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64th EAGE Conference & Exhibition
- Conference date: 27 May 2002 - 30 May 2002
- Location: Florence, Italy
- Published: 27 May 2002
21 - 40 of 688 results
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Can Joint PP and PS Velocity Analysis Manage to Corner d, the Anisotropic Depthing Parameter?
Authors F.S. Audebert, P.Y. Granger, C. Gerea and A. HerrenschmidtA-11 CAN JOINT PP AND PS VELOCITY ANALYSIS MANAGE TO CORNER δ THE ANISOTROPIC DEPTHING PARAMETER ? Introduction 1 FRANÇOIS AUDEBERT 1 PIERRE-YVES GRANGER 1 CONSTANTIN GEREA 2 The depthing or tying of seismic images to the well has been a perennial and frustrated demand made by the geologist. Anisotropy usually got the blame. Though nowadays we have at hand the theoretical understanding and tools to extract velocity anisotropy information from surface seismic there is still doubt about the sensitivity of surface seismic upon the parameter δ responsible for depthing as described by Thomsen (1986). Maybe the PS converted waves
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An Inverse-Scattering Sub-Series for Predicting the Spatial Location of Reflectors without the Precise Reference Medium and Wave Velocity
Authors S.A. Shaw, A.B. Weglein, D.J. Foster, K.H. Matson, P.M. Carvalho and D. CorriganA-13 AN INVERSE-SCATTERING SUB-SERIES FOR PREDICTING THE SPATIAL LOCATION OF REFLECTORS WITHOUT THE PRECISE REFERENCE MEDIUM AND WAVE VELOCITY Summary 1 The accurate location resolution and identification of targets beneath complex media (e.g. salt basalt and karsted sediments) are high priority and essentially unsolved problems today. Imaging methods that are tested and compared using synthetic data with precise model velocity as input are not addressing the real-world problem. At the very least imaging methods need to be tested using synthetic data and a velocity model that corresponds to what would be estimated from the data using current best velocity analysis
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Three-Dimensional Prestack Inversion, Lobo Trend, South Texas
Authors P. Anno, M. Wuenscher, R. Corbin, J. Hooper and F. ChlumskyA-14 THREE-DIMENSIONAL PRESTACK INVERSION LOBO TREND SOUTH TEXAS Summary 1 We demonstrate the difficulty with mapping a Lobo (Paleocene) hydrocarbon reservoir directly from stacked seismic data. A strong response in the stacked volume is ambiguous indicating either a large impedance contrast or a contrast in Poisson’s ratio. That is stacking of reflection amplitudes over offset (or reflection angle) incorporates reflections from impedance perturbations with those due to a change in Poisson’s ratio. Dipole sonic log data indicate Poisson’s ratio but not impedance distinguishes this particular Lobo reservoir from shale. The hydrocarbon reservoir impedance is similar to that of encasing shales.
