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65th EAGE Conference & Exhibition
- Conference date: 02 Jun 2003 - 05 Jun 2003
- Location: Stavanger, Norway
- Published: 02 June 2003
1 - 100 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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Oil Field Water Injection – a Large-Scale Water-Rock Experiment – Results and Applications
Authors H. Johansen, B.V. Nystrand, H. Stray, I. Johansen and Ø. DugstadA-21 OIL FIELD WATER INJECTION – A LARGE SCALE WATER-ROCK EXPERIMENT – RESULTS AND APPLICATIONS Summary 1 H. JOHANSEN 1 B.V. NYSTRAND 2 H. STRAY 1 I. JOHANSEN 1 and Ø. DUGSTAD 1 1 Institute for Energy Technology P.O.Box 40 2027 Kjeller Norway EAGE 65th Conference & Exhibition — Stavanger Norway 2 - 5 June 2003 2 A/S Norske Shell Water-rock interaction during sea water injection in the Norne Field Norwegian Sea has been investigated by natural chemical and isotopic tracers. A procedure to identify good breakthrough monitors has been developed. The nature of mineral reactions in the reservoir during
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4D Seismic Response of Primary Production and Waste Injection at the Valhall Field
Authors O. Barkved, K. Buer, K.B. Halleland, R. Kjelstadli, T. Kleppan and T. KristiansenA-22 4D SEISMIC RESPONSE OF PRIMARY PRODUCTION AND WASTE INJECTION AT THE VALHALL FIELD Introduction A new 3D seismic data set was acquired across the Valhall field during the summer of 2002. The presences of strong production induced seismic responses were expected due to the nature of the field and earlier observations. The Valhall reservoir is a highly porous chalk which compacts as the reservoir is depleted. The compaction results in a “hardening” and thickness reduction of the reservoir and subsequent subsidence of the overburden and the seafloor. The new data was processed using a “similar” processing flow as was
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Use of PP and PS Time-Lapse Stacks for Fluid-Pressure Discrimination
Authors A. Stovas, M. Landro and B. ArntsenA-23 USE OF PP AND PS TIME-LAPSE STACKS FOR FLUID-PRESSURE DISCRIMINATION Abstract 1 A complementary method to achieve quantitative information about reservoir property changes during production is to measure shift in two-way traveltime within a given reservoir section. A practical example of how this method can be used to give additional information about pressure and saturation changes in reservoir segment is given in Landrø 2001 Landrø 2002 and Landrø et al. 2003. In this paper we investigate how combined use of time-lapse PP and PS seismic data can be processed and analyzed for the discrimination between pressure and saturation changes.
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Super-Resolution Mapping of Thin Gas Pockets
Authors H.G. Borgos, T. Randen and L. SonnelandA-24 SUPER-RESOLUTION MAPPING OF THIN GAS POCKETS Summary 1 Improved resolution in seismic prospecting implies better resolving power of objects in the subsurface. It is well known that resolution is directly related to the frequency bandwidth of the seismic measurement. Various criteria for the resolving power exist like the Rayleigh criterion [1]. Under certain conditions the resolution can be improved beyond the limits of i.e. the Rayleigh criterion. These conditions can be that additional information about the scene being analyzed is available. Procedures that enable such improved resolution are referred to as super-resolution. We will present a seismic super-resolution procedure
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Modeling of Fluid Effects in Compartmentalized Areas, an Oseberg South Case Study
Authors S.A. Petersen, B.A. Farrelly and B.I. BraathenA-25 MODELING OF FLUID EFFECTS IN COMPARTMENTALIZED AREAS AN OSEBERG SOUTH CASE STUDY 1 S.A. PETERSEN B.A. FARRELLY and B.I. BRAATHEN Norsk Hydro E&P PO Box 7190 N-5020 Bergen Norway Summary In order to evaluate the seismic (or any other physical) response of the subsurface one should be able to combine a model of the matrix with a model of the pore fluid distribution. The task becomes more especially difficult when the matrix distribution reflects a compartmentalization of the subsurface and/or if more fluid regimes are present. A method to construct such several models is presented and applied in a
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Absolute and Relative Gravity Integration for High Precision 4D Reservoir Monitoring
Authors J.M. Brown, T. Chen, T.M. Niebauer, F.J. Klopping, J. Ferguson and J. BradyA-26 ABSOLUTE AND RELATIVE GRAVITY DATA INTEGRATION FOR HIGH PRECISION 4D RESERVOIR MONITORING 1 Based on an estimate 3µGals per 1cm. EAGE 65th Conference & Exhibition — Stavanger Norway 2 - 5 June 2003 1 Abstract In October 2002 BP Exploration Alaska (BPXA) the primary operator of the Prudhoe Bay Oil Field began a large-scale water injection program to counter decreasing pressure on the Prudhoe Bay gas cap. To monitor the progress of the injection program surface gravity measurements will be taken once per year. Reservoir models require total measurement uncertainty to be better than ±10µGals a challenging specification to
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Azimuth Preserved Trace Binning of 4D Seismic Data for Improved Repeatability
Authors X.-P. Li, J. Brittan, S. Harwood and M. WidmaierA-27 AZIMUTH PRESERVED TRACE BINNING OF 4D SEISMIC DATA FOR IMPROVED REPEATABILITY Abstract 1 During the processing of 4D seismic data it is vital to adequately compensate for the nonrepeatability that is a function of acquisition and processing effects. In this paper it is demonstrated that the seismic repeatability can be improved if an azimuth preserved trace binning methodology is implemented between base and monitor survey during the preprocessing stage. This improvement is illustrated using synthetic seismic data generated utilising real navigation data and a model of an isotropic medium. Different types of azimuth based trace binning can be done
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Feasibility of Inverting 3-D FTG Data for Reservoir Monitoring
Authors A. Druzhinin, A. Vasilevsky, J.R. Evans, C.A. Murphy and X-Y. LiA-28 FEASIBILITY OF INVERTING 3-D FTG DATA FOR RESERVOIR MONITORING 1 Abstract Three-Dimensional Full Tensor Gradiometry (3-D FTG) acquisition system takes ultra sensitive realtime measurements of small gravity changes (gradients) caused by density differences in all directions. We have undertaken a numerical examination of the feasibility of using this system for reservoir monitoring. Special gravity modeling and inversion algorithms that can describe and predict the dynamic behavior of a hydrocarbon reservoir have been developed and tested on synthetic FTG data based on realistic 4-D petrophysical models. Our inversion yields estimates of uncertainty in hydrocarbon production data. Results show that the
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New Approach for 4D Processing with OBC Data and Marine Streamer Data
Authors D. Lecerf and T. WeisserA-29 NEW APPROACH FOR 4D PROCESSING WITH OBC DATA AND MARINE STREAMER DATA Abstract 1 The repeatability of marine streamer data and OBC data is generally rather poor because they are acquired in completely different conditions. So can we successfully combine both types of acquisition in order to detect a weak 4D signal? To examine this we introduce the concept of a common seismic cube and partial differences. The common seismic cube represents the invariant geology and is computed with a geostatistical method taking advantage of the redundancy of the seismic data. It shows a better signal to noise ratio
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Seismic Monitoring of the Heidrun, Norne and Midgard Fields Using Steerable Streamers
