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63rd EAGE Conference & Exhibition
- Conference date: 11 Jun 2001 - 15 Jun 2001
- Location: Amsterdam, Netherlands
- Published: 11 June 2001
101 - 200 of 516 results
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The Use of Distributed Well Temperature Measurements in Waterflood Management
Authors D.J. Element, S.G. Goodyear and C. BlenkinsopIOR-06 THE USE OF DISTRIBUTED WELL TEMPERATURE MEASUREMENTS IN WATERFLOOD MANAGEMENT Abstract 1 Fibre optic sensor technology is being increasingly used by the oil industry. Optical fibres can be permanently installed in a well providing distributed real time temperature data at a one-metre resolution. This paper investigates the link between the temperature distribution in the well and the reservoir performance. A range of fine grid reservoir simulations have been examined to study the temperature changes in a production well over the course of field history aiming to assess the potential value of accurate distributed well temperature data for management of
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Pulse Injection Technology for IOR
Authors A.S. Cable, M.P. Dorey, S.G. Goodyear and A.J. JayasekeraIOR-07 PULSE INJECTION TECHNOLOGY FOR IOR Abstract 1 This study investigated the effects of pressure pulsing on laboratory SCAL measurements using an unconsolidated and consolidated sand refined oils and γ-ray in-situ saturation monitoring (ISSM). Published literature presented at the 1999 European IOR Symposium has suggested that under pulsed flow conditions Darcy’s law may no longer be a valid description of single phase flow and that suppression of viscous fingering may also lead to significant improvement in oil productivity. It was possible to reproduce the published single phase data but our measurements showed that by careful measurement of the flow rate
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Dacion Field Rehabilitation
Authors M. Frorup, S. Adams, N. Charlwood and R. WoodIOR-08 DACION FIELD REHABILITATION Abstract 1 The Dacion field which is located in the eastern Venezuelan basin came on production about 50 years ago. In the early years of development more than 300 wells were drilled and production reached a peak of 45000 bbl/D of oil at about 1958. After that the drilling slowed down and the field was operated on a rate maintenance basis. By 1997 the rate had fallen to approximately 11500 bbl/D. In 1998 Lasmo Venezuela took over operations of the Dacion field after the third Venezuelan licensing round lead by PDVSA and has in two years
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Combination of Enhanced Oil Recovery and Near Zero CO2 Emission Power Plants
Authors C. Schroeder, S. Houyou, P. Illing, P. Mathieu and A. MonjoieIOR-09 COMBINATION OF ENHANCED OIL RECOVERY AND NEAR ZERO CO2 EMISSION POWER PLANTS Abstract 1 This paper addresses two basic today’s issues namely the release of CO2 in the atmosphere from fossil fuels combustion and the depletion of fossil fuels resources. The objective here is double : mitigate the CO2 emissions and increase the resources of fossil fuels. For this purpose it is proposed to combine a new type of power plants designed to control the CO2 releases and the increase of the recovery rate from oil wells by injection of CO2 instead of water. Up to now the production
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Foam Assisted WAG, a Summary of Field Experience at the Snorre Field
Authors A. Skauge, L. Rasmussen, T. Blaker, H. Celius, H.A. Martinsen, I. Svorstøl and M.G. AarraIOR-10 FOAM ASSISTED WAG A SUMMARY OF FIELD EXPERIENCE AT THE SNORRE FIELD Abstract 1 A. SKAUGE 1 L. RASMUSSEN 2 T. BLAKER 2 H. CELIUS 3 H.A. MARTINSEN 3 I. SVORSTØL 2 and M.G. AARRA 1 1 Norsk Hydro ASA 5020 Bergen Norway 2 Norsk Hydro ASA Norway 3 SEPRO Trondheim Norway The Foam Assisted WAG (FAWAG) is a large-scale demonstration of foam for gas mobility control. Foam has been applied at the Snorre field several times first as a production well treatment thereafter in a large scale gas mobility control process. The WAG process on Snorre is limited
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Optimum Rock Bit Program Selection by Integrated Geostatistics and Artificial Intelligence
Authors S. Akin, S. Yilmaz and C. DemirciogluIOR-11 OPTIMUM ROCK BIT PROGRAM SELECTION BY INTEGRATED GEOSTATISTICS AND ARTIFICIAL INTELLIGENCE Abstract 1 Optimum bit selection is one of the important issues in drilling engineering. Usually optimum bit selection is determined by the lowest cost per foot and is a function of bit cost and performance as well as penetration rate. Conventional optimum rock bit selection program involves development of computer programs created from mathematical models along with information from previously drilled wells in the same area. Based on the data gathered on a daily basis for each well drilled the optimum drilling program may be modified and revised
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Physico-Chemical IOR Method for Cyclic Steam Stimulation of High-Viscosity Oil Reservoir
Authors V.A. Kuvshinov, L.K. Altunina and V.V. KuvshinovIOR-12 PHYSICO-CHEMICAL IOR METHOD FOR CYCLIC STEAM STIMULATION OF HIGH- VISCOSITY OIL RESERVOIR Abstract 1 Technology has been developed to improve the efficiency of steam-cyclic treatment of wells in high-viscosity oil fields using chemical reagents. We propose to inject the composition of substances before steam infusion which are capable to form CO2 and ammoniac buffer system in the formation under the influence of steam temperature. In this case the formation of steam tongues (fingers) is realized at a maximum. 2D computer cluster model has been developed for the formation and propagation of steam tongues due to which steam-heated zone is
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Thermal Gas-Dynamical Technologies for Recovery of Viscous Oils - Application Experience
Authors Y.I. Stashok, D.G. Antoniadi, G.G. Gilaev and E.A. LysenkovIOR-13 THERMAL GAS-DYNAMICAL TECHNOLOGIES FOR RECOVERY OF VISCOUS OILS – APPLICATION EXPERIENCE Abstract 1 Presented in the paper are the basic results of pilot-commercial introduction of technological processes for production of viscous oils. The essence of the process lies in cyclic stimulation of bottom-hole formation zone with gas-steam heat-carrier. Pilot-commercial works are performed by oil-producing companies ROSNEFT-Termneft and ROSNEFT-Krasnodarneftegas subsidiaries of the state oil company ROSNEFT. Included in the paper are only the results obtained in Achtyrsko-Bugundyrskoe oil field operated by ROSNEFT-Krasnodarneftegas. Introduction Achtyrsko-Bugundyrskoe oil field has been developed for more than 50 years and now the development is in
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Influence of Collector's Irreversible Deformation on Oil Recovery
Authors N.A. Cheremisin, V.P. Sonich and P.A. EfimovIOR-14 INFLUENCE OF COLLECTOR’S IRREVERSIBLE DEFORMATION ON OIL RECOVERY N.A. CHEREMISIN V.P. SONICH and P.A. EFIMOV Abstract 1 The rocks of hydrocarbon deposits consisting of granular reservoirs and occurring on their historical maximum depth are subject to an additional stress at a reservoir pressure drop during their development. This additional stress leads to not only the elastic but also to the plastic deformation of rocks. Based on the laboratory and theoretical studies results it is shown that the irreversible deformation has a considerable influence on the deposit performance changing not only reservoir properties and a ratio of the fluids saturating
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The Application of Magnetic Liquide Treatment in Oil Fields of West Siberia
Authors O.V. Gavriluk and O.V. GlazkovIOR-15 THE APPLICATION OF MAGNETIC LIQUIDE TREATMENT IN OIL FIELDS OF WEST SIBERIA O.V. GAVRILUK and O.V. GLAZKOV 1 Russian Academy of Sciences Institute of Petroleum Chemistry 3 Akademichesky Avenue 634021 Tomsk Russia The formations of asphalt-resin-paraffin (ARPD) and saline deposits in the tubing string (TS) and in delivery lines are considered as the most urgent problems arising during exploitation of some oil fields in West Siberia. As a consequence – increased equipment failures shortened cleaning (CP) and overhaul (OP) periods of well operation as well as the increased pulling the tubing for cleaning and partial replacement causing production losses
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Current Statue and Prospects of EOR Methods and Oil Production - Intensification in the Fields of OJSC "SURGUTNEFTEGAZ
Authors G.A. Malyshev, V.P. Sonich and D.F. SedachIOR-16 CURRENT STATUE AND PROSPECTS OF EOR METHODS AND OIL PRODUCTION INTENSIFICATION IN THE FIELDS OF OJSC “SURGUTNEFTEGAZ” G.A. MALYSHEV 1 V.P. SONICH 1 and V.F. SEDACH 2 Abstract 1 One of the first priority trends of OJSC Surgutneftegaz's activities is an oil recovery enhancement and oil production intensification. During the period from 1990 to 2000 more than 53 thousand well operations were performed using about 60 various techniques that resulted in production of more than 60 million tons of incremental oil. The annual increase in the volumes of EOR methods application is more than 20% which allowed for planning
