- 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
101 - 150 of 489 results
-
-
Choice of Measurement Angles for Derivation of Ultrasonic Transverse Isotropy
Authors T. A. Johansen and A. K. KvalheimUse of ultrasonic data for recovering the elastic properties of transverse isotropic materials may be of great importance for various calibration purposes of seismic data in well locations. A complete description of the elastic properties of a transverse isotopic material requires 5 parameters. Four of these may be determined from P and S velocity data taken parallel and perpendicular to the axis of the elastic symmetry. The fifth parameter, in Voigt notation referred to as c13, requires additional velocity data measured along some off-symmetry direction.
-
-
-
The Inter Relationships between Velocity, Stress, Pore Fluid and Permeability in Clean Sandstones
Authors J. A. Khazanehdari, C. McCann, J. Sothcott and T. R. AstinSeismic compressional- and shear- wave velocities and attenuation were measured on a number of shoreface facies sandstone samples from a hydrocarbon reservoir of the North Sea. The samples show a wide range of permeabilities (between 10 md and 600 md) and relatively similar porosities (about 20%) and composition (96% quartz). The samples differ only in their average grain sites (from 100 μm up to 400 μm) which is believed to be the main factor controlling their permeability. The measurements were conducted at room temperature and at confining pressures ranging from 5 Mpa up to 45 MPa. The measurements were carried out in vacuum dry, brine- and kerosene- saturated samples. In the case of fully saturated samples, the pore fluid pressure was kept at 5 MPa.
-
-
-
Low Frequency Acoustic Measurements in the Laboratory
Authors J. Sothcott, C. McCann and G. JeronimidisThis paper describes the results of calibration tests on a resonant bar apparatus designel to measure the acoustic properties of consolidated rock core at frequencies in the range of 3kHz to 45kHz and at confining pressures to 70MPa.
-
-
-
Fracture Size Determined from Amplitude Data
Authors E. Fjær and R. Suarez-RiveraFractures may have a significant impact on the flow proporties of a rock. Large fractures in particular may serve as channels for the fluid flow, while a large number of small, isolated cracks will on the other hand contribute less to the flow capacity.
-
-
-
Data Management - the State of the Industry
Authors D. Nesser and J. PohlmanData Management has always been an issue in the E&P industry. Whether electronic or paper records, the information needs of the industry have always exceeded our capacity to catalog and store the data. Documenting the current state of this problem was the principal goal of a yearlong study. The study included oil companies and vendors both as study sponsors and as data sources. The eight sponsors (Amoco, BP. Phillips. Shell, GeoQuest, Legacy Solutions, Petroconsultants and PGS) aided in the study design and participated in the survey. Final results included information from nearly one hundred interviews with nearly fifty companies worldwide. The companies split almost evenly between oil companies and vendors.
-
-
-
The Geophysical Capabilities of Epicentre - POSC's E&P Data Model
Authors P. Maton Ltd, J. Bobbit and G. MastersThis paper describes the view of geophysics embodied in POSC's data model, Epicentre. Epicentre is an integrated model of the geoscience and reservoir engineering information used in the Upstream Petroleum industry. POSC is chartered to develop and maintain specifications to be used as standerds for information describing the full life cycle of hydrocarbon exploration and production assets.
-
-
-
Improved Data Management for Interpretation Systems Using Compression
Authors P. L. Donoho, R. Ergas and R. PolzerAs new methods of interpreting 3D seismic data, particularly prestack and derived attribute data, increase in popularity, the management of ever-larger data volumes becomes critical. Compared with acquisition and processing, however, the interpretation use of seismic data requires faster and non-sequential, random acces to large data volumes.
