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69th EAGE Conference and Exhibition incorporating SPE EUROPEC 2007
- Conference date: 11 Jun 2007 - 14 Jun 2007
- Location: London, UK
- ISBN: 978-90-73781-54-2
- Published: 11 June 2007
1 - 100 of 574 results
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Overview of the Challenges Facing Oil Industry Recruitment and Training
Authors C. Goscomb and D. MacdonaldA001 Overview of the Challenges Facing Oil Industry Recruitment and Training C. Goscomb* (Shell International BV) & D. Macdonald (University of Aberdeen) SUMMARY EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007
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The Experience of the Multinationals
By M. BrownNO PAPER AVAILABLE EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007
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Recruitment Challenges Facing SMEs
By H. AllenNO PAPER AVAILABLE EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007
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The Recruiters Tale
By D. O‘DonnellNO PAPER AVAILABLE EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007
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The Future Role of Universities
By H. JohnstonNO PAPER AVAILABLE EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007
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Summary of Themes – An Introduction to the Open Session
Authors D. MacDonald and G. GoscombA006 Summary of Themes – An Introduction to the Open Session D. MacDonald* (University of Aberdeen) & G. Goscomb (Shell International BV) SUMMARY EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007
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Arctic Oil and Gas Potential in a Global Perspective
More LessA009 Arctic Oil and Gas Potential in a Global Perspective D.L. Gautier* (USGS) SUMMARY EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007 The Arctic is known to hold the world’s largest hydrocarbon province the West Siberian Basin and several other demonstrated world-class basins as well (Timan- Pechora North Slope Norwegian Sea). Other Arctic provinces also have significant potential but high costs and engineering complexity have been barriers to exploration and development. The Arctic remains largely unexplored with respect to petroleum and extreme geologic uncertainty characterizes the resource potential of the entire region. Standard tools
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Canadian Arctic - Perspectives for the Petroleum Industry
By D. EvoyA010 Canadian Arctic - Perspectives for the Petroleum Industry D. Evoy* (Petro-Canada) SUMMARY The oil and gas prospectivity of the Canadian Arctic has been demonstrated through exploration dating back to the 1960s; resources in the order of 20 Tcf of gas and 1.5 Bbbls of oil have been identified. However there has been no gas production to date and only a modest amount of oil has been produced. The Mackenzie Valley Pipeline currently under regulatory review is the proposed transportation route for development from the Mackenzie Delta / Beaufort Sea. More preliminary is the concept of LNG shipment from the
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Greenland – Petroleum Potential, Ongoing and Future Exploration
More LessA011 Greenland – Petroleum Potential Ongoing and Future Exploration F.G. Christiansen* (GEUS) SUMMARY EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007 A high stable oil price political instability in many oil-producing regions in the World and relatively close distances to western markets has given a growing interest from many supermajors and majors for exploration in the Arctic and other high latitude areas including both West and East Greenland. In recent years exploration focus in Greenland has mainly been on central West Greenland with several licensing rounds but activities in the coming years are likely
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Opportunities & Challenges Working in a "Arctic" Environment, Offshore Sakhalin
More LessA012 Opportunities & Challenges Working in a "Arctic" Environment Offshore Sakhalin M. Gunningham* (Sakhalin Energy Investment Company) SUMMARY Sakhalin Energy is currently developing 3 oil and gas fields offshore Sakhalin Island off the east coast of mainland Russia. This is a challenging area for exploration and development with potentially billions of barrels of oil and gas. The key problem is that in the winter drifting sea ice several meters thick heavy snow and temperatures down to minus 40°C all contribute to Arctic type conditions. Under these conditions the offshore developments use the latest technology with concrete gravity based platforms which
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Oil and Gas Development in Norway’s Northern Areas
By O. BirkelandA013 Oil and Gas Development in Norway’s Northern Areas O. Birkeland* (Statoil ASA) SUMMARY The Northern areas include the areas west of the Lofoten Islands in the Norwegian Sea and to the northern shelf edge of the Barents Sea. Exploration was initiated in 1980 with the drilling of the first well. Close to 70 exploration wells have since been drilled in the south-western Barents Sea. Until the decision to develop the Snøhvit gas fields through an LNG plant on the Finnmark coast was made no commercial solutions were seen for the discoveries in the area. Snøhvit will come on stream
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North Caspian Sea - An Ice Design Strategy
By D. MayneA014 North Caspian Sea - An Ice Design Strategy D. Mayne* (AGIP KCO) SUMMARY This paper is focused on developing and implementing a strategy for development of the North Caspian Sea. Specific data needs are identified for Engineering Operations and other areas of the development. Costing of designs are tied back to an overall strategy to determine the motivation for design criteria refinement. Specific field data gathering activities are discussed in light of design criteria needs apparatus development data gathering and processing. Winter logistics and operational challenges are discussed. EAGE 69 th Conference & Exhibition — London UK 11 -
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Exploration of the Lower Cretaceous Sands in Leland Area, Alberta, Using Seismically Derived Rock Properties
Authors C. C. Dumitrescu and F. MayerA017 Exploration of the Lower Cretaceous Sands in Leland Area Alberta Using Seismically Derived Rock Properties C.C. Dumitrescu* (Sensor Geophysical Ltd) & F. Mayer (Devon Canada Corporation) SUMMARY This paper provides a case study of a 3D seismic survey in the Leland area of the Deep Basin of Alberta Canada where seismically derived rock properties were used for exploration. In this case study identifying the gas sands within the lower Cretaceous was the primary interpretive focus. Conventional interpretation of Lower Cretaceous sands on normal migrated seismic has typically presented a number of difficulties. First we ran AVO analysis and deterministic
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r Gas Hydrates Based on Seismic Information – With Examples from Northern Gulf of Mexico
More LessA018 Exploration for Gas Hydrates Based on Seismic Information – With Examples from Northern Gulf of Mexico J. Dai* (Schlumberger) & N. Dutta (Schlumberger) SUMMARY A five-step integrated workflow is developed to delineate shallow gas hydrates using seismic information. We applied the workflow and estimated gas hydrate saturations in two study areas in the northern deepwater Gulf of Mexico. Due to lack of hard data (well control) for the shallow seismic data our predictions used analogue models based on geologic interpretation seismic inversion and the basic principles of rock physics. To examine our predictions we analyzed the hydrate from the
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Atlantis Static Connectivity Study – Predicting Compartmentalization Prior to First Oil
Authors J. A. Reeve and K. F. A. AngelA019 Atlantis Static Connectivity Study – Predicting Compartmentalization Prior to First Oil J.A. Reeve* (BP) & K.F.A. Angel (BP) SUMMARY Every oil field is challenged with understanding and characterizing compartmentalization from the first exploration well to the cessation of production. This challenge is even more pronounced in regions like the Gulf of Mexico where dynamic well test data is seldom available prior to first production. Hence utilization of all available static data to predict field performance becomes essential. But how should we integrate seismic geologic models pressures and fluids in a meaningful way? The Atlantis subsurface team took on this
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Prestack Stochastic Seismic Inversion of the Brenda Field
Authors G. J. Hicks and A. M. FrancisA020 Prestack Stochastic Seismic Inversion of the Brenda Field G.J. Hicks* (Earthworks Environment & Resources) & A.M. Francis (Earthworks Environment & Resources) SUMMARY Joint AI-GI stochastic seismic inversion was performed for 100 pairs of equi-probable AI-GI realizations over the Brenda field which is located in block 15 in the North Sea. Stochastic inversion enables the possible variability in impedance and hence the uncertainty in lithology and fluid classification to be explored. These can be represented using probability and connected probability volumes calculated using joint AI-GI thresholds. EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007
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Petrophysical Seismic Inversion for Porosity and 4D Calibration on the Troll Field
Authors T. Coleou, A. J. van Wijngaarden, A. Norenes Haaland, P. Moliere, R. Ona and J. L. FormentoA021 Petrophysical Seismic Inversion for Porosity and 4D Calibration on the Troll Field T. Coleou* (CGG) A.J. van Wijngaarden (Hydro) A. Norenes Haaland (Hydro) P. Moliere (Hydro) R. Ona (Hydro) & J.L. Formento (CGG) SUMMARY We present an application of petrophysical seismic inversion a method driven by petro-elastic models updating a fine-scale geological model in depth to make it fully compatible with pre-stack seismic measurements on the western part of the Troll Field in the North Sea. The results are being evaluated for infill drilling and for 4D inversion to determine the remaining oil in the thin oil leg. EAGE
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Fractal Behavior of Fractures Derived from Seismic and FMI Data
Authors H. Trappe, H. Endres, P. Thierer, T. Lohr, C. M. Krawczyk, D. C. Tanner, O. Oncken and P. A. KuklaA022 Fractal Behavior of Fractures Derived from Seismic and FMI Data H. Trappe* (TEEC) H. Endres (TEEC RWTH Aachen) P. Thierer (TEEC) T. Lohr (GFZ Potsdam) C.M. Krawczyk (GFZ Potsdam) D.C. Tanner (GZG University Goettingen) O. Oncken (GFZ Potsdam) & P.A. Kukla (RWTH Aachen) SUMMARY This study is part of a larger research project. The results presented are from an area located east of the city Bremen where gas is produced from a deep Rotliegend sandstone reservoir. Faults fractures and associated deformation bands at reservoir depth have an important influence to the productivity of the gas field as fractures are
