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65th EAGE Conference & Exhibition
- Conference date: 02 Jun 2003 - 05 Jun 2003
- Location: Stavanger, Norway
- Published: 02 June 2003
1 - 20 of 487 results
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Lithology and Fluid Prediction in the Impedance Domain
Authors P. A. Connolly, T. L. Redshaw and D. N. WhitcombeSeveral domains have been proposed to analyse the effects of changing lithology and fluid on
seismic data. These include intercept/gradient (Castagna et al 1998), lamda-rho/mu-rho
(Goodway et al 1997) and acoustic impedance/gradient impedance (Whitcombe and Fletcher
2001).
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Multiple attenuation using an apex-shifted Radon transform
Authors N. Hargreaves, R. Wombell and R. Ver WestMultiples from sea-floor scatterers and peg-leg multiples in complex
geology are often resistant to conventional multiple removal
techniques such as Radon demultiple. They have a
complicated moveout behaviour in prestack gathers which can only be
approximately represented by a conventional parabolic or
hyperbolic Radon decomposition.
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Draugen Field – Successful Reservoir Management Using 4D Seismic
Authors K. Guderian, M. Kleemeyer, A. Kjeldstad, S.E. Pettersson and J. RehlingA-01 DRAUGEN FIELD – SUCCESSFUL RESERVOIR MANAGEMENT USING 4D SEISMIC Summary 1 K. GUDERIAN 1 M. KLEEMEYER 1 A. KJELDSTAD 1 S.E. PETTERSSON 1 and J. REHLING 2 1 A/S Norske Shell P.O. Box 40 4098 Tananger Norway 2 Petroleum Development Oman (PDO) formerly AS Norske Shell With the application of the current state-of-the-art technology exploitation from the Draugen Field is estimated to reach a world-class recovery factor of about 66%. Through additional optimisation of reservoir management further realisation of development options and high-end technology applications Draugen is aspiring to further increase the recovery factor to some 75%. The key
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3D Pre-Stack Seismic Modeling of Reservoir Grids for 4D Feasibility and Calibration
Authors S. Toinet, E. Brechet, P. Ruelland and Y. ElouairA-02 3D PRE-STACK SEISMIC MODELING OF RESERVOIR GRIDS FOR 4D FEASIBILITY AND CALIBRATION 1 E. BRECHET 1 S. TOINET 1* P.RUELLAND 1 and Y. ELOUAIR 2 1 TotalFinaElf CSTJF Avenue Larribau Pau France 2 previously TotalFinaElf CSTJF now Statoil Norway Abstract Predicting seismic amplitudes changes according to reservoir simulation results in 3D is not obvious but is required in order to perform realistic 4D feasibilities and to calibrate the 4D seismic interpretation in terms of pressure and saturation changes. We present here a methodology to quickly compute 3D pre-stack seismic cubes in depth and time from reservoir simulation grids and
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4D Seismic for Oil Rim Monitoring
Authors R. Staples, P. Hague, T. Weisenborn and P. AshtonA-03 4D SEISMIC FOR OIL RIM MONITORING Abstract 1 4D or time-lapse seismic methods are now being routinely used throughout Shell to monitor fluid movements in producing fields. In most cases 4D seismic data has been used to track the displacement of a single hydrocarbon phase by displacing water or to measure pressure changes. However the seismic response to fluid movements becomes considerably more complex when three fluid phases are involved. The problem is further complicated in fields with thin oil rims where the seismic response from the gas-oil contact (GOC) interferes with the seismic response from the oil-water contact
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Constraining Geological Models Using 4D Seismic at Ekofisk Field
Authors Y. Yin and J. GuilbotA-04 CONSTRAINING GEOLOGICAL MODELS USING 4D SEISMIC AT EKOFISK FIELD Summary 1 Three geological models have been built at Ekofisk field using a well log compactiondecompaction process to describe porosity changes with time due to chalk compaction. In order to constrain these geomodels using 4D seismic information a 1D modeling workflow has been built to efficiently study the seismic responses to reservoir parameter changes and in particular the compaction of the porous chalk. Different compaction models were considered based on laboratory derived equations and output from the flow simulation. A rock physics model for porous chalk was used to relate
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4D Modelling of OWC Movement in Low NTG Areas of the Nelson Field
Authors C. Macbeth, K.D. Stephen and A. McInallyA-07 4D MODELLING OF OWC MOVEMENT IN LOW NTG AREAS OF THE NELSON FIELD 1 Summary A workflow has been established to build detailed meso-scale geological and reservoir models of turbidite systems from core log and laboratory data from which the 4D seismic response can then be calculated. This is used to investigate oil and water movement in the channel margins and interchannel regions of the Nelson field where poor net-to-gross is known to compromise 4D seismic resolution. The analysis confirms that saturation effects dominate and that the characteristic troughpeak signature in the difference volumes formed by the sweep of
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Quantifying Rise in Gas Water Contact from Time-Lapse Seismic on the Sleipner Øst Field