-
-
-
POSC and its Role in the E&P industry
More LessAll the world is information and energy in flux. Increasing complexity has resulted in an accelerating pace of change over the past decades. Communications technologies (tools we use on information and data) are the primary driver of this change. Our processes (how we use these tools) have responded accordingly to accommodate the changing environment. However, it is people (the agents who use these tools, engineer new processes, and build new tools) that are the bridge between both processes and technologies. People make decisions in knowledge work. This paper wilt discus complexity, change, knowledge work and the role of POSC in the E&P industry. It is proposed that all three factors, people, technology and proces, must be in harmony and confluence with each other in order for companies doing knowledge work to realise the projected benefits of teams sharing knowledge and learning from each other.
-
-
-
JavaSeis - Web-Based Seismic Data Processing
Authors S. Hassanzadeh and C. C. MosherThe Java programming language and environment are designed to solve a number of problems in modern programming practice (Hassanzadeh and Mosher, 1996). Java is a "simple, object-oriented, distributed, interpreted, robust, secure, architecture neutral, portable, high-performance, multithreaded, and dynamic" language (The Java Language: http://java.sun.com).
-
-
-
Prestack Depth-Migration - the Right Tool for Precaspian Basin Imaging
Authors K. Sydykov and M. KorostyshevskyThe Precaspian Basin is one of major and one of the deepest salt dome - type basins in the world The Basin potential reserves essentially exceed the ones of the North Sea Basin. In terms of fits 3D seismic and prestack depth migration (PDM) study, it has fallen behind other salt dome - type basins (Ward et al., 1994) However, due to the salt sediment thickness that can be over 4 - 5 km and to the salt shape that varies from the layer to the most complex dome configuration the application of the two techniques and their combination in the area is quite necessary. The paper deals with efficiency of the PDM on several areas of the Precaspian Basin.
-
-
-
Practical Steep-Dip Subsalt Imaging
Authors U. K. Albertin, J. Kapoor and W. ChangSince the discovery of large subsalt oil reserves in the Gulf of Mexico, subsalt imaging has become an area of significant interest throughout the seismic industry. Because of the large salt-sediment velocity contrast, however, accomplishing accurate subsalt imaging typically requires poststack, and in many cases, prestack depth migration. In regions such as the Gulf of Mexico, sediments outside the salt can typically be described by a smoothly varying interval velocity field.
-
-
-
A Multi-Survey 3D Prestack Depth Migration Case History from the UK Southern North Sea
Authors B. Henry, A. Strachan, M. Gainski and J. KommendalThe combination of tectonically complex overburden with variable lithologies in the UK Southern North Sea lends itself to the application of 3D prestack depth migration (PreSDM). A multi-survey 3D PreSDM project was undertaken in the study area in order to improve the imaging of both the Rotleigendes reservoir and the complex overburden.
-
-
-
3D Depth Imaging Through a Gas Cloud Using a Phased Velocity Modelling Approach
Authors T. Dunbar Exploration Co., G. Hofland and B. DavisThe need to fulfill a long term Gas Sales Agreement, dictates drilling two infill rate acceleration wells in 1999. Improved imaging through and beneath a gas chimney is needed to lower the risk on any wells drilled. A fast method of improving the imaging is needed to properly place the welIs.
-
-
-
Dip-Velocity Analysis of Converted Waves on a 2D-2C Land Profile
By L. ZanziThe analytical solution of the problem of estimating the conversion point and the traveltime for P-SV waves reflected by a dip interface within a homogeneous medium exists and it can be demonstrated that under some assumptions its applicability can be extended to a layered structure through the use of RMS velocities.
-
-
-
Components of 3D Converted Wave Imaging
More LessThere are now several convincing examples of improved imaging using shear-wave data from 2-D multi-component surveys (e.g. Thomsen et al., 1996). The evolution from 2-D to 3-D acquisition and processing for converted wave data is rapidly occurring, due to the well known advantages of 3-D seismic images.
-
-
-
Two-Ship Large Aperture Seismic Profiles - Application to Imaging through Basalt
By J. FrühnWe discuss the acquisition and processing of synthetic aperture seismic profiles, using two 2D seismic vessels to achieve continuous offsets to arbitrarily large offsets. The acquisition of high density, large aperture seismic data may allow the deep crustal structure to be studied in areas that have traditionally proven difficult to image using conventional seismic profiling techniques, such as those where high-velocity basalt flows or sills overlie sedimentary sections.