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Geological and Geophysical Inversion by Hierarchical Classification – Combining Seismic Stratigraphic and AVO Attributes
Authors A. Carrillat, T. Basu, R. Ysaccis, J. Hall, F. Mohamed, A. Mansor, M. Brewer and S. MahmoudA023 Geological and Geophysical Inversion by Hierarchical Classification – Combining Seismic Stratigraphic and AVO Attributes A. Carrillat* (Schlumberger) T. Basu (Schlumberger) R. Ysaccis (Schlumberger) J. Hall (Schlumberger) F. Mohamed (Schlumberger) A. Mansor (Petronas Carigali) M. Brewer (Petronas Carigali) & S. Mahmoud (Petronas Carigali) SUMMARY We present a case study in which both texture facies and fluid prediction are linked by performing a hierarchical classification and estimation scheme whereby a multiattributes volume which captures seismic stratigraphy and texture information is combined with AVO attributes to map fluid response into a single coherent seismostratigraphic and reservoir facies volume. EAGE 69 th Conference
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Nile Delta Reservoir Case Study Using a Novel Broad Band Pre–Stack Seismic Inversion to Rock Properties Technique
By M. E. SmithA024 Nile Delta Reservoir Case Study Using a Novel Broad Band Pre–Stack Seismic Inversion to Rock Properties Technique M.E. Smith* (Geotrace Technologies Inc.) SUMMARY Exploration for hydrocarbons within a concession located onshore in the Nile Delta Egypt has been ongoing for several years however so far has not afforded any significant discoveries. A pre-stack seismic inversion to rock properties procedure using a novel technique to provide broad bandwidth has provided increased understanding of the lithology and highlighted potential reservoir targets. EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007 INTRODUCTION Exploration for hydrocarbons within an
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Using 4D Seismic Data and Geomechanical Modelling to Understand Pressure Depletion in HPHT Fields of the Central N Sea
Authors R. Staples, J. Ita, R. Nash, P. Hague and R. BurrellA025 Using 4D Seismic Data and Geomechanical Modelling to Understand Pressure Depletion in HPHT Fields of the Central N Sea R. Staples* (Shell Exploration & Production in Europe) J. Ita (Shell Exploration & Production in Europe) R. Nash (Shell Exploration & Production in Europe) P. Hague (Shell Exploration & Production in Europe) & R. Burrell (Shell Exploration & Production in Europe) SUMMARY 4D is most conventionally used to monitor saturation changes but in high-pressure environments it can be used to indicate pressure compartmentalisation. 4D seismic has been used to investigate compartmentalisation in Central North Sea high-pressure high-temperature (HPHT) reservoirs including
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Elgin-Franklin 4D Seismic – Encouraging Results for Reservoir Monitoring & Development Planning
Authors N. Taylor, L. Ben-Brahim, C. Tindle, G. Joffroy, C. Hubans and A. OnaisiA026 Elgin-Franklin 4D Seismic – Encouraging Results for Reservoir Monitoring & Development Planning N. Taylor* (Total E&P UK) L. Ben-Brahim (Total E&P UK) C. Tindle (Total E&P UK) G. Joffroy (Total E&P UK) C. Hubans (Total Research Center Pau) & A. Onaisi (Total Research Center Pau) SUMMARY Elgin and Franklin are deep HP/HT (1100 bar 190degC) gas condensate fields situated in the Central Graben of the North Sea. A 4D seismic monitor survey was acquired in 2005 four years after production start-up when the reservoir pressure had declined by 600 – 650 bars. Compaction of the reservoir has caused a
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4D Time Strain and the Seismic Signature of Geomechanical Compaction at Genesis
Authors J. E. Rickett, L. Duranti, T. Hudson, B. Regel and N. HodgsonA027 4D Time Strain and the Seismic Signature of Geomechanical Compaction at Genesis J.E. Rickett* (Chevron) L. Duranti (Chevron) T. Hudson (Chevron) B. Regel (Chevron) & N. Hodgson (Heriot-Watt University) SUMMARY The unconsolidated reservoirs of the Genesis field have experienced significant production-related compaction since first oil in 1999. This compaction causes stretching in the overburden and is visible as time-shifts between the monitor and baseline 4D surveys. We measured local time-shifts between these two surveys at every point in the volume and took their vertical derivative to produce an interval estimate of the fractional change in traveltime which we call
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The 3D Reservoir Geological Model – A Hub for 4D Seismic Interpretation
Authors T. Ottesen, I. Magnus, N. B. Jørgensen, L. Vestergaard and M. G. StageA029 The 3D Reservoir Geological Model – A Hub for 4D Seismic Interpretation T. Ottesen* (DONG E&P AS) I. Magnus (PA Resources Norway AS) N.B. Jørgensen (DONG E&P AS) L. Vestergaard (DONG E&P AS) & M.G. Stage (DONG E&P AS) SUMMARY A 3D time-lapse seismic survey was acquired in 2004 over a 50MMbbls Paleocene oil field in the Danish Central Graben to facilitate improved reservoir management and identify potential drilling targets. To obtain a 3D impedance model relationships between reservoir composition porosity fluid fill and acoustic impedance were applied to the 3D reservoir geological model based on log and core
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3D and 4D Seismic AVO Inversion for Updating the Schiehallion Reservoir Model and Prediction of Production Effects
Authors A. C. Evans, H. Dankbaar and J. StammeijerA030 3D and 4D Seismic AVO Inversion for Updating the Schiehallion Reservoir Model and Prediction of Production Effects A.C. Evans* (Shell UK Ltd) H. Dankbaar (Shell UK Ltd) & J. Stammeijer (Shell UK Ltd) SUMMARY Located West of Shetland on the UKCS the Schiehallion Field oil reservoir lies in a Palaeocene deep marine turbidite complex characterized on seismic data by direct hydrocarbon indicators. Amplitude attributes strongly influence the distribution of sand in the full field model built as a reservoir management tool. Recently a test of this existing model involving a comparison of synthetic and real data from a new
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4D Driving Developments at Gannet E & F
Authors R. Staples, J. Brain, K. Hunt, M. Behrens, Y. Charreyron and A. CookA031 4D Driving Developments at Gannet E & F R. Staples* (Shell Exploration & Production in Europe) J. Brain (Shell Exploration & Production in Europe) K. Hunt (Shell Exploration & Production in Europe) M. Behrens (Shell Exploration & Production in Europe) Y. Charreyron (Shell Exploration & Production in Europe) & A. Cook (Shell Exploration & Production in Europe) SUMMARY 4D seismic has been used extensively over the Gannet cluster in the UK Central North Sea since 1998 (Kloosterman et al. 2003 Staples et al. 2005 Staples et al. 2006). Here we focus on recent results from 4D seismic over the
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Full Bandwidth Inversion for Time Lapse Reservoir Characterization on the Girassol Field
Authors P. R. Mesdag, M. Feroci, L. Barens, P. H. Prat and W. PilletA032 Full Bandwidth Inversion for Time Lapse Reservoir Characterization on the Girassol Field P.R. Mesdag* (Fugro-Jason Netherlands BV) M. Feroci (Fugro-Jason UK Ltd London) L. Barens (Total E&P CSTJF Pau) P.H. Prat (Total E&P Luanda) & W. Pillet (Total E&P CSTJF Pau) SUMMARY Full band-width simultaneous inversion was performed on a base and two monitor surveys over the Girassol field offshore Angola. It is well known that the low frequencies need to be added to the band limited seismic data to derive elastic parameter models that are directly related to well log measurements. Careful calibration of the low frequency models
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Scientific Strategy to Explain Observed spectral Anomalies over Hydrocarbon Reservoirs Generated by Microtremors
Authors E. H. Saenger, S. M. Schmalholz, Y. Y. Podladchikov, R. Holzner, M. Lambert, B. Steiner, B. Quintal and M. FrehnerA033 Scientific Strategy to Explain Observed spectral Anomalies over Hydrocarbon Reservoirs Generated by Microtremors E.H. Saenger* (ETH Zurich / Spectraseis) S.M. Schmalholz (ETH Zurich) Y. Y. Podladchikov (PGP Oslo) R. Holzner (Spectraseis) M. Lambert (ETH Zurich) B. Steiner (ETH Zurich) B. Quintal (ETH Zurich) & M. Frehner (ETH Zurich) SUMMARY Worldwide one has observed narrow-band low-frequency (1.5-4 Hz) tremor signals on the surface over hydrocarbon reservoirs (oil gas and water multiphase fluid systems in porous media). These ‘hydrocarbon tremors’ possess remarkably similar spectral and signal structure characteristics pointing to a common source mechanism even though the depth (some hundreds to
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Evaporite Mapping Using High Resolution Passive Seismic Tomography and Kohonen Neural Networks
Authors G. Tselentis, N. Martakis, P. Paraskevopoulos and S. KapotasA034 Evaporite Mapping Using High Resolution Passive Seismic Tomography and Kohonen Neural Networks G. Tselentis* (University of Patras Seismological Laboratory) N. Martakis (LandTech Enterprise SA) P. Paraskevopoulos (University of Patras Seismological Laboratory) & S. Kapotas (LandTech Enterprises SA) SUMMARY Passive seismic tomography application for exploration shows great potential. We present two case studies in Greece that successfully use the passive seismic tomography method in combination with Kohonen neural networks in order to better map subsurface features EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007 Introduction Evaporite identification from geophysical data is an important task
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Spatial Reservoir Localization Using Seismic Emission Data
A035 Spatial Reservoir Localization Using Seismic Emission Data V.E. Shulakova* (Geophysical Data Systems Ltd) A.P. Zhukov (Geophysical Data Systems Ltd) M.B. Shneerson (Geophysical Data Systems Ltd) K.I. Loginov (Geophysical Data Systems Ltd) R.G. Kharisov (TNG-group) V.A. Ekimenko (TNG-group) & N.M. Khusnimardanov (TNGgroup) SUMMARY The classic theory of seismic methods assumes that the geological medium is passive and doesn’t generate its own microseism. But in practice we often confronted with seismic activity of geological environment. The authors assert the real geological medium is an active system: it can generate microseism itself. This effect of seismo-acoustic emission becomes pronounced in hydrocarbon reservoir.
