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67th EAGE Conference & Exhibition
- Conference date: 13 Jun 2005 - 16 Jun 2005
- Location: Madrid, Spain
- Published: 13 June 2005
651 - 683 of 683 results
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Workflows - Key to Consistent Results
More LessSuccessful projects are composed of three distinct components: people, technology and the processes used to accomplish the task. Process improvements, including workflows incorporated within applications will be the next quantum leap in increasing the productivity of geoscientists.
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Process Capture – Enabling New Workflows
More LessGeomodelling systems are rapidly evolving into integrated systems that cover the whole seismic to simulation workflow. This trend clearly leads to much tighter integration across domains with all of the well documented advantages.
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BG and the 3D Modelling Workflow
More LessBG Group has developed a number of 3D modelling workflows, which are tailored to different modelling requirements. These workflows are based on standard methods of data generation (in specialist petrophysical and geophysical software packages), data QC, grid construction (incorporating seismic horizons and faults), facies and petrophysical modelling, and the upscaling the fine grid geological model into a coarser simulation grid as appropriate.
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Improve Model Accuracy by Integrating Geological Modelling Software Packages
By A. LindThe overview for this session refers to the fact that “geomodelling tools are far from perfect and may create a false impression of accuracy”. The focus of this presentation will be to show that whilst this statement is broadly correct, in some circumstances, a flexible approach to modelling using the most appropriate software tool for each task will lead to greater accuracy in the final geological model.
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The pearls and perils of interactive geomodelling tookits; the global deployment of PETREL in Shell E&P
By R. BennettShell has traditionally developed its own high-end geo-modelling tools for detailed reservoir geological analysis, from the introduction of the IPGW (Interactive Production Geology Workbench) in the late 1980s, through to its GEOCAP-2 and DEPSIM packages of the mid to late 1990s.
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SBED Studio – An integrated workflow solution for multi-scale geo-modelling
By R. WenSBED Studio is an integrated software solution for multi-scale reservoir heterogeneity modelling in reservoir characterization. We use a process-oriented approach to model geological processes that result in reservoir heterogeneity at three scales: bedding structure scale (mm to cm), internal stratification scale (~ 1 m), and reservoir architecture scale (> 1 m). Reservoir heterogeneity at these three scales must be modelled in an integrated manner in order to improve the prediction of production profiles.
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Use of lithofacies-scale models in reservoir appraisal and simulation
Authors P. S. Ringrose, K. Nordahl and C. ElfenbeinA lithofacies-scale modeling tool, SBEDTM, has been used to create multiple realizations of facies heterogeneity at the sub-metre to metre scale. These lithofacies models have been used in a range of reservoir studies, including formation appraisal, geological modeling, singlephase flow upscaling and multiphase flow upscaling. This paper summarizes the multi-scale geological modeling approach used in this work and the potential value of the approach for other reservoir appraisal and modeling studies.
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Modelling a thin oil rim – The impact of cell geometry on Oil-In-Place and potential for upscaling to simulation
By A. RobinsonA geological model of an onshore oil field was constructed during 2004 as part of an evaluation to deliver up-to-date (static model) Oil-in-Place based upon current structure interpretation, well data and a recent petrophysical evaluation of reservoir properties. The field, located onshore Gabon, is producing from an 11m thick oil rim from a series of horizontal producers within a good net to gross system of Gamba and Dentale Sands.
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Start with the End in mind – Methods for Modelling in Flow Simulation Grids
By G. FielderUpscaling of subsurface data is an undesirable task that is difficult to avoid. Upscaling is generally necessary because our subsurface geologic data are more dense than geologic models can use, and most geologic models are too detailed to flow simulate in practical time frames.
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Can a Small Specialist Vendor Fill a Global Strategic Need for Niche Technology
By A. GibbsThe challenge and opportunity for the specialist vendors is to provide quality and flexibility in detailed analysis which allows the Client user to add value to the modelling environment provided by the "Wal-Mart"s of the vendor community. However, it is the specialist vendors who frequently carry the innovation and need to be at the sharp end.
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Reservoir-Scale 3D Sedimentary Modelling – Approaches and Impact of Integrating Sedimentology into Reservoir Characterization Workflow
Authors R. Labourdette, Ja. Hegre, P. Imbert and E. InsalacoSedimentological cross-sections and maps contain most of the knowledge and concepts of sedimentologists. They represent the outcome of sedimentological studies, including available well data, seismic interpretation and especially sedimentological and environmental concepts, incorporating all facies transitions and successions in a high-resolution stratigraphic framework.