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Thermoreversible Polymer Gels Used to Increase Conformance of High-Viscosity Reservoirs by Heat Stimulation
Authors L.K. Altunina and V.A. KuvshinovIOR-17 THERMOREVERSIBLE POLYMER GELS USED TO INCREASE CONFORMANCE OF HIGH- VISCOSITY RESERVOIRS BY HEAT STIMULATION L.K. ALTUNINA and V.A. KUVSHINOV Abstract 1 Physico-chemical rheological and filtration characteristics as well as oil displacing capacity of gel forming thermoreversible polymer solutions with lower critical dissolution point have been studied in the temperature interval ranging from 90 to 250 o C. Such gel forming solutions were prepared based on the system cellulose ethers – carbamide – aqueous phase. Gel forming solutions have been proposed to regulate filtration patterns and to increase conformance of highviscosity oil reservoirs by heat stimulation. The experimental studies were
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Static Perturbation Corrections on Single Sensor Data
Authors G.J.M. Baeten, L. Combee and L. WestIS-1 STATIC PERTURBATION CORRECTIONS ON SINGLE SENSOR DATA G.J.M. BAETEN 1 L. COMBEE 2 and L. WEST 1 Abstract 1 One of the main determining factors for the quality of land seismic data is the accuracy of the static corrections. Static corrections aim at correcting for time shifts between traces which are principally due to near-surface effects. As far as conventional statics techniques are concerned there are two classes of solutions: • Deterministic statics solutions. For example field statics based on upholes and elevation measurements; refraction statics solutions based on first break picking and assumptions about the layered structure of
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Problems in Measuring the Coherent Noise Produced in Near-Surface Scattering
By C. RegoneIS-2 PROBLEMS IN MEASURING THE COHERENT NOISE PRODUCED IN NEAR-SURFACE SCATTERING C. REGONE SUMMARY “Measurement and identification of 3D coherent noise generated from irregular surface carbonates” EAGE 63rd Conference & Technical Exhibition — Amsterdam The Netherlands 11 - 15 June 2001 1 When near-surface scattering produces high levels of coherent noise successful acquisition design requires knowledge of the noise characteristics. Most field tests conducted to measure noise characteristics have serious deficiencies. 2D methods such as walkaway wave tests and CMP stacked sections may sometimes reveal the presence of in-line scattered noise. Often scattered energy arrives from many azimuths with equal
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Application of Two Ground Roll Reduction Techniques to Scattered Ground Roll
Authors J. Meunier and M. BecqueyIS-3 APPLICATION OF TWO GROUND ROLL REDUCTION TECHNIQUES TO SCATTERED GROUND ROLL JULIEN MEUNIER 1 and MARC BECQUEY 2 1 Summary Scattered noise attenuation is one of the most challenging problems of the land seismic method. Even full fold 3D geometry does not provide an effective solution to this problem. This paper shows how 2 ground roll reduction techniques namely 3D FK filtering and Polarisation filtering designed to attenuate radial noise can be adapted to also reduce scattered noise. Introduction Any ground roll reduction technique must take advantage of the difference between Signal (the reflected waves) and Noise (the ground
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Spatially Fixed Patterns for Resolving Large Magnitude Short Wavelength Statics and More
Authors P.I. Pecholcs, L. Lafreniere, S. Hubbell, V. Kozyrev, I. Korotkov and A. ZhukovIS-4 SPATIALLY FIXED PATTERNS FOR RESOLVING LARGE MAGNITUDE SHORT WAVELENGTH STATICS AND MORE Abstract 1 In Saudi Arabia the complex three-dimensional near-surface overburden can introduce large magnitude short-wavelength time delays greater than half a period and wavelengths greater than half an effective spread length. Since automatic residual statics algorithms fail to resolve these statics additional geologic information is needed during the interpretation phase to constrain the near-surface model. These errors are overcome by combining this interpretation phase with a new partial-offset stack domain within a standalone PC-based interpretation system. This interpretation system uses multiple forward and reverse partial-offset stack displays
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Impact of Near Surface Scattering on Seismic Data in Oman
Authors M. Van der Veen and G.C. HermanIS-5 IMPACT OF NEAR SURFACE SCATTERING ON SEISMIC DATA IN OMAN M. VAN DER VEEN 1 and G.C. HERMAN 2 Abstract 1 This paper describes the case history of the "Misfar" 3D seismic survey in Oman that suffered from severe near-surface scattering. In terms of near-surface and subsurface geology this survey is representative for large areas of Oman. Traditional processing methods yielded data of moderate quality. In order to improve the data an inverse scattering method was tried. Results are shown from application of this process as run on a small subset of Misfar. It shows that on individual shot
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Overview of Some Coherent Noise Separation Methods
Authors G.T. Schuster and J. YuIS-006 Abstract OVERVIEW OF SOME COHERENT NOISE SEPARATION METHODS GERARD T. SCHUSTER AND JIANHUA YU University of Utah Salt Lake City Utah 84112 U.S.A Coherent noise in seismic data particularly ground roll PS converted waves multiples and near-source scattering are major problems amplified by near-surface velocity variations. A partial remedy to coherent noise is to separate it from the signal by a suitable transform mute out the noise in the transformed domain and then inverse transform to get the noise-reduced signal. I will review five coherent noise separation methods: FK linear ¡ £ parabolic ¡ £ hyperbolic
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Discriminating Near Surface Effects from Signal via Azimuthal Offset Sampling in Land 3D Acquisition Design and Processing
Authors W. Goodway, D. Cooper, S. Cheadle, R. Kendall and A. HaaseIS-7 DISCRIMINATING NEAR SURFACE EFFECTS FROM SIGNAL VIA AZIMUTHAL OFFSET SAMPLING IN LAND 3D ACQUISITION DESIGN AND PROCESSING 1 W. GOODWAY 1 D. COOPER 1 S. CHEADLE 2 R. KENDALL 2 and A. HAASE 3 1 PanCanadian Petroleum 150-9th Avenue S.W. PO Box 2850 Calgary Alta T2P 2S5 Canada 2 Veritas GeoServices 3 Geo-X Systems INTRODUCTION Ensuring comparable land 3D to 2D quality requires sampling a four dimensional spatial wavefield (shots receivers in x y) at a comparable density to a 2D wavefield in two dimensions (linear shots receivers in x). As this density of shots and receivers is cost
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On the Use of Seismic Velocities in Model Building for Depth Conversion
By T. CouleouIV-1 ON THE USE OF SEISMIC VELOCITIES IN MODEL BUILDING FOR DEPTH CONVERSION Introduction 1 The most common depth conversion method over the last few decades has been to use functions derived from well data. Stacking velocities have traditionally been regarded as less precise and have only been preferred in those cases where lateral velocity variations were dominating. In recent years this has changed. Modern stacking velocity data and methods are of better quality due to improvements in seismic processing and numerical modelling techniques. Today stacking velocity depth conversion is the preferred method in many areas around the world especially
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Velocity Anomalies and Depth Conversion - Drilling Success on Nelson Field, Central North Sea
By T. ArmstrongIV-2 VELOCITY ANOMALIES AND DEPTH CONVERSION – DRILLING SUCCESS ON NELSON FIELD CENTRAL NORTH SEA T. ARMSTRONG Summary 1 The Nelson Field overburden appears to be ‘simple’ comprising smooth horizontal or gently-dipping layers overlying a low-relief Top Reservoir structure. In fact a number of velocity anomalies of Quaternary Mio-Pliocene and Lower Eocene age introduce significant complexity via both steep and gradual lateral velocity gradients which need to be constrained for reliable depth conversion. Introduction The Nelson Field lies about 2.5 km SE of the giant Forties Field along the Forties-Montrose Ridge in the central North Sea. Oil is produced from
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An Assessment of the Impact on Depth Uncertainty of Different Velocity Models
Authors N.J. Crabtree, O. Allen, L.J. West and M. BeasleyIV-3 AN ASSESSMENT OF THE IMPACT ON DEPTH UNCERTAINTY OF DIFFERENT VELOCITY MODELS N.J. CRABTREE O. ALLEN L.J. WEST and M. BEASLEY Abstract 1 The problem of assessing the uncertainty of depth predictions calls for a thorough investigation of all valid methods and techniques. A combination of different methods such as interval velocity crossplotting instantaneous velocity curve fitting and kriging can be used to generate an optimum velocity model for time-to-depth conversion. When choosing an optimum velocity model one particular method has to be chosen at the expense of other nearly equivalent methods. A rigorous estimation of uncertainty needs to
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Pre-Stack Depth Migration for Time-to-Depth Conversion - the Ultimate Tool?