-
-
-
Sub-Basalt Imaging Using Long Offset Reflection Seismic Data
Authors D. Emsley, P. Boswell and P. DavisLong offset, towed cable marine seismic data have been used to successfully image underneath basalts in the Northern Rockall Trough, West of Hebrides. The method employs standard seismic processing techniques to stack and migrate S-wave energy reflected from below the basalt, generated by mode conversion at the top basalt reflector.
-
-
-
Seismic Feasibility Study - the Comprehensive Approach
Authors A. Firmano, F. Baldino, V. De Tomasi and E. LoingerThe high costs of seismic exploration leaves no room for mistakes. Seismic planning (i.e. acquisition and dedicated processing strategies) must be optimized for the Exploration and Production needs and for Geophysical requirements.
-
-
-
Seismic Penetration Problem in the Wadi Field, Sirte Basin
Authors I. M. Uheida and N. R. GoultyOver the past decade, a considerable amount of effort has been devoted to both acquisition and processing of 2-D seismic data over the palaeo-high structure which forms the Wadi Field in the onshore part of the Sirte Basin, Libya.
-
-
-
Shallow Reflection Seismic Survey on Karacadag Basalts South East Turkey
Authors Y. Sakallioglu, U. Gönülalan, H. Gaertner and R. SeitzQuaternary Karacadag Basalts, spread out most part of South East Anatolia and adversely affecting seismic reflection quality. The degree of quality change is depending upon the thickness of basalt layer and is not due to the energy radiation problems on areas where lateral variations of topography and thickness of basalt are high. Rapid changes in thickness and velocity variations of the overlaying basalt will influence static corrections whereas high thickness of basalt close to the earth surface will cause velocity inversions during NMO-corrections.
-
-
-
A Simultaneous Acquisition Test of High Density 'Global Offset' Seismic in Complex Geological Settings
Authors E. Ceragioli, P. Dell‘Aversana, S. Morandi and A. ZolloOn May 1997 an innovative land acquisition technique, called "global offset 2D seismic", was tested in Italy (Southern Apennines). The studied area is a thrust belt province characterised by extreme structural complexity where Tertiary to Mesozoic allochtonous units overly autochtonous Mesozoic carbonates.
-
-
-
A New Method of Marine Seismic Source Signature Estimation from Near Field Measurements
By M. SafarOne of the most important new seismic tools currently used in the E&P industry is the Time-lapse 3D seismic reservoir monitoring technology sometimes referred to as 4D seismic. However, it is only recently that geoscientists in the E&P industry have become aware of its limitations. One of the problems associated with acquisition is the seismic source consistency. The solution to this problem for the case of marine seismic sources can be easily achieved by monitoring each air-gun forming the marine seismic source.
-
-
-
A New Look at Simultaneous Sources
Authors C. J. Beasley and R. C. ChambersA fundamental factor in the cost of seismic data acquisition is the efficiency of source and receiver effort. On the receiver side, the increase in seismic channel count of recent years has resulted in increased spatial sampling and more efficient 3-D operations. Much has been done to increase source efficiency as well. Simultaneous drill and shooting operations and multiple vibrator groups are effective on land; flip-flop shooting for streamer surveys essentially doubles single-source production rates.
-
-
-
Real-Time Sweep Optimization - an Example of Automated Parameter Selection
Authors D. Kraaijpoel, J. Brouwer, K. Roy-Chowdhurry and P. BakkerOver the last few years several papers have addressed the development of objective monitoring systems for seismic data quality (Scott et al., 1996; Armstrong et al., 1997; Scheffers et al., 1996). These systems are based on an attempted quantification of seismic data quality; a number of indicators are used to keep track of data attributes that somehow quantify various aspects of data quality.