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An Innovative Geostatistical Approach to Build Geologically Realistic Reservoir Models – the MPS/FDM Workflow
Authors S. Strebelle and M. LevyBuilding geologically realistic reservoir models that honor well data and seismic-derived information remains a major challenge for Geostatisticians. Conventional variogram-based modelling techniques typically fail to capture complex geological structures while objectbased techniques are severely limited by the amount of conditioning data. This talk presents new reservoir facies modelling tools developed at ChevronTexaco in collaboration with Stanford University that improve both model quality and efficiency relative to traditional geostatistical techniques.
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Representation of Complex Fault Zone Structure in Cellular Geomodels
Authors S. J. Dee, B. Freeman, G. Yielding, P. G. Bretan, A. F. Foster and J. ParsonsGeological modelling is frequently carried out in two stages. Initially a layer- and fault-based framework is constructed where the main goal is to represent faithfully the 3D geometry of the real geology, as imaged by seismic data. At this stage close attention is paid to the shape, location and connectivity of fault planes.
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Covisualization of Uncertainty and Multidisciplinary Data for Reservoir Characterisation
Authors A. Paradis, G. Brew, P. Luxey and J. MartinieClear trends are apparent in geomodelling and reservoir characterization. These include data proliferation, incorporation of uncertainty, and integration of data from numerous disciplines. These trends, if handled correctly, will all lead to better reservoir characterization, and ultimately higher levels of hydrocarbon recovery.
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Introduction to Mining Geostatistics
By F. RambertGeostatistics, in combination with other statistical methods, offers a wide range of mathematical tools that can be used to analyze, model, provide estimates and assess uncertainties, for different types of spatial features – e.g. grades or geological facies –
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Optimizing Sampling Strategies in Kimberlite Mining
By D. FarrowSouth African diamond mining of kimberlites dates back over 100 years. During this time, several of the pipes have been depleted and the mines closed, but a number of mines have extensive resources at depths below their current infrastructural capacity. Exploitation of these resources will require substantial capital investment. Risk has become a major driving force in evaluation of these resources. Any delineation or drilling program has to ensure that the delineated resource will be within acceptable risk levels. Designing drilling campaigns has usually been a subjective process. Following recent investigations , a methodology to plan drilling programs to meet acceptable risk targets will be demonstrated.
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Recoverable Resources Estimation – Indicator Kriging or Uniform Conditioning?
By J. DeraismeConsideration of the mining method is an essential component of ore reserves evaluation. This is particularly true when the profitability of a project is conditioned by the ability to mine selectively. Linear estimation methods such as Ordinary and Simple Kriging commonly fail to provide unbiased estimates of recovered ore and metal tonnage after cutoff, which means that a mining project can be exposed to undue risk.
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Application of the Truncated Gaussian Simulation Method to the MM deposit at Codelco Norte, Chile
Authors P. Carrasco, F. Ibarra, G. le Loc’h, R. Rojas and S. SeguretThe MM ore body is a satellite of Chuquicamata porphyry copper deposit in Chile, exploited by Codelco. MM ore body is not yet open to exploitation. Its geology is ore complex than a classical porphyry copper, due to the superimposition of various geological processes, such as the presence of high grade vein type breccias, of variable thickness and of variable continuity.
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P' Is a Different Kind of Animal
By P. R. RoseMost of the "E" part of the E&P business has, by now, embraced the main principles of probabilistic risk analysis: - Reserves distribution forecasts for prospects. - Prediction of chance of completion. - Probabilistic NPV forecasts, given success. - Chance-weighted economic yardsticks, allowing comparison of projects.
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Can hydrocarbon saturation be estimated using density contrast parameter?
More LessThe density contrast parameter may reveal important and crucial information about the presence and saturation of hydrocarbon. In this paper, we demonstrate the relation between density contrast and gas saturation and one method for extracting these parameters from seismic data. We use a reparameterization of the Knott-Zoeppritz equation without any approximation in terms of a background and three contrast parameters: P-velocity, S-velocity and density contrasts. Synthetic and real data examples show that a reliable estimation of the density contrast is possible by using data with higher angles of incidence and performing a nonlinear inversion. Density contrast appears to be indicative of gas saturation.