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Using Multiple Downhole VSP Arrays for Monitoring and Locating Passive Microseisms in Oil Reservoirs
By Z. C. ChenA036 Using Multiple Downhole VSP Arrays for Monitoring and Locating Passive Microseisms in Oil Reservoirs Z.C. Chen* (CREWES University of Calgary) SUMMARY Using a classical hypocenter location method which depends only on the first arrival times the uncertainties of the hypocenter location as determined by a microseismic monitoring network composed of multiple VSP downhole geophone arrays in the surrounding wells is calculated. Error analysis illustrates that if the multiple arrays are properly designed the events recorded by this kind of monitoring network can be located at an accuracy of 5-10 m in the areas between the arrays. Compared to the
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Determining the Fluid Saturation and Depth of Reservoirs by Passive Seismic SLEC-Monitoring Technology
A037 Determining the Fluid Saturation and Depth of Reservoirs by Passive Seismic SLEC-Monitoring Technology A.V. Volkov* (Institute for New Oil-and-Gas Technologies) O.L. Kuznetsov (Institute for New Oil-and-Gas Technologies) I.A. Chirkin (Institute for New Oil-and-Gas Technologies) I.G. Raylyan (Institute for New Oil-and-Gas Technologies) B.Y. Meltchouk (Institute for New Oil-and-Gas Technologies) V.A. Dyblenko (Oil Engineering Co.) R.K. Khismatullin (Oil Engineering Co.) S.I. Slionkin (Slavneft-NPTS R&P Center) G.V. Kashirin (Slavneft-NPTS R&P Center) V.V. Firsov (Orenburgneft TNK-BP) & G.V. Rogotsky (R&P Company Geoacoustic) SUMMARY Considered is application of passive seismic monitoring technology “Seismic Location of Emission Centers” (SLEC) to determining the fluid saturation type
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Valhall Microseismicity Revisited – Relocated Sources, Seismic Multiplets and S-Wave Splitting
Authors J. M. Kendall, K. De Meersman and M. van der BaanA038 Valhall Microseismicity Revisited – Relocated Sources Seismic Multiplets and S-Wave Splitting K. De Meersman (CGG Veritas) J.M. Kendall* (University of Bristol) & M. van der Baan (University of Leeds) SUMMARY We relocate 303 microseismic events that were recorded in the North Sea Valhall oilfield in 1998. A semiautomated re-picking of P-wave and S-wave arrival times and array based P-wave polarisation analysis improves the accuracy of the locations. Our multiplet analysis identifies 40 multiplet groups that include 208 events. Using cross correlation we then further increase the relative location accuracy between multiplet members. The P-waveform similarities between the different multiplets
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Imaging Micro–Seismicity Using Surface Sensors
Authors K. Chambers, J. M. Kendall, O. Barkved, S. Brandsbreg-Dahl and G. A. JonesA039 Imaging Micro–Seismicity Using Surface Sensors K. Chambers* (University of Bristol) J.M. Kendall (University of Bristol) O. Barkved (BP) S. Brandsbreg-Dahl (BP) & G.A. Jones (University of Bristol) SUMMARY We outline an imaging procedure for micro-seismic events recorded on seismic arrays. The approach is based around stacking all the data consistent with an arrival from a particular time and point in the reservoir. The method does not require any hands on analysis of the data such as picking arrival times which makes it ideal for the application to large arrays of surface sensors. We present results of the migration applied
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A Comparison of Collapsing and Precise Arrival-Time Mapping of Microseismicity
Authors R. H. Jones and J. T. RutledgeA040 A Comparison of Collapsing and Precise Arrival- Time Mapping of Microseismicity J.T. Rutledge (Los Alamos National Laboratory New Mexico USA) & R.H. Jones* (Schlumberger Cambridge Research) SUMMARY In this paper we compare the improvements in microseismic location images obtained using precise arrival times with that obtained by the collapsing technique. We first collapse the initial locations for a hydraulic-fracture dataset from the Carthage Cotton Valley gas field. We then use the precise-arrival-time locations as measure for the effectiveness of the collapsing. Finally we examine the changes when applying collapsing to the precise-arrival-time locations. EAGE 69 th Conference & Exhibition
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Optimization of Gas-Cycling, Voidage-Replacement and Production-Allocation for an Offshore Oil Field
Authors B. Guyaguler and J. W. Da SieA041 Optimization of Gas-Cycling Voidage- Replacement and Production-Allocation for an Offshore Oil Field B. Guyaguler* (Chevron) & J.W. Da Sie (Chevron) SUMMARY The application of an optimization methodology to a rate allocation case study for an offshore oil field is discussed. Conventional allocation methods available in most commercial simulators provide a familiar way for the reservoir engineers to carry out predictions while attempting to honor all desired field group and well operating conditions. However most of these conventional approaches are of a sequential nature and they fail to fulfill the requirements of this real field case. The conventional approaches fail
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Efficient Integration of Pressure Data to Estimate OGIP and Production Rates in Dry-Gas Reservoirs
More LessA043 Efficient Integration of Pressure Data to Estimate OGIP and Production Rates in Dry-Gas Reservoirs Nestor Rivera* (Chevron) SUMMARY Pressure data integration contributes significantly to proper reservoir management in dry-gas reservoirs. In this study we used wellbore and surface pressure data to determine the range of Original Gas in Place (OGIP) and perform production predictions for a large dry-gas reservoir. We developed a process to integrate and process wireline wellhead and gas-lines pressure data resulting in a comprehensive set of static reservoir pressure and dynamic information on well by well basis. Then we built numerical reservoir simulation models for several
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Radius of Investigation and Condensate Banking Evaluation of Gas Condensate Reservoirs
By S. Y. ZhengA045 Radius of Investigation and Condensate Banking Evaluation of Gas Condensate Reservoirs S.Y. Zheng* (Institute of Petroleum Engineering Heriot Watt Univ.) SUMMARY In this work we propose a method to calculate the condensate bank size and the radius of investigation of a well test in a gas condensate reservoir. The work was purely based on numerical flow simulation. We performed some basic multiphase flow simulations in a gas condensate reservoir. Radius of investigation and condensate bank size were both calculated numerically and compared to the single phase radius of investigation formulae. On the basis a new formula is developed for
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Integrated Probabilistic Static and Dynamic Reservoir Modelling, Lunskoye Field, Offshore Sakhalin, Russian Federation
Authors L. Ross, K. King, G. Bodewitz, H. van Hasselt, G. Stone, A. James, W. Swinkels, C. Parsons, T. Addis, W. Twigt, P. Jackson, V. Cholovsky and E. LamersA047 Integrated Probabilistic Static and Dynamic Reservoir Modelling Lunskoye Field Offshore Sakhalin Russian Federation L. Ross* (SEIC) K. King (SEIC) G. Bodewitz (Shell International) H. van Hasselt (Shell International) G. Stone (Shell International) A. James (Shell International) W. Swinkels (Shell International) C. Parsons (SEIC) T. Addis (Shell International) W. Twigt (Shell International) P. Jackson (SEIC) V. Cholovsky (SEIC) & E. Lamers (Shell International) SUMMARY The Lunskoye Field is a centrepiece of the Sakhalin II development one of Shell's most significant current projects. Demand for LNG in the nearby Asia-Pacific market and availability of a large (18.2 Tcf GIIP) gas resource
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Channel-Count Requirements for 3D Land Seismic Acquisition in Kuwait
By G. R. RachedB001 Channel-Count Requirements for 3D Land Seismic Acquisition in Kuwait G.R. Rached* (Kuwait Oil Company) SUMMARY Recent advances in land seismic recording equipment have increased the options available for acquisition geophysicists. There are now four main competing types of sensors. The selection of sensor type is today a major decision in seismic survey design as it will greatly affect the channel-count requirements for 3D land seismic acquisition and the resulting data quality. Channel-count requirements for 3D land acquisition in Kuwait and the concepts involved which are not limited to Kuwait environment are herein presented and their impact examined. The analysis
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Operational Implementation of Full Azimuth, High Density land Acquisition – 3D Irharen (Algeria)
Authors M. Girard, D. Mougenot, C. Paulet, A. Rhamani, J. J. Griso and Y. BoukhalfaB002 Operational Implementation of Full Azimuth High Density land Acquisition – 3D Irharen (Algeria) M. Girard* (Total SA) D. Mougenot (Sercel) C. Paulet (Total) A. Rhamani (Sonatrach) J.J. Griso (Cepsa) & Y. Boukhalfa (Enageo) SUMMARY Using a square spread of dense receiver stations (25 m) a full azimuth dense 3D survey (730 km² full fold 225) was recorded in 2005-06 over the Irharen gas discovery in Algeria. This land acquisition is representative of the coming trends aimed at improving reservoir illumination and anisotropy detection. If the basic square spread (7 200 channels) was defined from geophysical considerations its practical implementation
