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Numerical modeling of freezing and swelling processes in the ‘foundation - bed’ system
PROPERTIES:DYNAMICS An experimental system has been employed to introduce sets of fractures and microcracks oriented in a plane perpendicuiar to the minimum principal stress in cubic sandstone specimens. The results suggest that for sandstones with sets of oriented fractures and cracks, there is a relation between the velocity of shear waves propagating in a direction perpendicular to the plane of the cracks and the permeability, as the cracks are progressively closed by the application of stress. The relation appears to be rock type specific. The experimental system provides the opportunity to study the influence of changes in the intermediate principal stress on the mechanical (static, dynamic and failure properties) and transport (permeability and electrical resistivity) behaviour of porous sedimentary rocks. (from Authors)
958146 Dolomite reservoirs: porosity evolution and reservoir characteristics S. Qing Sun, American Association of Petroleum Geologists Bulletin, 79(2), 1995, pp 186-204. Systematic analyses of the published record of dolomite reservoirs worldwide reveal that the majority of hydrocarbonproducing dolomite reservoirs occurs in: 1) peritidal-domihated carbonate, 2) subtidal carbonate associated with evaporitic tidal fiat]lagoon, 3) subtidal carbonate associated with basinal evaporite, and 4) nonevaporitic carbonate sequence associated with topographic high]unconformity, platform-margin buildup or fault/fracture. Reservoir characteristics vary greatly from one dolomite type to another. This paper discusses the origin of dolomite porosity and demonstrates the porosity evolution and reservoir characteristics of different dolomite types. (from Author)
958147 Modemng of the compaction behaviour of fractured chalk M. Gutierrez, L. Tunbridge, H. Hansteen, A. Makurat, N. Barton & G. H. Landa, Publikasjon - Norges Geotekniske Institutt, 192, 1994, 8 pp; reprinted from: Prec. ISRM symposium EUROCK'94. Numerical modelling of the behaviour of the fractured chalk in the Ekofisk reservoir was performed using the distinct element code UDEC-llB. The non-linear fracture behaviour was modelled by the Barton-Bandis model, while the pore collapse of the rock matrix was modelled by NGI's cap plasticity formulation. The analyses were performed to investigate the effects of fractures, both natural and compaction induced on the compaction behaviour of the Ekofisk reservoir, and to determine the shear/normal displacement and permeability coupling of the fractures during pressure depletion and water injection. The results of the modelling could be used as a basis for explaining the observed behaviour of the Ekofisk field, provide possible guidelines to future actions in the development of the Ekofisk field, and as input to large-seale models of the Ekofisk field. (Authors)
958148 Intercorrelation of capillary pressure derived parameters for sandstones of the Tortel Formation, Hungary A. M. A. El Sayed, Geophysical Transactions - Eotvos Lorand Geophysical Institute of Hungary, 39(1), 1994, pp 7787. Porosity, permeability and capillary pressure data of 50 sandstone core samples obtained from the Tortel Formation have been used to evaluate reservoir quality. Throe types of reservoir rocks and capillary curves are outlined, and various correlation charts constructed to delineate porosity, permeability, pore throat size, recovery efficiency, height above free water level and capillary pressure at different water saturation values of the reservoir rock. The capillary pressure techniques utilized are typically favoured for geological and engineering
377A
applications to develop sandstone pay zones of the Tortel Formation. (Author)
Compression, swelling and consolidation 958149 Investigation of sediment compaction in the Pannonian Basin using 3D gravity modelling G. Papp & J. Kalmar, Physics of the Earth & Planetary Interiors, 88(2), 1995, pp 89-100. A 1D model was applied to the observed gravity field over a selected area of the Pannonian basin, and an extensive analysis of the sediment compaction was carried out based on a high-resolution digital depth model (DDM) and volume model of the sediments covering the Pannonian basin with an average thickness of 2 km. The obtained density contrast function resulted in apparent density values for the sediments higher than given by the reference model used in 3D gravity field model computations. This systematic deviation may be a consequence of the crustal thinning which is supposed to be a consequence of basin evolution. A crust-mantle model of the investigated area extending below the Moho discontinuity was used to support this assumption. (from Authors)
958150 Numerical modeling of freezing and swelling processes in the 'foundation - bed' system A. B. Fadeev, I. I. Sakharov & P. I. gepina, Soil Mechanics & Foundation Engineering, 31(5), 1995, pp 161-165; translated from: Osnovaniya, Fandamenty i Mekhanika Grunter, 5, 1994, pp 6-9. A method of modelling the process of soil swelling as the bed freezes through is investigated. An algorithm for FEM calculation and basic characteristic features of the developed software are presented. The potential of the software is illustrated in examples of the solution of a number of problems. (Journal summary)
958151 General solution of the spatial problem of the theory of interrelated seepage consolidation V. B. Shvets & V. G. Shapoval, Soil Mechanics & Foundation Engineering, 31(5), 1995, pp 177-180; translated from: Osnovaniya, Fundamenty i Mekhanika Grunter, 5, 1994, pp 19-21. An exact solution is obtained for the three-dimensional problem of the theory of seepage consolidation with axial symmetry, which is distinguished from familar approximate solutions by consideration of Poisson's ratio in computational equations. This makes it possible to predict more accurately the development of strains and stresses in saturated beds over time. (Journal summary)