Authors O. Eiken, H. Aronsen, A.-K. Furre, L. Klefstad, L.H. Nordby, B. Osdal and M. SkaarA-30 SEISMIC MONITORING OF THE HEIDRUN NORNE AND MIDGARD FIELDS USING STEERABLE STREAMERS Abstract 1 Seismic reservoir monitoring has considerable unrealised potential if higher repeatability can be obtained. Today’s towed streamer systems impose basic limitations on repeatability as streamer feather is difficult to repeat. Horizontally steerable streamers can potentially make repeated streamer positions possible. During the 2001 summer season time-lapse data were acquired over three producing fields in the Norwegian Sea using the new technology. We show in this paper some results of these surveys. Introduction Several 4D success stories have been reported but there are also a number of
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Detection of Saturation Changes in a Turbidite Sand by 4D AVOA
Authors A. Shams and C. MacBethA-31 DETECTION OF SATURATION CHANGES IN A TURBIDITE SAND BY 4D AVOA Summary 1 A seismic data processing methodology is developed on the basis of parallelized restricted offset and azimuth pre-stack processing (PROAP) for P-wave OBC time-lapse data. It is designed to preserve the directional signature cross-equalize datasets and generate a suitable input to a filter that separates seismic anisotropy from the static and isotropic ‘geological’ response. Application of this procedure reveals discrete time-lapse anisotropy anomalies in a turbidite sand body. These anomalies change intensity during production with their position and orientation coinciding with the highest net-to-gross sands. The anomalies
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Spectral Decomposition Provides Rapid Screening Tool for Gas Potential in the Norwegian Sea
Authors R.H. Leadholm, T.J. Austin and P.F. OstendorfA-33 SPECTRAL DECOMPOSITION PROVIDES RAPID SCREENING TOOL FOR GAS POTENTIAL IN THE NORWEGIAN SEA 1 R.H. LEADHOLM T.J. AUSTIN and P.F. OSTENDORF ConocoPhillips Norge PO Box 220 N-4098 Tananger Norway EAGE 65th Conference & Exhibition — Stavanger Norway 2 - 5 June 2003 Summary Investigation of 3D data sets over two deep water gas accumulations several dry tests and various undrilled prospects in the Vøring Basin of the Norwegian Sea shows that spectral decomposition phase and amplitude spectra can be used to define gas accumulations. This technique provides a rapid screening methodology and compliments the more traditional utilization of spectral
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Havsule – Exploration in Deep Water Offshore Norway
Authors K.J. Hansch, J.R. Berry and J.J. DoorenbosA-34 HAVSULE – EXPLORATION IN DEEP WATER OFFSHORE NORWAY 1 K.J. HANSCH J.R. BERRY and J.J. DOORENBOS BP Norge Godesetdalen 8 4065 Stavanger Norway The Havsule licence (PL254) was seen as one of the most interesting areas in the Norwegian 16 th licence round. Four licence blocks covering an area of 1800 km 2 were awarded in May 2000 to a consortium of BP Norge Norske Conoco (now ConocoPhillips) SDFI (now Petoro) and TotalFinaElf. BP was assigned operatorship. The licence is located in the Møre basin offshore Mid Norway with an average water depth of about 1500 m. In the
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Identification of Reservoir Rock with Lamé Parameters – An Atlantic Canada Case History
By R. TonnA-35 IDENTIFICATION OF RESERVOIR ROCK WITH LAMÉ PARAMETERS – AN ATLANTIC CANADA CASE HISTORY Abstract Figure 1: EnCana’s landposition in Newfoundland EAGE 65th Conference & Exhibition — Stavanger Norway 2 - 5 June 2003 1 RAINER TONN EnCana Corporation 150 9 th Avenue S.W. P.O. Box 2850 Calgary Alberta T2P 2S5 Canada Summary: Lamé parameters allow the identification of reservoir rock and fluids (Goodway et al.1999 Goodway 2001). This case study demonstrates how λρ and µρ inverted from 3D marine seismic made it possible to classify reservoir rock in an exploration prospect offshore Newfoundland Canada. The analysis of crossplots discriminates
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Challenges in Deep Offshore Imaging, West Africa
Authors C. Lafond, H. Houllevigue, Y. Kerdraon, J.F. Riou, M. Bridson and I. JonesA-36 CHALLENGES IN DEEP OFFSHORE IMAGING WEST AFRICA Abstract 1 The deep offshore of the Gulf of Guinea is a challenge to seismic processing and imaging techniques due to the complexity of the salt body structures and the omnipresence of mode conversions that mask the primary signal. Even though true (Kirchhoff) prestack time migration can recover the top of salt and wide sedimentary basins (not salt covered) it fails elsewhere. We show that wave equation 3D PreSDM is necessary to properly image target sedimentary reflectors in between and below salt domes compared to Kirchhoff 3D PSDM. However this is true
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3-D Prestack Depth Migration and Illumination Analysis - A Case Study from Offshore Norway
Authors C. Gerea, O. Riise, F. Assouline and M. RhodesA-37 3-D PRESTACK DEPTH MIGRATION AND ILLUMINATION ANALYSIS - A CASE STUDY FROM OFFSHORE NORWAY Abstract 1 We present a 3-D prestack depth migration case study from Halten area offshore Norway. Although the geological structure is not very complex we apply advanced migration algorithms to yield accurate seismic images in terms of focusing and positioning and valuable reflection-point gathers for amplitude analysis. The aim of this study is two-fold; to improve the quality of seismic image of the main fault/reservoir segments towards better positioning of production wells and to preserve amplitudes for enhanced mapping of reservoir sands. Advanced 3-D prestack
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Amplitude Brights and Hydrocarbon Occurrence in License PL128, Offshore Mid-Norway
Authors G. Richardsen, K.O. Hartvigsen, F. Karlsen, L. Michelsen, J.O. Hansen and G.R. AhmadiA-38 AMPLITUDE BRIGHTS AND HYDROCARBON OCCURRENCE IN LICENSE PL128 OFFSHORE MID-NORWAY Introduction 1 License PL128 is located on northern Dønna Terrace between the Nordland Ridge and the Træna Basin offshore mid-Norway. Eleven exploration wells have been drilled in the license between 1986 and 2002. Exploration has been successful with discovery of the Norne (1992) Svale (2000) Falk (2002) and Stær (2002) fields. Two additional exploration wells will be drilled during first half of 2003. Within the license area there is a correlation between amplitude brights on top reservoir level and oil discoveries. This relationship has to some extent been used
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Risking Sediment Acces and Charge – Structural and Basin Modelling, Norwegian North Sea
Authors E. Thompson, S. Jones, R. Satter, S. Wigger, N. McCormak and P. GriffithsA-39 RISKING SEDIMENT ACCESS AND CHARGE – STRUCTURAL AND BASIN MODELLING NORWEGIAN NORTH SEA Summary 1 A Norwegian Sea prospect was assessed for risk due to charge and reservoir presence. The prospect was identified by seismic attribute analysis and supporting evidence was sought from modelling. The impact on prospect viability of the sediment access and charge probabilities was examined. It was found that although modelling showed the sediment access to the area was possible the model did not identify known accumulations to the north and was therefore unreliable in this area. The charge modelling accurately identified known reserves to the
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The Importance of Wide Azimuth in Imaging
Authors B. Arntsen and M. ThompsonA-40 THE IMPORTANCE OF WIDE AZIMUTH IN IMAGING 1 B. ARNTSEN and M. THOMPSON Statoil Research Centre Postuttak N-7005Trondheim Norway Summary Comparing 3D depth migrated streamer data and 3D depth migrated OBC data from the same area it is demonstrated that the better quality of OBC data is related to the relatively wider azimuths used in the OBC data acquisition geometry. Introduction The benefits of wide azimuth acquisition geometries have been recognized for a long time in land seismics (Cordsen and Galbraith 2002). Offshore true 3D OBC data has recently become available and the importance of better azimuth coverage both
