refracted wavefield along the borehole to determine acoustic slowness close to the borehole. Evolution of this technology to arrayed receivers and downhole digitization of the wavefield has allowed evaluation of both compressional and shear slownesses through coherence semblance techniques.
-
-
-
Compressional-Wave Attenuation from Full Waveform Sonic Data
Authors A. Dasios, T. R. Astin and C. McCannEstimation of anelastic attenuation for a wide range of frequencies is very important for lithology monitoring, fracture and fluid detection, prediction of petrophysical properties and fluid monitoringin hydrocarbon exploration.
-
-
-
Uniwell Borehole Seismic Data on Tube Wave Noise Abatement
More LessThe sensitivity to oil-water fluid-substitution events of Uniwell sourcing and sensing seismic waves in the same borehole is degraded by tubewave noise generated by the source. To assess some abatement measures, a ten-level clamped vector-motion sensor string was ganged with a high-frequency or a low-frequency seismic source to record data on tubewave noise levels.
-
-
-
Removal of Scattered Tube Waves
Authors G. C. Herman, P. A. Milligan, Q. Dong and J. W. RectorIn many VSP or crosswell datasets, tube waves are the major source of coherent noise, leading to difficulty in separation of the reflected wavefield. A variety of techniques has been developed for suppressing the direct tube wave, either based on wavenumber-frequency, polarization or median filtering.
-
-
-
Kirchoff Depth Migration for 3D-VSP Data
By P. BicquartThe Kirchhoff depth migration has been widely used for processing 3D surface seismic data. Several useful implementations have been presented in many publications. Recently, more effort has been devoted to adapting this method to 3D VSP data.
-
-
-
Three Dimensional Subsalt Semirecursive Kirchoff Migration
Authors D. Bevc and A. M. PopoviciWe obtain accurate images of complex subsalt structures by combining Kirchhoff datuming and Kirchhoff migration info a three dimensional semirecursive Kirchhoff migration. By datuming to the top of salt, or even through the salt, and then imaging below the salt, a greatly improved image is obtained.
-
-
-
Target Oriented FD Migration by Lateral Domain Shrinking
By B. DuquetFinite difference migration is a very attractive method for correct imaging of 3D complex geologic structures.
-
-
-
3D Prestack Migration with Cross-Spreads
Authors G. J. O. Vermeer and J. L. T. GrimbergenData acquired with parallel geometry can be described as a collection of common-offset gathers. Prestack migration of such data can be conveniently considered as the repeated application of the migration process to all common-offset gathers. In contrast, data acquired with orthogonal geometry in land or OBC surveys do not allow the construction of common-offset gathers. Instead, the data of an orthogonal geometry 3D survey can be described as a collection of cross-spreads. Each cross-spread has illuminated its own little part of the subsurface which can be imaged by migration. This paper introduces some of the problems associated with migration of cross-spreads.
-
-
-
A Comparison of Isotropic and Anisotropic Ray-Based Prestack Depth Migration
Authors J. Mispel and P. WilliamsonSeismic anisotropy is widespread in sedimentary basins. Vertical transverse isotropy associated with shale deposition and horizontal layering may give errors in "seismic depth", as well as reduced stack power and mispositioning of dipping events.
-
-
-
Improved Prestack Depth Imaging by Novel Raypath Selection
Authors D. Nichols, P. Farmer and G. PalacharlaEfficient imaging of large volumes using 3-D prestack depth migration usually uses only one traveltime in the Kirchhoff integral. The quality of the image depends on which traveltime branch is selected. We demonstrate that both first-arrival and maximum-amplitude traveltimes have their problems and we propose a new selection criterion that gives improved image quality.
-
-
-
The Maximum Depth Principle as a Dual to Fermat's Minimum Time Principle
By S. H. BickelThe maximum depth principle for finding a depth model from traveltimes is a dual to Fermat's minimum time principle for computing traveltimes.
-
-
-
Aperture Selection to Improve Kirchoff Depth Imaging Using the Maximum Depth Principle
Authors C. Harris, M. Marcoux and S. BickelIn Kirchhoff depth migration, traces in the input data aperture for a migrated output trace are individually mapped (stretched) from recording time to depth.