Authors C. Hanitzsch, E. Robein and P. SextonIV-4 PRE-STACK DEPTH MIGRATION FOR TIME-TO- DEPTH CONVERSION – THE ULTIMATE TOOL? Introduction The use of seismic data for accurately predicting the depth of a geological horizon remains one of the most difficult and risky tasks in the geophysicist’s job. In this paper we assess the role of Pre-Stack Depth Migration (Pre-SDM) as a depth conversion technique and question whether Pre-SDM can provide us with not only a better focused image of the subsurface but an image that is closer to true depth. There are many ways that the geophysicist can transform seismic data recorded as a function of wave
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Highlights of Deepwater E and P, with Special Emphasis on West Africa
By J. RoelofsenL-01 HIGHLIGHTS OF DEEPWATER E&P WITH SPECIAL EMPHASIS ON WEST AFRICA J. ROELOFSEN IHS ENERGY GROUP PO Box 152 1258 Perly-Geneva Switzerland 1 Introduction Deepwater exploration has been much on the frontpage of E&P news the last couple of years. And the statement of the early nineties that deepwater was the new frontier exploration area has become true with a series of giant oil and gas fields been discovered beyond the 500-meters water depth line. Notwithstanding this success in deepwater exploration the impact of the discovered reserves on the worldwide existing resources is limited. The probabiltiy to find future oil
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Prospecting in the Palaeocene Deep Water Sandstones of the Norwegian North Sea
Authors J.S. Willoughby, A. Van Bockstaele, J. Kristensen and T.H. DaleL-02 PROSPECTING IN THE PALAEOCENE DEEP WATER SANDSTONES OF THE NORWEGIAN NORTH SEA J. S. WILLOUGHBY A. VAN BOCKSTAELE J. KRISTENSEN and T. H. DALE Statoil Grenseveien 21 4035 Stavanger Norway 1 The Tertiary of the Norwegian North Sea is in its Renaissance period. It has been the focus of recent licence rounds and it is actively being explored. This paper will focus on the exploration of the deep-water fans of the Heimdal and Hermod Formations and will consider techniques used to define the presence of trap reservoir and hydrocarbons. It will include a review of the regional setting stratigraphic
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Nuggets Area Deep Marine Turbiditic Fan Complex, Northern North Sea
Authors R.N. Kimber, R. Cooper, M.C.R. Thomas, L.J. Burns, S.D. Harker and P. CornickL-03 NUGGETS AREA DEEP MARINE TURBIDITIC FAN COMPLEX NORTHERN NORTH SEA Abstract 1 R.N KIMBER 1 R. COOPER 1 M.C.R. THOMAS 2 L.J BURNS 1 S.D HARKER 1 and P. CORNICK 3 1 TotalFinaElf Exploration UK PLC 1 Claymore Drive Bridge of Don Aberdeen AB23 8GB UK 2 Adma-Opco 3 PCA Stratigraphic Consultants Ltd The Nuggets area is located between the Alwyn and Frigg Fields in UKCS Quadrant 3 North Sea and comprises four separate dry gas accumulations (Figure 1). The four Nuggets gas structures were discovered between 1972 and 1991 and are called N1 N2 N3 and N4 (operated
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Sub-Seismic Scale Heterogeneity in Sand-Rich Submarine Fans - Application of the 'Multi-System' Approach within the Greater Brae Area (UKCS)
More LessL-06 SUB-SEISMIC SCALE HETEROGENEITY IN SAND-RICH SUBMARINE FANS – APPLICATION OF THE ‘MULTI-SYSTEM’ APPROACH WITHIN THE GREATER BRAE AREA (UKCS) RICHARD HINEY 1 AND ANDREW HURST 2 1 1 PGS Data Processing PGS House Mayfield Road Walton-on-Thames Surrey KT12 5PL UK 2 Abderdeen University The Brae trend located approximately 145 miles (233 km) north-east of Aberdeen on the western edge of the Fladden Ground Spur is dominated by submarine fan sequences deposited against a background sedimentation of hemi-pelagic clay and low density turbidites. Producing intervals range from Jurassic conglomeratic units to Eocene channel sands. Rationale Using extensive well data and
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Seismic Expression of Large-Scale Sand Remobilisation and Injection in Paleogene Reservoirs of the North Sea Basin and Beyonds
Authors M. Huuse, D. Duranti, J. Cartwright, A. Hurst and B. CroninL-07 SEISMIC EXPRESSION OF LARGE-SCALE SAND REMOBILISATION AND INJECTION IN PALEOGENE RESERVOIRS OF THE NORTH SEA BASIN AND BEYOND 1 1 2 2 1 2 2 MADS HUUSE DAVIDE DURANTI JOE CARTWRIGHT ANDREW HURST and BRYAN CRONIN 1 Wales University 2 Aberdeen University Department of Geology & Petroleum Geology King’s College Aberdeen AB24 3UE UK Introduction Clastic intrusions have been studied in outcrop for more than a century but it is less than a decade since large-scale sand remobilisation and injection features were first recognised in seismic data from the Paleogene of the North Sea Central Trough. As even large-scale
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High Resolution Reservoir Characterization in the Deep Water Gulf of Mexico
Authors B. Bankhead, E. Meanley, D. Jordan and G. SchnerkL-08 HIGH RESOLUTION RESERVOIR CHARACTERIZATION IN THE DEEP WATER GULF OF MEXICO B. BANKHEAD E. MEANLEY D. JORDAN and G. SCHNERK Introduction 1 As the industry pushes into deeper water for hydrocarbon exploration the importance of High-Resolution Reservoir Characterization (HRRC) has increased dramatically as project costs often exceed $1.5 billion. HRRC encompasses the 3-dimensional quantitative determination of reservoir limits structure volume heterogeneity and reservoir properties through the detailed integration and continued iteration of petrophysics geology geophysics and reservoir engineering. This iterative and integrated approach results in the development of a reservoir simulation model which will yield better forecasts of field
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Some PS Mode Acquisition Requirements
Authors R.J. Garotta and P.Y. GrangerL-09 SOME PS MODE ACQUISITION REQUIREMENTS ROBERT GAROTTA and PIERRE-YVES GRANGER 1 Compagnie Générale de Géophysique 91341 Massy France Introduction The combination of compressional and PS converted mode data offers promising exploration tools. However the full benefits of this combination can be expected only when comparable resolution is obtained from the two modes at target level. It is currently often observed that PS resolution deteriorates with depth at a faster rate than P resolution. Some of the differences in P or PS propagations and recordings related to asymmetry or anisotropy have been closely investigated and are generally taken into account
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Triple Sensor Wavefield Separation
Authors M. Gidlow and J. SonnierL-10 TRIPLE SENSOR WAVEFIELD SEPARATION Summary 1 A method is described of identifying different wave modes recorded by ocean bottom multi-component detectors. Vertical geophone horizontal geophone and hydrophone data are combined to form filters which when applied to the input wavefields separate the upgoing P-waves upgoing S-wave and downgoing P-waves. Introduction Four component ocean bottom hardware consists of three orthogonal geophones and a hydrophone. This allows for the recording of compressional as well as shear energy. Shear energy mode converted from the compressional energy upon reflection provides additional information about the subsurface. Benefits of mode-converted seismic include: i) the enhanced
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Dispersive Noise Attenuation for Converted Wave Data
By R. SoubarasÄ �ÁËÈ�ÊËÁÎ� ÆÇÁË� �ÌÌ�ÆÍ�ÌÁÇÆ �ÇÊ �ÇÆÎ�ÊÌ�� Ï�Î� ��Ì� ÊÇ��ÊÌ ËÇÍ��Ê�Ë ËÙÑÑ�ÖÝ ��� ÖÙ� Ä��ÓÒ Å���ÙÜ � � Å�××Ý �Ö�Ò � Ì�� ÓÒÚ�ÒØ�ÓÒ�Ð Û�Ý Ó� �ØØ�ÒÙ�Ø�Ò� Ó��Ö�ÒØ ÒÓ�×� �× ØÓ Ù×� ��Ò ¬ÐØ�Ö× Ö�ÑÓÚ�Ò� � ��Ú�Ò Ú�ÐÓ �ØÝ Ö�Ò�� Ì��×� ¬ÐØ�Ö× �ÒÒÓØ �� Ú�ÖÝ ×�Ð� Ø�Ú� ��Ø��Ö �� �Ù×� Ó� �ÒØÖ�×� Ð�Ñ�Ø�Ø�ÓÒ× ÓÖ �� �Ù×� Ø�� Ú�ÐÓ �Ø��× �Ö� ÒÓØ �ÒÓÛÒ �Ü� ØÐÝ �Ò� Ú�ÖÝ �ÖÓÑ ��Ø��Ö ØÓ ��Ø��Ö Ì�� ÔÖÓ �××�Ò� Ó� È Ë ÓÒÚ�ÖØ�� Û�Ú�× �× � �×� Û��Ö� Ø�� ¬ÐØ�Ö× Ù×�� ØÓ �ØØ�ÒÙ�Ø� Ø�� Ó��Ö�ÒØ ÒÓ�×� ��Ú� ØÓ �� ×�Ð� Ø�Ú� ÁÒ Ø��× Ô�Ô�Ö �Ò �Ð�ÓÖ�Ø�Ñ �×
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Converted-Wave Prestack Imaging and Velocity Analysis by Pseudo-Offset Migration
More LessL-12 CONVERTED-WAVE PRESTACK IMAGING AND VELOCITY ANALYSIS BY PSEUDO-OFFSET MIGRATION WEIZHONG WANG and LONG D. PHAM Summary A new technique for converted-wave (Cwave) prestack imaging and velocity analysis is presented. This technique called pseudo-offset migration (POM) differs from equivalent-offset migration (EOM) (Bancroft et al. 1998) in how the migration mapping offset is defined. In this paper we show that POM is less dependent on the initial velocity than EOM and can produce better images and C-wave velocities than P- S DMO plus poststack migration. Introduction Converted-wave processing is more difficult than pure-mode processing. A simple common-conversion-point stack requires an input
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True Amplitude Migration of PS Converted Waves
Authors C. Vanelle and D. Gajewskiin terms of second order spatial derivatives of traveltimes � . Provided that a traveltime curve is smooth and single-valued (the approach is the same for multi-valued traveltimes but the different branches of the traveltime curve have to be treated separately) � can be expanded into a Taylor series corresponding to the paraxial approximation: � � © � � � � � � � (3) � � � � are the slownesses at the source and receiver the matrices and are the � second order derivatives of the traveltime with respect to receiver source and mixed coordinates. and� Vectors and
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Preserved Amplitude Depth Imaging - Application to an OBC Line (Mahogany)
Authors M. Alerini, S. Le Bégat and G. LambaréL-14 PRESERVED AMPLITUDE DEPTH IMAGING – APPLICATION TO AN OBC LINE (MAHOGANY) Abstract 1 We present a first application of our 2D elastic prestack depth processing sequence to an OBC line recorded on the Mahogany field. This sequence is based on ray tracing in smooth velocity models and oriented towards amplitude preservation. Common Image Gathers (CIG) in the angle domain are computed by P-P and P-S migration/inversion using a Vp velocity macro-model obtained by stereotomography and a Vs velocity macro-model deduced from the Vp model by iterative pre-stack depth migrations. Introduction Ocean Bottom Seismology provides an opportunity to improve reservoir
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P-P and P-S Joint Velocity Inversion for Multicomponent Seismic Data
By Y. ZhangL-15 P-P AND P-S JOINT VELOCITY INVERSION FOR MULTICOMPONENT SEISMIC DATA YAOHUI ZHANG 1 PGS Seres Division 738 Highway 6 South Suite 300 Houston TX 77079 USA Abstract A novel and robust method to extract P and S interval velocities from multicomponent seismic data via P-P and P-S joint velocity inversion is presented in this paper. The joint inversion was performed on time migrated data and the estimated initial velocities are decomposed and reconstructed into an invertible form for the derivation of P and S interval velocities. This method is a poststack inversion and is different from conventional velocity inversion
