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EAGE Winter Symposium - Reservoir Geophysics, the Road Ahead
- Conference date: 27 Oct 1996 - 30 Oct 1996
- Location: Venice Lido, Italy
- ISBN: 978-94-6282-124-8
- Published: 27 October 1996
33 results
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Monitoring Reservoir Flow Using Magnetometry
More LessIt is well known that fluid tlow in porous rocks has a concomitant electrokinetic effect (Morgan et al. 1989; Sprunt et al. 1994). The principal electrokinetic effect occurring in a flowing reservoir (i.e. reservoirs undergoing production) is the development of a streaming potential, due to the applied pressure drop across the reservoir.
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3D PreSDM Model Building via CRP Image Gather Scans - a North Sea Case Study
Authors I. F. Jones, M. Grimshaw, K. Ibbotson and B. JolleyHere we present a North Sea case history of 3D pre-stack depth migration, where the velocity-depth model has been built iteratively using a new pre-stack velocity updating scheme. In order to assess improvement in image quality throughout the model building process, we analyse post-stack depth migration results, their corresponding pre-stack images, and image gathers for each iteration.
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Automated Travel Time Estimation
By S. MortonAlthough prestack depth migration has become a part of mainstream seismic imaging technology, its full application is limited in part by our ability to determine models of the earth quickly and accurately. Most current methods for analysing prestack images and updating the underlying earth model depend upon the complex, global relationship between the model and the moveout on image gathers. However, common focal point (CFP) technology (Berkhout, 1996a,b).breaks the model determination process into two simpler processes, operator estimation and tomographic inversion, which can both be automated.
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Trace Continuity Analysis for Structure Interpretation - Case Studies on Carbonate Reservoirs
Authors H. Hagiwara, K. Yoshioka and N. ShimadaIn order to define accurate reservoir models for the enhancement of the oil production, a methodology of the structure lineament extractions from the 3-D post-stack seismic data is becoming more important, not only for exploration, but also for exploitation. Following the increasing use of interpretation software, which works on the powerful workstation system, structure interpretation has been made easier. However, the fault interpretation still has some difficulties. This is because the fault planes are mainly recognized as the discontinuity of the seismic reflectors. In other words, faults have not been revealed as the numerical fault "surface" to date.
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Application of Neural Networks and Cokriging for the Mapping of a Reservoir Property
Authors K. Yoshioka and N. ShimadaThis presentation introduces the case study of reservoir characterization in the offshore oil field. This field is in a dome approximately 7km wide, superimposed on anticlinal structure. The two Jurassic zones comprise the main oil reservoirs in the field. The formation of these reservoirs consists mainly of carbonates, accompanied by subordinate anhydrite. The upper zone ('A') is separated from the lower ('B') by an anhydrite layer 20 feet thick.
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Borehole Seismology - a High Resolution Technique for Aiding Development and Production
Authors B. N. P. Paulsson and M. S. KingBorehole seismology represents a rapidly developing technology for obtaining considerably better reservoir characterisation than that possible with the surface seismic techniques currently used. It is anticipated that borehole seismology will in the near future be used routinely for aiding in hydrocarbon development and production.
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A New Approach to Acoustic Facies Classification from Full Waveform Sonic Logging Tools
Authors F. Pampuri, A. Corrao, M. Gonfalini and M. PonziThe recent introduction of digital multipole source/multi receivers sonic tools gave the industry the possibility to record down hole at in-situ conditions high quality acoustic waveforms suitable for a detailed characterisation of complex reservoirs.
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Linearized Target-Oriented Inversion - Application to Real Data
Authors G. Bernasconi, G. Drufuca and F. L. RoccaWe have developed a procedure for target-oriented linearized elastic inversion in the k-w domain (Bemasconi et al., 1994), exploiting to the limit the weak scatter hypothesis. The technique is based upon two separate phases: linearized seismic inversion (limited to the target) and the description and compensation of propagation effects through the overburden (datuming).
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Azimuthal AVO Analysis of a Vertically Fractured Reservoir
Authors B. Ursin and G. U. HaugenGood knowledge of fracture systems is of great importance in reservoir characterization. This requires mapping of fracture properties away from well locations, which, to significant distances, can only be done with seismic data.
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Stochastic Reservoir Characterization Using AVO Inversion
Authors A. Buland, O. Hansen, P. Abrahamsen and A. HektoenSeveral attempts to utilize information from seismic data for stochastic reservoir characterization have been published, see references in Abrahamsen et al. (1996). To our knowledge none of them consider prestack data. Poststack data contain information on acoustic impedances whereas prestack data contain information on pressure- and shear wave velocities as well as density. This additional information can be used to improve the relationship between seismic data and petrophysical parameters.