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Competence and Technology Needs for the E&P Business
By B. NylandB-01 COMPETENCE AND TECHNOLOGY NEEDS IN THE E & P BUSINESS 1 The paper will discuss the changes the use of technology in the E & P business has experienced during the last 10 – 15 years and the causes this has had on competence needs the interaction between different technical subjects and the changes in the working processes. The statement is that the E & P business has become a digital business and how is this being handled both in the industry but also in the academia. What has been achieved during these years and is there something that
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University Curricula and Industry Needs
More LessB-02 UNIVERSITY CURRICULA AND INDUSTRIAL NEEDS 1 The talk with consider the issues that must be addressed by university staff when designing geoscience and engineering course curricula. First and foremost we ignore at our peril the simple fact that our customer is the student. Plausible arguments are sometimes presented for a return to basics; more on classical mechanics for example. However the danger of customers voting negatively with their feet is a very real constraint on the balance and content of course curricula. The customer also expects and assumes that her/his employability will have been increased by studying the course
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E-Learning in Geosciences
More LessB-03 MAKING E-LEARNING WORK – EXAMPLES OF PRODUCTS DEVELOPED BY STATOIL AND NORWEGIAN ACADEMIA Abstract 1 Learning used to be synonymous with attending a formal course or a conference. Nowadays we would also include learning-on-demand and informal learning anytime and anywhere hence the popular term “life-long learning”. Among other things this has been made possible by computers the Internet and the emergence of “e-learning” believed by many to be the great new market of the Internet age. In academia e-learning is usually taken to refer to courses available online with content provided in digital format. However a company employee may
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Technical Skill Assessment – Measuring Staff Capabilities and Optimizing Training Investments
Authors J.D. Johnsen and M. LaPrea-BigottB-06 TECHNICAL SKILL ASSESSMENT – MEASURING STAFF CAPABILITIES AND OPTIMIZING TRAINING INVESTMENTS 1 The value of E&P technology applications can only be realized when technical staff has the skills and knowledge to apply the technology. Significant challenges for E&P companies and vendors today are to deliver focused training for staff in relevant technology applications and to understand the breadth depth and location of technical expertise within their companies. An important yet simple tool to help meet these challenges is rigorous skill or competency assessment. Many companies today (e.g. Shell BP) have implemented skill assessment and are using results to add
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Experience with Generalized-Screen Methods in Wave Equation Migration
Authors C. Notfors, Y. Zhang, Y. Xie and G. ZhangB-09 EXPERIENCE WITH GENERALIZED-SCREEN METHODS IN WAVE EQUATION MIGRATION Summary We present a stable least squares optimized generalized-screen (GS) formula for migration. Theoretical analysis and numerical examples show that our GS method has potential to provide high quality wave equation migration results. It removes splitting errors suppresses numerical dispersion and images steeply dipping reflectors. However when large lateral velocity variations are present the required normalization operator appears to degenerate image quality. Hence improving the normalization method or seeking a more stable algorithm is required for its practical use. Introduction Finite-difference migration based on one-way wave extrapolation (Claerbout 1985) automatically handles
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Angle Gathers for Shot-Record Migration by Local Harmonic Decomposition
By R. SoubarasB-10 ANGLE GATHERS FOR SHOT-RECORD MIGRATION BY LOCAL HARMONIC DECOMPOSITION 1 Summary EAGE 65th Conference & Exhibition — Stavanger Norway 2 - 5 June 2003 ROBERT SOUBARAS CGG 1 rue Léon Migaux 91341 Massy France It is now recognized that shot-record wave-equation migration is the best method for imaging in complex media. However it is also recognized that producing one output image is not enough. Velocity analysis can only be done when a gather is produced as well as AVO analysis or multiple attenuation. This paper starts by describing the local harmonic decomposition: it is an efficient algorithm which can
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One Way vs Two Way Wave Equation Imaging – Is Two-Way Worth It?
Authors J.B. Bednar, K. Yoon, C. Shin and L. LinesB-11 ONE WAY VS TWO WAY WAVE EQUATION IMAGING – IS TWO-WAY WORTH IT? 1 KWANGJIN YOON 1 CHANGSOO SHIN 1 J. BEE BEDNAR 2 and LARRY LINES 3 Abstract 1 Seoul National University Seoul Korea 2 Core Laboratories Houston Texas U.S.A. 3 University of Calgary Calgary Alberta Ca Current production-grade-wave-equation migration technology is almost totally based on one-way methods. These methods are typically derived through an asymptotic approximation of the square root of a one-way propagator derived by factoriaztion of some form of wave equation. Primary reasons for the dominance of one-way approaches are most certainly the relative ease
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Beam-Wave Migration
Authors S. Brandsberg-Dahl and J.T. EtgenB-12 BEAM-WAVE MIGRATION Summary 1 We present a hybrid beam/wavefield migration scheme that overcomes the dip limitation in conventional downward continuation schemes. The resulting migration operators are not limited to downward propagating waves only and in contrast to ray tracing methods they contain the full waveform in areas with large/sharp velocity contrasts. Introduction S. BRANDSBERG-DAHL and J. T. ETGEN BP America Inc. 200 Westlake Park Blvd Houston TX 77079 USA Downward continuation wavefield migration has gained in popularity in recent years and has proven to be an accurate and reasonably stable method for imaging seismic data in complex geology. There
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Delayed-Shot 3-D Prestack Depth Migration
Authors J. Sun, Y. Zhang, C. Notfors, S. Gray, L. Chernis and J. YoungB-13 DELAYED-SHOT 3-D PRESTACK DEPTH MIGRATION YU ZHANG 1 JAMES SUN 1 CARL NOTFORS 2 SAM GRAY 3 LEON CHERNIS 1 and JERRY YOUNG 1 1 Veritas DGC Inc. 10300 Town Park Drive Houston TX 77072 USA Summary We present a formulation for delayed-shot migration of marine data in 2-D (plane-wave sources) and in 3-D (linear sources and planar sources). We present speedup factors for these delayedshot migrations over common-shot migration and we discuss some sampling theory issues associated with the formation of delayed-shot records. On both synthetic and real data examples delayed-shot migration has produced images comparable to those
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VSP Salt Flank Imaging through Wavefield Continuation
Authors S. Brandsberg-Dahl, J.P. Van Gestel, J.T. Etgen and B. HornbyB-14 VSP SALT FLANK IMAGING THROUGH WAVEFIELD CONTINUATION Summary We present a method for imaging steeply dipping features such as salt flank by wavefield migration with horizontal propagation. By literally turning a standard shot record migration scheme on its side we ensure that the horizontally propagating waves are properly treated enabling us to image steeply dipping salt flanks. Introduction 1 Sedimentary layers terminating against salt are a common reservoir structure in many hydrocarbon regions around the world. When mapping the closure of such reservoirs both in the prospect evaluation phase and during development and production knowing the location of the