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Anisotropic Analysis and Processing of ALBA 4C OBC Data
Authors H. Dai, X.-Y. Li and M. MacLeodL-16 ANISOTROPIC ANALYSIS AND PROCESSING OF ALBA 4C OBC DATA H. DAI 1 X-Y. LI 1 and M. MACLEOD 2 Summary 1 In this paper we present the anisotropic analysis and processing results from the Alba 3D-4C OBC data. The results show strong evidence of both azimuthal and polar anisotropies. For the azimuthal anisotropy 20ms time-delay was identified from a shallow PS event at PS two-way time 1.4s and the principal direction is about 40 0 from the inline direction. The polar anisotropy estimated from a non-hyperbolic moveout analysis indicates an average 30% converted-wave anisotropy which yields about 2.0% P-wave
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Reservoir Architecture of a Barrier-Type Oil Field Explained by Process-Response Modelling
Authors L.J.H. Alberts and C.R. GeelL-17 RESERVOIR ARCHITECTURE OF A BARRIER- TYPE OIL FIELD EXPLAINED BY PROCESS- RESPONSE MODELLING LUC J.H. ALBERTS and CEES R. GEEL Summary 1 A numerical model that simulates processes responsible for sediment distribution in coastal areas was applied to the Lower Cretaceous Rijn Field West Netherlands Basin. A reconstructed sealevel curve and characterisation of the paleotopography of the region enabled a representative input for the model. Synthetic well logs were generated and compared to the measured well logs and showed generally a good match where the larger differences can be explained by specific geological characteristics that were not accounted for
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Application of Parallel Neural Networks for Reservoir Characterisation while Drilling
Authors A. Bhatt, H.B. Helle and B. UrsinL-18 APPLICATION OF PARALLEL NEURAL NETWORKS FOR RESERVOIR CHARACTERISATION WHILE DRILLING Abstract A new class of networks has been applied to reservoir characterisation using measurements while drilling (MWD) data. The parallel neural network consists of a number of identical networks (experts) trained on identical or overlapping patterns. We demonstrate that this approach is a pragmatic and accurate alternative for converting MWD data to common reservoir parameters such as porosity permeability and water saturation which leads to generation of relative permeability logs for input to real-time reservoir simulation for optimisation of well completion. Parallel Neural Networks Committee machines (CM) belong to
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The Definition of Transmissive-Dominated Hydraulic Units (THU) and Storage-Dominated Hydraulic Units (SHU) and Their Role in the Understanding of Reservoir Dynamics
Authors P.W.M. Corbett, Y. Ellabad and K. MohammedL-19 THE DEFINITION OF TRANSMISSIVE- DOMINATED HYDRAULIC UNITS (THU) AND STORAGE-DOMINATED HYDRAULIC UNITS (SHU) AND THEIR ROLE IN THE UNDERSTANDING OF RESERVOIR DYNAMICS Abstract 1 Two techniques in petrophysics have been combined for the first time to produce a description of the rock that links primary texture through to well test response. The method is proposed as a new approach to dynamic reservoir characterisation and is illustrated for two North African clastic reservoir examples. Introduction PATRICK CORBETT 1 YASIN ELLABAD 1 2 and KHALIFA MOHAMMED 1 3 1 Department of Petroleum Engineering Heriot-Watt University Edinburgh EH14 4AS UK 2 Wintershall
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Ground Penetrating Radar (GPR) Used to Measure 3D Architecture in the Carboniferous Ross Formation, County Clare, Western Ireland
Authors J.K. Pringle, A.R. Westerman, J.D. Clark and A.R. GardinerL-20 GROUND PENETRATING RADAR (GPR) USED TO MEASURE 3-D ARCHITECTURE IN THE CARBONIFEROUS ROSS FORMATION COUNTY CLARE WESTERN IRELAND Summary Ground Penetrating Radar data have been acquired on indurated turbidite sandstones from the Carboniferous Ross Formation in Western Ireland. A variety of frequencies was investigated to image turbidite channel margins bedding geometry and fine-scale sedimentological changes observed at outcrop. GPR data and interpreted horizons have been incorporated into outcrop models to create 3-D Digital Solid Models which can be interrogated and used as reference datasets for petroleum reservoir modellers. Introduction Petroleum reservoir models are typically constrained by data sets that
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Reservoir Modelling Analogues and Knowledge Management
Authors J. Marshall, M. Kosters and V. HitchingsL-21 RESERVOIR MODELLING ANALOGUES AND KNOWLEDGE MANAGEMENT 1 M. KOSTERS J. MARSHALL and V. HITCHINGS Shell International Expl. & Prod. B.V. PO Box 60 2280 AB Rijswijk The Netherlands Shell’s Reservoir Modelling Knowledge Base is a web-based knowledge management tool aimed at providing appropriate information to reservoir modellers at their point of need. The information may be numerical data analogue information or workflows. For the numerical data the tool provides browser applets and downloadable spreadsheets of outcrop and subsurface analogue geometries. The data is drawn from a wide range of published and in-house sources: considerable effort is spent in checking
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Bonga Field - an Integrated Approach to Subsurface Modelling in an Uncertain World
Authors P. Swinburn and R. van der Weiden1 L-22 BONGA FIELD – AN INTEGRATED APPROACH TO SUBSURFACE MODELLING IN AN UNCERTAIN WORLD P. SWINBURN and R. VAN DER WEIDEN Abstract Introduction The key to successful development planning is the building of earth models integrating all relevant subsurface data and predicting reservoir performance in the presence of uncertainties. In this paper we will show how the application of Shell’s propriety probabilistic layer-based seismic inversion programme is used in the building of reservoir models and how this is integrated with the dynamic simulations and surface facilities to optimise future production of the Bonga Field offshore Nigeria. The Bonga Field
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Reservoir Performance Prediction of the Nubia Sandstone, October Field, Gulf of Suez, Egypt
Authors G.R. Gaafar and M.Y. Zein El-DinL-23 RESERVOIR PERFORMANCE PREDICTION OF THE NUBIA SANDSTONE OCTOBER FIELD GULF OF SUEZ EGYPT G.R. GAAFAR 1 and M.Y. ZEIN EL-DIN 2 1 1 Gulf of Suez Petroleum Company 24 Palestine Street New Maadi Cairo Egypt 2 Al-Azhar University Summary: The Nubia sandstone reservoir in October oil field is one of the most prolific reservoirs in Egypt. It is represented by a massive sandstone body separated by shale beds. The most effective of these shale beds is the M II shale which extends throughout the field and appears to form a vertical barrier to the flow of fluids and pressure
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The Effect of the Geological Model on History Matching in the Lower Cretaceous Wassenaar Field, NL
Authors H. Dronkert and E.P. de NijsL-24 THE EFFECT OF THE GEOLOGICAL MODEL ON HISTORY MATCHING IN THE LOWER CRETACEOUS WASSENAAR FIELD NL Abstract 1 The Wassenaar Field started up production in 1956 and was closed in in 1989. It provides a excellent real case for oil field modelling and “what if” scenarios for the testing of models based on modern technology. This paper focusses on the construction of a reservoir model and the subsequent history matching. The production history of all 60 wells has been analysed. The existing geological models were modernised. However the latest geological models are still insufficient to explain the discrepancies in
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Reliable Parameter Fields for Non-Hyperbolic Normal Move Out
Authors R. Siliqi, D. Le Meur and F. AdlerL-25 Reliable parameter fields for Non-Hyperbolic Normal Move Out D. LE MEUR 1 R. SILIQI 1 F. ADLER 2 Abstract The focusing quality of far-offset volumes is strongly dependent on the density of the Non-Hyperbolic Normal Move Out (NHNMO) parameter estimation. The automatic picking of the residual time-shift due to the non-hyperbolic behavior of the reflection curve attempts to achieve this goal. The anellipticity η field containing many errors related to mis-picks and artifacts is replaced by anelliptic velocity ν which is related to the asymptote of the reflection curve. This new NHNMO parameter field thanks to the short spread
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Approximate and Exact Traveltimes in Layered, Anisotropic Media - Pure-Mode and Converted Waves
Authors M. Van der Baan, J.-M. Kendall and D. SmitSummary APPROXIMATE AND EXACT TRAVELTIMES IN LAYERED ANISOTROPIC MEDIA: PURE-MODE AND CONVERTED WAVES M. VAN DER BAAN 1 J-M.KENDALL 1 and D. SMIT 2 1 School of Earth Sciences Univ. of Leeds Leeds LS2 9JT UK 2 Shell Expro 1 Altens Farm Road Nigg Aberdeen AB12 3FY UK The presence of anisotropy in uences many aspects of seismic wave propagation and has therefore implications for conventional processing schemes. To estimate the anisotropy we need both forward modelling and inversion tools. Exact forward modelling in anisotropic media is generally done by raytracing. However we present a new and fast method using
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Converted-Wave Moveout Analysis in Layered Anisotropic Media - a Case Study
Authors J. Yuan, X.-Y. Li and A. ZiolowskiL-27 CONVERTED-WAVE MOVEOUT ANALYSIS IN LAYERED ANISOTROPIC MEDIA – A CASE STUDY JERRY YUAN 1 2 XIANG-YANG LI 2 and ANTON ZIOLKOWSKI 3 Summary 1 We present a new and improved non-hyperbolic moveout equation for converted waves (C-waves) propagating in layered media with vertical transverse isotropy (VTI) and demonstrate its application through a case study. The new equation is accurate up to offset-depth ratio x/z=2.0 forming the basis for parameter estimation. A new parameter χ is introduced to quantify the anisotropic effect on C-wave reflection moveout. With a priori knowledge of the vertical velocity ratio and the P-wave stacking velocity
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Attenuation Measurements from Surface Seismic Data - Azimuthal Variation and Time-Lapse Case Studies