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How Radar Shaped the Vibroseis Sweep
Authors P. I. Pecholcs, H. Hussein and R. SaadB003 How Radar Shaped the Vibroseis Sweep P.I. Pecholcs* (Saudi Aramco) H. Hussein (Saudi Aramco) & R. Saad (Saudi Aramco) SUMMARY Attenuation of aliased and often scattered vibroseis source-generated coherent surface wave energy is one of the greatest challenges in seismic exploration on the Arabian Peninsula. To evaluate the signal-toground roll energy ratio for different vibroseis sweep designs and test the claimed benefits of in-field shaped sweep design technology (Trantham 1994) we derived a new hybrid nonlinear frequency modulated chirp signal and directly compared several full-fold nonlinear versus linear vibroseis sweep field experiments. Analysis of single-fold source records demonstrate that
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Enhancing the Low-Frequency Content of Vibroseis Data with Maximum Displacement Sweeps
By C. BagainiB004 Enhancing the Low-Frequency Content of Vibroseis Data with Maximum Displacement Sweeps C. Bagaini* (Schlumberger Cambridge Research) SUMMARY The maximum reaction mass displacement in Vibroseis acquisition limits the energy that can be transmitted to the ground at low frequencies. A method to design the low-frequency end of Vibroseis sweeps that optimally uses the vibrator’s mechanical and hydraulic specifications is proposed. This method which is to a large extent independent of the near-surface elastic properties requires vibrator specifications typically provided by the manufacturers and the desired ground-force power spectral density that depends on the geophysical requirements. The outputs of this sweep
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Acquisition Using Simultaneous Sources
Authors J. Stefani, G. Hampson and E. F. HerkenhoffB006 Acquisition Using Simultaneous Sources J. Stefani* (Chevron Energy Technology Company) G. Hampson (Chevron Energy Technology Company) & E.F. Herkenhoff (Chevron Energy Technology Company) SUMMARY We present a technique in which 2 or more shots are acquired during the time it normally takes to acquire 1 shot. The 2 or more shots are fired in a near simultaneous manner with small random time delays between the component sources. A variety of processing techniques are applied to produce the same seismic images which would have resulted from firing the simultaneous shots separately. These processing techniques rely on coherency of the wavefield
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Do We Reduce Noise by Towing Deeper?
By E. MuyzertB007 Do We Reduce Noise by Towing Deeper? E. Muyzert* (Schlumberger Cambridge Research) SUMMARY Common seismic industry wisdom is that a streamer towed close to the surface is noisier than a deeper streamer. Deep tow techniques such as over/under marine seismic acquisition therefore deliver quiet seismic data. An analysis of over/under marine seismic noise records acquired in moderate good weather showed that the reality is more complicated. It was found that the RMS energy of the full bandwidth of a noise record did not decrease with tow depth contradicting conventional wisdom. It was shown the noise records at frequencies above
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Air–Leak Detection Using Frequency Domain Deconvolution
Authors A. J. Day, S. Hegna, G. Parkes and N. TurnbullB008 Air–Leak Detection Using Frequency Domain Deconvolution A.J. Day* (PGS Geophysical AS) S. Hegna (PGS Geophysical AS) G. Parkes (PGS Geophysical AS) & N. Turnbull (PGS Geophysical AS) SUMMARY Air-leaks in marine seismic sources are known to have a detrimental effect on the source signature and they are therefore not tolerated during production. If an air-leak is detected acquisition must cease whilst the fault is rectified leading to costly “downtime”. A method for detecting air-leaks has been developed that makes use of signatures recorded by near-field hydrophones positioned near each gun in an array. The complex spectrum of each trace
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Time Variant Coloured Inversion and Spectral Blueing
By J. P. NeepB009 Time Variant Coloured Inversion and Spectral Blueing J.P. Neep* (BP Exploration Operating Company Ltd.) SUMMARY Seismic reservoir characterisation can be enhanced by applying two post-stack processes to the seismic data: coloured inversion to invert to relative acoustic impedance and spectral blueing to enhance seismic resolution. Both these methods make the assumption that the seismic spectrum does not change in the time window of interest. However attenuation in the earth results in a reducing seismic bandwidth with twoway time so for interpretation of large time windows this constant bandwidth assumption fails. The use of a single operator will then give
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Demystifying Tight–Gas Reservoirs Using Multi–Scale Seismic Data
Authors M. W. Roth, J. Shemeta and T. DavisB010 Demystifying Tight–Gas Reservoirs Using Multi– Scale Seismic Data M.W. Roth* (Transform Software & Services Inc.) J. Shemeta (Pinnacle Technologies) & T. Davis (Colorado School of Mines) SUMMARY Low permeability fluvial reservoirs in the US Rocky Mountain region are estimated to hold nearly 7000 tcf of gas reserves (DOE 2003). In a typical reservoir several hundred feet of stacked sands are gas charged with natural and induced fractures being essential for economic gas production. While “traditional” seismic data is useful for identifying major geologic interfaces and faults the thin and complex nature of these channel sands are typically below seismic
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Indications for Pressure Release from Zechstein Rafts during Late Kimmerian - Implications for Reducing Drilling Risks
More LessB011 Indications for Pressure Release from Zechstein Rafts during Late Kimmerian - Implications for Reducing Drilling Risks J.H. Ligtenberg* (NAM B.V. - Nederlandse Aardolie Maatschappij) SUMMARY Newly acquired 3D seismic data has revealed details that provide additional information to better understand the Late Kimmerian tectonic phase. Within the study area fluid migration pathways were observed at specific locations. Their occurence location and extend suggest a direct relation with this major tectonic event. In addition a direct correlation appears to exist with Zechstein rafts and deep-seated (reactivated) faults and fault intersections. These fluid migration paths are interpreted to indicate pressure release
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RGB Visualisation Based Delineation of Geological Elements from Volumetric Spectral Decomposition of 3D Seismic Data
Authors S. J. Purves, J. Henderson and C. LeppardB012 RGB Visualisation Based Delineation of Geological Elements from Volumetric Spectral Decomposition of 3D Seismic Data S.J. Purves* (Foster Findlay Associates) J. Henderson (Foster Findlay Associates) & C. Leppard (Hydro) SUMMARY The paper describes a novel set of multi-channel RGB 3D visualisation and GeoBody detection and delineation techniques that form the basis of a true spectral decomposition based volume interpretation workflow developed as part of a research and development collaboration between ffA and Hydro. EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007 Introduction The spectral content of recorded seismic data is dependent on the
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Dip, Azimuth and Fault – Volume Extraction and Visualization
Authors A. Alam and J. D. TaylorB013 Dip Azimuth and Fault – Volume Extraction and Visualization A. Alam* (Prime Geoscience Corporation) & J.D. Taylor (Prime Geoscience Corporation) SUMMARY We present an automatic method to estimate dip azimuth and fault continuously in a 3D seismic volume. Spectral decomposition methods provide time-continuous phase spectrum at each trace. Laterally continuous local phase surface at a fixed time indicates a reflector. The surface gradient divided by frequency and averaged over high signal-to-noise ratio frequency bands provides an estimate of time-dip and azimuth. In contrast a discontinuous local time-dip/azimuth indicates a point on a fault conflicting dips interference or noise. Inter-linked
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Automated Horizon and Geobody Extraction Using 3D Seismic Waveform Sequences
Authors H. G. Borgos, O. Gramstad, G. V. Dahl, P. Le Guern, L. Sonneland and J. F. RosalbaB014 Automated Horizon and Geobody Extraction Using 3D Seismic Waveform Sequences H.G. Borgos* (Schlumberger) O. Gramstad (Schlumberger) G.V. Dahl (Schlumberger) P. Le Guern (Schlumberger) L. Sonneland (Schlumberger) & J.F. Rosalba (Petrobras) SUMMARY A methodology for automated 3D interpretation is presented. Sequences of horizons (seismic events) are constructed from pre-computed horizon primitives. These horizon primitives are subsequently used to generate geobodies. Classification techniques can be applied to automatically group seismic events into classes of similar seismic waveform when performing seismic interpretation as described by Borgos et al. (2003). In this work we describe how the classification approach can be used to