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Limited Frequency Migration with Interpolation
By J.B. BednarB-15 LIMITED FREQUENCY MIGRATION WITH INTERPOLATION 1 Abstract EAGE 65th Conference & Exhibition — Stavanger Norway 2 - 5 June 2003 J. BEE BEDNAR Core Laboratories 2316 Windfern Houston TX 77040 USA Zero-offset migration/inversion of single-frequency data produces asubsurface image with spatialwavenumbersconfinedtoanEwaldspheredefinedbythedouble-square-rootdispersion relation. Fornon-zero-offsetdata theEwaldspherebecomesanEwalddoughnut. Asaresult a single frequency images avolume of wave-numbers. This fact can be exploited to substantially reduce the number of frequencies needed to accurately map subsurface reflectors. This paper investigates a simple recipe for calculating a sparse set of frequencies for use in frequency-slice migration algorithms. While the migration process is unaltered the smaller set of
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A Roadmap for the Maze of 3-D Depth Imaging Choices
More LessB-16 A ROADMAP FOR THE MAZE OF 3-D DEPTH IMAGING CHOICES 1 Summary Today’s explorationist is confronted with a large array of three dimensional depth imaging options ranging from a variety of Kirchhoff implementations to a variety of wave-equation implementations. Historically the choice of a depth migration algorithm was simple: Kirchhoff was the only practical choice. This is no longer the case. Advances in computing and clever algorithms have made waveequation migration an economically feasible alternative. With so many choices making the right choice of imaging method for a given objective can be a daunting task. We briefly examine the
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The International Year of Geosciences, 2004-2007
By H. SchalkeB-17 THE INTERNATIONAL YEAR OF PLANET EARTH GEOSCIENCES FOR SOCIETY 2004-2007 The International Union of Geological Sciences (IUGS) is the international organisation which is representing on behalf of more than 100 national committees the earth scientific community in the International Council for Science (ICSU) where all disciplines meet. The Executive Committee of IUGS has taken the initiative to proclaim an International Year by the UN System and IUGS jointly. The very successful International Geophysical Year in 1957 served as a stimulus and a model. The foremost objective for this initiative is “to demonstrate the substantial and wide-ranging contribution the Earth
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Geoscience and Sustainable Resources in a Global Framework
By A. BjørlykkeB-19 GEOSCIENCE AND SUSTAINABLE RESOURCES IN A GLOBAL FRAMEWORK 1 ARNE BJØRLYKKE Geological Survey of Norway Today the term 'sustainable resource' is propagated widely by scientists the media and international organisations. From a global perspective certain categories of 'sustainable resource' include natural resources—whether solid liquid or gas—which when extracted can be used in the support of human societies. The term 'sustainable' implies thorough knowledge of the nature and extent of the resource as well as an implemented strategy for ensuring its environmentally sound extraction over long time periods and possibly also for securing its renewal. A sustainable use of resources
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Understanding Geohazards
By S. LacasseB-20 UNDERSTANDING GEOHAZARDS Geohazards are events due to geological features and processes that present severe threats to humans property and the natural as well as the built environment. Landslides caused by heavy rainfall floods erosion and human activities are the most common geohazards on land. Near shore and offshore various geological processes earthquakes and human activities for example in connection with petroleum exploration and production can trigger slides. 1 SUZANNE LACASSE ANDERS SOLHEIM and FARROKH NADIM Norwegian Geotechnical Institute P.O. Box 3930 Ullevål Stadion N-0806 Oslo Norway The need to improve the understanding of geohazards is easily exemplified: • In
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Geoscience and Nuclear Waste Disposal – Examples from the Baltic Region
By A.G. MilnesB-21 GEOSCIENCE AND NUCLEAR WASTE DISPOSAL WITH EXAMPLES FROM THE BALTIC REGION 1 Abstract Up to the late 1960s the importance of geoscience for society was seen almost exclusively in terms of the discovery and exploitation of natural resources. The "Limits to Growth" controversy and the growing public perception of environmental degradation started to change and complicate this simple image. In particular in the 1970s the problem of nuclear waste disposal came to dominate the political scene and in many countries thrust geoscience and geoscientists into public view. Since those turbulent years the disposal of nuclear waste in deep underground
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Seismic Arrays – and Their Role in Society
By A. DahleB-22 SEISMIC ARRAYS AND THEIR ROLE IN THE SOCIETY Abstract 1 Prime Minister Nehru of India voiced the heightened international concern over the frequent testing of nuclear arms in 1954 when he proposed the elimination of all nuclear test explosions worldwide. Already during negotiations in Geneva in 1958 it was recognized that seismic arrays could play a vital role in monitoring compliance with nuclear testing treaties. Following a stepwise approach during the next 40 years where international agreements on limited nuclear testing as well as non-proliferation of nuclear arms were achieved the Comprehensive Nuclear-Test-Ban Treaty (CTBT) was finally opened for
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Oceans Apart? Geologists, the Oil Industry and Coping with Climate Change
By H. WilsonB-23 OCEANS APART? GEOLOGISTS THE OIL INDUSTRY AND COPING WITH CLIMATE CHANGE 1 BRYAN LOVELL and HAMISH WILSON In 1997 the year of the Kyoto Climate Summit an Atlantic Divide in the oil industry became apparent. It symbolised the distance between those who think that climate change may not be much influenced by mankind and those who believe that it is. Behind this division lies a serious scientific argument concerning the messages to be read from the story of climate change recorded in rocks and ice. On the one hand are those who suggest that contemporary changes in climate simply
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Paradigm Shift in Fault Interpretation
Authors S.I. Pedersen, A. Hetlelid, P. Fayemendy, T. Skov, T. Randen, T. Iversen and L. SonnelandB-25 PARADIGM SHIFT IN FAULT INTERPRETATION Abstract 1 A high-level fault interpretation workflow using automatically extracted surfaces is presented with special attention on the human interaction part. The first step of the workflow is to generate a fault attribute that enhances the discontinuities in the seismic data. Fault-like surfaces are then extracted using an algorithm called “Ant Tracking”. The surfaces are then loaded into a 3D analysis tool where the interpreter by interactively verifying combining and deleting surfaces decides what is to be the final interpretation. The interpreter works on two levels in the analysis tool; on the fault system
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Improved Imaging in PP and PS, 4C Reservoir Characterization at the Grane Field
Authors J.P. Fjellanger, A.-L. Skjerdingstad, P. Riste, M. Nickel and A. CarrillatB-26 IMPROVED IMAGING IN PP AND PS 4C RESERVOIR CHARACTERIZATION AT THE GRANE FIELD Summary The 3D 4C acquisition at the Grane field was completed in May 2001. Both PP and PS have good quality and high utility value separately. In addition the PP and the PS data are complementary. The data set has high a potential for combined interpretation and analysis. In the following PP is synonymous with PZ the combined hydrophone and vertical geophone data while PS is the converted wave data. Introduction 1 J.P. FJELLANGER 1 A.-L. SKJERDINGSTAD 2 P. RISTE 1 M. NICKEL 3 and A.