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Seismic Repeatability, Normalised RMS and Predictability
Authors E. Kragh and P. ChristieA-15 SEISMIC REPEATABILITY NORMALISED RMS AND PREDICTABILITY ED KRAGH and PHIL CHRISTIE 1 Summary: Time-lapse seismic requires quantifiably repeatable data. In this paper we present a repeated 2D seismic line and show that the repeatability is correlated with streamer position differences. We examine repeatability in terms of the normalized RMS difference and the predictability (normalized cross power or coherence). An inverse relationship exists between the two metrics and while neither metric is an intuitive measure of repeatability their combination offers a possible methodology for matching datasets. Introduction: Time-lapse data are increasingly used to study production-induced changes in the seismic response
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4D Acquisition Geometry Requirements and QA
Authors R.W. Calvert, P. Hatchell and C. JonesA-17 4D ACQUISITION GEOMETRY REQUIREMENTS AND QA Summary. 1 RODNEY CALVERT PAUL HATCHELL and CHARLES JONES Shell International Exploration and Production B.V PO Box 60 2244 AB Rijswijk The Netherlands 4D seismic monitoring surveys aim to determine production effects by comparing 2 or more repeat surveys. These comparisons often indicate false changes due to production where non exist. These false indications are caused by system “Non-Repeatability” and represent a limitation to the 4D method. In many places the most serious form of non-repeatability occurs when acquisition source and receiver locations are not repeated. This paper describes a practical method for
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Time-Lapse Filtering and Improved Repeatability with Automatic Factorial Co-Kriging, AFACK
By T. ColeouA-18 TIME-LAPSE FILTERING AND IMPROVED REPEATABILITY WITH AUTOMATIC FACTORIAL CO-KRIGING (AFACK) T. COLEOU Summary 1 Acquisition and processing imprints are considered negligible with standard 3D processing but become critical when computing time-lapse seismic differences. A new technique AFACK particularly effective for equalising surveys and removing unwanted imprints is presented here. It uses an automated version of a geostatistical technique called Factorial Co-Kriging. Variograms and cross-variograms also provide a measure of the spatial cross variability that lead to a good indicator of spatial repeatability. Introduction CGG Vantage West Great West Road Brentford Middlesex TW8 9GG UK Geostatistics is widely used in
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Quantitative Time-Lapse AVO - Initial Application to the Oseberg Field
Authors G.J. Hicks and P. WilliamsonA-19 QUANTITATIVE TIME-LAPSE AVO - INITIAL APPLICATION TO THE OSEBERG FIELD Summary 1 Time-lapse (TL) seismic monitoring has become an increasingly successful tool for reservoir management. Currently we are investigating the possibilities for extracting quantitative information from the time-lapse AVO signature. In general this should allow more precise interpretation of time-lapse observations which is necessary for the future step of direct inversion of time-lapse changes to update reservoir parameters (Rowbotham et al 2001). In this study we show the harmful effect on quantitative TL analysis of substantial acquisition differences between the two seismic vintages used and of strong velocity anomalies
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The Impact of New 4D Seismic Technology on the Magnus Field
Authors B.D. Ritchie, A.G. MacGregor, A. Strudley and R. GotoA-20 THE IMPACT OF NEW 4D SEISMIC TECHNOLOGY ON THE MAGNUS FIELD BRYAN RITCHIE 1 ALAN MACGREGOR 1 ALAN STRUDLEY 2 and RICHARD GOTO 2 Summary 1 Improving both signal bandwidth and repeatability of seismic data are key requirements for reservoir monitoring surveys. This paper details how recent improvements in acquisition systems have impacted these requirements through a case study over the Magnus field in the UK sector of the North Sea. The key objectives of the Magnus survey were to improve seismic resolution of the reservoir and to provide a repeatable 4D baseline survey. The 2001 survey provides a
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Application of the Automatic Factorial Co-Kriging Method (AFACK) to Optimize the 4D Seismic Signature
