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Ida Lykke Fabricius - One of the best experts on this subject based on the ideXlab platform.
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elasticity and electrical resistivity of chalk and Greensand during water flooding with selective ions
Journal of Petroleum Science and Engineering, 2018Co-Authors: Konstantina Katika, Mohammad Monzurul Alam, Artem Alexeev, Krishna Hara Chakravarty, Philip Loldrup Fosbol, A Revil, Erling Halfdan Stenby, Ioannis Xiarchos, A Yousefi, Ida Lykke FabriciusAbstract:Abstract Water flooding with selective ions has in some cases lead to increased oil recovery. We investigate the physical processes on a pore scale that are responsible for changes in petrophysical and mechanical properties of four oil-bearing chalk and four oil-bearing Greensand samples caused by flooding with brines containing varying amounts of dissolved NaCl, Na 2 SO 4 , MgCl 2 and MgSO 4 . Ultrasonic P-wave velocity and AC resistivity measurements were performed prior to, during and after flow through experiments in order to identify and quantify the processes related to water flooding with selective ions. Low field Nuclear Magnetic Resonance (NMR) spectrometry measurements were performed at full water saturation, at irreducible water saturation, after aging and after flooding. CT-scanning, X-ray diffraction (XRD), backscatter electron microscopy images (BSEM), mercury injection capillary pressure (MICP) curves and specific surface analysis (BET) reveal the mineralogy and texture of the rock samples before and after the injection. Low field NMR data indicates changes in the pore fluid distribution and wettability of chalk after aging of one of the samples. NMR data for other samples indicate that chalk is water-wet after flooding. Greensand remained mixed wet throughout the experiments. Electrical resistivity data are in agreement with this interpretation. The electrical resistivity data during flooding revealed that the formation brine is not fully replaced by the injected water in both chalk and Greensand. Changes in the elasticity of chalk during flooding illustrate the softening effect of magnesium bearing brines as compared to the sodium bearing brines. The stiffness of Greensand was not affected by water flooding with selective ions as determined from the elastic wave measurements. Precipitation of fines during flooding of chalk samples is indicated by an increase in specific surface area and a shift in the MICP to lower values but no fines were detected by NMR. No changes were observed for Greensand samples.
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rock physics based non linear avo waveform inversion of north sea Greensand
Seg Technical Program Expanded Abstracts, 2013Co-Authors: Asger S Johansen, Thomas Mejer Hansen, Ida Lykke FabriciusAbstract:SUMMARY We present a method for inverting seismic pre-stack angle gather data to obtain a probabilistic estimate of rock physical properties of a hydrocarbon reservoir. The method is based on knowledge about a reservoir’s lithology as well as an identifiable reservoir AVO (amplitude variation with offset) response. We make use of a Bayesian formulation of the inverse problem that allows a complex non-linear forward model and describes the properties of the reservoir as an a posteriori probability distribution. We use the extended Metropolis algorithm to sample the a posteriori probability density. The inverse method is studied by inverting seismic data of a Greensand hydrocarbon reservoir in the North Sea. The forward model is nonlinear, comprised of a non-linear Greensand rock physics model and a non-linear AVO waveform model. The rock physics model is based on a Hertz-Mindlin grain contact model combined with the Gassmann equation for fluid substitution. The inverse problem is parametrized as a 3-layer model, where the intermediate layer is known to be Greensand. In a synthetic study we find that the AVO response of Greensand is sensitive to the oil saturation. This facilitates the possibility of inverting this property. The physical properties inverted are the oil saturation, glauconite fraction and porosity of Greensand. The performance of the inversionis foundtobe sensitivetothe degreeof priorinformationprovided and conditional on the effective pressure, the glauconite microporosity and coordination number being defined due to the complexity of the rock physics model. The oil saturation, glauconite fraction and porosity of Greensand are successfully inverted from seismic data of the Nini-4 well location, in case the elastic properties of a single layer of the three-layer model are well known a priori. Inversion results are compared to well log and published laboratory core plug data from the field.