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From Seismic Impedances to Reservoir Porosities - the Road Is not Always Straight
Authors N. Lucet and F. FournierSeismic data are nowadays commonly used to improve the reservoir image between wells, with techniques for quantitative lithologie interpretation. In particular, when the reservoir is not too heterogeneous, it is standard to use seismic derived acoustic impedances to predict reservoir properties such as average porosities [1, 2], Acoustic impedances are extracted from post-stack seismic amplitudes with inversion techniques. Then, they are turned into porosities with a regression approach (simple regression or eventually cokriging) after a calibration in the vicinities of wells. In this paper, a case study is used to examine some difficulties in this approach and to carry out sensitivity tests for defining critical parameters in the prediction of seismic porosities.
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Poststack Inverted Seismic Data Used in Well Planning on the Oseberg Field
Authors E. Zachariassen, A. Ryseth and H. FjellbirkelandThis paper presents a case study where geophysical techniques including post-stack inversion and seismic modeling, are integrated with geological data and knowledge in order to determine an optimal location for a new horizontal production well.
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AVO Walkaway Processing - a Case Study from the North Sea
Authors K. Ediriweera, P. Guerendel and M. GundemAVO analysis of surface seismic data has become a widely used technique in recent years. lts success is dependent on the quality of log data available for modelling the AVO at the weIl positions and the availability of AVO Walkaway (VSP) data surrounding the well. The AVO response observed on the CMP gathers often does not match the weIl response, and this mismatch may have several reasons (Amstrong, et. al., 1995).
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4Front - a Perspective on 4D Seismic Methods
Authors R. C. Uden and A. J. H. LittleThe underlying principle of 4D or time-Iapse seismic is that production from a hydrocarbon reservoir causes changes to the reservoir fluid acoustic properties and fluid saturations as a function of time, which may be detected by repeat seismic surveys. In this paper we show the key elements of 4D seismic technology from the perspective of integration between static and dynamic reservoir modeIs, drawing on experience gained in both full 4D projects and in pre-4D feasibility or scoping studies.
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Seismic Reservoir Monitoring in the Arabian Gulf
Authors P. G. Kelamis, R. D. Chimblo, A. A. Al-Towailib, D. S. Al-Qudaihy, R. C. Uden and C. S. MarshallSeismic reservoir monitoring is gaining popularity within the Exploration and Producing industry. Analysis of repetitive seismic surveys provides direct measurements of the fluid movements and saturation changes within the hydrocarbon accumulation. Tracking saturation fronts is essential to design and improve depletion and production strategies in order to properly manage as well as predict the performance of the field. In this paper, we present the analysis and results of a seismic reservoir monitoring project over an offshore clastic field in the Arabian Gulf. After rotation and repositioning of the two seismic datasets, a difference 3D volume was computed, validated by geological data and calibrated to a reservoir simulation model that has been history matched. The seismic difference between the two 3D surveys indicates gas encroachment within the upper part of the reservoir and is in overall agreement with production logging measurements at the wells.
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Reservoir Monitoring - a Multi-Disciplinary Feasibility Study in 3D
Authors B. Biondi, G. Mavko, T. Mukerji, J. Rickett, D. Lumley, C. Deutsch, M. Thiele and R. GundesøMonitoring reservoir changes with time-lapse seismic holds the promise to significantly improve reservoir characterization and reservoir management. Relating time-dependent changes in seismie to the underlying flow processes requires inputs from: (1) geological modeling/geostatistics, (2) flow simulation, (3) rock physics, and (4) seismic imaging. This paper documents the results from a project that brings these disciplines together. In this study we have considered the forward problem for a 3-D reservoir monitoring problem: creating a detailed geological model, performing flow simulation, relating the dynamic rock properties to seismic properties, and, finally, imaging the reservoir at multiple times.
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A 3D Ocean Bottom Cable Repeatability Study
Authors C. J. Beasley, R. E. Chambers, R. L. Workman, K. Craft and L. MeisterThere has been a resurgence of interest lately in using repeated seismic surveys as a reservoir description and production monitoring tooI.
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Stochastic Inversion
Authors H. W. J. Debeye, E. Sabbah and P. M. van der MadeIn addition to traditional modeIs, geostatistics offers a variety of methods to build a stochastic model of the reservoir. Geostatistics offers interpolation techniques that account for the spatial relationship of variables. Some advantages of stochastic modelling are: • The impact of uncertainty on the models can be assessed. • Spatial heterogeneity as described by distributions, variograms and cross-variograms is modelled statistically correct. • Complex information can be incorporated. The basics of geostatistics are described by Journel et al (1978). Geostatistical algorithms are outlined by Deutsch et al (1992).