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Geological Process Controlled Interpretation Based on 3D Wheeler Diagram Generation
Authors E. M. Monsen, H. G. Borgos, P. Le Guern and L. SonnelandB015 Geological Process Controlled Interpretation Based on 3D Wheeler Diagram Generation E.M. Monsen* (Schlumberger) H.G. Borgos (Schlumberger) P. Le Guern (Schlumberger) & L. Sonneland (Schlumberger) SUMMARY The techniques of a new seismic stratigraphic interpretation paradigm are presented whereby geology is made explicit and is brought into the interpretation process through interactive use of an automatically generated 3D Wheeler diagram. The Wheeler diagram explicitly captures the geological context throughout the interpretation process and provides a great tool for fast QC and data understanding. EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007 Introduction Chronostratigraphy is the
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Complex Volumic Seismic Interpretation by New Geobodies Extraction Strategy
Authors F. Pivot, G. Dupuy, S. Gillon and J. N. FerryB016 Complex Volumic Seismic Interpretation by New Geobodies Extraction Strategy F. Pivot* (Total E&P Angola) G. Dupuy (Total S.A.) S. Gillon (Total S.A.) & J.N. Ferry (Total E&P Angola) SUMMARY In this paper we present how new triangulation and propagation algorithms are combined in order to extract relevant and precise geobodies on large lithoseismic cubes. Combined with 3D vizualisation and edition facilities it opens a new way of screening specific geological features of any type in 3D and to obtain triangulated envelopes suited for prospect definition volumetric computations wellbore design and reservoir model construction. Such an approach is illustrated on
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Polarisation Analysis of Ocean Bottom 3C Sensor Data
Authors B. Olofsson and C. MassacandB017 Polarisation Analysis of Ocean Bottom 3C Sensor Data B. Olofsson* (Multiwave Geophysical Company member of CGG group) & C. Massacand (Multiwave Geophysical Company member of CGG group) SUMMARY We analyse seismic polarisation of direct and reflected PS arrivals on multi-component ocean bottom (OB) data by mapping vector fidelity as a function of azimuth and angle of incidence at the seabed. We compare data from a cable system with data from nodes as well as buried and unburied cable sensors. As expected nodes show overall best vector fidelity. For OB cable data on the other hand buried sensors show significantly
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Multicomponent Velocity Analysis with Quaternions
Authors A. Grandi, A. Mazzotti and E. StucchiB018 Multicomponent Velocity Analysis with Quaternions A. Grandi* (University of Pisa presently in Total E&P UK Ltd) A. Mazzotti (University of Pisa) & E. Stucchi (University of Milano) SUMMARY Multicomponent seismic data are acquired by orthogonal geophones that record a vectorial wavefield. Since the single component recordings are not independent the processing and in particular the velocity analysis should be performed jointly for all the components. A way to perform vectorial processing is to exploit quaternions hyper-complex numbers that for their very nature are apt to represent multidimensional data. As an application we show the quaternion velocity analysis for an
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Clair 3D/4C – Demonstrating the Value in Reprocessing 3D Multicomponent Surveys
Authors M. Aitchison, A. Ashby, A. Dawson, M. Ibram, J. McGarrity, C. McKenzie and S. FowlerB019 Clair 3D/4C – Demonstrating the Value in Reprocessing 3D Multicomponent Surveys A. Ashby (WesternGeco) M. Aitchison* (WesternGeco) A. Dawson (WesternGeco) M. Ibram (BP) J. McGarrity (BP) C. McKenzie (BP) & S. Fowler (BP) SUMMARY The Clair field is located 75km west of Shetland and covers an area of 220km2. In 2002 a 3D multicomponent survey was acquired as a result of a successful multi-azimuth 2D test in 2000. The objective was to use wide azimuth OBC data to improve demultiple imaging and to utilise the potential of converted wave (PS) imaging to improve the understanding of fractures in the
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Grane - Converted Wave Imaging for Well Planning
Authors J. P. Fjellanger, F. Bøen and K. J. RønningB020 Grane - Converted Wave Imaging for Well Planning J.P. Fjellanger* (Hydro Oil & Energy) F. Bøen (Hydro Oil & Energy) & K.J. Rønning (Hydro Oil & Energy) SUMMARY The Grane reservoir is difficult to image with ordinary pressure wave (PP) seismic data. In 2001 Hydro acquired a 3D multi-component (4C) survey with ocean bottom cables in the north of the field. A new 4C survey was shot in the south in 2003. The two surveys together cover the whole Grane field. Converted wave data (PS) has proven to give a much better definition of the reservoir sand on Grane
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Anisotropic PP and PSv Prestack Depth Imaging of 4C Data, Pamberi, Offshore Trinidad
Authors T. D. Johns, C. Vito and R. SarmientoB021 Anisotropic PP and PSv Prestack Depth Imaging of 4C Data Pamberi Offshore Trinidad T.D. Johns* (WesternGeco) C. Vito (WesternGeco) & R. Sarmiento (EOG Resources Inc.) SUMMARY In 2004 EOG Resources acquired an OBC 4C swath survey across the Pamberi-1 well location in the Columbus basin eastern offshore Trinidad. Details of the P- and PSv-wave processing through anisotropic PrSTM were previously described (Johns et al. 2006) in which it was demonstrated there existed a qualitative correlation between derived parameters and attributes from P and Sv anisotropic migration velocities and regional geology. Under the “Future work” section of the previous publication
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Imaging through Gas-Filled Sediments with Land 3C Seismic Data
More LessB022 Imaging through Gas-Filled Sediments with Land 3C Seismic Data Y. Li* (BGP) P. Sun (BGP) D. Tang (BGP) Y. He (BGP) H. Chen (BGP) & Y. Yue (BGP) SUMMARY It has been proved in many 4C OBC cases that gas cloud imaging can be improved with converted wave (Li et al. 2001) but few cases have been demonstrated in land 3-C exploration. This paper shows how multi-component (3-C) land data with dynamite source is used to image sub-gas-cloud sediments in CS gas field China. The conventional P-wave data provides unreliable structural images and the interpretation is dubious in an
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Analysis of Shear-Wave Splitting in Multicomponent Seismic Data for Oil-Water Discrimination during Water Flooding
Authors X. Y. Li, M. Chapman, Y. Zhang, Y. Wang and J. XiaB023 Analysis of Shear-Wave Splitting in Multicomponent Seismic Data for Oil-Water Discrimination during Water Flooding X.Y. Li* (British Geological Survey) M. Chapman (British Geological Survey) Y. Zhang (SinoPec) Y. Wang (SinoPec Shengli Oilfield Ltd.) & J. Xia (SinoPec Shengli Oilfield Ltd.) SUMMARY Understanding pore-pressure and saturation changes is important in mature reservoirs. Here we analyze shear-wave splitting in a 3D3C onshore survey from Shengli Oilfield China where the thin sand-reservoir has been undergone production through water-flooding which altered the fluid composition and the porefluid pressure. Dividing the data into orthogonal azimuthal sectors and processing each sector separately reveals significant shear-wave
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Identifying Gas Channel Sweet Spots through Multi-Component Seismic Interpretation
By M. W. RothB024 Identifying Gas Channel Sweet Spots through Multi-Component Seismic Interpretation M.W. Roth* (Transform Software & Services Inc.) SUMMARY Lower Cretaceous fluvial sands offer tantalizing yet challenging gas plays in the Rocky Mountain basins of Canada and the United States. Reservoirs range from single sand channels often with high porosity and permeability to stacked sequences of channels hundreds or even thousands of feet thick generally of low porosity and permeability. Across this spectrum of reservoir types the similar objective is to identify drilling “sweet spots” using available seismic and other E&P data. In this case study the effectiveness of multi-component seismic
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Irregular Sampling – From Aliasing to Noise
Authors G. Hennenfent and F. J. HerrmannB025 Irregular Sampling – From Aliasing to Noise G. Hennenfent* (University of British Columbia) & F.J. Herrmann (University of British Columbia) SUMMARY Seismic data is often irregularly and/or sparsely sampled along spatial coordinates. We show that these acquisition geometries are not necessarily a source of adversity in order to accurately reconstruct adequately-sampled data. We use two examples to illustrate that it may actually be better than equivalent regularly subsampled data. This comment was already made in earlier works by other authors. We explain this behavior by two key observations. Firstly a noise-free underdetermined problem can be seen as a noisy