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Reservoir Characterization of the Grane Field with Multi-Component Seismic Data
Authors A. Carrillat, M. Nickel, T. Randen, L. Sonneland, T.S. Valen, J.P. Fjellanger and A.-L. SkjerdingstadB-27 RESERVOIR CHARACTERIZATION OF THE GRANE FIELD WITH MULTI-COMPONENT SEISMIC DATA Introduction 1 The Grane Field is located at the eastern margin of the Viking Graben on the western flank of the Utsira high. The Grane Field consists of Palaeocene turbidite sandstones (Heimdal Formation) which originate from the East Shetland Platform to the West of the field. The deposition and geometry of the turbidite sand lobes were mostly controlled by the original basin morphology which forced the sand to deposit along a main N-S axis parallel to the Utsira High. The Heimdal Fm consists of high-density turbidite sandstones that were
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Preconditioning for Optimal 3D Stratigraphical and Structural Inversion
Authors T. Randen, L. Sønneland, A. Carrillat, T.S. Valen, T. Skov, S.I. Pedersen, B. Rafaelsen and G. Elvebakk1 B-28 PRECONDITIONING FOR OPTIMAL 3D STRATIGRAPHICAL AND STRUCTURAL INVERSION Tectonic forces bend and tilt the earth’s crust and thereby create many of the structures under which we find hydrocarbons. However the bending and tilting also present a challenge to attribute computation and automated interpretation of the seismic data. Nevertheless local dip information is a crucial element in seismic stratigraphic internal reflection configuration [1]. Hence a robust seismic attribute should be able to handle dipping layers in a consistent way. For example the traditional approach of extracting attributes along vertical traces irrespective of any dipping nature of the data clearly
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Using Wavelet Transform and Self Organizing Maps for Seismic Reservoir Characterization of a Deep-Water Field, Campos Basin, Brazil
Authors P.L.M. Osório, M.C. Matos and P.R.S. JohannB-29 USING WAVELET TRANSFORM AND SELF ORGANIZING MAPS FOR SEISMIC RESERVOIR CHARACTERIZATION OF A DEEP-WATER FIELD CAMPOS BASIN BRAZIL Introduction 1 Seismic facies analysis is not a deterministic and simple task. Usually facies analysis is performed through the following steps [1]: 1- Geological oriented spatial and temporal segmentation of seismic traces (input space); 2- Seismic attributes selection (variable space); 3- Choosing the optimal number of classes (facies) and algorithm iterations; 4- Training and classification of the selected attributes using some statistical or neural networks methods (pattern space); 5- Building and interpreting facies map. Normally the geological oriented spatial and temporal
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Multiple Attribute Analysis for a Jurassic Oil Field in the North Sea
Authors F. Barclay and D.J. DaviesB-30 MULTIPLE ATTRIBUTE ANALYSIS FOR A JURASSIC OIL FIELD IN THE NORTH SEA Summary: 1 Multiple-Attribute analysis (MAAT) has been applied for a Jurassic (Brent Sequence) field in the UK North Sea to help define the remaining oil in the reservoir section after several years production. 3D seismic from 1997 was used in this study. Both full-stack acoustic impedance (AI) inversion and AVO-inversion were used to provide precise well-ties between the attributes and lithology/fluid units defined from logs. Neural net modeling enables prediction of (1-Sw) and porosity volumes that may be combined to predict high remaining pay potential. Method: An
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Fault System Analysis Using a New Interpretation Paradigm
Authors T. Skov, S.I. Pedersen, T.S. Valen, P. Fayemendy, A. Grønlie, J.O. Hansen, A. Hetlelid, T. Iversen, T. Randen and L. SønnelandB-31 FAULT SYSTEM ANALYSIS USING A NEW INTERPRETATION PARADIGM Abstract 1 Based on two field examples from offshore Mid Norway a new fault interpretation paradigm is presented. The paradigm allows the user to apply principles from structural geology to analyze fault systems and it reduces significantly the subjectivity inherent in manual interpretation. This is especially valuable for the main data example presented which is structurally complex area with a dense network of faults. The final analyzed result from this data set is considered as a detailed and a reasonable objective 3D fault interpretation. Introduction T. SKOV 1 S. I. PEDERSEN
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Seismic Mapping of « Infra-Tuning » Reservoir Objects by a Geology Driven Classification Approach
Authors F. Pivot, G. Bailly, F. Bertini and D. ClaudeB-32 SEISMIC MAPPING OF « INFRA-TUNING » RESERVOIR OBJECTS BY A GEOLOGY DRIVEN CLASSIFICATION APPROACH Abstract 1 Most geophysicists think that it is impossible to recover some reservoir property if this property is associated with layers under tuning thickness. It is true when using amplitudes only but becomes sometimes false when amplitudes are analysed as waveforms in pre-stack domain combined with apriori geological constraints. The developed methodology in this paper applies this more subtle reality: it allows to recover the Hydrocarbon Pore Thickness of a thin sheet complex of deep-offshore Angola and proposes a confidence interval at each point of
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Real Data to Real Decisions in Real Time
More LessB-33 REAL DATA TO REAL DECISIONS IN REAL TIME Abstract Exploration and production is one of the most information intensive activities in business. Over the last decade considerable effort has been devoted to improving the management of E&P information and many companies now have corporate data stores populated by validated high quality E&P data. Recently new techniques have been employed to make data more timely and accessible to E&P professionals and managers while adding context to data so we can make business decisions better and faster. 1 EAGE 65th Conference & Exhibition — Stavanger Norway 2 - 5 June 2003
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Real-Time Dataflow in the ConocoPhillips Norge Onshore Drilling Center
Authors L. Gåseby, M. Herbert and J. PedersenB-34 REAL-TIME DATAFLOW IN THE CONOCOPHILLIPS NORGE ONSHORE DRILLING CENTER 1 LARS GÅSEBY MIKE HERBERT and JARLE PEDERSEN Abstract In 2002 ConocoPhillips Norway implemented an Onshore Drilling Center in their main onshore facility in Norway. This center is used to support not only drilling operations on the Eldfisk and Ekofisk fields but also well trajectory planning. Key elements of the center are “real-time data” “collaborative work processes” and “integrated data views”. This presentation will review the recent history and background that lead up to the center: • Main drivers • Scope • Infrastructure • Supported work processes Furthermore a close
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Developing Sub-Surface Work Processes to Exploit Real-Time Data – Experiences from the Heidrun Field
By A. McCannB-35 DEVELOPING SUB-SURFACE WORK PROCESSES TO EXPLOIT REAL-TIME DATA - EXPERIENCES FROM THE HEIDRUN FIELD 1 Production and injection wells on the Heidrun Field are drilled from a 56-slot template below the TLP plus five 4-slot sub-sea templates. Drilling from the platform template has been continuous since 1993 which together with periodic sub-sea drilling has meant that up to 16 wells have been drilled per year. After 7 years of production many wells now being drilled are high-angle infill wells requiring precision placement in the reservoir. In 2000 the Heidrun sub-surface team introduced a Statoil-developed data transfer system (DART Link)
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Effective Management of Production Data for Corporate Value in a Dispersed Environment
Authors A.H. Smith, H. Banister and S.J. RobertsB-36 EFFECTIVE MANAGEMENT OF PRODUCTION DATA FOR CORPORATE VALUE IN A DISPERSED ENVIRONMENT Summary 1 The collection of escalating volumes of data characterise the current E&P industry. It is essential that this be managed so that the data supports the requirements of the corporation. In the case of production data these needs are rapidly changing as “real time” information is gathered to help with field management. Experience shows that within most companies the advent of real time data delivery is exposing weaknesses in current processes that need to be addressed to ensure the accuracy and speed of reporting both in
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Using WITSML for Distributing and Managing Real-Time Data
By Ø. MydlandB-37 USING WITSML FOR DISTRIBUTING AND MANAGING REAL-TIME DATA Abstract Summary 1 The WITSML standard provides a new Information Transfer Standard that gives real-time seamless flow of well site data between operators and service companies to speed and enhance decision-making within Drilling Completion and Well Services. Sense Technology has developed SiteCom which use WITSML for distributing and managing real-time data. SiteCom has been in operation in BP Stavanger since October-02. The WITSML project is an oil industry initiative sponsored by BP Statoil and Shell to define a new standard for drilling information transfer. Initial participation is from the major service
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Oil and Gas Exploration and Production Portals – Present and Future
Authors D. Camden and P. CleverleyB-38 OIL AND GAS EXPLORATION AND PRODUCTION PORTALS – PRESENT AND FUTURE 1 Aim To discuss the business requirements which have led to the existing array of portals (and associated terminology) used within the Oil & Gas Exploration and Production Industry. A classification model for current portal ‘types’ will be proposed according to shared characteristics enabling companies to clarify the position of their existing developments and develop a shared understanding of the current industry environment. A strategic approach towards information management will be presented to equip the portal of the future with the structure it needs to meet future business