Authors T. Alsos, R. Tøndel, F. Aanvik and O.A. SolheimA-08 QUANTIFYING RISE IN GAS WATER CONTACT FROM TIME-LAPSE SEISMIC ON THE SLEIPNER ØST FIELD Abstract A methodology for quantifying the rise in the gas water contact from time-lapse seismic data is described. The method is based on time-lapse tuning effects and utilizes a combination between horizon interpretation and seismic attribute analysis. The method is applied at the Sleipner Øst Field on marine seismic data acquired in 1994 and 2002. Introduction 1 The Sleipner Øst Fields are located in the southern part of the North Sea. They are producing from three reservoirs; the Paleocene Ty Formation the Jurassic Hugin Formation
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Modeling by True-Amplitude Demigration and Its Application in Time-Lapse Seismics
More LessA-09 MODELING BY TRUE-AMPLITUDE DEMIGRATION AND ITS APPLICATION IN TIME-LAPSE SEISMICS Summary 1 Seismic forward modeling is a frequently used technique to produce seismic time sections for inhomogeneous earth models and arbitrary measurement configurations. However there exists another method to obtain seismograms based on the imaging process “true-amplitude demigration”. Starting with a model an artificial migrated section is created and subsequently demigrated to obtain a seismic section which is similar (but not identical) to the forward calculated one. This proceeding is called “modeling by demigration” and its application is advantageous in some special seismic imaging problems e.g. in the simulation
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Quantitative Estimation of Compaction and Velocity Changes Using 4D Impedance and Travel Time Changes
Authors J. Stammeijer and M. LandrøA-10 QUANTITATIVE ESTIMATION OF COMPACTION AND VELOCITY CHANGES USING 4D IMPEDANCE AND TRAVEL TIME CHANGES Abstract 1 J. STAMMEIJER 1 and M. LANDRØ 2 1 Shell Expro 1 Altens Farm Road Aberdeen AB12 3FY UK 2 Dep. Of Petroleum Engineering and Appl. Geophysics NTNU For some hydrocarbon reservoirs severe compaction of the reservoir rocks is observed. This compaction is caused by the production and is often associated with changes also for the overburden. Time-lapse seismic data can be used to monitor this compaction process. Since the compaction causes both changes in layer thickness as well as changes in the seismic
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4D Signal Enhancement Using Singular Value Decomposition – OWC Movement on the Nelson Field
Authors F.J.L. Reid, C. Macbeth and A.T. McInallyA-11 4D SIGNAL ENHANCEMENT USING SINGULAR VALUE DECOMPOSITION – OWC MOVEMENT ON THE NELSON FIELD Summary 1 In this paper we present a new method for time-lapse signal enhancement using singular value decomposition. Singular value decomposition is used to separate a 4D signal into its constituent parts: common geology time-lapse response and noise. This signal enhancement technique is used to map out both the original and moved oil-water contact across the Nelson field. The SVD technique allows the oil-water contact to be mapped across regions which would have been missed using traditional methods. The oil-water contact is observed to move
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9C, 4D Seismic Processing for the Weyburn CO2 Flood, Saskatchewan, Canada
Authors R.R. Kendall, R. Winarsky, T.L. Davis and R.D. BensonA-12 9C 4D SEISMIC PROCESSING FOR THE WEYBURN CO2 FLOOD SASKATCHEWAN CANADA Abstract 1 We present a summary of the 9C 4D processing used for the seismic monitoring of a CO2 flood in the Weyburn Field Saskatchewan Canada. The resultant time-lapse anomalies for both the P- and S-wave volumes are coincident with the locations of the CO2 injection patterns. Furthermore the anomalies that we observe are extremely robust and are typically observed far before the final processed sections were produced. That is they are evident on the differenced brute stacks. We believe this is largely due to the similarity of
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Processing of OBC and Surface Seismic Data for Reservoir Monitoring at the Statfjord Field
Authors G. Oexnevad, K. Duffaut, F. Foldal, J. Helgesen, D. Lecerf and M. ThompsonA-13 PROCESSING OF OBC AND SURFACE SEISMIC DATA FOR RESERVOIR MONITORING AT THE STATFJORD FIELD Summary 1 We have investigated how processing can improve repeatability between surface seismic and OBC (P/Z) data from the Statfjord Field with application in seismic monitoring. We first tried post-stack matching of previously processed data sets. This proved sufficient for realistic mapping of production effects. Further improvements in repeatability were obtained by a proper 4D concurrent processing of OBC and surface seismic data. Introduction Seismic data acquired at the sea bottom will play a more important role in future reservoir monitoring. The potential benefits compared
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Discrimination between Real and Artificial Time-Lapse Changes in OBC-Data