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Seismic Interference Noise Removal, Interpolation, and Regularization
Authors R. L. Abma, P. Jilek, S. S. Rothe and J. E. MikaB026 Seismic Interference Noise Removal Interpolation and Regularization R.L. Abma* (BP) P. Jilek (BP) S.S. Rothe (BP) & J.E. Mika (BP) SUMMARY Seismic interference noise also referred to as crew noise is the result of acquiring a survey while the sources used to acquire another nearby survey are being fired. Because large 3D surveys may last several months and may be close to each other it is likely that a survey suffering from any seismic interference will have a significant number of shot records with interference noise. Due to the size of 3D surveys an automatic method of removing the
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Application of Frequency Split Structurally Oriented Filtering to Seismic Whitening and Seismic Inversion Workflows
Authors S. Helmore, A. P. Merry and I. HumberstoneB027 Application of Frequency Split Structurally Oriented Filtering to Seismic Whitening and Seismic Inversion Workflows S. Helmore* (Helix RDS) A.P. Merry (Helix RDS) & I. Humberstone (Helix RDS) SUMMARY This paper describes a new method that uses dip-steered filtering to improve the performance of subsequent seismic whitening and relative impedance inversion. Given favourable acquisition and processing parameters the availability of high frequency signals is ultimately limited by poor Signal/Noise ratio (S/N) at high frequencies. Dealing with this noise is key to accessing the high frequency information. We show that though spatial filters applied to broadband seismic data affect mainly the
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Predictive Deconvolution for Correction of Nonstationary Seismic Records
Authors M. A. Poluboyarinov and D. B. FinikovB028 Predictive Deconvolution for Correction of Nonstationary Seismic Records D.B. Finikov (GeoTechSystem) & M.A. Poluboyarinov* (Deco Geophysical) SUMMARY Generalization of the autoregressive model for the case of nonstationarity is used. Proposed way of parameterization of nonstationarity allows effective correction of the waveform at even significantly nonstationary seismic data. Nostationary predictive deconvolution described can be used both for elimination of reverberations and for wavelet correction and provides better results than the traditional approach. EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007 When seismic record does not satisfy stationary convolutional model the problem of waveform correction
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Robust Wavelet Estimation and Blind Deconvolution of Noisy Surface Seismics
Authors M. A. van der Baan and D. T. PhamB029 Robust Wavelet Estimation and Blind Deconvolution of Noisy Surface Seismics M.A. van der Baan* (University of Leeds) & D.T. Pham (LMC-IMAG) SUMMARY Robust blind deconvolution is a challenging problem - in particular if the bandwidth of the wavelet is quite narrow (say around 2 octaves). The principal problem is to estimate the phase of the wavelet with sufficient accuracy. The mutual information rate is a general-purpose criterion to measure whiteness using statistics of all orders. We derive a modification of this criterion that measures the phase of the wavelet within its passband yet remains stable in the presence of
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Unified Green's Function Representation for Interferometry
Authors K. Wapenaar, E. Slob, R. Snieder, D. Draganov, J. Thorbecke, J. van der Neut and S. de RidderB031 Unified Green's Function Representation for Interferometry K. Wapenaar* (Delft University of Technology) E. Slob (Delft University of Technology) R. Snieder (Colorado School of Mines) D. Draganov (Delft University of Technology) J. Thorbecke (Delft University of Technology) J. van der Neut (Delft University of Technology) & S. de Ridder (Delft University of Technology) SUMMARY It has been shown by many authors that the cross-correlation of two acoustic wave field recordings yields the Green's function between these receivers (in geophysics this is also known as ‘seismic interferometry’). Recently the theory has been extended for situations where time-reversal invariance does not hold
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Data-Driven Regularization/Extrapolation Using Interferometry with the Direct Wave
Authors A. C. Ramírez Pérez, K. Hokstad and E. OtnesB032 Data-Driven Regularization/Extrapolation Using Interferometry with the Direct Wave A.C. Ramírez Pérez* (M-OSRP University of Houston) K. Hokstad (Statoil R&D Trondheim Norway) & E. Otnes (Statoil R&D Trondheim Norway) SUMMARY We present a method to extrapolate and regularize data. The procedure is based on crosscorrelation of the measured field with the direct wave and it is independent of earth properties. The method is derived from Green’s theorem and in principle requires the total field and its normal derivative at the receiver locations. Hence it is well-suited for OBS data. In order to apply the method to towed streamer data certain
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Applications of Time-Domain High-Resolution Radon Demultiple
Authors M. A. Schonewille and P. A. AaronB033 Applications of Time-Domain High-Resolution Radon Demultiple M.A. Schonewille* (PGS) & P.A. Aaron (PGS) SUMMARY The frequency domain high-resolution (HR) Radon transform can provide improved resolution in the curvature direction compared with the frequency domain least squares transform. The time domain HR transform also provides improved resolution in the time direction and paradoxically in many cases also a further improvement of the resolution in the curvature direction. In this paper the effect of the improved resolution is studied on synthetic and field data and it is shown that particularly for more complex data the time domain HR Radon transform can
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A Model-Based Two-Way Wave-Equation Approach for Multiple Prediction
More LessB034 A Model-Based Two-Way Wave-Equation Approach for Multiple Prediction Z. Jiang* (BP) & B. Hornby (BP) SUMMARY Multiples from the sea bed or salt boundary are usually strong and will interfere and generate artifacts on migration images. In order to attenuate these multiples one approach is to first predict and then subtract them. We use a model-based prediction method that requires a velocity model which contains the strong multiple generating interfaces such as the sea bed or salt boundary. This method is also a two-way waveequation approach in the sense that it solves the full wave equation by finite-difference approximation
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Surface Related Multiple Prediction from Incomplete Data
More LessB035 Surface Related Multiple Prediction from Incomplete Data F.J. Herrmann* (University of British Columbia) SUMMARY Incomplete data unknown source-receiver signatures and free-surface reflectivity represent challenges for a successful prediction and subsequent removal of multiples. In this paper a new method will be represented that tackles these challenges by combining what we know about wavefield (de-)focussing by weighted convolutions/correlations and recently developed curvelet-based recovery by sparsity-promoting inversion (CRSI). With this combination we are able to leverage recent insights from wave physics towards a nonlinear formulation for the multiple-prediction problem that works for incomplete data and without detailed knowledge on the surface
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Seismic Processing in the Inverse Data Space, Removal of Surface–Related and Internal Multiples
Authors A. J. Berkhout and D. J. VerschuurB036 Seismic Processing in the Inverse Data Space Removal of Surface–Related and Internal Multiples A.J. Berkhout* (Delft University of Technology) & D.J. Verschuur (Delft University of Technology) SUMMARY Considering the dominant role of multiple scattering in seismic data it is proposed to replace data matrix P by its inverse P-1 before starting seismic processing. Making use of the feedback model for seismic data it is shown that surface-related multiple scattered energy is mapped onto the zero time axis of the inverse data space. The practical consequence of this property may be significant: multiple elimination in the inverse data space simplifies
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Advantages and Challenges of Wide Azimuth Data for 3D SRME
Authors D. Lin, W. Lin and B. VerWestB037 Advantages and Challenges of Wide Azimuth Data for 3D SRME D. Lin* (CGGVeritas) W. Lin (CGGVeritas) & B. VerWest (CGGVeritas) SUMMARY We use a synthetic dataset to demonstrate that 3D SRME is still effective and important for wide azimuth data. The wide distribution of azimuths actually helps 3D SRME processing with trace reconstruction by replacing extrapolations with interpolations. Therefore better predictions can be obtained from wide azimuth data compared to those obtained from narrow azimuth data. Migration results show that the stacking power of wide azimuth data suppresses multiples but leaves significant amount of multiple noise in the images.