Authors A.J. Carter, R.A. Clark, P.C. Nevill and P.M. BensonL-28 ATTENUATION MEASUREMENTS FROM SURFACE SEISMIC DATA – AZIMUTHAL VARIATION AND TIME-LAPSE CASE STUDIES R. A. CLARK 1 A. J. CARTER 1 P.C. NEVILL 1 2 and P.M. BENSON 1 3 1 School of Earth Sciences University of Leeds Leeds LS2 9JT UK 2 now at: Chevron UK Ltd. 3 now at: TGS-NOPEC Geophysical Company UK 1. Introduction Quantitative knowledge of Q the seismic quality factor would be valuable both in processing and analysis of seismic reflection surveys for hydrocarbons. Intrinsic Q is a useful lithology and pore-fluid indicator; AVO data could be corrected to show reflectivity properties more accurately;
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Parameter Estimation for VTI Media Using PP and PS Reflection Data
Authors I.D. Tsvankin and V. Grechka¡ £ ¥ § ¨ © � © � � � � � � � � � � © � � � � � � � � � � � � � � © � � � � � � © � � � � � � � � � � � � � � © � © � � � � � � � �� � � � � � � � � � � � � � � �� � � � ��� �� � � � � � � � � � � � �
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Anisotropic Prestack Depth Migration for Multicomponent Data - Methodology and Examples
Authors R.R. Kendall, S. Gray and X. MiaoL-30 ANISOTROPIC PRESTACK DEPTH MIGRATION FOR MULTICOMPONENT DATA – METHODOLOGY AND EXAMPLES Abstract 1 We show using both synthetic and real data the effects of anisotropy on converted-wave prestack depth migration. We also introduce a methodology for producing accurate velocity models for these anisotropic prestack depth migrations. We use the synthetic data to illustrate the depth and lateral mispositioning that can occur when isotropic migration techniques are applied to anisotropic rocks. We then introduce a methodology for accurately determining velocity models that are in turn crucial for depth imaging. Finally we show a real data example from the Mahogany Field
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Joint Inversion of PP and PS Reflection Data for VTI Media - A North Sea Case Study
Authors A.V. Bakulin, V. Grechka, I. Tsvankin and J.O. Hansen¡ £ ¥ § © � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �� � � � � � � �� � � � � � � � � � ��
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The Effect of Seismic Anisotropy on Multicomponent Imaging and AVO
Authors J.O. Hansen and A. BakulinL-32 THE EFFECT OF SEISMIC ANISOTROPY ON MULTICOMPONENT IMAGING AND AVO Summary 1 This paper shows how seismic anisotropy affects the imaging and AVO of multicomponent seabed data acquired over the Siri reservoir in the North Sea. Model-based processing is used to analyze the data and compare results from isotropic and anisotropic velocity models. A layered vertically transversely isotropic (VTI) model was used in this study constructed by Grechka et al. (2001). Neglecting the overburden anisotropy causes 0−550 m smearing of the reflection points of converted PS-waves at the target level and results in false PS AVO. Such smearing greatly
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A New Strategy for Characterising Uncertainties in Thermal History Modelling for Hydrocarbon Generation
Authors C. Ferrero and K. GallagherL-33 A NEW STRATEGY FOR CHARACTERISING UNCERTAINTIES IN THERMAL HISTORY MODELLING FOR HYDROCARBON GENERATION C. FERRERO and K. GALLAGHER Imperial College London University TH Huxley School of Environment Earth Science and Engineering London SW7 2BP UK 1 Summary Most companies use a risking function that estimates the probability of discovery by evaluating a number of parameters considered as being essential for the accumulation of hydrocarbons. A typical form of this function is: P(discovery) = P(Source) x P(Trap) x P(Reservoir) x P(Seal) x P(Timing) The quantification of these respective probabilities is paramount for a proper risking of the prospect to be
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Decision Support in Oil Exploration - A Colombian Case Study
Authors I. Reyes Coral and F.J.T. FlorisL-34 DECISION SUPPORT IN OIL EXPLORATION – A COLOMBIAN CASE STUDY I. REYES CORAL 1 2 and F.J.T. FLORIS 3 1 1 International Institute for Aerospace Survey and Earth Sciences (ITC) Hengelosestraat 99 P.O. Box 6 7500 AA Enschede The Netherlands 2 Empresa Colombiana de Petroleos (ECOPETROL) 3 TNO Netherlands Institute of Applied Geoscience Abstract For the evaluation of reservoir performance and the subsequent decision-making process companies use different methodologies that incorporate information from different disciplines. Typically due to the level of integration those companies have reached and/or the technology available the methodologies tend to loose critical information after each
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A Promising Approach to Subsurface Information Integration
By J. LeguijtL-35 A PROMISING APPROACH TO SUBSURFACE INFORMATION INTEGRATION J.LEGUIJT Shell International Expl. & Prod. B.V. SEPTAR Volmerlaan 8 2288 GD Rijswijk The Netherlands 1 Business abstract Reliable knowledge about hydrocarbon containing reservoirs is of vital importance both for optimising the production of oil and gas and also for sound economical decision making. Reliable knowledge also consists of a sound understanding of the lack of knowledge the uncertainty which can be obtained by combining all available information about the reservoir in a consistent manner. Shell geoscientists have obtained experience with a probabilistic method that combines all available geological petrophysical and geophysical
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Stochastic Structural Modeling in Havana
Authors B.F. Nielsen, L. Holden, A. Vazquez and C. TownsendL-36 STOCHASTIC STRUCTURAL MODELING IN HAVANA L. HOLDEN 1 B. F. NIELSEN 1 A. VAZQUEZ 1 and C. TOWNSEND 2 Summary 1 The Havana program can be used to model both large faults that are visible on seismic images and small faults for which there is only indirect evidence. Each fault is modeled individually using complex and flexible models for the large faults and simpler models for the small faults. Not only the geometry of the fault plane is modeled but also the actual rock movement and deformation causing the fault. This latter property of the fault model is the
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From Imaging of Geophysical Data to Imaging of Geological Properties
Authors V. Kolessov, I. Datsenko and T. KutepovaL-37 FROM IMAGING OF GEOPHYSICAL DATA TO IMAGING OF GEOLOGICAL PROPERTIES Summary 1 We present a new approach for reservoir appraisal and characterization based upon Multi-D Interpretation of G&G data. The principles of the technology are illustrated with the results from real case studies. The case example from Western Siberia shows how reliable can be analysis of a thin bed reservoir when using all the relevant geophysical information. Principles The specialists who try to characterize the reservoir always have to overcome two main difficulties. The first one arises from geological and geophysical data uncertainty resulting from their Fussiness Incompleteness and
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Implications of the Choice of the Forward Model Used in the Multi-Component Imaging of Ground Penetrating Radar Data
More LessM001 IMPLICATIONS OF THE CHOICE OF THE FORWARD MODEL USED IN THE MULTI-COMPONENT IMAGING OF GROUND PENETRATING RADAR DATA Introduction J. VAN DER KRUK Delft University of Technology Subfaculty of Applied Earth Sciences Mijnbouwstraat 120 2628 RX Delft In the past the imaging algorithms for GPR data were adapted from seismic imaging algorithms. However important differences between the seismic and radar wave propagation exist like the vectorial nature of the electric field the conductivity and the dipole nature of the electric current sources. For imaging of ground penetrating radar data the three important parameters which have to be taken into
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Survey for Ancient Foundation Remains by Enhanced C-Scan Processing of GPR Data
Authors R.K. Fruhwirth, G. Fuchs and R. MorawetzM-02 SURVEY FOR ANCIENT FOUNDATION REMAINS BY ENHANCED C-SCAN PROCESSING OF GPR DATA Abstract 1 Ground Penetrating Radar is a widely used tool for shallow investigation of the subsurface covering several fields of application e.g. geological and geotechnical surveys UXO and utility detection archaeological investigation and many others. Depending on the problem a more or less large number of anomalies can be expected in the subsurface and needs to be distinguished by the GPR and interpretated by the operator. To distinguish close objects a proper resolution is required and to interpretate these objects a proper penetration is necessary. Especially in
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Imaging of Mine Tailings Leachate Using GPR and EM Methods at Tui Mine, New Zealand
Authors C.A. Locke, M.I. Watson and J. CassidyM-003 IMAGING OF MINE TAILINGS LEACHATE USING GROUND PENETRATING RADAR AND ELECTROMAGNETIC METHODS AT TUI MINE NEW ZEALAND AUTHORS M.I.WATSON C.A.LOCKE and J.CASSIDY Address Department of Geology The University of Auckland Private Bag 92019 Auckland New Zealand email: [email protected] Summary Ground Penetrating Radar (GPR) and electromagnetic (EM) methods have been used to delineate contaminated groundwater in the vicinity of the tailings pile at the abandoned Tui Mine Te Aroha New Zealand. Anomalously high signal attenuation or 'shadow zones' have been clearly observed in GPR profiles at a number of locations downstream of the mine tailings dam. These shadow zones are
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Application of Geophysical Methods to the Safety Analysis of an Earth Dam
More LessM-04 APPLICATION OF GEOPHYSICAL METHODS TO THE SAFETY ANALYSIS OF AN EARTH DAM JUNG-HO KIM 1 MYEONG-JONG YI 1 YOONHO SONG 1 SOON JEE SEOL 1 SEUNG-HWAN CHUNG 1 and KI-SEOG KIM 2 Summary 1 Integrated geophysical surveys have been performed at an earth dam where small-scale subsidence occurred on the crest. All the survey results of various geophysical methods consistently showed that some problems threatening the safety have been developing. In particular we could locate the parts of the dam having more serious problem. Through analyzing and comparing the various kinds of geophysical data we have concluded that the
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A GPR Study for Highway Reconstruction in the Netherlands
Authors E.C. Slob, J. Van der Kruk and J.T. FokkemaM-05 A GPR STUDY FOR HIGHWAY RECONSTRUCTION IN THE NETHERLANDS Summary 1 In the 1990's considerable experience has been built up in GPR surveys for asphalt layer thickness determination. The application of GPR in the whole sequence of highway design and construction structure evaluation of road decks and quality control of new or repaired structures is in an introductory phase for many of the highway agencies in most countries. Even though this life cycle is not routinely applied the GPR technique has proven very powerful in aiding in the solution to many aspects of highway engineering problems. Here we report