-
-
-
Sound Propagation and Attenuation from Airgun Sources in Shallow Water
Authors B. VerWest and D. BremnerThere has been recent concern about the impact of marine airgun sources on marine life such as dolphins, killer whales and baleen whales. The sources produce very high sound pressure levels at very short range, however several physical phenomena act to attenuate these high sound levels at long range. This study utilizes calibrated sound pressure recordings from an airgun source in shallow water and ocean acoustics modeling to better understand and quantify the the propagation and attenuation as a function of range from the source.
-
-
-
Seismic Trace Shape Classification - Takes the 'Magic' out of Stratigraphic Interpretation?
Authors J. D. Kerr and I. AbatzisThe use of seismic attributes to map hydrocarbons & geology is now widespread throughout the industry. As the technique has become accepted a large number of alternative attributes have become available to interpreters.
-
-
-
Attributes for Automated Seismic Stratigraphic Analysis
Authors T. Randen, B. Reymond and L. SønnelandSeismic stratigraphy represents an attractive framework for interpretation of 3D data. However the termination and truncation mapping for stratigraphic interpretation is an important but time-consuming and tedious talk.
-
-
-
The Integration of Seismic Inversion and Coherence Cube Imaging - a New Seismic Tool
More LessSubstantial improvement in the subsurface resolution of 3D seismic data is gained by running either seismic inversion or coherente cube processing. The acoustic impedance results represent an improved subsurface image of absolute acoustic impedance variations, which can be used for lithologic and stratigraphic interpretations.
-
-
-
The Geological Connection - the Need to Integrate Structural Modelling with AVO Studies
Authors P. Ware, M. Hession and C. ShannonResults of amplitude variation with offset (AVO) studies in a major Tertiary hydrocarbon province show the seismic character of the main reservoir to be a low impedance event regardless of fluid fill. Based on full waveform modeling, it appears that AVO response at this level may be strongly influenced by porosity.
-
-
-
Using Migration Uncertainties to Predict Risk in Well Positioning
More LessThis paper presents a technique to assess risk in well positioning.
-
-
-
Evaluation of Remaining Oil Potential with 3D Seismic Using Neural Networks
Authors P. De Groot, P. Krajewski and R. BischoffThe potential of porefïll characterisation from seismic measurements was studied for oil-filled Jurassic / Lower Cretaceaus sandstone reservoirs in Lüben-West, Germany, where recently a 3D seismic dataset was acquired.
-
-
-
Calculation of Traveltimes by Gridded Rays in 3D Media
Authors L. Battù, G. Bernasconi and G. DrufucaTraveltimes are useful in Kirchhoff migration, seismic modeling and tomography. They can be computed efficiently and precisely by integration of the eikonal equation on a regular grid, through a finite-difference method (Van Trier and Symes, 1991; Vidale, 1990). Unfortunately, this approach is potentially unstable because of the Courant-Friedrich-Levy stability condition that might not be satisfied in certain directions, unless the vertical step is kept small. This reduces the efficiency.
-
-
-
Multi-Valued Two-Point Ray Tracing by Wavefront Construction
Authors T. Chang, L. Canales and C-C. ShihImaging in complex geological areas requires multi-valued traveltime and amplitude information [1], [2]. Traditionally two- point raytracing is used to calculate the shortest traveltime and ray path between two points .
-
-
-
A 3D FD Eikonal Solver for Non-Cubical Grids
Authors A. Leidenfrost, D. Kosloff and D. GajewskiEfficient calculation of first arrival travel times in gridded 3D volumes plays an important role in various areas of applied geophysics such as tomography, earth quake location and also prestack Kirchhoff depth migration. The class of methods most widely known and commonly accepted because of the combination of excellent speed and good accuracy still is the finite-difference (FD) eikonal solvers all derived from Vidale's (1988, 1990) original implementation.