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3D Surface Related Multiple Elimination for Wide Azimuth Towed Streamer Seismic Data
By K. H. MatsonB038 3D Surface Related Multiple Elimination for Wide Azimuth Towed Streamer Seismic Data K.H. Matson* (BP America) SUMMARY The application of 3D SRME to Wide Azimuth Towed Streamer Seismic data represents a step forward in terms of predicting complex 3D multiples compared to methods that use Narrow Azimuth Streamer data alone. We present synthetic and field data tests and discuss some of the data processing challenges. EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007 Introduction The application of Surface Related Multiple Elimination (SRME) has provided significant added value to practical processing projects over the
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Adaptive Subtraction of Multiples – Application to Complex Seismic Data Onshore Libya
Authors C. Hanitzsch, L. J. van Veen, J. Ali and R. van BorselenB039 Adaptive Subtraction of Multiples – Application to Complex Seismic Data Onshore Libya C. Hanitzsch* (Wintershall) L.J. van Veen (Wintershall) J. Ali (PGS Geophysical) & R. van Borselen (PGS Geophysical) SUMMARY The main difficulties for processing seismic data in Wintershall’s onshore concessions in the Libyan Sirte Basin are the presence of severe noise high-amplitude surface related multiples and internal reverberations that are interfering and partially masking the primary signal and some localized complexities in the overburden. This paper discusses the application of a cascaded de-multiple approach that resulted in a significant enhancement of the structural image of the 3D seismic
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Adaptive Multiple Subtraction in the 2D Wavelet Transform Domain
Authors I. Ahmed, K. H. Matson and Z. YuB040 Adaptive Multiple Subtraction in the 2D Wavelet Transform Domain I. Ahmed* (BP) K.H. Matson (BP) & Z. Yu (BP) SUMMARY In SRME the multiples are predicted by convolving the data by itself. It is a common practice in the industry to use Least-Squares adaptive subtraction in the space-time domain to match the predicted multiples to the multiples in the data. The existing Least-Squares adaptive subtraction in the space-time domain though quite robust does have some limitations. This paper will try to address some of those limitations by doing the Least-Squares adaptive subtraction in the 2D Wavelet-Transform domain. EAGE 69
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Generalized Non-Hyperbolic Moveout Approximation
Authors S. B. Fomel and A. M. StovasB041 Generalized Non-Hyperbolic Moveout Approximation S.B. Fomel* (University of Texas at Austin) & A.M. Stovas (NTNU) SUMMARY We propose a general functional form for nonhyperbolic moveout approximations that can be applied to any kind of seismic media. The proposed form includes five coefficients as opposed to two coefficients in the classic hyperbolic approximation. In certain cases the number of coefficients can be reduced. In the general case determining the optimal coefficients requires tracing of only one non-zero-offset ray. Using analytical ray tracing solutions and numerical experiments we compare the accuracy of our approximation with the accuracy of other known approximations
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NMO Inversion for Multilayer Subsurface with Horizontal Transverse Isotropic Layers
By E. BliasB042 NMO Inversion for Multilayer Subsurface with Horizontal Transverse Isotropic Layers E. Blias* (VSFusion) SUMMARY The NMO inversion problem for HTI medium was solved by Contrera et al (1999) using a technique originally developed by Grechka and Tsvankin (1999). They derived a formula for azimuth-dependent NMO velocity using 2x2 matrices responsible for the ‘interval’ NMO ellipses in each layer. Here I suggest an alternative approach to NMO velocity derivation for the multilayered transverse isotropic model with depth-varying orientation of the symmetry axis. This approach leads to a simplier explicit formula for NMO velocity. Explicit analytical formula for azimuth-dependent NMO velocity
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Using CRS Processing to Design a Sparse 3D Acquisition Geometry
Authors G. Gierse, H. Bezouska-Strozyk, J. Thiessen and U. WeberB043 Using CRS Processing to Design a Sparse 3D Acquisition Geometry G. Gierse* (TEEC) H. Bezouska-Strozyk (TEEC) J. Thiessen (RWE Dea AG) & U. Weber (RWE Dea AG) SUMMARY 3D seismic acquisition proved to solve many complex subsurface problems which could not be addressed by 2D seismics. However 3D acquisition is expensive. This is the reason why sparse 3D acquisition has become popular which results in a lower image quality at lower cost. CRS processing is a tool which increases image quality again without the need for high subsurface fold in acquisition. It therefore proves to be the ideal combination
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CRS Stacking – A Simplified Explanation
Authors J. Mann, J. Schleicher and T. HertweckB044 CRS Stacking – A Simplified Explanation J. Mann* (Geophysical Institute University of Karlsruhe) J. Schleicher (Dept. Applied Math. IMECC/UNICAMP Brazil) & T. Hertweck (Fugro Seismic Imaging Ltd) SUMMARY Stacking velocity analysis and stacking is usually performed within common-midpoint gathers. Generalized approaches like the Common-Reflection-Surface stack method additionally include neighboring common-midpoint gathers to fully exploit the redundancy in the data and to extract additional stacking parameters. In many publications the basics of the CRS stack are obscured by the uncommon parameterization. Our aim is to relate this often poorly understood approach to the established CMP-based approach in a simple and
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Multi-Scale Attenuation in Seismic Transmission Measurements Using the Wavelet Transform
Authors N. Filippidou, G. G. Drijkoningen and E. C. SlobB045 Multi-Scale Attenuation in Seismic Transmission Measurements Using the Wavelet Transform N. Filippidou* (Delft University of Technology) G.G. Drijkoningen (Delft University of Technology) & E.C. Slob (Delft University of Technology) SUMMARY We present a methodology that bridges the scale gap between ultrasonic acoustic measurements and VSP seismic measurements in terms of attenuation and dispersion. It is used to tie different datasets acquired at different frequencies and account for the scaling effects without compromising the fine scale information inherent in large scale measurements but often overlooked. The method is demonstrated on a synthetic velocity log with statistics of fractal Brownian motion.
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Seismic Attenuation Models for Partially Saturated Media
Authors B. B. S. A. Vogelaar and D. M. J. SmeuldersB047 Seismic Attenuation Models for Partially Saturated Media B.B.S.A. Vogelaar* (Delft University of Technology) & D.M.J. Smeulders (Delft University of Technology) SUMMARY Usually wave propagation in the presence of partial fluid saturation is modeled according to the White- Dutta-Odé (WDO) model which is based on the calculation an effective wave modulus of the saturated medium from a boundary value problem. We present here a new model that overcomes some disadvantages in that model by the definition of an effective bulk modulus of the fluid which includes gas bubbles according to the Smeulders-Van Dongen (SvD) model. This paper compares the frequencydependent
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Acoustics of Random Patchy Saturation
Authors J. Toms, B. Gurevich, T. M. Mueller and D. L. JohnsonB048 Acoustics of Random Patchy Saturation J. Toms* (Curtin University of Technology) B. Gurevich (Curtin University and CSIRO Petroleum) T.M. Mueller (University of Karlsruhe) & D.L. Johnson (Schlumberger-Doll Research) SUMMARY Mesoscale heterogeneities occur on a spatial scale which is greater than pore-scale but less than wavelength scale. The presence of mesoscale heterogeneities in saturating fluids within porous rock causes significant attenuation and phase velocity dispersion. In particular both contrast in fluid properties and spatial distribution of fluids significantly affects attenuation and dispersion. Thus patchy saturation models need to be flexible in order to account for both contrast and distribution effects.
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Solving Short-Wavelength Velocity Variations with High-Resolution Hybrid Grid Tomography
Authors M. Dazley, P. J. Whitfield, B. Santos-Luis, A. Sellars, P. Szabo, F. Nieuwland and L. LemaistreC001 Solving Short-Wavelength Velocity Variations with High-Resolution Hybrid Grid Tomography M. Dazley* (WesternGeco Ltd) P.J. Whitfield (WesternGeco Ltd.) B. Santos-Luis (WesternGeco Ltd) A. Sellars (WesternGeco Ltd) P. Szabo (WesternGeco Ltd) F. Nieuwland (Total E & P Nederland B.V.) & L. Lemaistre (Total S.A.) SUMMARY Short wavelength velocity variations are observed within the Cretaceous chalk in some areas of the Southern North Sea. Depth imaging is required because of the strong lateral velocity variations but building a suitable high-resolution velocity model is not easy. Here we present a case history of a pre-stack depth migration project where five overlapping surveys with
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Velocity Analysis in the Dip-Angle Domain
By M. ReshefC002 Velocity Analysis in the Dip-Angle Domain M. Reshef* (Tel Aviv University) SUMMARY When interval velocity analysis is carried out over complex geological regions the use of scattering-angle CIGs may cause significant inaccuracies. The reason for it is the summation over dip-angles which can eliminate information from the analysed CIGs. In this study the idea of performing the interval velocity analysis in the dip-angle domain is discussed and demonstrated with synthetic and field data examples. EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007 Introduction The advantage of using common scattering-angle gathers as the output
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Subsalt Velocity Analysis by Combining Wave Equation Based Redatuming and Kirchhoff Based Migration Velocity Analysis
Authors B. Wang, F. Audebert, V. Dirks, J. Liu and P. ZhangC003 Subsalt Velocity Analysis by Combining Wave Equation Based Redatuming and Kirchhoff Based Migration Velocity Analysis B. Wang* (CGGVeritas) F. Audebert (CGGVeritas) V. Dirks (CGGVeritas) J. Liu (CGGVeritas) & P. Zhang (CGGVeritas) SUMMARY Due to the geometrical complexity of the typical Gulf of Mexico (GOM) velocity models with embedded salt bodies of any shapes wave equation migration is used preferentially over Kirchhoff methods for subsalt velocity model building. This preference is based on the ability of wave-equation based migrations to overcome the need for tracing complex ray paths through the salt bodies and for a better handling of multi-path arrivals