More LessA-21 APPLICATION OF THE AUTOMATIC FACTORIAL CO-KRIGING METHOD (AFACK) TO OPTIMIZE THE 4D SEISMIC SIGNATURE Summary 1 4D technology is moving into an accelerated phase with several successful projects to date for example in the North Sea and in Canada. As new 4D methodologies emerge we integrate a geostatistical technique into 4D processing. This new method is named AFACK (Auto Factorial Co Kriging) and has been successfully used on several projects in order to increase the repeatability of the seismic data and to optimize the 4D signature. The AFACK technology is used to compensate small variations in time and amplitude
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Joint Geostatistical Inversion of Time-Lapse Data
Authors L.M. Barens, P. Williamson, P. Rowbotham and P. SwabyA-22 JOINT GEOSTATISTICAL INVERSION OF TIME- LAPSE DATA 1 LEON BARENS 1 PAUL WILLIAMSON 1 PETER ROWBOTHAM 1 2 and PETER SWABY 1 3 1. TotalFinaElf Geoscience Research Centre 33 Cavendish Square London W1G 0PW UK 2. Now at: Shell UK Ltd. 3. Now at: BNP Paribas Abstract Inverting time-lapse seismic data to acoustic impedance has potential for enhanced quantitative interpretation of saturation and/or pressure changes in a reservoir. By simultaneously inverting both base and monitor seismic data sets the impedance results are better and more consistently constrained. Using a geostatistical inversion method the time-lapse derived impedance change can be
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Virtual Reality Quality Control in 4D Processing
Authors J. Brittan Inc., M. Widmaier and J. LimaA-23 VIRTUAL REALITY QUALITY CONTROL IN 4D PROCESSING JOHN BRITTAN 1 MARTIN WIDMAIER 2 and JOSTEIN LIMA 2 Introduction 1 The rapid development of stereographic visualization over the last years has given a new dimension to seismic analysis and interpretation. Modern analysis tools have the capability to interactively inspect large 3D data volumes in a virtual environment. The possibility to look simultaneously at several data volumes and attributes in a true 3D sense opens the door to numerous applications. This paper shows how a visualization system is utilized for efficient volume-based quality control in the framework of 4D projects. Volume
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Comparing Time-Lapse Seismic and Reservoir Model Predictions in Producing Oil and Gas Fields
Authors P.J. Hatchell, S. Kelly, M. Muerz, T.C. Jones, P. Engbers, J. van der Veeken and R. StaplesA-24 COMPARING TIME-LAPSE SEISMIC AND RESERVOIR MODEL PREDICTIONS IN PRODUCING OIL AND GAS FIELDS Summary The main value of time-lapse seismic is the additional information to constrain or update a model of the reservoir. Knowledge of reservoir connectivity flow barriers or bypassed hydrocarbons is the kind of information we hope to get from time-lapse data in order to optimize reservoir investment decisions. Though reservoir models are in general constrained by history matching with well production data the solution is most often not unique as the amount of well data is rather sparse compared to time-lapse seismic. 1 A key step
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4D Monitoring of Schiehallion Field, UKCS
Authors C.P. Slater, J. Fletcher, D. Walder, J.M. Marsh and J. MacGregorA-25 4D MONITORING OF SCHIEHALLION FIELD UKCS Summary 1 The principal objectives in acquiring time-lapse (4D) seismic data are to constrain reservoir models and improve reservoir management. To meet these objectives we must estimate the dynamic changes in reservoir properties such as pore pressure and fluid saturation from the 4D seismic data. Until recently this has been done mostly through qualitative interpretations of 4D data. Many qualitative interpretations have been successful especially during the early stages of field life when the changes in reservoir properties are localized around wells and have provided reliable ‘first-order’ constraints to the reservoir model (Parr
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4D-Driven Asset Optimisation
Authors J.G.F. Stammeijer, G. Cooke and H.J. KloostermanA-26 4D-DRIVEN ASSET OPTIMISATION 1 JAN STAMMEIJER GRAHAM COOKE and HENK JAAP KLOOSTERMAN Shell UK Exploration and Production 1 Altens Farm Road Abstract Given the relative maturity of the North Sea as an oil and gas province it is not surprising to see a fast uptake in recent years of 4D time-lapse seismic methods for reservoir monitoring and management 1 . Whereas it is accepted that 4D seismic can have large value in “young” fields in terms of optimising field development decisions and capital expenditure also in mature fields it is found that 4D seismic can add considerable value 2
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The GLISP 4D Monitoring Project - A Lesson in How to Avoid Successful Failure
