Simulation of anisotropic heterogeneous near-well flow using MPFA methods on flexible grids     

Sissel Slettemark Mundal  Eirik Keilegavlen  Ivar Aavatsmark 《Computational Geosciences》2010,14(4):509-525

Control-volume multipoint flux approximations (MPFA) are discussed for the simulation of complex near-well flow using geometrically flexible grids. Due to the strong non-linearity of the near-well flow, a linear model will, in general, be inefficient. Instead, a model accounting for the logarithmic pressure behavior in the well vicinity is advocated. This involves a non-uniform refinement of the grid in the radial direction. The model accounts for both near-well anisotropies and heterogeneities. For a full simulation involving multiple wells, this single-well approach can easily be coupled with the reservoir model. Numerical simulations demonstrate the convergence behavior of this model using various MPFA schemes under different near-well conditions for single-phase flow regimes. Two-phase simulations support the results of the single-phase simulations.  相似文献   

Balancing aquaculture with other coastal interests: A study of regional planning as a tool for ICZM in Norway   总被引：1，自引：0，他引：1  

Sissel Hovik  Knut Bjrn Stokke 《Ocean & Coastal Management》2007,50(11-12):887-904

Coastal zone planning at regional level has been introduced in Norway to deal with the problems of integration that coastal zone planning at municipal level has not been able to solve. In particular, this relates to coordination between the relevant sectors at regional level. The present article discusses the effects of different planning strategies at regional (county) level in terms of achieving integration between the interests of the aquaculture industry with those of other coastal interests. The findings are based on a study comparing the experiences in three counties. The authors argue that the individual county's choice of planning strategy influence the way in which the integrated coastal zone management (ICZM) is carried out. The more active the county authorities have been as a meta-governor in the planning and implementation processes, the higher level of integration is achieved.  相似文献   

Utilizing spectral decomposition to determine the distribution of injected CO2 at the Snøhvit Field          下载免费PDF全文

Gareth A. Williams  Sissel Grude  R. Andrew Chadwick 《Geophysical Prospecting》2015,63(5):1213-1223

Time‐lapse 3D seismic reflection data, covering the CO₂ storage operation at the Snøhvit gas field in the Barents Sea, show clear amplitude and time‐delay differences following injection. The nature and extent of these changes suggest that increased pore fluid pressure contributes to the observed seismic response, in addition to a saturation effect. Spectral decomposition using the smoothed pseudo‐Wigner–Ville distribution has been used to derive discrete‐frequency reflection amplitudes from around the base of the CO₂ storage reservoir. These are utilized to determine the lateral variation in peak tuning frequency across the seismic anomaly as this provides a direct proxy for the thickness of the causative feature. Under the assumption that the lateral and vertical extents of the respective saturation and pressure changes following CO₂ injection will be significantly different, discrete spectral amplitudes are used to distinguish between the two effects. A clear spatial separation is observed in the distribution of low‐ and high‐frequency tuning. This is used to discriminate between direct fluid substitution of CO₂, as a thin layer, and pressure changes that are distributed across a greater thickness of the storage reservoir. The results reveal a striking correlation with findings derived from pressure and saturation discrimination algorithms based on amplitude versus offset analysis.  相似文献   

Stochastic inversion of pressure and saturation changes from time-lapse multi component data     

Helene Hafslund Veire  Hilde Grude Borgos  Martin Landrø 《Geophysical Prospecting》2007,55(6):805-818

Knowledge about saturation and pressure distributions in a reservoir can help in determining an optimal drainage pattern, and in deciding on optimal well designs to reduce risks of blow‐outs and damage to production equipment. By analyzing time‐lapse PP AVO or time‐lapse multicomponent seismic data, it is possible to separate the effects of production related saturation and pressure changes on seismic data. To be able to utilize information about saturation and pressure distributions in reservoir model building and simulation, information about uncertainty in the estimates is useful. In this paper we present a method to estimate changes in saturation and pressure from time‐lapse multicomponent seismic data using a Bayesian estimation technique. Results of the estimations will be probability density functions (pdfs), giving immediate information about both parameter values and uncertainties. Linearized rock physical models are linked to the changes in saturation and pressure in the prior probability distribution. The relationship between the elastic parameters and the measured seismic data is described in the likelihood model. By assuming Gaussian distributed prior uncertainties the posterior distribution of the saturation and pressure changes can be calculated analytically. Results from tests on synthetic seismic data show that this method produces more precise estimates of changes in effective pressure than a similar methodology based on only PP AVO time‐lapse seismic data. This indicates that additional information about S‐waves obtained from converted‐wave seismic data is useful for obtaining reliable information about the pressure change distribution.  相似文献