Authors J. Spetzler and Ø. KvamA-14 DISCRIMINATION BETWEEN REAL AND ARTIFICIAL TIME-LAPSE CHANGES IN OBC- DATA Abstract 1 JESPER SPETZLER 1 and ØYVINDKVAM 2 1 Dept. of Applied Earth Sciences TU-Delft TheNetherlands 2 Dept. of Petroleum Engineering and Applied Geophysics NTNU Wepresent anew method for time-lapse monitoring of OBC data. The time-lapse monitoring accounts for several important non-repeatability effects which is shown in a synthetic experiment. Introduction Non-repeatability effects (e.g. acquisition differences between two surveys noise and overburden effects) in 4D experiments can easily result in unrealistic time-lapse changes where actually none exists. Before continuing reading try the following exercise; Decide which one of the
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The Case for 4D Monitoring with Sparse OBC
Authors R.W. Calvert and P. WillsA-15 THE CASE FOR 4D MONITORING WITH SPARSE OBC Abstract Introduction We seek a better faster cheaper way of performing 4D seismic monitoring to improve reservoir management. We present the case for sparse OBC surveys as a candidate for this. “Better” would be an ability to detect smaller changes due to production and thus make 4D applicable for more fields and to allow earlier spatial diagnosis of production effects. This increased sensitivity depends upon an ability to produce more repeatable data where the subsurface has not changed so that small differences relate to real subsurface effects. This repeatability depends upon
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Seismic Forward Modeling in a Chalk Reservoir with Permanent Monitoring
By O.J. AskimA-16 SEISMIC FORWARD MODELING IN A CHALK RESERVOIR WITH PERMANENT MONITORING Abstract Advances in the last decade of time-lapse seismic technologies have developed a better understanding of the controlling parameters in seismic imaging repeatability and rock properties. This paper presents the seismic modeling element of a feasibility study for a permanent seabed 4C installation over Valhall a North Sea chalk field. Such a permanent installation allows for ‘acquisition on demand’ whose timing is driven by the dynamic changes in the reservoir. 1 An initial feasibility study addressed whether the expected reservoir depletion and subsequent water flood would generate a detectable
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Andrew Seismic Reservoir Surveillance
Authors R. Trythall, R.S. Parr, J. Wreford and A. SmoutA-17 ANDREW SEISMIC RESERVOIR SURVEILLANCE Overview A 4D (time lapse 3D) seismic survey was acquired in May 2001 across the Andrew field in the UKCS. A weak seismic 4D response was observed which was compared against two contemporaneous time lapse production logs. The close agreement between the results of these complimentary surveillance methods allowed the validity and calibration of the water and gas saturation changes to be tested across the whole field. The production logs provided indications of fluid flow at the wellbore whilst the 4D provided its regional perspective. The application of this method across the whole field has
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Calibration of 4D Seismic Fluid and Lithology Amplitudes over the Arbroath Field
More LessA-18 CALIBRATION OF 4D SEISMIC FLUID AND LITHOLOGY AMPLITUDES OVER THE ARBROATH FIELD 1 Introduction The Arbroath Field is located within UKCS Blocks 22/17 and 22/18 and together with the adjacent producing oil fields Montrose and Arkwright comprise the MonArb group of fields. The main producing horizon of all three fields is the Forties Sandstone lying at approximately 8150 ft TVD SS in the Montrose and Arbroath Fields and 8430 TVD SS in the Arkwright Field. Production of oil from the Montrose Field started in 1976 and decreased to very low levels in 1990. The Arbroath and Arkwright Fields are
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Integrated AVO Reservoir Characterization and Time-Lapse Analysis of the Widuri Field
Authors P.R. Mesdag, R. Van Eykenhof, W.E. Harmony, L. Harvidya, M. Sams and P. Van RielA-19 INTEGRATED AVO RESERVOIR CHARACTERIZATION AND TIME-LAPSE ANALYSIS OF THE WIDURI FIELD Summary 1 Reservoir characterization of the Widuri field offshore SE Sumatra is complicated by complex lithology and difficulties in predicting changes in fluid distribution during production. In 2000 a monitor 3D seismic data set of the Widuri field was acquired and processed to take advantage of seismic AVO effects. The base line 1991 seismic data set was reprocessed in parallel. The primary reason for the monitor data set was to observe the reservoir pressure depletion state around a water-flooding project. Furthermore there was a need to improve the
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Improving Reservoir Understanding Using Time-Lapse Seismic at the Heidrun Field
Authors A-K. Furre, F.R. Munkvold and L.H. NordbyA-20 IMPROVING RESERVOIR UNDERSTANDING USING TIME-LAPSE SEISMIC AT THE HEIDRUN FIELD Abstract 1 A time-lapse repeated seismic survey was last year conducted over the southern part of the Heidrun oil field. The main purpose of the repeated survey was to identify remaining infill drilling targets in the Fangst Group. The results from the seismic monitoring study were together with reservoir simulation results production data repeated logs and other data integrated to generate drainage maps for three reservoir levels. These drainage maps were actively used in planning infill and up-flank drilling locations in Fangst and served as an important tool in
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