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vp vs relationship and amplitude variation with offset modelling of glauconitic Greensand
Geophysical Prospecting, 2012Co-Authors: Zakir Hossain, Tapan Mukerji, Ida Lykke FabriciusAbstract:The relationship between Vp and Vs may be used to predict Vs where only Vp is known. Vp/Vs is also used to identify pore fluids from seismic data and amplitude variation with offset analysis. Theoretical, physical, as well as statistical empirical Vp-Vs relationships have been proposed for reservoir characterization when shear-wave data are not available. In published work, the focus is primarily on the Vp-Vs relationship of quartzitic sandstone. In order to broaden the picture we present Vp-Vs relationships of Greensand composed of quartz and glauconite by using data from the Paleocene Greensand Nini oil field in the North Sea. A Vp-Vs relationship derived from modelling is compared with empirical Vp-Vs regressions from laboratory data as well as from log data. The accuracy of Vs prediction is quantified in terms of root-mean-square error. We find that the Vp-Vs relationship derived from modelling works well for Greensand shear-wave velocity prediction. We model the seismic response of glauconitic Greensand by using laboratory data from the Nini field. Our studies here reveal that brine-saturated glauconitic Greensand can have a similar seismic response to that from oil-saturated quartzitic sandstone and that oil-saturated strongly cemented Greensand can have a similar amplitude variation with offset response to that from brine-saturated weakly cemented Greensand.
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rock physics model of glauconitic Greensand from the north sea
Geophysics, 2011Co-Authors: Zakir Hossain, Tapan Mukerji, Jack Dvorkin, Ida Lykke FabriciusAbstract:The objective of this study was to establish a rock physics model of North Sea Paleogene Greensand. The Hertz-Mindlin contact model is widely used to calculate elastic velocities of sandstone as well as to calculate the initial sand-pack modulus of the soft-sand, stiff-sand, and intermediate-stiff-sand models. When mixed minerals in rock are quite different, e.g., mixtures of quartz and glauconite in Greensand, the Hertz-Mindlin contact model of single type of grain may not be enough to predict elastic velocity. Our approach is first to develop a Hertz-Mindlin contact model for a mixture of quartz and glauconite. Next, we use this Hertz-Mindlin contact model of two types of grains as the initial modulus for a soft-sand model and a stiff-sand model. By using these rock physics models, we examine the relationship between elastic modulus and porosity in laboratory and logging data and link rock-physics properties to Greensand diagenesis. Calculated velocity for mixtures of quartz and glauconite from the Hert...
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CO2 Injection Effect on Physical Properties of Greensand from the North Sea
73rd EAGE Conference and Exhibition incorporating SPE EUROPEC 2011, 2011Co-Authors: Zakir Hossain, Ida Lykke FabriciusAbstract:The objective of this study is to investigate CO2 injection effects on physical properties of Greensand reservoir rocks from the North Sea. Greensands are sandstones composed of a mixture of clastic quartz grains and glauconite grains. A CO2 flooding experiments was carried to inject the CO2 into brine saturated samples and flush the CO2 saturated samples with brine at reservoir conditions. Helium porosity, Klinkenberg permeability, and specific surface area (SSA) by BET were measured on dry Greensand samples before and after the CO2 experiment. NMR T2 distribution and electrical resistivity were measured on brine saturated Greensand samples before and after the CO2 experiment. Ultrasonic P-and S-wave velocities were measured on brine saturated samples as well as on dry samples. Our laboratory results show that CO2 injection has no major effect on porosity, electrical and elastic properties of Greensand. The Klinkenberg permeability of Greensand increased after CO2 injection. An NMR T2 distribution and NMR permeability modeling approach was tested to evaluate the effect on matrix permeability of CO2 injection. It appears that permeability after CO2 injection increased due to the increase of macro-pores in the Greensand. The increase of macro-pores size is probably due to migration of fine pore-filling minerals.
Graeme J Millar - One of the best experts on this subject based on the ideXlab platform.
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investigation of manganese Greensand activation by various oxidants
Journal of environmental chemical engineering, 2018Co-Authors: John G Outram, Sara J Couperthwaite, Graeme J MillarAbstract:Abstract Manganese Greensands are used routinely in industry for Mn(II) and Fe(II) removal from drinking water and groundwater, however little is understood about the effect of changing the activation conditions on removal performance. This study directly compared the change in removal performance for Mn(II) and Fe(II) across five commercially available Greensands when using bleach or potassium permanganate as the oxidant for Greensand activation. The performance of these medias when no activation process was employed was also compared. The results indicated that enhanced performance was achieved when higher concentrations of oxidant were used. Activating the medias with potassium permanganate was found to achieve slightly higher removal performance for both Mn(II) and Fe(II), although bleach was found to limit the effect of reductive dissolution when treating Fe(II) solutions. A notable observation was that activation of the medias induced a discrete removal mechanism that involved a negatively charge surface species. This species was thought to exist as a higher oxidation state than Mn(IV), analogous to a Mn(VII) species. XPS spectra indicated that activation influenced the Greensands’ surface structure, and supported the change in surface Mn oxidation state, however the surface speciation was inconclusive as to an exact structure. This study used fixed bed columns to examine the various activation conditions, as well as XPS to observe any changes in Mn oxidation state.