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Pre-Stack Depth Imaging Via Simultaneous Joint Inversion of Seismic, Gravity and Magnetotelluric Data
Authors D. Colombo and M. De StefanoC004 Pre-Stack Depth Imaging Via Simultaneous Joint Inversion of Seismic Gravity and Magnetotelluric Data M. De Stefano (Geosystem SRL) & D. Colombo* (Geosystem SRL) SUMMARY The problem of velocity model building for depth-imaging applications (i.e. Pre-Stack Depth Migration) is approached from the point of view of simultaneous Joint Inversion of multiple geophysical domains. For this purpose a general formulation of the joint inversion problem is provided which integrates geological constraints within a data-driven procedure. The method is then applied to synthetic (long offset) seismic data where seismic travel-time residuals (first-break and post-migration Common Image Gather residuals) are jointly inverted with
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Salt Interpretation Enabled by Reverse Time Migration
Authors J. Buur, J. Keating and T. KuehnelC005 Salt Interpretation Enabled by Reverse Time Migration J. Buur* (Shell International Exploration & Production) J. Keating (Shell International Exploration & Production) & T. Kuehnel (Shell International Exploration & Production) SUMMARY With the success of reverse time migration focus in the geophysical community has shifted towards the final frontier. How to build a velocity model which is accurate enough for imaging with advanced wave equation algorithms? We show that early utilization of reverse time migration in the model building loop can help to delineate complex structures in a salt diapir province offshore West Africa. EAGE 69 th Conference & Exhibition
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From Time to Depth Imaging – A Fast and Accurate Workflow
Authors P. Guillaume, G. Lambaré, P. Herrmann, J. P. Touré, L. Capar, N. Bousquié, D. Grenié and S. ZimineC006 From Time to Depth Imaging – A Fast and Accurate Workflow G. Lambaré (CGG) P. Herrmann (CGG) J.P. Touré (CGG) L. Capar (CGG) P. Guillaume* (CGG) N. Bousquié (CGG) D. Grenié (CGG) & S. Zimine (CGG) SUMMARY We present a new strategy for depth velocity model building from pre-stack time migrated gathers (PreSTM). It is based on dense volumetric dip and residual move-out picking in the PreSTM domain. The kinematic information is de-migrated to compute multi-offset un-migrated attributes - called seismic invariants - used as input data for a multi-offset depth tomography. Compared to the corresponding existing strategy based
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Imaging Beneath Shallow Gas Using Wave Equation Tomography – A Field Data Example from Greater Cassia, Trinidad
Authors M. M. N. Kabir, U. Albertin, M. Zhou, V. Nagassar, E. Kjos and P. WhitakerC007 Imaging Beneath Shallow Gas Using Wave Equation Tomography – A Field Data Example from Greater Cassia Trinidad M.M.N. Kabir* (BP America Inc.) U. Albertin (BP America Inc.) M. Zhou (BP America Inc.) V. Nagassar (BP Trinidad) E. Kjos (BP Trinidad) & P. Whitaker (BP Trinidad) SUMMARY Shallow localized gas pockets cause challenging problems in seismic imaging because of the sags and disturbances they produce on imaged reflectors deep in the section. In addition the presence of shallow gas produces strong surface related and interbed multiples making velocity updating very difficult. Usual reflection tomography techniques may need many iterations to
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Application of Anisotropic Velocity Modeling and Pre-Stack Depth Migration in the Deepwater Gulf of Mexico
By S. L. NealC008 Application of Anisotropic Velocity Modeling and Pre-Stack Depth Migration in the Deepwater Gulf of Mexico S.L. Neal* (Chevron) SUMMARY Seismic imaging in the Deepwater Gulf of Mexico (GoM) has been and continues to be a challenge for all phases of exploration and development. Although the presence of an anisotropic velocity structure has long been recognized it is only occasionally analyzed rigorously or integrated into seismic imaging. A significant challenge posed in the shift to anisotropic imaging is the development of stable and geologically robust workflows. Our anisotropic Pre-Stack Depth Migration (PSDM) workflow consists of three key steps: building the
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Wide Azimuth 3D 4C OBC – A Key Breakthrough to Lead to the Development of Hild Field
Authors D. Vaxelaire, K. Kravik, F. Bertini and J. M. MougenotC009 Wide Azimuth 3D 4C OBC – A Key Breakthrough to Lead to the Development of Hild Field D. Vaxelaire* (Total SA) K. Kravik (Total E&P Norge) F. Bertini (Total E&P Norge) & J.M. Mougenot (Total SA) SUMMARY Seismic imaging is a major challenge for some complex fields in the North Sea. That is the case for the Hild Brent field discovery (Total E & P Norge operator) not yet developed due to inconsistent dynamic data and poor seismic image resulting from a seismic obscured area created by gas dismigration strong energy multiples and a highly faulted reservoir. Conventional 3D
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Mult-Azimuth 3D Provides Robust Improvements in Nile Delta Seismic Imaging
Authors J. Keggin, W. Rietveld, M. Benson, E. Manning, P. Cook, B. Barley and C. PageC010 Mult-Azimuth 3D Provides Robust Improvements in Nile Delta Seismic Imaging J. Keggin* (BP) W. Rietveld (BP) M. Benson (BP) E. Manning (BP) P. Cook (BP) B. Barley (BP) & C. Page (PGS) SUMMARY After covering over 3000 sq km of the Nile Delta with Multi-Azimuth (MAZ) data we demonstrate how and why the technique improves illumination demultiple and lateral resolution. The technique is shown to be robust and reliable providing improved seismic images for exploration and development purposes. EAGE 69 th Conference & Exhibition — London UK 11 - 14 June 2007 Introduction Since gas was first discovered in
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Wide Azimuth Feasibility Study – Key Processing Considerations for an Optimum Design
Authors E. Ceragioli, A. Melois and P. HugonnetC011 Wide Azimuth Feasibility Study – Key Processing Considerations for an Optimum Design E. Ceragioli* (Total SA) A. Melois (Total SA) & P. Hugonnet (CGGVeritas) SUMMARY The Wide Azimuth technique represents a very promising approach for the optimal definition of complex geological targets particularly in sub-salt environments. Encouraging results are being observed from the first “at scale” application in the Gulf of Mexico. In order to deliver the full potential of this technique and maximise the benefit-to-cost ratio a rigorous and detailed feasibility study is absolutely necessary. We examine three key elements of such a study: the expected illumination improvements
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Effect of Structure on Wide Azimuth Acquisition and Processing
Authors B. J. VerWest, D. Lin, Z. Meng and S. NealC012 Effect of Structure on Wide Azimuth Acquisition and Processing B.J. VerWest* (CGGVeritas) D. Lin (CGGVeritas) Z. Meng (CGGVeritas) & S. Neal (Chevron USA) SUMMARY This model study shows that narrow azimuth acquisition may be adequate for structures which are oriented dip to the acquisition direction but strike components are not well imaged. Wide azimuth acquisition with sufficient cross line offset gives improved results compared to narrow azimuth acquisition for both dip and strike components since this method is actually “directionless”. Also 3D SRME on narrow azimuth data shot dip gives a good image but narrow azimuth strike data does
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Multiple Elimination on Wide Azimuth Towed Streamer Data by Extended Wavefield Extrapolation
More LessC013 Multiple Elimination on Wide Azimuth Towed Streamer Data by Extended Wavefield Extrapolation G. Xia* (BP America Inc.) & K. Matson (BP America Inc.) SUMMARY Wide Azimuth Towed Streamer (WATS) data provides a step-change in our ability to illuminate complex subsurface structures. The WATS data with rich diversity of azimuth and offset is effective at attenuating multiples – through simple stacking of post-migration image gathers. However the effectiveness of stacking degrades for exploration scale sampling. Moreover simple stacking precludes prestack analysis for velocity estimation and angle dependent amplitudes on the image gathers. Therefore it is desirable to develop better techniques
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Shot Based Pre-Processing Solutions for a WATS Survey – An Example from a Field Trial in Green Canyon – Gulf of Mexico
Authors J. -C. Ferran, M. Magesan, S. Kaculini, C. J. Faulkner, P. Herrmann, A. Pica, G. Poole and S. Le RoyC014 Shot Based Pre-Processing Solutions for a WATS Survey – An Example from a Field Trial in Green Canyon – Gulf of Mexico M. Magesan (CGGVeritas) J.-C. Ferran* (CGGVeritas) S. Kaculini (CGGVeritas) C.J. Faulkner (CGGVeritas) P. Herrmann (CGGVeritas) A. Pica (CGGVeritas) G. Poole (CGGVeritas) & S. Le Roy (CGGVeritas) SUMMARY In July 2006 a 3D Wide Azimuth Towed Streamer (WATS) field trial was carried out in a deep water area of Green Canyon in the Gulf of Mexico. The purpose was to provide insight into the potential problems and complexities of such seismic datasets and to challenge conventional and newly
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Stress and Seismic Anisotropy Near Salt Bodies – Numerical Modeling and Observation from Wide-Azimuth Marine Data
Authors R. Bachrach, M. Sengupta and A. SalamaC016 Stress and Seismic Anisotropy Near Salt Bodies – Numerical Modeling and Observation from Wide- Azimuth Marine Data R. Bachrach* (WesternGeco) M. Sengupta (WesternGeco) & A. Salama (WesternGeco) SUMMARY Wide-azimuth marine data enable us to observe and analyze the azimuthal response of marine sediments. Modeling the stress near salt bodies using realistic salt geometry and a finite-element solver we show that the presence of salt bodies cause changes in the orientation of the stress in the sediment near the salt. Thus horizontal stresses magnitude and direction may vary near salt bodies. We use third-order elasticity (TOE) theory to quantify the
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Interactive Seismic Imaging by Fast Beam Migration
Authors F. Gao, P. Zhang, B. Wang, G. Thomas-Collignon and V. DirksC017 Interactive Seismic Imaging by Fast Beam Migration F. Gao* (CGGVeritas) P. Zhang (CGGVeritas) B. Wang (CGGVeritas) G. Thomas-Collignon (CGGVeritas) & V. Dirks (CGGVeritas) SUMMARY This paper presents a Fast Beam migration algorithm which has been specifically designed to facilitate very rapid migration turnarounds to allow for interactive velocity model building and validation. The very fast imaging turnaround is achieved by only migrating pre-picked events in a wavelet by wavelet fashion. Coherent noise and migration artifacts are reduced compared to classical Kirchhoff migration techniques by using a sophisticated event selection scheme during the event picking phase and by subsequent multi-path
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