-
-
-
Advances in 3D Seismic Survey Design
Authors J. A. Musser and R. KappiusWhile 3D seismic surveys have dramatically increased in number, site, and importance over the last decade, the techniques used to design and plan these surveys have only slowly evolved.
-
-
-
3D Wavefield Sampling in the CMP Method
By G. HampsonThe purpose of this work is to help understand the effects of 3D spatial sampling on the quality of the CMP stack in the presence of coherent noise.
-
-
-
Wavefield Interpolation - Continuation or Prediction Filter Techniques?
Authors P. Mazzuchelli, F. Rocca, U. Spognolini and S. SpitzIrregular and sparse sampling of the wavefield in 3-D surveys generates spabal aliasing. Wavefield interpolation yields densely sampled data either operating in a suitable domain where sampling is more regular and can then be densified (e.g., in common shot domain) or by exploiting the predictability of the wavefield as parameterized by one (or more) plane events.
-
-
-
Trace Interpolation with Dat Adaptive Filtering in the Frequency Wave-Number Domain
Authors N. Gulunay and R. C. ChambersBy using a data adaptive filtering method on the zero-trace inserted data one can obtain a generalized trace interpolation. The interpolation filter can be designed and applied in the f-k domain. This method can interpolate 2-D as well as 3-D data efficiently to lessen the artifacts that multichannel processes produce on aliased data.
-
-
-
Long Offset Recording in a Standard Seismic 3D Survey
Authors U. Weber, B. Roters, N. Cooper and G. WilliamsIn a 3-D seismic infill survey, a two dimensional, E-W trending salt intrusion in Mesozoic formations endangered the visibility of the underlaying target zone. Modification to the standard acquisition scheme incorporating all laid geophone lires resulted in more than 800 active traces per record and extended offsets up to 10.200 metres. Special processing of these extra long offsets show significant improvement in time-domain reflection continuity for pre-salt events.
-
-
-
QC of Prestack Seismic Processing and Attribute Extraction
Authors R. D. Thomas, A. Castoro and R. E. WhiteQuantitative controls on the quality of seimic data used in pre-stack attribute analysis are important to understand the limitations of any results obtained.
-
-
-
Source/Receiver Directivity Effects on Q Measurements from Surface Seismic Reflection Data
Authors B. Hustedt, R. Clark and M. ScherwathThe seismic quality factor (Q) is an important lithology and porefluid indicator, as well as being important e.g. in AVO inversion. Dasgupta & Clark (1993, 1994) introduced a method (termed QVO) to measure Q from routine marine reflection data, facilitating large scale Q measurements. Here, we give a short review of QVO, then examine the impact of source and receiver directivity on Q estimates made this way.
-
-
-
Wave Swell Noise Suppression Using a Wavelet Packet Transform
Authors A. J. Deighan, D. R. Watts and C. RiedelAs exploration moves into progressively deeper waters, wave swell noise becomes a more significant barrier to acquisition of high quality marine seismic data.
-
-
-
Integrating Geophysical Data into Bedrock Model in Site Characterization for Nuclear Waste Disposal
Authors E. J. Heikkinen and P. J. SaksaThe Finnish power companies Teollisuuden Voima Oy and Imatran Voima Oy prepare for disposal of high-level nuclear fuel waste deep into the Precambrian crystalline bedrock in Finland. Posiva Oy carries out the research and development programme related to the disposal. This includes tentative design of the fuel containers, the sealing plant and the underground facilities, and geological characterization of the candidate sites. Geophysics is an important tool for the studies.
-
-
-
Geoelectrical Investigations with Hydraulic Conductivity Estimates at Two Waste Disposal Sites
Authors E. Aristodemou and A. Thomas-BettsNumerous studies have been reported in the literature showing the applicability and limitations of geophysical methods in different environmental problems. Mary such problems are associated with groundwater pollution, and what is also becoming increasingly important is the determination of aquifer properties such as hydraulic conductivity from the measured geophysical parameters. This is beneficial to the hydrogeologist because hydraulic conductivity values are needed in predictive groundwater modelling.