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ferrous poisoning of surface mno2 during manganese Greensand operation
Journal of environmental chemical engineering, 2017Co-Authors: John G Outram, Sara J Couperthwaite, Graeme J MillarAbstract:Abstract This study investigated the fundamental performance of manganese Greensands for the removal of both dissolved manganese and iron species from solution. The hypothesis was that iron ions may detrimentally impact manganese removal and that the magnitude of this outcome was dependent upon Greensand composition. Consequently, five Greensand materials were examined in terms of repeatability of operation, the relationship of performance to physical criteria, the mechanism of removal, influence of solution pH and the performance changes that occur when manganese and iron were co-present in solution. All Greensand medias were shown to remove Mn(II) over 5 treatment cycles, where the solid MnO2 media had a larger removal capacity (0.35 mg/g) compared to the two coated medias (0.09 and 0.05 mg/g, respectively). The Greensand medias also showed a significant capacity reduction from 72 to 93% when Fe(II) containing solutions were examined. Fe(II) species were also found to leach considerable amounts of Mn(II) through reductive dissolution which negated the beneficial Mn(II) removal when treating solutions with co-present Fe(II) and Mn(II). Material characterization revealed that the Mn(II) removal mechanism did not involve any surface MnO2 phase change or rely solely on Mn(II) adsorption.
John G Outram - One of the best experts on this subject based on the ideXlab platform.
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investigation of manganese Greensand activation by various oxidants
Journal of environmental chemical engineering, 2018Co-Authors: John G Outram, Sara J Couperthwaite, Graeme J MillarAbstract:Abstract Manganese Greensands are used routinely in industry for Mn(II) and Fe(II) removal from drinking water and groundwater, however little is understood about the effect of changing the activation conditions on removal performance. This study directly compared the change in removal performance for Mn(II) and Fe(II) across five commercially available Greensands when using bleach or potassium permanganate as the oxidant for Greensand activation. The performance of these medias when no activation process was employed was also compared. The results indicated that enhanced performance was achieved when higher concentrations of oxidant were used. Activating the medias with potassium permanganate was found to achieve slightly higher removal performance for both Mn(II) and Fe(II), although bleach was found to limit the effect of reductive dissolution when treating Fe(II) solutions. A notable observation was that activation of the medias induced a discrete removal mechanism that involved a negatively charge surface species. This species was thought to exist as a higher oxidation state than Mn(IV), analogous to a Mn(VII) species. XPS spectra indicated that activation influenced the Greensands’ surface structure, and supported the change in surface Mn oxidation state, however the surface speciation was inconclusive as to an exact structure. This study used fixed bed columns to examine the various activation conditions, as well as XPS to observe any changes in Mn oxidation state.
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ferrous poisoning of surface mno2 during manganese Greensand operation
Journal of environmental chemical engineering, 2017Co-Authors: John G Outram, Sara J Couperthwaite, Graeme J MillarAbstract:Abstract This study investigated the fundamental performance of manganese Greensands for the removal of both dissolved manganese and iron species from solution. The hypothesis was that iron ions may detrimentally impact manganese removal and that the magnitude of this outcome was dependent upon Greensand composition. Consequently, five Greensand materials were examined in terms of repeatability of operation, the relationship of performance to physical criteria, the mechanism of removal, influence of solution pH and the performance changes that occur when manganese and iron were co-present in solution. All Greensand medias were shown to remove Mn(II) over 5 treatment cycles, where the solid MnO2 media had a larger removal capacity (0.35 mg/g) compared to the two coated medias (0.09 and 0.05 mg/g, respectively). The Greensand medias also showed a significant capacity reduction from 72 to 93% when Fe(II) containing solutions were examined. Fe(II) species were also found to leach considerable amounts of Mn(II) through reductive dissolution which negated the beneficial Mn(II) removal when treating solutions with co-present Fe(II) and Mn(II). Material characterization revealed that the Mn(II) removal mechanism did not involve any surface MnO2 phase change or rely solely on Mn(II) adsorption.
Zakir Hossain - One of the best experts on this subject based on the ideXlab platform.