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Waste Disposal Sites Evaluation by Means of GPR
Authors M. Pipan, E. Forte, F. Guangyou and I. FinettiM-06 WASTE DISPOSAL SITES EVALUATION BY MEANS OF GPR M. PIPAN 1 E. FORTE 1 F. GUANGYOU 1 2 3 and I. FINETTI 1 Abstract 1 We focus on the application of Ground Penetrating Radar (GPR) to study waste dumps and obtain information about volume and physical properties of waste soil contaminated by seepage from waste and underlying bedrock/soil. GPR data acquisition is performed using three different paradigms: common offset (single-fold SF) multi-offset (linear multi-fold LMF) and multi-azimuth (azimuthal multi-fold AMF). Data processing is performed using a novel algorithm based on the Wavelet Transform to calculate the instantaneous parameters of
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EM and Electrical Studies of Environmental Impacts Caused by a Landfill
Authors J. Lohva, T. Jokinen, H. Vanhala, M. Lahti and H. SoininenM-07 EM AND ELECTRICAL STUDIES OF ENVIRONMENTAL IMPACTS CAUSED BY A LANDFILL Introduction 1 JAANA LOHVA TARMO JOKINEN HEIKKI VANHALA MARI LAHTI and HEIKKI SOININEN Geological Survey of Finland PO Box 96 02151 Espoo Finland Groundwater contamination is a risk at old landfill areas. Modern landfills can also be environmental hazards. Airborne EM ground EM and electrical surveys can map subsurface resistivity anomalies associated with possible contamination zones. In this paper we present a case study where we have tried to locate smallest possible changes in conductivity by modeling and interpreting AEM and detailed ground electrical and EM anomalies. Jokinen
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A Geophysical Survey to Investigate Aquifers Contamination by Graveyards
Authors M.J. Senos Matias, M.A. Marques da Silva, L. Gonçalves, C. Peralta and C. GrangeiaM-08 A GEOPHYSICAL SURVEY TO INVESTIGATE AQUIFERS CONTAMINATION BY GRAVEYARDS Abstract 1 Some graveyards are installed in Quaternary high porous and permeable rocks. In such geological environments and when the water table is close to the surface there is a strong possibility that local shallow aquifers can be contaminated. Such contamination should be complex as organic and inorganic pollutants must be present. Geophysics has been used succefully to investigate aquifers contamination by industrial sources but little is known about its use in aquifers contamination by graveyards. Therefore Geophysical studies have been carried out in the vicinity of two graveyards installed
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Downhole Orbital Vibrator Source and Single Well Imaging
Authors G. Yu, L.A. Walter, B. Chmela, L. Jahren, J. O‘Brien and J.C. LimeM-09 DOWNHOLE ORBITAL VIBRATOR SOURCE AND SINGLE WELL IMAGING Summary 1 GANG YU 1 LARRY A. WALTER 1 BILL CHMELA 2 LEIF JAHREN 2 JOHN O’BRIEN 3 AND JUSTIN C. LIME 3 The downhole orbital vibrator source originally developed by Conoco Inc. operates as a free-hanging device in the fluid column on a standard 7-conductor wireline. An internal spinning eccentric mass produces a rotating force vector from the tool to the formation. This new downhole seismic source generates a 50 to 400 Hz bandwidth energy sweep which is energized from a surface controller with programmable sweep length and start/stop times.
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Reconstruction of High-Resolution Velocity Models Using Joint Tomography of Crosswell and VSP Data
Authors Z. Zhang, J. Jackson and J. ZhangM-10 RECONSTRUCTION OF HIGH-RESOLUTION VELOCITY MODELS USING JOINT TOMOGRAPHY OF CROSSWELL AND VSP DATA Z. ZHANG 1 J. JACKSON 1 and J. ZHANG 2 ABSTRACT Seismic tomography images can provide useful information about complicated geological structures. These images can be used directly in the interpretation or as the input to migration processing. The resolution of tomography greatly depends upon ray coverage and frequency bandwidth. Crosswell seismic data because of their higher bandwidth can be used to provide high-resolution velocity images. Ideal ray coverage is achieved only if ray paths illuminate the target zone evenly from all angles. In reality however
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Anisotropic Traveltime and Polarisation Tomography of 3D VSP Data
Authors A.J. Cherrett and S.C. SinghM-11 ANISOTROPIC TRAVELTIME AND POLARISATION TOMOGRAPHY OF 3-D VSP DATA A.J. CHERRETT 1 2 and S.C. SINGH 1 3 Abstract 1 1 LITHOS Bullard Laboratories Department of Earth Sciences University of Cambridge Cambridge CB3 0EZ UK 2 Total Fina Elf GRC 3 IPG Paris The results of a simultaneous tomographic inversion of traveltime and polarisation data from a multicomponent 3-D walkaway VSP experiment in the North Sea are shown. Despite the presence of significant levels of noise and poor aperture ray coverage laterally heterogenous structures are imaged and robust measurements of seismic anisotropy are obtained both at depth in the
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3D RVSP Drill-Bit Survey - Preliminary Results
Authors F. Miranda, F. Poletto, L. Petronio, L. Bertelli, M. Malusa, A. Luca and A. SchleiferM-12 3D RVSP DRILL-BIT SURVEY – PRELIMINARY RESULTS Introduction 1 An onshore 3D drill-bit Reverse VSP was acquired for the purposes of the Seisbit 3D RVSP project (EC project THERMIE no. OG 278/98/IT/UK entitled "Seisbit 3DRVSP: while drilling seismic imaging and areal velocity investigation by using the drill bit signal "). The aim of the project is to obtain detailed 3D information in the well area by using the working drill-bit source and to demonstrate the reliability of the 3D seismic-while-drilling onshore method. This result needs acquiring by a large number of surface channels and a relevant number of source
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Autocorrelogram Migration of Drill-Bit Data
Authors J. Yu, L. Katz, F. Followill and G.T. SchusterM-013 AUTOCORRELOGRAM MIGRATION OF DRILL-BIT DATA JIANHUA YU 1 LEW KATZ 2 FRED FOLLOWILL 3 and GERARD T. SCHUSTER 1 1 University of Utah Salt Lake City Utah 84112 U.S.A 2 Utah Geophysical Inc. 3 Lawrence Livermore National Laboratory Abstract The goal of Inverse Vertical Seismic Profiling While Drilling (IVSPWD) is to image the subsurface structure with seismic data generated by a rotating drill bit at depth. Here the data are recorded on the earth’s free surface. This paper presents the results of applying an autocorrelogram migration method to seismic data recorded while a tri-cone drill-bit and down hole motor
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Imaging of Orebodies with a Polarization Stack Migration
Authors E. Duveneck, C. Mueller and T. BohlenM014 IMAGING OF OREBODIES WITH A POLARIZATION STACK MIGRATION E. DUVENECK 1 CF.MÜLLER 2 and T. BOHLEN 3 1 Geophysical Institute University of Karlsruhe Hertzstr. 16 76187 Karlsruhe Germany 2 Geological Survey of Canada 3 Kiel University Summary A migration method is presented that makes use of polarization information present in multicomponent data to image deep ore bodies in 3D from VSP data acquired with a limited number of shotpoints. The method solves the problems of spatial ambiguity and of the complexity of the scattered wavefield including strong amplitude variations and interference of different scattering modes. It is tested on
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3D Imaging of Crustal Lithology with Diffraction Coherency Migration for VSP
Authors C. Mueller, G. Bellfleur, G. Perron, K. Stevens, D. Snyder and B. MilkereitM-15 3-D IMAGING OF CRUSTAL LITHOLOGY WITH DIFFRACTION COHERENCY MIGRATION FOR VSP CF. MUELLER 1 G. BELLFLEUR 1 G. PERRON 4 K. STEVENS 2 D. SNYDER 1 and B. MILKEREIT 3 Summary 1 Diffraction coherency migration (DCM) was applied to a multi-offset multi-azimuth vertical seismic profiling survey conducted in the northeastern part of the Sudbury impact structure in Ontario Canada. Seismic data was collected by the downhole seismic imaging (DSI) consortium with a three component geophone array in two boreholes using five shot points at the surface. Based on diffraction stack migration DCM was developed to enhance the subsurface image
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3D VSP Converted Wave Depth Migration
Authors P. Bicquart and L. MorleyM-16 3D VSP CONVERTED WAVE DEPTH MIGRATION P. BICQUART and L. MORLEY Summary 1 WesternGeco 10001 Richmond Avenue P.O. Box 2469 Houston TX 77252-2469 USA Even as surface-seismic surveys have moved to increasing levels of product sophistication over the last twenty years the borehole-seismic industry has continued to maintain step. Initial product offerings in near-offset VSPs gave way to 2D walkaway surveys which in turn were upstaged by full 3D/3C acquisition and processing. Indeed the ability of 3D VSPs to image small-scale features in the reservoir was recently demonstrated in a paper by Constance et al (1999). These authors showed
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A Different Approach in Delineating Near Surface Buried Structures
Authors H.A. Baker, M. Djeddi, A.G. Boudjadja and K. BenhamamM-17 A DIFFERENT APPROACH IN DELINEATING NEAR SURFACE BURIED STRUCTURES Abstract 1 H.A. BAKER M. DJEDDI A.G. BOUDJADJA and K. BENHAMAM Department of Geophysics FSTGAT-USTHB Algiers Algeria Introduction: It is a fact that cavities tunnels old mine-works etc. are considered hazardous when existing under or nearby building sites especially when these structures are missing or badly marked on old maps. Therefore locating these structures and if possible giving their exact forms has become a prime necessity for civil and environmental engineers. Beside this locating and protecting archaeological sites have always been of great importance. Archaeological sites are of two kinds:
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Determination of Hydraulic Conductivity Values from Geo-Electrical Data
Authors E. Aristodemou and A. Thomas-BettsM-18 DETERMINATION OF HYDRAULIC CONDUCTIVITY VALUES FROM GEO- ELECTRICAL DATA E. ARISTODEMOU and A. THOMAS-BETTS The T.H. Huxley School of Environment Earth Science and Engineering Royal School of Mines Imperial College of Science Technology and Medicine Prince Consort Road London SW7 2BP UK 1 Two different methodologies (DCR and DCR-IP) have been implemented at two sites in order to obtain hydraulic conductivity (k) values. The methodologies differ in one important aspect: the first approach (DCR) utilises only the in-phase bulk resistivities of the subsurface whilst the second method (DCR-IP) uses both the in-phase and out-of phase components of complex conductivity.