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Fluid prediction versus lithology prediction from inverted seismic data
Authors A. -J. Van Wijngaarden and P. AvsethAs a result of continuous improvement in seismic data quality the lithology and fluid prediction from seismic data has become more reliable during the last decade. This is also a requirement for more complex and less robust exploration targets, as well for increased hydrocarbon recovery in production. Milestones on the road for improved LFP have been Elastic Inversion and Simultaneous Inversion.
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Gas saturation estimation from seismic data: What is the accuracy of our prediction and how can we improve it?
Authors N. Dutta and R. BachrachSeismic inversion can be viewed as a process in which one estimates the parameters governing the propagation of seismic waves in the subsurface. Seismic inversion technology can provides estimates of P-impedance, S-impedance, and density using prestack seismic data. AVO analysis (Castanga, 1993) based on Zeoppritz equations (or subsequent approximations) is the most popular tool with which to derive subsurface elastic attributes from seismic data. We note that other techniques such as waveform inversion (Malick, 1995) have been also used to derive the subsurface elastic attributes.
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Seismic Amplitude Anomalies associated with Low Gas Saturation Sands A Case Study from Green Canyon Block 473 in the Gulf of Mexico
By J. O‘BrienGas saturation is suspected of being the cause of some observed seismic bright spots, resulting in drilling of several dry holes. Seismic amplitudes are sensitive indicators of the presence of gas in tertiary age sediments but poor indicators of gas saturation. As a result, a reservoir with low gas saturation is expected to have a seismic amplitude response comparable to that of a reservoir with high, commercial level, saturation. Interpretation of seismic anomalies faces a significant risk that the anomaly may be due to low gas saturation; Gross and Oliver (AAPG Bulletin, 1998) estimate that 18% of the bright spots drilled in the deepwater Gulf of Mexico are due to low gas saturation.
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Various examples of how to use spectral decomposition for fluid separation.
Authors M. Rauch-Davies and M. RalstonThe spectral decomposition of seismic data is the process that transforms seismic amplitudes in time and space to spectral amplitudes in frequency, time and space. Spectral decomposed data have been used for a more accurate structural mapping over the last few years. Recently, spectral amplitudes have also been applied as Direct Hydrocarbon Indictors (DHI).
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Link Between Attenuation and Velocity Dispersion
By J. DvorkinIn a viscoelastic sample, the causality principle links the attenuation of a stress wave to the changes in its speed as the frequency varies. This rigorous theoretical link helps explain the velocity-frequency dispersion and attenuation commonly observed in rocks with fluid. Usually, the attenuation is maximum in the frequency range where the velocity change is most rapid.
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A Field Invesitgation of the Permeability Dependence of Seismic Amplitudes
Authors S. S. Payne, M. H. Worthington, N. E. Odling and L. J. WestThe direct determination of permeability from seismic data is a greatly desired but still unattained goal. There has been significant recent progress due to the work of Pride and Berryman (2003a, 2003b) and Pride et al (2004). They have developed theoretical relationships for seismic attenuation resulting from wave induced fluid flow. The theory includes the case of heterogeneity in the elastic moduli at scales greater than grain sizes but smaller than wavelengths (mesoscopic scale).
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Low frequency attenuation in a saturated rock
Authors B. B. S. A. Vogelaar and D. M. J. SmeuldersHigh porosity zones bearing reservoir fluids are often interbedded with relatively impermeable lithologies. Fluids in the pores and fractures in the reservoir significantly affect the acoustic bulk characteristics, which are delineated from surface seismics, vertical seismic profiling, cross-well tomography, and sonic logging. The detected waves contain information about the rock along the wave path and the objective of all techniques is to extract this information in terms of geological structures and rock/fluid properties.
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Observation and modeling of anisotropic attenuation in VSP data
Authors S. Maultzsch, M. Chapman, E. Liu and X. -Y. LiWe analyze a range of VSP datasets for evidence of fracture related attenuation anisotropy, focusing on three attributes: P-wave attenuation anisotropy, differential shear-wave attenuation and frequency dependent shear-wave splitting. We find examples of all three phenomena and are able to reproduce the behaviour with well constrained, unified, theoretical models. Our results suggest a correlation between attenuation anisotropy and fracture properties. It is apparent that in all cases the reservoir displays much higher attenuation than the overburden. Measuring relative attenuation appears to be more robust than measuring absolute attenuation.
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