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vp vs relationship and amplitude variation with offset modelling of glauconitic Greensand
Geophysical Prospecting, 2012Co-Authors: Zakir Hossain, Tapan Mukerji, Ida Lykke FabriciusAbstract:The relationship between Vp and Vs may be used to predict Vs where only Vp is known. Vp/Vs is also used to identify pore fluids from seismic data and amplitude variation with offset analysis. Theoretical, physical, as well as statistical empirical Vp-Vs relationships have been proposed for reservoir characterization when shear-wave data are not available. In published work, the focus is primarily on the Vp-Vs relationship of quartzitic sandstone. In order to broaden the picture we present Vp-Vs relationships of Greensand composed of quartz and glauconite by using data from the Paleocene Greensand Nini oil field in the North Sea. A Vp-Vs relationship derived from modelling is compared with empirical Vp-Vs regressions from laboratory data as well as from log data. The accuracy of Vs prediction is quantified in terms of root-mean-square error. We find that the Vp-Vs relationship derived from modelling works well for Greensand shear-wave velocity prediction. We model the seismic response of glauconitic Greensand by using laboratory data from the Nini field. Our studies here reveal that brine-saturated glauconitic Greensand can have a similar seismic response to that from oil-saturated quartzitic sandstone and that oil-saturated strongly cemented Greensand can have a similar amplitude variation with offset response to that from brine-saturated weakly cemented Greensand.
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rock physics model of glauconitic Greensand from the north sea
Geophysics, 2011Co-Authors: Zakir Hossain, Tapan Mukerji, Jack Dvorkin, Ida Lykke FabriciusAbstract:The objective of this study was to establish a rock physics model of North Sea Paleogene Greensand. The Hertz-Mindlin contact model is widely used to calculate elastic velocities of sandstone as well as to calculate the initial sand-pack modulus of the soft-sand, stiff-sand, and intermediate-stiff-sand models. When mixed minerals in rock are quite different, e.g., mixtures of quartz and glauconite in Greensand, the Hertz-Mindlin contact model of single type of grain may not be enough to predict elastic velocity. Our approach is first to develop a Hertz-Mindlin contact model for a mixture of quartz and glauconite. Next, we use this Hertz-Mindlin contact model of two types of grains as the initial modulus for a soft-sand model and a stiff-sand model. By using these rock physics models, we examine the relationship between elastic modulus and porosity in laboratory and logging data and link rock-physics properties to Greensand diagenesis. Calculated velocity for mixtures of quartz and glauconite from the Hert...
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CO2 Injection Effect on Physical Properties of Greensand from the North Sea
73rd EAGE Conference and Exhibition incorporating SPE EUROPEC 2011, 2011Co-Authors: Zakir Hossain, Ida Lykke FabriciusAbstract:The objective of this study is to investigate CO2 injection effects on physical properties of Greensand reservoir rocks from the North Sea. Greensands are sandstones composed of a mixture of clastic quartz grains and glauconite grains. A CO2 flooding experiments was carried to inject the CO2 into brine saturated samples and flush the CO2 saturated samples with brine at reservoir conditions. Helium porosity, Klinkenberg permeability, and specific surface area (SSA) by BET were measured on dry Greensand samples before and after the CO2 experiment. NMR T2 distribution and electrical resistivity were measured on brine saturated Greensand samples before and after the CO2 experiment. Ultrasonic P-and S-wave velocities were measured on brine saturated samples as well as on dry samples. Our laboratory results show that CO2 injection has no major effect on porosity, electrical and elastic properties of Greensand. The Klinkenberg permeability of Greensand increased after CO2 injection. An NMR T2 distribution and NMR permeability modeling approach was tested to evaluate the effect on matrix permeability of CO2 injection. It appears that permeability after CO2 injection increased due to the increase of macro-pores in the Greensand. The increase of macro-pores size is probably due to migration of fine pore-filling minerals.