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Dealing with the Geoscientific Scaling Problem - an Object-Oriented Approach
Authors P. F. M. de Groot and A. H. BrilUp- and downsealing of geoscientific information represents one of the major challenges in characterising reservoirs. The sealing problem originates from the fact that various types of data and knowledge becomes available during the life cycle of a field. Information with widely varying scales and accuracies is gathered from 0 to 4 dimensions (e.g. core-plug, well log, 2D seismic line, 3D seismic volume, time-lapse seismic). All available information needs to he integrated in order to arrive at consistent resulls on which economic decisions can be made with confidence.
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Conditioning a Stochastic Model of Fluvial Channel Reservoirs Using Seismic and Well Data
Authors J. I. Berg, A. MacDonald, G. Johnsen and R. HaugeFluvial reservoirs are highly heterogeneous and comprise a complex network of channel-like bodies. To optimise the development of these reservoirs it is important to model the channel distribution between well observations in a realistic manner, and stochastic modelling techniques are becoming increasingly applied for this purpose. This paper presents a stochtastic method where seismic data are used to constrain the modelled spatial distribution of channels between wells.
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The Seismic Contribution to Reservoir Characterization
By S. J. PharezThere are many attributes now available to help characterise hydrocarbon reservoirs. Typically these attributes can be examined in three main groups - first those pertaining to the geometrical relationship of the reservoir; second the reservoir content, for example, lithology, fluid and petrophysics; and finally attributes which change with time over the life of the reservoir (figure 1). This paper will examine these groupings and the contribution that seismic data can offer in quantifying the attributes. The issues faced in integrating this wide variety of attributes will also be explored.
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3D Seismic Volume Interpretation for Reservoir Characterization - a Nigerian Field Case Study
More LessDetailed understanding of the reservoir properties and hydrocarbon distribution pattern within a Nigerian field complex has been one of the main uncertainties affecting the development. To help in this aspect, 3D visualisation and seismic attribute work was carried out as part of an integrated study.
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The Integrated Approach to Reservoir Evaluation - Myths and Realities
More LessThere is general consensus among oil and service companies that total integration of all available data by a multi-disciplinary team is a more cost effective and productive method of reservoir evaluation than the conventional isolated piecemeal approach. To this end, multi-disciplinary teams formed to work on specific fields are a common occurrence. These teams are composed of individuals that not only belong to different disciplines but also to different cultures.
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Enhanced Subsurface Geological Modelling Through Integration of Dipmeter Structural and Surface Seismic Data
Authors G. Maletti and P. BiffiThe integration between dipmeter structural data and seismics has proven to be a powerful tooI for enhancing the subsurface geological model in mature or partially explored areas. By using "stick plots" (projection of dips on avertical plane) the integration between these two types of data is made possible, and two objectives are achieved: improvement of the structural interpretation of dipmeter and seismics data, and the quality assessment of the processed seismic data. Two are the main steps for dipmeter to seismics integration: - dipmeter results filtering and reduction - projection of selected dips on the seismic line
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The Effects of Attenuation and Dispersion on Log Calibration and Wavelet Estimation
Authors J. P. Neep, M. H. Worthington and R. E. WhiteMany modern interpretation techniques in the general subject area known as seismic lithology are critically dependent on the quality of the tie between the surface seismic data and weIl data and the consequent estimation of the seismic wavelet.
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Reservoir Characterization by Using Permanent Downhole Geophones in 4D Seismic and Micro-Seismic Monitoring Applications
Authors J. -P. Deflandre, J. Laurent, S. Serbutoviez, F. Huguet and F. VerdierTwo types of Permanent Downhole Geophones (PDG) [1,2] have been developed for use in a permanent way (several years) in oil or gas wells. These geophones were designed to be installed between the casing and the tubing (Figure 1) or, if needed, behind the casing of new wells. They can be adapted to different well completions. PDGs are suitable for two types of applications: 4D seismic measurements and microseismic monitoring.
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Prestack Depth Migration by 3D Tomographic Inversion of Reflected and Refracted Arrivals
Authors A. Vesnaver, H. Biaolong, G. Böhm, G. Madrussani, S. Petersen and G. RossiReflection tomography produces reliable macro-models in depth for the velocity field of seismic waves and other geophysical properties, when complex 3-D structures are present. The well-known inversion ambiguities due to the null space can be avoided by fitting the grid to the distribution of the available ray paths.
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Reservoir Description Using Acoustic Impedance - Hallettsville 3D
More LessA seismic reservoir prediction methodology generated seismic porosity measurements after conversion of migrated seismic traces to acoustic impedance.
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