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Web Technologies for Information Access and Workflow Support – Technical Workspace Portals
Authors U. Algan and M. PiantanidaB-39 WEB TECHNOLOGIES FOR INFORMATION ACCESS AND WORKFLOW SUPPORT – TECHNICAL WORKSPACE PORTALS Abstract 1 UGUR ALGAN 1 and MARCO PIANTANIDA 2 Since the early beginnings in 1997 Web-enabled technologies have grown to become as much a part of our daily lives as the telephone and the television. A significant percentage of the world's population today relies on the Web for a variety of information and services. Although the impact of the Web technologies on us the consumers is significant it is even more so in the workplace. The main focus of this presentation is technical workspace portals for the
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A New Approach for Discovering, Exploring and Exploiting Exploration Data over Intranets and the Internet
Authors A. Johnson, T. Wilson, R. Tinnion and T. NgwisanyiB-40 A NEW APPROACH FOR DISCOVERING EXPLORING AND EXPLOITING EXPLORATION DATA OVER INTRANETS AND THE INTERNET Abstract 1 T. WILSON 1 R. TINNION 2 A. JOHNSON 3 and T. NGWISANYI 4 The Internet Intranets and general globalization of networking technology have produced a dramatic increase in the type and volume of digital exploration data that is available to geoscientists. The development of useful protocols for computers to access and share the data both privately within an organization and globally on the Internet is key to our ability to use this information efficiently. Current barriers include insufficient bandwidth for large data
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The Search for Interbed Multiples Using a Model Based Approach
Authors C.J. Tsai and D.R. SedgeleyB-41 THE SEARCH FOR INTERBED MULTIPLES USING A MODEL BASED APPROACH Summary 1 One of the problems in seismic interpretation is the presence of multiples. Unlike marine acquisition where surface multiples are the dominant noise land data has predominant interbed multiples. As exploration and development focuses on deeper reservoirs multiple interference becomes increasingly significant and frequently makes the interpretation of seismic data ambiguous. To identify these deep multiple generators a model-based approach has been developed. The method consists of four steps: (1) well log blocking and model creation (2) synthetic seismogram generation (3) layer stripping and (4) identification of multiple
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Enhanced Post-Stack Multiple Prediction Using Demigration
Authors M.S. Al-Bannagi and D.J. VerschuurB-42 ENHANCED POST-STACK MULTIPLE PREDICTION USING DEMIGRATION Abstract 1 The theory of surface-related multiple removal has been developed for pre-stack data. However for laterally smooth media the method can be approximated in the post-stack domain. Although less accurate it makes the application very fast and easy to apply in many practical situations especially for low-relief structures. The objective of the proposed method is to combine the advantages of both approaches: the robustness and efficiency of the poststack domain with the accuracy of the pre-stack domain. In this method the zero offset prestack multiple prediction result is calculated from demigrated post-stack
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It's Magic – Industry First 3D Surface Multiple Elimination and Pre-Stack Depth Migration on Ormen Lange
Authors G. Kleemeyer, S.E. Pettersson, R. Eppenga, C.J. Haneveld, J. Biersteker and R. den OudenB-43 IT’S MAGIC – INDUSTRY FIRST 3D SURFACE MULTIPLE ELIMINATION AND PRE-STACK DEPTH MIGRATION ON ORMEN LANGE Introduction 1 The giant Ormen Lange field is the first commercial deepwater discovery in Norway. Discovered in 1997 the field is the second largest gas discovery offshore Norway. The field is located about 100 km west of the coast of Møre in water depths of about 1000 m. Situated underneath the huge Storegga slide that happened 8000 years b.p. the development of Ormen Lange faces tremendous challenges. Norsk Hydro operates the Ormen Lange development and Norske Shell is the designated operator for the
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Multiple Prediction and Subtraction – An SRME and IME Case History
Authors D. Ellis and R. van BorselenB-44 MULTIPLE PREDICTION AND SUBTRACTION – AN SRME AND IME CASE HISTORY Summary 1 Surface-related multiple elimination (SRME) and internal multiple elimination (IME) were applied to a 2D line extracted from a marine 3D dataset. Results were compared with those obtained from parabolic Radon filtering. Owing to the complex 3D geological environment the multiples’ indistinct nature their uncertain origin and the relatively poor dip contrast with the primary reflections it has proven to be a challenge to judge the accuracy of the predicted multiples and in particular the effectiveness of the adaptive subtraction of the multiples predicted through SRME and
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An Evaluation of Peak and Bubble Tuning in Sub-Basalt Imaging – Modelling and Results
Authors Z.C. Lunnon, P.A.F. Christie and R.S. WhiteC-01 AN EVALUATION OF PEAK AND BUBBLE TUNING IN SUB-BASALT IMAGING - MODELLING AND RESULTS Summary 1 Z. LUNNON 1 P. CHRISTIE 2 and R. WHITE 1 1 Bullard Labs Madingley Road Cambridge CB3 0EZ UK 2 Schlumberger Cambridge Research As part of the iSIMM project (White et al. 2002) a 6 360 in 3 airgun source array was used to shoot twice a deep seismic profile into a 380 km array of Ocean Bottom Seismometers (OBS) east of the Faroe Islands. The first pass used peak tuning and the second used bubble tuning with other source parameters constant. The
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Improved Imaging by Pre-Stack Depth Migration of Multi-Azimuth Towed Streamer Seismic Data
More LessC-02 IMPROVED IMAGING BY PRE-STACK DEPTH MIGRATION OF MULTI-AZIMUTH TOWED STREAMER SEISMIC DATA Summary 1 STIAN HEGNA and DOROTHEE GAUS EAGE 65th Conference & Exhibition — Stavanger Norway 2 - 5 June 2003 PGS Geophysical Oslo Norway Seismic imaging is a major challenge over the Varg Field in Block 15/12 offshore Norway due to complex salt structures and a high velocity Chalk layer above the target levels. The original 3D survey covering the Varg Field has been processed many times to try to improve the quality of the seismic data. In spite of all the processing attempts seismic imaging remained
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Repeatability Enhancement in Deepwater Permanent Installations
Authors A. Bertrand and C. MacbethC-03 REPEATABILITY ENHANCEMENT IN DEEPWATER PERMANENT INSTALLATIONS Summary 1 Seawater velocity variations can have a significant impact on the repeatability of frequently acquired time-lapse seismic data. Here this effect is assessed by processing modelled data based on a real hydrocarbon reservoir in the West of Shetlands. The repeatability metrics calculated for synthetic seabed data perturbed by realistic seawater velocity variations indicate poor seismic repeatability. The data are then corrected in the shot domain according to a new method which removes the dynamic traveltime differences for each trace. After correction the distortions caused by the water changes are virtually eliminated. We
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Azimuth Preservation in Marine 4D Acquisition
Authors M. Widmaier, S. Hegna, F. Smit and E. TijdensC-04 Azimuth Preservation in Marine 4D Acquisition Summary - An Acquisition Strategy for Marine 4D Repeating source-receiver azimuths can be an important aspect of 4D acquisition. Seismic repeatability will decrease with an increase of source-receiver azimuth differences between base and monitor surveys. This paper discusses a marine acquisition strategy with respect to the optimal preservation of source-receiver azimuths in the presence of feathering. We show that repeating shot positions is favourable for azimuth preservation in 4D acquisition in combination with overlap configurations (additional outer streamers). With a dense streamer separation source-receiver azimuths can be repeated very accurately by using this
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Positioning Accuracy and 4D Seismic Sensitivity in Land Acquisition
Authors S. Herculin and J. MeunierC-05 POSITIONING ACCURACY AND 4D SEISMIC SENSITIVITY IN LAND ACQUISITION 1 Abstract The most challenging difficulty of marine 4D seismic technology is repeating a given acquisition geometry with high precision. This challenge does not exist onshore. It is therefore possible to aim for the higher 4D sensitivity needed to observe changes in carbonated reservoirs. The required precision of source and receiver deployment is first evaluated on synthetic data. A field experiment is conducted its results are analyzed and as a conclusion recommendations are made to achieve higher 4D sensitivity. Introduction The slower development of 4D seismic technology onshore than offshore
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Simultaneous Coded Vibroseismics
By M. BecqueyC-06 SIMULTANEOUS CODED VIBROSEISMICS Abstract Vibrations from two vibrators emitting simultaneously with shifted coded signals were recorded and separated. Processing and stacked sections are similar to the results obtained with a classical sweep acquisition. The possibilities of separation of simultaneous records offered by the experimented codes may lead to an increase in productivity. They may also lead to an increase in resolution by allowing to dissociate and reconstruct the shot arrays. Introduction Methods for separating overlapping sweeps have been developed for productivity purposes (Rozemond 1996). These methods encounter some problems with the presence of harmonic noise (Meunier et al. 2001).