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Interference Analysis of Cemented-Permanent-Sensor Data from a Field Experiment
Authors B. Raghuraman and T.S. RamakrsihnanM019 INTERFERENCE ANALYSIS OF CEMENTED- PERMANENT-SENSOR DATA FROM A FIELD EXPERIMENT B. RAGHURAMAN and T. S. RAMAKRISHNAN Schlumberger Doll Research Old Quarry Road Ridgefield Connecticut 06877 USA Introduction 1 In 1999-2000 an oilfield experiment was conducted to test the application of electrical pressure and fiber optic measurement technologies to permanent reservoir monitoring. The principal objective of the experiment was to demonstrate the feasibility of monitoring water movement between an injection and observation well. Bryant et al. [1] describe results and interpretation of the cemented resistivity array data and show how the movement of the front could be tracked at the
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Permanent Monitoring of a Waterflood Using Cemented Resistivity Arrays - Indiana, USA
Authors I. Bryant, M-Y. Chen, B. Raghuraman, I. Raw, J.-P. Delhomme, C. Chouzenoux, D. Pohl, Y. Manin, E. Rioufol, G. Oddie, D. Swager and J. SmithM-20 PERMANENT MONITORING OF A WATERFLOOD USING CEMENTED RESISTIVITY ARRAYS – INDIANA USA Introduction 1 In 1999 an oilfield experiment was conducted to test the application of electrical measurement technologies to permanent reservoir monitoring. The principal objective of the experiment was to demonstrate the feasibility of monitoring water movement between an injection and observation well. Experimental Configuration Two wells were drilled into the Mansfield sandstone reservoir in the Ashworth lease Indiana USA. The D-8 injector well was located in the center of four development wells. The OB-1 monitoring well was offset 71 m to the southwest in a location midway
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Joint Inversion of Surface-NMR and VES
Authors M. Hertrich and U. YaramanciM-21 JOINT INVERSION OF SURFACE-NMR AND VES Abstract 1 The method of Surface Nuclear Magnetic Resonance (SNMR) is a new method in groundwater prospection. Its direct sensitivity to water molecules provides a uniquely new information about subsurface properties. The combination with conventional electric electromagnetic methods here Vertical Electrical Sounding (VES) which are sensitive to the water content via the conductivity in a porous media promises improved aquifer characterization. The new developed inversion scheme is based on Simulated Annealing (SA) a guided random search algorithm. Detailed investigations have been conducted with different inversion and model settings on synthetic data. The processing
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Correlation of the IP Effect with the Depth of Polarised Layers in Transient EM Sounding
More LessM-22 CORRELATION OF THE IP EFFECT WITH THE DEPTH OF POLARISED LAYERS IN TRANSIENT EM SOUNDING F. KAMENETSKY Ludwig-Maximalian University Munich Institute of General and Applied Geophysics Dieselstrasse 1 80993 Munich Germany 1 Introduction The influence of induced polarisation (IP) on electromagnetic (EM) data has been considered by different authors in particular in connection with the phenomenon of so-called high-resolution electromagnetics (HRE) or in other words with the unusually high vertical resolving power of transient sounding (TS) curves experimentally observed while exploring sedimentary formations mainly for oil and gas. The resolution is sometimes comparable to that of seismics. The mechanism
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Ground Water Exploration Using High Resolution RMT and CSTMT Methods
Authors L.B. Pedersen, M. Bastani, L. Dynesius and B. OskooiM-23 GROUND WATER EXPLORATION USING HIGH RESOLUTION RMT AND CSTMT METHODS 1 L.B. PEDERSEN M. BASTANI L. DYNESIUS and B. OSKOOI 1 Uppsala University Department of Earth Sciences Villavägen 752 36 Uppsala Sweden INTRODUCTION The EnviroMT technique has been employed in a variety of conditions to study its capacity to map in detail the upper few tens of meters of the uppermost vulnerable part of the loose sedimentary layers. One such study is reported on here. The objective is rather simple: determine the geometry of a glacio-fluvial aquifer system made up of a sand/gravel formation lying on top of the
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Electromagnetic Energy Velocity in Magnetotelluric Sounding Interpretation
Authors J. Miecznik and J. CzerwinskiM-24 ELECTROMAGNETIC ENERGY VELOCITY IN MAGNETOTELLURIC SOUNDING INTERPRETATION J. MIECZNIK 1 2 and T. CZERWIŃSKI 2 1 Results of magnetotelluric measurements are usually presented as apparent resistivity curves and plots of the phase shift between the electric vector and magnetic vector versus frequency. One of the reasons of such presentation is that the amplitude sounding curves reproduce changes of real resistivity in a geoelectric medium. On the other hand in the case of 2D geoelectric medium the shape of magnetotelluric sounding curves depends on the azimuth of the measurement system. When one axis of the measurement system coincides with the
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A Method for Investigating the Effect of Mud Invasion on the Acoustic and Density Logs
Authors B.A. Farrelly, S.E. Johnstad and R. KanestrømM-25 A METHOD OF INVESTIGATING THE EFFECT OF MUD INVASION ON THE ACOUSTIC AND DENSITY LOGS BRIAN A. FARRELLY SVEIN E. JOHNSTAD and REIDAR KANESTRØM Summary 1 In this paper we have demonstrated how wireline logs can be combined with the results of core analysis to investigate the effect of mud filtrate on the density and acoustic logs. The density log is most seriously affected by the mud filtrate but the P - waves are also significantly influenced. The invasion of mud filtrate is related to the permeability. Since the synthetic seismic response is computed from the wireline logs it
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Macroscopic Electrical Anisotropic Reservoirs - Petrophysical Characteristic and an Iterative Hybrid Evaluation Method
Authors O.N. Fanini, J.H. Schön and D.T. Georgiv 2 R λ = . In a vertical well traditional logging tools measure only the horizontal component of the R h resistivity or conductivity for these formations (Fig.1). The new multicomponent induction logging tool TM (3DEX ) provides all necessary data to compute both horizontal and vertical resistivities (i.e. Rh and Rv) for vertical deviated and horizontal wells. Thus this tool gives us the “tensorial” information about the spatial orientation of the different conducting parts of the reservoir (anisotropy). Types of macroscopic anisotropic reservoirs and a hybrid interpretation Two geological types of finely laminated sediments can be considered with
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New Multicomponent Induction Tool for Evaluation of Electrically Anisotropic Thinly Laminated Formations
Authors O.N. Fanini, B. Kriegshäuser, R.A. Mollison, J.H. Schön and L. YuM-27 NEW MULTICOMPONENT INDUCTION TOOL FOR EVALUATION OF ELECTRICALLY ANISOTROPIC THINLY LAMINATED FORMATIONS O.N. FANINI 1 B. KRIEGSHÄUSER 1 R. A. MOLLISON 1 J. H. SCHÖN 2 and L. YU 1 Abstract 1 The new multicomponent induction logging tool (3DEX TM ) surveys the formation in three dimensions with mutually orthogonal multicomponent transmitter-receiver induction coil arrays (Fig. 1) providing the necessary measurements to compute both horizontal and vertical resistivities (i.e. Rh and Rv) for vertical deviated and horizontal wells (Kriegshauser et al. 2000). These resistivities are needed for improved delineation and evaluation of low resistivity low contrast pay zones frequently
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Some Considerations on the Apparent Resistivity in the Cross Hole Resistivity Method
Authors I.K. Cho, J.H. Kim and S.H. ChungM-28 SOME CONSIDERATIONS ON THE APPARENT RESISTIVITY IN THE CROSS HOLE RESISTIVITY METHOD I.K. CHO 1 J.H. KIM 2 and S.H. CHUNG 2 INTRODUCTION 1 For dc resistivity method conversion to apparent resistivity can be thought of as simply a normalization of the measured potential difference for the transmitted current and the geometric factor of the array so that the data can be presented in units of the intrinsic rock property-resistivity. In reality the sub-surface ground is not a homogeneous medium and thus the resistivity obtained is no longer the 'true' resistivity but the apparent resistivity which can even be
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Relationship between Acoustic Body Waves and in Situ Stresses around a Borehole
By A. RousseauM-29 RELATIONSHIP BETWEEN ACOUSTIC BODY WAVES AND IN SITU STRESSES AROUND A BOREHOLE ANDRÉ ROUSSEAU CNRS-Université Bordeaux 1 351 cours de la Libération 33405 Talence cédex France 1 Summary This paper shows that there are three types of shape of acoustic body waves propagating inside competent formations crossed by a borehole. This fact is connected to the modification undergone by the area located around a well after drilling in relation to the in situ state of stress. The multiple waves inside the modified area allows to calculate its size which depends on the ratio between vertical stress (equivalent to ground
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Inversion of VSP First Arrival Traveltimes for Anisotropy Parameters
Authors R.T. Newrick, D.C. Lawton and D.A. SprattM-30 INVERSION OF VSP FIRST ARRIVAL TRAVEL- TIMES FOR ANISOTROPY PARAMETERS Abstract 1 First arrival traveltimes from a multi-offset Vertical Seismic Profile (VSP) in the Alberta Basin were modelled to determine the Thomsen anisotropy parameters of clastic Mesozoic rocks. Computed traveltime data were matched successfully to those observed using either a geologically controlled or arbitrarily divided horizontally stratified earth. Although the solution was found to be non-unique the average velocity anisotropy was found to be about 18%. An empirical relationship was developed between gamma-ray count and the anisotropy parameter ε that was used successfully in the modelling. Introduction First arrival
