A. Hiorth
University of Stavanger
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Publication
Featured researches published by A. Hiorth.
Human Biology | 2002
Theresa Kumar; Knut Liestøl; Jan Mæhlen; A. Hiorth; Espen Jettestuen; Helge Lind; Sverre-Henning Brorson
This study examines the distribution of apolipoprotein E (APOE) alleles in a population of healthy male and female Norwegians (n = 798) below the age of 40. The -491A/T polymorphism of the promoter region of the APOE gene was also examined. A seminested polymerase chain reaction was applied in the genotyping. The results showed that the E3 allele had the highest frequency (0.744), followed by E4 (0.198) and E2 (0.058). The APOE frequencies found in this study differ significantly from those obtained in earlier Norwegian APOE phenotypings. The allele frequencies in the -491 site of the promoter region were 0.845 for the A allele and 0.155 for the T allele. The genotype frequency was highest for AA (0.707), followed by AT (0.277) and TT (0.016). Moreover, the A allele was in linkage disequilibrium to E4.
Journal of Geophysical Research | 2015
Anders Nermoen; Reidar I. Korsnes; A. Hiorth; M.V. Madland
We report the complete chemical alteration of a Liege outcrop chalk core resulting from a 1072 flow-through experiment performed during mechanical compaction at 130°C. Chemical rock-fluid interactions alter the volumetric strain, porosity, and permeability in a nontrivial way. The porosity reduced only from 41.32% to 40.14%, even though the plug compacted more than 25%. We present a novel analysis of the experimental data, which demonstrates that the geochemical alteration does not conserve the volume of the solids, and therefore, the strain is partitioned additively into a pore volume and solid volume component. At stresses beyond yield, the observed deformation can be explained by grain reorganization reducing the pore space between grains and solid volume changes from the rock-fluid interactions. The mechanical and chemical effects are discussed in relation to the observed permeability development.
Networks and Heterogeneous Media | 2009
Steinar Evje; A. Hiorth; M.V. Madland; Reidar I. Korsnes
In this work a mathematical model is proposed for modeling of coupled dissolution/precipitation and transport processes relevant for the study of chalk weakening effects in carbonate reservoirs. The model is composed of a number of convection-diffusion-reaction equations, representing various ions in the water phase, coupled to some stiff ordinary differential equations (ODEs) representing species in the solid phase. More precisely, the model includes the three minerals
Physical Review D | 2002
A. Hiorth; J.O. Eeg
\text{CaCO}_3
AAPG Bulletin | 2015
Udo Zimmermann; M.V. Madland; Anders Nermoen; Tania Hildebrand-Habel; S.R. Bertolino; A. Hiorth; Reidar I. Korsnes; Jean-Nicolas Audinot; Patrick Grysan
(calcite),
Nuclear Physics B - Proceedings Supplements | 2005
J.O. Eeg; Svjetlana Fajfer; A. Hiorth; A. Prapotnik
\text{CaSO}_4
Physics Letters B | 2003
J.O. Eeg; Svjetlana Fajfer; A. Hiorth
(anhydrite), and
Journal of Computational Physics | 2017
Olav Aursjø; Espen Jettestuen; Jan Ludvig Vinningland; A. Hiorth
\text{MgCO}_3
75th EAGE Conference and Exhibition incorporating SPE EUROPEC 2013 | 2013
Reidar I. Korsnes; Udo Zimmermann; M.V. Madland; S.R. Bertolino; Tania Hildebrand-Habel; A. Hiorth
(magnesite) in the solid phase (i.e., the rock) together with a number of ions contained in the water phase and essential for describing the dissolution/precipitation processes. Modeling of kinetics is included for the dissolution/precipitation processes, whereas thermodynamical equilibrium is assumed for the aqueous chemistry. A numerical discretization of the full model is presented. An operator splitting approach is employed where the transport effects (convection and diffusion) and chemical reactions (dissolution/precipitation) are solved in separate steps. This amounts to switching between solving a system of convection-diffusion equations and a system of ODEs. Characteristic features of the model is then explored. In particular, a first evaluation of the model is included where comparison with experimental behavior is made. For that purpose we consider a simplified system where a mixture of water and
IOR 2017 - 19th European Symposium on Improved Oil Recovery | 2017
A. Omekeh; A. Hiorth; Arne Stavland; Arild Lohne
\text{MgCl}_2