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One Step Better than Static Corrections – The Topographic Datuming Operator
Authors C. Bagaini and T. AlkhalifahC-07 ONE STEP BETTER THEN STATIC CORRECTIONS - THE TOPOGRAPHIC DATUMING OPERATOR Abstract 1 We formulate an analytical expression of a new prestack operator the Topographic Datuming Operator (TDO). This datuming operator generalizes the operation of static corrections which is very well known in the seismic exploration community and widely used in land seismic data processing. TDO eliminates the essential assumption of vertical incidence to the Earth’s surface of the downward- and upward-propagating reflected wavefield which is not valid in the presence of high-velocity shallow layers and/or large offset-to-reflector depth ratios. The assumptions of equivalent constant velocities for the overburden
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Influence of Acquisition-Related Amplitude Variations on Imaged-Reflector Amplitude Accuracy
Authors M.B. Koch, G.G. Drijkoningen, A.W.F. Volker and N. FilippidouC-08 INFLUENCE OF ACQUISITION-RELATED AMPLITUDE VARIATIONS ON IMAGED- REFLECTOR AMPLITUDE ACCURACY Summary 1 MENNO KOCH 1 GUY DRIJKONINGEN 1 ARNO VOLKER 2 and NIKOLETTA FILIPPIDOU 1 1 Delft University of Technology Department of Applied Earth Sciences EAGE 65th Conference & Exhibition — Stavanger Norway 2 - 5 June 2003 2 TNO TPD Delft Many factors in aseismic acquisition and processing sequence affect the reliability of the amplitudes in a seismic image. On land data the acquisition footprint is usually not observed due to other amplitude errors like source- and geophone-to-ground interaction effects. The CFP method enables the assessments of the
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Rock Physics around the World – Local Differences and Global Similarities
Authors P. Avseth, R. Ona, S.L. Jensen and A-J. van WijngaardenC-09 ROCK PHYSICS AROUND THE WORLD – LOCAL DIFFERENCES AND GLOBAL SIMILARITIES Abstract 1 Rock physics and seismic properties of rocks are highly controlled by local geologic factors. Thus rock physics properties can change dramatically within a given sedimentary basin. For the same reason rocks in different areas of the world may have very different seismic properties even if the burial depth is the same. Critical geologic factors that control seismic properties are either related to mineralogy depositional environment or burial history. In this paper we demonstrate that local geology is important when analyzing rock physics and seismic properties in
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Views of Rock Physics in a Ternary Space
Authors W.D. Pennington and D. ForelC-10 VIEWS OF ROCK PHYSICS IN A TERNARY SPACE Summary 1 Elastic properties of rocks can be made easier to understand and to compare among models when viewed in a three-dimensional “ternary space” with parameters plotted above a ternary diagram that represents the composition of a rock. Vagaries of certain models and differences or similarities among models that are difficult to explain when viewed in the conventional two-dimensional framework suddenly appear intuitive and straightforward. The ternary space model can be extended to additional dimensions although then it is difficult to visualize. In any number of dimensions the model can be
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Elastic Behaviour of North Sea Chalk
Authors L. Gommesen, I.L. Fabricius and J.M. PedersenC-11 ELASTIC BEHAVIOUR OF NORTH SEA CHALK 1 L. GOMMESEN 1 I. L. FABRICIUS 2 and J. M. PEDERSEN 3 . 1 Ødegaard A/S Titangade 15 DK-2200 Copenhagen Denmark formerly E&R Technical University of Denmark. 2 E&R Technical University of Denmark. Summary This work describes the elastic behaviour of chalk from the Ekofisk Tor and Hod formations from the Danish sector of the North Sea from a study of log data from four wells. We discuss the detection of cementation and how it affects the elastic behaviour of the chalk. By applying a suitable fluid substitution model to an established
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Velocity, Saturation and Fluid Distribution Measured by a 4D-CT Laboratory Method
Authors S.E. Johnstad and K. MonsenC-12 VELOCITY SATURATION AND FLUID DISTRIBUTION MEASURED BY A 4D-CT LABORATORY METHOD Summary 1 A recently developed laboratory method allows for simultaneous imaging of fluid distribution and measurement of acoustic wave velocities during flooding experiments. Using a specially designed acoustic sample holder that combines high pressure capacity with good transparency for X-rays it is possible to investigate velocity-fluid saturation relations at reservoir stress levels. High-resolution 3-D images are constructed from thin slices of cross-sectional CT-scans covering the entire rock core volume showing the distribution of fluid at different saturation levels. The system is briefly described and examples are presented from
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Wave Velocities in Shales – A Rock Physics Model
More LessC-13 WAVE VELOCITIES IN SHALES – A ROCK PHYSICS MODEL Abstract 1 A rock physics model for predicting wave velocities in shale has been established based on the Hashin-Shtrikman (1963) theory for elastic properties of composite media. The model has been used to analyse P-wave velocity measurements on 20 different shale cores with porosities ranging from 3 to 70 %. At present it seems to capture the porosity dependence as well as the stress sensitivity of the P-wave velocity. Introduction Elastic wave propagation in shale is of interest to the petroleum industry for several reasons. All seismic investigations of reservoirs
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Rock Physics of Gas Hydrate Reservoir
Authors J. Dvorkin and A. NurC-14 ROCK PHYSICS OF GAS HYDRATE RESERVOIR 1 Summary. Enormous amounts of methane gas hydrate are present in sediments under the world's oceans as well as in on-shore sediments in the Arctic. These hydrates are a potential future energy resource. The most well-developed geophysical tool for exploring large volumes of the subsurface where gas hydrate is found is seismic reflection profiling. To characterize a natural gas hydrate reservoir with seismic data we must be able to relate the elastic properties of the sediment to the volume of gas hydrate present. One way of achieving this goal is through rock physics
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Experimental Study of Wettability and Seismic Velocity in Sandstones
Authors J. Sothcott, C McCann, S. Assefa, P.R. Domnesteanu and T.R. AstinC-15 EXPERIMENTAL STUDY OF WETTABILITY AND SEISMIC VELOCITY IN SANDSTONES Summary 1 This abstract presents the results of a laboratory investigation into the effect of changed wettability and of pore fluid type on the acoustic properties of two sandstones. The compressional wave velocity and the shear wave velocity were measured for the core plugs saturated with brine with a mixed phase of crude oil/brine and with crude oil at effective pressures up to 60 MPa. The wettability of the core was changed by ageing wettability state being determined by environmental scanning electron microscope observations. Introduction Oil fields exhibit a wide