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Integrated Prestack Depth Migration of VSP and Surface Seismic Data
Authors M.G. Kirtland Grech and D.C. LawtonM-31 INTEGRATED PRESTACK DEPTH MIGRATION OF VSP AND SURFACE SEISMIC DATA Summary 1 A new prestack depth migration algorithm has been developed for the integrated depth imaging of Vertical Seismic Profile (VSP) and surface seismic data. The algorithm which is Kirchhoff-based includes anisotropic velocities and can also be applied to depth migration of converted waves and multimodes. Results from the depth imaging of a numerical model data set from a complex structural model shows that the integrated imaging of VSP and surface seismic data yields a result that is superior to those obtained from the migration of either data set
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The Use of VSP and Modelling Techniques in the Definition of Salt Structures and Pre-Salt Lithologies - Examples from the Kashagan Field, North Caspian Basin, Kazakhstan
Authors A.R. Verdel, C.T.A.M. Leo, K. van Ojik, W. Zempolich and T. ter BurgM-32 THE USE OF VSP AND MODELLING TECHNIQUES IN THE DEFINITION OF SALT STRUCTURES AND PRE-SALT LITHOLOGIES: EXAMPLES FROM THE NORTH CASPIAN BASIN KAZAKHSTAN Abstract 1 A.R. VERDEL 1 C.T.A.M. LEO 2 K. VAN OJIK 2 W. ZEMPOLICH 2 and T. TER BURG 3 1 Shell Technology Exploration and Production Volmerlaan 8 P.O. Box 60 2280 AB Rijswijk The Netherlands 2 Offshore Kazakhstan International Operating Co. (OKIOC) 3 Schlumberger Petroleum Services C.V. Drilling for sub-salt Paleozoic carbonate reservoirs in the North Caspian Sea offshore Kazakhstan presents numerous subsurface and surface challenges. The goal of such drilling is to safely penetrate
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Migration Velocity Analysis in Complex Media - Application to the Marmousi Data Set
Authors H. Chauris, S. Xu, M. Noble and G. LambaréM-33 MIGRATION VELOCITY ANALYSIS IN COMPLEX MEDIA: APPLICATION TO THE MARMOUSI DATA SET H. CHAURIS 1 previously 2 M. NOBLE 2 S.XU 2 and G. LAMBARÉ 2 1 Shell International Exploration and Production Volmerlaan 8 P.O. Box 60 2280 AB Rijswijk The Netherlands 2 Ecole des Mines de Paris Abstract – We demonstrate a method for 2D velocity estimation in complex media characterized by triplicated ray fields. Due to multipathing Migration Velocity Analysis (MVA) principle has to be revisited requiring in particular the use of Common Angle Gathers (CAGs) instead of the classical common offset panels. For the inversion itself
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Velocity Model Determination Using Migrated Cylindrical Wave Data
Authors F. Assouline and P. LaillyM 034 VELOCITY MODEL DETERMINATION USING MIGRATED CYLINDRICAL WAVE DATA F. ASSOULINE and P. LAILLY Institut Français du Pétrole 1 et 4 avenue de Bois-Preau 92852 Rueil-Malmaison France Abstract The SMART (Sequential Migration Aided Reflection Tomography) method is a Migration Velocity Analysis method based on tomographic reflection that enables velocity model determination in the prospect of seismic imaging of complex geologic structures. In this method the access to multioffset kinematic information is done by demigrating the corresponding interpreted prestack migrated events and an inversion of the obtained traveltimes allows velocity model determination. The implementation in 3D of this method is
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Tomographic Inversion of Focusing Operators
Authors B.E. Cox and D.J. VerschuurM035 Summary TOMOGRAPHIC INVERSION OF FOCUSING OPERATORS B.E. COX and D.J. VERSCHUUR Delft University of Technology Lab. of Acoustic Imaging and Sound Control PO Box 5046 2600 GA Delft The Netherlands The Common Focus Point (CFP) method has proven to be an appropriate tool for velocity model estimation. The CFP velocity estimation that is described in this paper is based on a separated inversion method in which first the focusing operators are updated with a data-driven procedure and after that the velocity model is estimated. The estimation of the propagation velocities and the focus point locations is done by one-way
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Combining Turning Ray and Reflection Tomography - the Whittle Case
Authors J.H. Kommedal, M. Gainski, C. Taylor and R. RandallM-36 COMBINING TURNING RAY AND REFLECTION TOMOGRAPHY – THE WHITTLE CASE Abstract 1 Over the last decade 3D pre stack depth migration has become the standard tool for imaging structures with rapid lateral velocity changes. The main challenge in getting a good seismic image is the construction of an accurate depth - interval velocity model. This paper presents a case where it was necessary to combine both turning ray tomography and the more commonly used reflection tomography to create the velocity model to migrate the data successfully. The Whittle structure in UKCS Block 42/28b is a complicated structure with strong
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3D Tomographic Velocity Model Determination for Two North Sea Case Studies
Authors A. Ehinger, K. Broto, A. Jardin and the KIMASI project teamM–037 3D TOMOGRAPHIC VELOCITY MODEL DETERMINATION FOR TWO NORTH SEA CASE STUDIES A. EHINGER * K. BROTO A. JARDIN and the KIMASI project team Institut Français du Pétrole 1 et 4 avenue de Bois Préau 92852 Rueil-Malmaison cedex France Summary Traveltime tomography properly implemented can be a powerful tool for subsurface velocity model determination. A blocky model representation with smooth constituting elements coupled with a dedicated two point ray tracing and a formulation of the tomographic inverse problem that allows the introduction of a priori information have been used in the software employed for two North Sea case studies. Traveltimes
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A New Approach for the Velocity Estimation and Depth Imaging of Converted Waves
More LessN-01 A NEW APPROACH FOR THE VELOCITY ESTIMATION AND DEPTH IMAGING OF CONVERTED WAVES LONG D. PHAM WEIZHONG WANG and YAOHUI ZHANG Summary We present a new approach for the velocity estimation and depth imaging of convertedwaves (C-waves). Depth imaging has been an important tool for P-wave data and has recently been demonstrated to be even more important for C-wave data (SEG/EAGE Summer 2000 Research Workshop: Recent advances in shear wave technology for reservoir characterization). Though pre-stack depth migration is the most advanced imaging method it requires an accurate initial velocity model. Without an accurate initial model depth migration can
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C-Wave Focusing and Short Spread Kinematics Controlled through the CCP-Scan Technique
Authors P.-Y. Granger, F. Audebert and A. HerrenschmidtN-02 C-WAVE FOCUSING AND SHORT SPREAD KINEMATICS CONTROLLED THROUGH THE CCP-SCAN TECHNIQUE Introduction 1 Converted wave velocity analysis is well understood in the case of flat reflectors in horizontally stratified media. In this case the kinematics of the CMP (Common Mid-Point) gathers is identical to the kinematics of the CCP- (Common Conversion Point) gathers so that the problems of NMO velocity analysis and CCP-binning can be decoupled. In this case the move-out on the CMP is symmetrical and hyperbolic at short spread and Velocity Analysis follows the classic NMO formula. Nevertheless the converted wave CMP-gathers never correspond to true CCP
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PP and PS Travel Time Reflection Anisotropic Tomography on a Case Study
Authors P. Berthet, Y. Le Stunff, P. Guillaume, J. Mispel and J.L. BoelleN-03 PP AND PS TRAVEL TIME REFLECTION ANISOTROPIC TOMOGRAPHY ON A CASE STUDY P. BERTHET 1 Y. LE STUNFF 2 P. GUILLAUME 3 J. MISPEL 1 4 and J.L. BOELLE 1 Abstract 1 The 4C data obtained in the case of an Ocean Bottom Cable survey (OBC) provide information of P and S-wave propagation velocities through PP and PS reflections. The conventional assumption of seismic isotropy may cause mispositioning of PP and PS reflections in the depth domain when anisotropy is significant. The 3D pre-stack PP travel time reflection tomography algorithm presented by Le Stunff et al (2000) has been
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Imaging of 4C Data in Depth - Residual Velocity Analysis and Anisotropy Parameter Estimation
Authors O. Mikhailov, G.J. Ball, J. Johnson and E. ShoshitaishviliN-05 IMAGING OF 4C DATA IN DEPTH – RESIDUAL VELOCITY ANALYSIS AND ANISOTROPY PARAMETER ESTIMATION Introduction The goal of this study is to produce structurally consistent PP and PS images of the Alba reservoir (located in the Central North Sea UK block 16/26) that are suitable for joint interpretation and inversion. Our approach is to image PP and PS data in depth rather than in time so that the need for image correlation and re-stretching is minimized. Our Pre- Stack Depth Migration workflow for multicomponent data consists of three steps: (1) isotropic imaging of PP and PS data; (2) derivation
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Azimuthal Anisotropy - More Than Just Theory
Authors S. Ronen, M. Jarvis and A. ProbertN-06 AZIMUTHAL ANISOTROPY—MORE THAN JUST THEORY S. RONEN M. JARVIS and A. PROBERT 1 WesternGeco Schlumberger House Gatwick RH6 0NZ UK Abstract The effect of azimuthal anisotropy on reflection seismic data is significant to the extent that the imaging of such data is often poor if azimuthal isotropy is assumed. An analysis of azimuthal anisotropy can be based on the sign flipping of the transverse component of wide azimuth multicomponent data. Following the analysis the data are imaged properly by taking the anisotropy into account. We have applied such processing to a wide-azimuth 3-D multicomponent survey from the North Sea
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