-
-
-
A Robust and Accurate Green's Function Interpolation for Imaging
Authors M. Mendes and L. NicoletisThis paper describes a simple interpolation methodology for the accurate Green's function estimates in order to be used by the seismic imaging - migration or inversion. The methodology is based on Dix's hyperbolic equation and revealed successfuly, and even applicable when the Green's function is interpolated from spatially wider fictitious sources. These features decreases the overall CPU time, the data volume and the associated data-handling costs, yelding to a computational effort reduction of the imaging algorithm.
-
-
-
Homogenization through Velocity Replacement in Inhomogeneous Acoustic Media
Authors J. Fokkema, R. Smit and K. WapenaarIn the following analysis we consider the action of a point source of the injection type in an acoustic medium. The seismic medium response is recorded with a set of point receivers.
-
-
-
Upscaling for Seismic Waves in Heterogeneous Elastic Isotropic Media
Authors T. M. Müller, N. Gold and S. A. ShapiroIn seismic processing very often a smooth elastic medium is required (e.g., for a successful application of ray tracing methods). Therefore a smoothing method is necessary when small scale heterogeneities are present. That means the elastic parameters have to be averaged such that the difference between the wavefields in the original and smoothed medium is minimized.
-
-
-
Saturation Mapping from Combined 4D Seismic and Reservoir Simulation
Authors H. H. Veire, C. Signer, B. Reymond, L. Sønneland and P. Tennebø4D seismic has the potential to monitor hydrocarbon movement in reservoirs during production, and could thereby supplement the predictions of the reservoir parameters offered by the reservoir simulator. However 4D seismic is often more bandlimited than the vertical resolution required in the reservoir model. As a consequence the seismic data holds a composite response from reservoir parameter changes during production so that the inversion becomes non-unique. A procedure that includes both the 4D seismic and reservoir simulations will be presented. The potential of such a procedure applied to a recent 4D survey over the Gullfaks field is demonstrated.
-
-
-
Reservoir Characterization Using 4C Seismic and Calibrated 3D AVO
By L. SønnelandIt is wellknown that the ratio of p-wave velocity and s-wave velocity (Vp/Vs) in porous media is sensitive to both lithology and type of pore fluids.
-
-
-
Estimation of Lithofacies from Seismic Data in a Tertiary Turbidite System in the North Sea
Authors A. K. Jørstad, P. Avseth, T. Mukerji, G. Mavko and J. R. GranliIn this study, we first introduce seismic lithofacies representing seismic scale sedimentary units with characteristic rock physics properties. This is the fundament for the quantitative facies and fluid estimation from seismic data.
-
-
-
Automated Seismic Fracture Characterization in Reservoir Modelling
Authors C. Signer, M. Nickel, T. Randen, B. Reymond, L. Sønneland and H. H. VeireMapping of fractures is important for the prediction of fluid flow in many reservoir types. The fluid flow depends mainly on the efficiency of the reservoir seals (Key, 1996). Consequently improved spatial mapping of the open and closed fracture systems will allow a better prediction of the fluid flow pattern.
-
-
-
Time Frequency Seismic Attributes for Reservoir Fluid Prediction
By J. GuilbotSeismic reservoir characterisation is one of the most challenging work for the seismic industry. With progresses in the quality of acquisition and data processing, we are now close to define processing standards for sophisticated studies aiming at solving difficult problems such as reservoir characterisation problems. With the help of appropriate signal processing tools, we can expect to go farther in the analysis of relationships between seismic attributes and reservoir attributes. We want to show in this paper a synthetic case study where non stationary seismic signals have been analysed with the Smoothed Wigner Ville distribution to characterise the fluid content of a real hydrocarbon reservoir.
-
-
-
Multi-Component Wavefield Separation Based on Polarization and Slowness Estimates
Authors S. Richwalski, K. Roy-Chowdhurry and J. C. MondtMulticomponent reflection seismics has enabled geophysicists to gain more information about the subsurface than by using vertical receivers only. In order to optimally proces the data, separation of the recorded wavefields is required. It is needed not only for shallow seismics where different wave types overlap in the data window, but also for deeper seismics where converted waves interfere with reflection data.
-