Dynamic properties 958152 The promise of elastic anisotropy P. Armstrong & 10 others, Oilfield Review, 6(4), 1994, pp 3647. Elastic anisotropy has blossomed from a bothersome anomaly into a promising measure of reservoir properties. This phenomenon, in which waves travel with different velocities in different directions, indicates the presence of alignments such as cracks of fractures, tectonic stresses, depositional layers or ordered anisotropic grains. Formerly of concern only to theorists, elastic anisotropy can now be
958146 Dolomite reservoirs: porosity evolution and reservoir characteristics S. Qing Sun, American Association of Petroleum Geologists Bulletin, 79(2), 1995, pp 186-204. Systematic analyses of the published record of dolomite reservoirs worldwide reveal that the majority of hydrocarbonproducing dolomite reservoirs occurs in: 1) peritidal-domihated carbonate, 2) subtidal carbonate associated with evaporitic tidal fiat]lagoon, 3) subtidal carbonate associated with basinal evaporite, and 4) nonevaporitic carbonate sequence associated with topographic high]unconformity, platform-margin buildup or fault/fracture. Reservoir characteristics vary greatly from one dolomite type to another. This paper discusses the origin of dolomite porosity and demonstrates the porosity evolution and reservoir characteristics of different dolomite types. (from Author)
958147 Modemng of the compaction behaviour of fractured chalk M. Gutierrez, L. Tunbridge, H. Hansteen, A. Makurat, N. Barton & G. H. Landa, Publikasjon - Norges Geotekniske Institutt, 192, 1994, 8 pp; reprinted from: Prec. ISRM symposium EUROCK'94. Numerical modelling of the behaviour of the fractured chalk in the Ekofisk reservoir was performed using the distinct element code UDEC-llB. The non-linear fracture behaviour was modelled by the Barton-Bandis model, while the pore collapse of the rock matrix was modelled by NGI's cap plasticity formulation. The analyses were performed to investigate the effects of fractures, both natural and compaction induced on the compaction behaviour of the Ekofisk reservoir, and to determine the shear/normal displacement and permeability coupling of the fractures during pressure depletion and water injection. The results of the modelling could be used as a basis for explaining the observed behaviour of the Ekofisk field, provide possible guidelines to future actions in the development of the Ekofisk field, and as input to large-seale models of the Ekofisk field. (Authors)
958148 Intercorrelation of capillary pressure derived parameters for sandstones of the Tortel Formation, Hungary A. M. A. El Sayed, Geophysical Transactions - Eotvos Lorand Geophysical Institute of Hungary, 39(1), 1994, pp 7787. Porosity, permeability and capillary pressure data of 50 sandstone core samples obtained from the Tortel Formation have been used to evaluate reservoir quality. Throe types of reservoir rocks and capillary curves are outlined, and various correlation charts constructed to delineate porosity, permeability, pore throat size, recovery efficiency, height above free water level and capillary pressure at different water saturation values of the reservoir rock. The capillary pressure techniques utilized are typically favoured for geological and engineering
377A
applications to develop sandstone pay zones of the Tortel Formation. (Author)
Compression, swelling and consolidation 958149 Investigation of sediment compaction in the Pannonian Basin using 3D gravity modelling G. Papp & J. Kalmar, Physics of the Earth & Planetary Interiors, 88(2), 1995, pp 89-100. A 1D model was applied to the observed gravity field over a selected area of the Pannonian basin, and an extensive analysis of the sediment compaction was carried out based on a high-resolution digital depth model (DDM) and volume model of the sediments covering the Pannonian basin with an average thickness of 2 km. The obtained density contrast function resulted in apparent density values for the sediments higher than given by the reference model used in 3D gravity field model computations. This systematic deviation may be a consequence of the crustal thinning which is supposed to be a consequence of basin evolution. A crust-mantle model of the investigated area extending below the Moho discontinuity was used to support this assumption. (from Authors)
958150 Numerical modeling of freezing and swelling processes in the 'foundation - bed' system A. B. Fadeev, I. I. Sakharov & P. I. gepina, Soil Mechanics & Foundation Engineering, 31(5), 1995, pp 161-165; translated from: Osnovaniya, Fandamenty i Mekhanika Grunter, 5, 1994, pp 6-9. A method of modelling the process of soil swelling as the bed freezes through is investigated. An algorithm for FEM calculation and basic characteristic features of the developed software are presented. The potential of the software is illustrated in examples of the solution of a number of problems. (Journal summary)
958151 General solution of the spatial problem of the theory of interrelated seepage consolidation V. B. Shvets & V. G. Shapoval, Soil Mechanics & Foundation Engineering, 31(5), 1995, pp 177-180; translated from: Osnovaniya, Fundamenty i Mekhanika Grunter, 5, 1994, pp 19-21. An exact solution is obtained for the three-dimensional problem of the theory of seepage consolidation with axial symmetry, which is distinguished from familar approximate solutions by consideration of Poisson's ratio in computational equations. This makes it possible to predict more accurately the development of strains and stresses in saturated beds over time. (Journal summary)
Dynamic properties 958152 The promise of elastic anisotropy P. Armstrong & 10 others, Oilfield Review, 6(4), 1994, pp 3647. Elastic anisotropy has blossomed from a bothersome anomaly into a promising measure of reservoir properties. This phenomenon, in which waves travel with different velocities in different directions, indicates the presence of alignments such as cracks of fractures, tectonic stresses, depositional layers or ordered anisotropic grains. Formerly of concern only to theorists, elastic anisotropy can now be