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influence of pore fluid and frequency on elastic properties of Greensand as interpreted using nmr data
Seg Technical Program Expanded Abstracts, 2011Co-Authors: Zakir Hossain, Tapan Mukerji, Ida Lykke FabriciusAbstract:Summary The objective of this study was to discuss the influence of pore fluid on elastic properties of Greensand. Gassmann’s equations generally work at low frequency and do not take into consideration the fluid related dispersion. In some cases Biot’s theory is used to describe the fluid related dispersion. However, Biot’s theory does not fully explain the frequency dispersion of sedimentary rocks. Greensands are composed of a mixture of quartz and micro-porous glauconite grains. In Greensand, it is possible that the contrast between flow in macro-pores and micro-pores within glauconites gives rise to a local stiffening pressure gradient in the fluid. Then fluid flow in Greensand could then be described as a kind of squirt flow. Greensand data from the North Nini filed was included in this study. Gassmann’s, Biot’s and squirt models were used to discuss the influence of pore fluid on elastic moduli. Biot’s critical frequency and NMR (nuclear magnetic resonance) T2 spectrum were combined to describe the differences in fluid flow within macro-pores and within micro-pores. NMR data show that Biot’s flow should occur only in large pores in the Greensand while, Biot’s flow should not occur in micro-pores. Differences of fluid flow in macro-pores and micro-pores pores are described as high frequency squirt flow in Greensand.
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vp vs relationship of glauconitic Greensand
72nd EAGE Conference and Exhibition incorporating SPE EUROPEC 2010, 2010Co-Authors: Zakir Hossain, Tapan Mukerji, Ida Lykke FabriciusAbstract:The relationship between Vp and Vs is used to predict Vs where only Vp is known. Thus theoretical, physical, as well as statistical empirical Vp-Vs relationships have been proposed for reservoir characterization. In published work, focus is primarily on the Vp-Vs relationship of quartzitic sandstone. Vp-Vs relationship of glauconitic Greensand is not well defined yet. We present Vp-Vs relationships of glauconitic Greensand by using laboratory and logging data from the Paleocene Greensand Nini oil field in the North Sea. We also investigated Vp-Vs relationships of glauconitic Greensand by an effective medium model. Both simple empirical Vp-Vs regression of Greensand and Vp-Vs relationship from effective medium modelling provide good prediction of Vs from the measured Vp. Published Vp-Vs relationship for sandstone matched data less well. Keywords: Greensand, glauconite, Vp, Vs
Sara J Couperthwaite - One of the best experts on this subject based on the ideXlab platform.
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investigation of manganese Greensand activation by various oxidants
Journal of environmental chemical engineering, 2018Co-Authors: John G Outram, Sara J Couperthwaite, Graeme J MillarAbstract:Abstract Manganese Greensands are used routinely in industry for Mn(II) and Fe(II) removal from drinking water and groundwater, however little is understood about the effect of changing the activation conditions on removal performance. This study directly compared the change in removal performance for Mn(II) and Fe(II) across five commercially available Greensands when using bleach or potassium permanganate as the oxidant for Greensand activation. The performance of these medias when no activation process was employed was also compared. The results indicated that enhanced performance was achieved when higher concentrations of oxidant were used. Activating the medias with potassium permanganate was found to achieve slightly higher removal performance for both Mn(II) and Fe(II), although bleach was found to limit the effect of reductive dissolution when treating Fe(II) solutions. A notable observation was that activation of the medias induced a discrete removal mechanism that involved a negatively charge surface species. This species was thought to exist as a higher oxidation state than Mn(IV), analogous to a Mn(VII) species. XPS spectra indicated that activation influenced the Greensands’ surface structure, and supported the change in surface Mn oxidation state, however the surface speciation was inconclusive as to an exact structure. This study used fixed bed columns to examine the various activation conditions, as well as XPS to observe any changes in Mn oxidation state.
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ferrous poisoning of surface mno2 during manganese Greensand operation
Journal of environmental chemical engineering, 2017Co-Authors: John G Outram, Sara J Couperthwaite, Graeme J MillarAbstract:Abstract This study investigated the fundamental performance of manganese Greensands for the removal of both dissolved manganese and iron species from solution. The hypothesis was that iron ions may detrimentally impact manganese removal and that the magnitude of this outcome was dependent upon Greensand composition. Consequently, five Greensand materials were examined in terms of repeatability of operation, the relationship of performance to physical criteria, the mechanism of removal, influence of solution pH and the performance changes that occur when manganese and iron were co-present in solution. All Greensand medias were shown to remove Mn(II) over 5 treatment cycles, where the solid MnO2 media had a larger removal capacity (0.35 mg/g) compared to the two coated medias (0.09 and 0.05 mg/g, respectively). The Greensand medias also showed a significant capacity reduction from 72 to 93% when Fe(II) containing solutions were examined. Fe(II) species were also found to leach considerable amounts of Mn(II) through reductive dissolution which negated the beneficial Mn(II) removal when treating solutions with co-present Fe(II) and Mn(II). Material characterization revealed that the Mn(II) removal mechanism did not involve any surface MnO2 phase change or rely solely on Mn(II) adsorption.