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Ranking Geological Drives for Mapping Fracture Intensity at the Pinedale Anticline
Authors P.M. Wong and S. BoernerC-17 RANKING GEOLOGICAL DRIVES FOR MAPPING FRACTURE INTENSITY AT THE PINEDALE ANTICLINE Abstract 1 Fractured reservoir characterization requires a good understanding of the spatial distribution of fracture intensity. In practice the relationships between various geological drivers and fracture indicator are complex and highly nonlinear. The problem is worse when there are many drivers but the number of sample locations is small. This paper compares the use of two ranking algorithms namely “fuzzy ranking” and “optimized piecewise rank correlation” or OPRAC for selecting relevant drivers for building regression models. The study uses a set of seismic and gas production data at
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Fracture Mapping Using Azimuthal Velocity/AVOA Seismic Data in Saudi Arabia
Authors F.A. Neves, A. Al-Marzoug, J.J. Kim and E. NebrijaC-18 FRACTURE MAPPING USING AZIMUTHAL VELOCITY/AVOA SEISMIC DATA IN SAUDI ARABIA Abstract 1 A wide-azimuth full-offset 3D P-wave seismic survey has been acquired over a sandstone gas reservoir in Saudi Arabia. The seismic data have been processed to preserve and extract anisotropic effects. Velocity and amplitude ellipticities were computed from pre-stack seismic data using a software developed in house by Saudi Aramco. Our results showed a slight azimuthal variation in P-wave velocity and significant variation in Amplitude-Variation-with- Offset-and-Azimuth (AVOA) at the reservoir level which were interpreted as being generated by either aligned vertical fractures or induced by the predominant tectonic
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Fracture Anisotropy Signatures in the Wudayhi Field Using Azimuthal Seismic Data
Authors K.A. Al-Hawas, M.S. Ameen, M. Wahab, E. Nebrija and C. MacBethC-19 FRACTURE ANISOTROPY SIGNATURES IN THE WUDAYHI FIELD USING AZIMUTHAL SEISMIC DATA 1 KHALID AL-HAWAS 1 MOHAMMED AMEEN 1 MOHAMMAD WAHAB 1 ED NEBRIJA 1 Summary The Wudyhi Field was discovered in Saudi Arabia in 1998. Well testing of the first few wells indicates that fractures are essential part of the reservoir. This makes it of paramount importance to detect and characterize the fracture distribution in the reservoir to optimize field development. Seismic data from a recently acquired wide-azimuth full-offset 3D survey shot over the Wudayhi are processed and interpreted to detect the azimuthal signature of aligned vertical fractures and
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Seismic Fracture Analysis on the Pinedale Anticline – Implications for Improving Drilling Success
Authors F.D. Gray, D. Todorovic-Marinic and M. LahrC-20 SEISMIC FRACTURE ANALYSIS ON THE PINEDALE ANTICLINE – IMPLICATIONS FOR IMPROVING DRILLING SUCCESS Summary 1 The Pinedale Anticline in Wyoming USA has become an area of significant interest since the recent success of several wells that have produced significant volumes of gas from its tight sandstone reservoirs. Production from these reservoirs is now possible using new stimulation techniques that were developed in neighboring Jonah Field. The best production rates appear to come from reservoirs that have had their permeability enhanced by natural fractures. Therefore the ability to detect the presence of natural fractures in the reservoir could have a
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Robust P-Wave Fracture Characterization from Wide-Azimuth Seismic Data
Authors E. Angerer, D. Lecerf and P. LanfranchiC-21 ROBUST P-WAVE FRACTURE CHARACTERIZATION FROM WIDE-AZIMUTH SEISMIC DATA Abstract 1 Reliable sub-seismic scale fracture characterization requires an integrated approach of wideazimuth wide-offset data acquisition data processing robust attribute generation and subsequent inversion of fracture-related azimuthal anisotropic effects. This workflow is illustrated on a real data example. A recently developed approach of geostatistical decomposition makes it possible to separate azimuthal seismic attributes into (1) a “geological” common part (2) the azimuth-dependent fracture information and (3) random and organized noise. A linear least-squares inversion leads to fracture density and orientation maps. Introduction Fractures cause second-order variations of both P- and S-wave
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PS-Wave Azimuthal Anisotropy – Seismic Properties for Fractured-Reservoir Management
Authors J.E. Gaiser and R.R. Van DokC-22 PS-WAVE AZIMUTHAL ANISOTROPY – SEISMIC PROPERTIES FOR FRACTURED- RESERVOIR MANAGEMENT Abstract 1 Fractures can significantly influence the behavior of reservoir porosity and permeability resulting in numerous dry wells and higher production costs. In some cases fractures can dominate storage and flow mechanisms within the reservoir and in other cases they can create barriers. 3D converted wave (PS-wave) surveys provide complimentary surface-seismic information to help identify fracture properties early in the production history of a reservoir. Based on azimuthal anisotropy measurements PS-waves indicate fracture density and strike and are also sensitive to fracture dip because of their asymmetry. These large-scale
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Azimuthal Anisotropy Analyses Using Multicomponent Seismic Data
Authors T. Probert, B. Olofsson, J. Gaiser, D. Underwood and P. KristiansenC-23 AZIMUTHAL ANISOTROPY ANALYSES USING MULTICOMPONENT SEISMIC DATA Abstract 1 There are numerous published case studies showing that 3D converted-wave processing can be successfully used to help solve a number of different geophysical problems. For instance imaging a low P-impedance contrast improved sub-gas imaging and characterizing reservoir fractures. However there is rarely a standard survey design and the processing is often dependent on the survey design and the geophysical objectives. One aspect that has become more important for all 3D converted-wave processing is the effect of S-wave splitting. This may be exploited to characterize reservoir fractures or it may be
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The Potential of Estimating Fracture Sizes from the Frequency Dependence of Anisotropy
Authors S. Maultzsch, M. Chapman and E. LiuC-24 THE POTENTIAL OF ESTIMATING FRACTURE SIZES FROM THE FREQUENCY DEPENDENCE OF ANISOTROPY Summary 1 Frequency-dependent anisotropy has been observed in seismic data and it can be explained by fluid flow in fractured porous rock. In this study we use a new equivalent medium theory that considers fluid movement due to a squirt-flow mechanism at two scales: the grain scale where the pore space consists of micro-cracks and equant matrix porosity and formation-scale fractures. The theory models velocity dispersion and frequency dependence of anisotropy with the fracture length being one of the key parameters. The model is first tested and
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