Authors K. Hirsche, N. Pullin and L. MatthewsA-27 THE GLISP 4D MONITORING PROJECT - A LESSON IN HOW TO AVOID SUCCESSFUL FAILURE KEITH HIRSCHE NORM PULLIN and LARRY MATTHEWS Abstract 1 Hampson Russell Software 510 715 5 th Ave SW Calgary Alta T2P 2X6 Canada A pioneering time-lapse seismic monitoring experiment was performed from 1985 to1987 at the Gregoire Lake In-situ Steam Pilot (GLISP) in Alberta Canada. This project was designed to predict and observe the progress of heat fronts in the tar sand reservoir. The monitoring program was very thorough carefully executed and extremely innovative for it’s time. All aspects of the monitoring process were carefully
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From Qualitative to Quantitative 4D Seismic Analysis of the Gullfaks Field
Authors T. Alsos, A.L. Eide, B.K. Hegstad, N.F. Najjar, D. Astratti, P. Doyen and D. PsailaA-28 FROM QUALITATIVE TO QUANTITATIVE 4D SEISMIC ANALYSIS OF THE GULLFAKS FIELD Abstract 1 To assist the interpretation of reservoir fluid movements in the Gullfaks field a 4D earth model has been created to integrate all the available well seismic and flow simulation data into a common framework. A rock physics model was applied to link the flow simulator output to acoustic impedance and enable the generation of time-dependent synthetic amplitude volumes for comparison with the real seismic amplitude data. Difference volumes derived from the synthetics represent the seismic signature of the fluid movements predicted by the flow simulator. Analysis
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Seismic Modelling of Eclipse Simulations and Comparsion with Real 4D Data at the Norne Field
More LessA-29 SEISMIC MODELLING OF ECLIPSE SIMULATIONS AND COMPARISON WITH REAL 4D DATA AT THE NORNE FIELD BÅRD OSDAL 1 and TRINE ALSOS 2 1 1 Statoil Harstad PO Box 40 9481 Harstad Norway 2 Statoil research center Trondheim Introduction The Norne Field is situated in the southern part of the Nordland II area in the Norwegian Sea approximately 100km north of the Aasgard Fields. The size of the field is approximately 9km x 3km. The reservoir rocks are of Lower and Middle Jurassic age. The hydrocarbon resources consist of a gas cap (25m) mainly situated in the Garn Formation and
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Integrating Time-Lapse Data in the History Match of a Gas-Condensate Reservoir
Authors A.C. Cominelli, R. Seymour, A. Stradiotti and J. WaggonerA-30 INTEGRATING TIME-LAPSE DATA IN THE HISTORY MATCH OF A GAS-CONDENSATE RESERVOIR 1 A. COMINELLI 1 R. SEYMOUR 2 3 A. STRADIOTTI 4 and J. WAGGONER 3 1 Eni/Agip Division Via Unione Europea 3 20097 San Donato Milanese Italy Abstract Time lapse analysis of 3D seismic surveys 4D seismic has been successfully used as a reservoir monitoring tool on several field over the years to detect fluid changes due to production. In this paper we present some novel aspects of a recent application of this technology to a Gulf of Mexico gas condensate reservoir. The field at issue is a
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Time-Lapse Elastic Inversion at the Oseberg Field
Authors H. Rutledal, R. Elde, A.-J. van Wijngaarden, J. Helgesen, H. Buran and T. WeisserA-31 TIME-LAPSE ELASTIC INVERSION AT THE OSEBERG FIELD H. RUTLEDAL 1 R. ELDE 2 AND A-J. VAN WIJNGAARDEN 2 Introduction 1 The Oseberg Field is a major oil and gas field located in the North Sea some 140 km off the coast of Norway. The reservoir comprises sandstones from the Middle Jurassic Brent Group in three eastward-dipping tilted fault-blocks. The northernmost one Alpha North is focused upon in this study. The production from Alpha North started late 1991 with a two front production drive system; gas injection in the initial gas cap and water injection in the water leg. It
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Application of Geostatistical Simulations and Statistical Analysis for Seismic Monitoring
Authors S. Vidal, C. Joseph, F. Gilbert and F. HuguetA-32 APPLICATION OF GEOSTATISTICAL SIMULATIONS AND STATISTICAL ANALYSIS FOR SEISMIC MONITORING Abstract 1 S. VIDAL 1 2 C. JOSEPH 2 F. GILBERT 2 and F.HUGUET 1 Seismic monitoring (time-lapse or 4D seismic) can be considered as an advanced seismic technology. It makes possible to obtain reliable information about fluid distribution in reservoirs. This information can help to provide better decisions and simulate various options to optimize production improve oil recovery and reduce costs. The changes in reservoir fluid saturation pressure and mean stresses induced by reservoir production may influence the process of wave propagation in rocks. Theses changes can be
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