-
-
-
Geophysical Borehole Measurements of Water Flow for Hydrology and Environmental Problems
By J. H. SchönGeophysical well logging methods and their application are increasingly important for the exploration, production, and protection of groundwater and for the solution of various environmental problems.
-
-
-
Numerical Studies on Wave Scattering at Open Fractures
Authors J. Falk and J. GroenenboomAcoustic Monitoring experiments at Delft University of Technology on hydraulic fracture growth (Savic 1995, Romijn and Groenenboom 1997) initiated these numerical investigations on the wave scattering at open fractures. In particular we are interested in body wave diffraction as well as in the generation and propagation of interface waves at the fracture. Such events play an important role in the determination of the fracture extension and the fracture width by sonic and seismic measurements.
-
-
-
3D Seismic Modelling by Demigration
Authors T. Pokrovskaia, L. T. Santos, J. Schleicher, M. Tygel and P. HubralSummary not available
-
-
-
Fast 3D Modelling of Complex Geological Structures
Authors R. W. Hobbs and A. J. WildTraditional ray tracing methods for seismic modelling become prohibitively difficult to implement for complex media, and are inappropriate for models where sub-wavelength scatterers domïnate the seismic response.
-
-
-
A New Modelling for Time-Lapse Application
Authors L. T. Santos, J. Schleicher, M. Tygel and P. HubralSummary not available
-
-
-
Making the Simulation of Monitoring Experiments More Efficient
Authors A. Kirchner and S. A. ShapiroThe aim of a reservoir monitoring project is to use seismic experiments in order to characterise the properties of a hydrocarbon reservoir in the process of production.
-
-
-
A 3D Elastic Hybrid Modelling Scheme
Authors R. Mittet and B. ArntsenFull scale 3D elastic finite-difference modeling requires very large CPU times. A hybrid modeling scheme which combines an elastic cylinder-symmetric finite-difference modeling scheme with a 3D elastic finite-differente modeling schemes can reduce the CPU time considerably. The main limitation is that the overburden must be close to a plane-layer geology. The coupling of the two schernes is performed using an elastic representation theorem. Calibration of the hybrid scheme by comparison with the solution from a frequency-wavenumber algorithm give good results.
-
-
-
Hybrid Modelling of Elastic Wavefield Propagation
Authors K. Hokstad, I. Lecomte, F. A. Maaø, M. Tuseth, A. E. Mjelva, H. Gjøystdal and R. SollieFinite differente (FD) schemes are well known tools for the most complete modelling of wave field propagation in elastic media.
-
-
-
Design of SWD 3D RVSP Using Seisbit Technology
Authors L. Bertelli, F. Miranda, F. Poletto and F. RoccaThe aim of 3D RVSP using the drill bit signal is to obtain detailed while-drilling (WD) 3D seismic information in the area around the well.
-
-
-
Seismic While Drilling and Geophysical Monitoring in the Southern Apennine Range
Authors L. Bertelli, F. Abramo and V. GattiSeismic While Drilling (SWD) and Geophysical monitoring of the well have been widely and successfully used during the last two years in the Southern Apennine Range, over and around the Monte Alpi oil field, the targest oil discovery in Italy.
-
-
-
SWD Interpretation by Modelling of Pilot and Seismic Signals
Authors M. Malusa, F. Poletto, F. Miranda and G. BernasconiThe seismic while drilling technique uses the bit energy during drilling ; this energy is transmitted through the drillstring and recorded by sensors placed on the drilling rig and derrick, and through the earth layers and recorded by the seismic live placed on the surface.
-
-
-
Interwell Imaging in 3D
Authors J. Washbourne and S. LazaratosAcquisition of 3D crosswell seismic datasets in complex structure has motivated the development of new interwell imaging techniques. High-resolution multiple profile acquisition in highly deviated or horizontal wells is the new crosswell seismic frontier.
-