Carbon dioxide sequestration in depleted oil/gas reservoirs and saline aquifers is one of the mos... more Carbon dioxide sequestration in depleted oil/gas reservoirs and saline aquifers is one of the most promising long-term carbon dioxide management strategies. Possible reservoir formations include limestones, chalks and carbonate- cemented sandstones. To evaluate possible CO2 escape scenarios, and to model the long- term behavior of such reservoirs, data concerning the response of carbonate rocks to carbon dioxide introduction are needed.
Major continental fault zones typically contain phyllosilicates and have long been recognised as ... more Major continental fault zones typically contain phyllosilicates and have long been recognised as zones of persistent weakness. To establish whether the presence of micas can explain this weakness, we studied the frictional behaviour of simulated muscovite fault ...
A hypothesis is advanced that dynamic recrystallization of Earth materials undergoing solid state... more A hypothesis is advanced that dynamic recrystallization of Earth materials undergoing solid state flow may represent a balance between grain size reduction and grain growth processes occurring directly in the boundary between the dislocation and diffusion creep fields. Accordingly, the recrystallized grain size (D) and flow stress (o) at steady state will be related by the equation delineating the field boundary, which in general is temperature dependent. Creep experiments on a metallic rock analogue, Magnox, yielded D-101-12exp[29.3/RT]o-1-23 and demonstrated that D (• tm) decreases with increasing o (MPa) and increasing temperature (T) in a manner which is in agreement with the field botlndary hypothesis. If the model applies to rocks, the widely accepted idea that dynamic recrystallization can lead to major rheological weakening in the Earth may not hold. Moreover, empirical Do relations, used in paleo-piezometry, will need to be modified to account for temperature effects.
Carbon dioxide sequestration in depleted oil/gas reservoirs and saline aquifers is one of the mos... more Carbon dioxide sequestration in depleted oil/gas reservoirs and saline aquifers is one of the most promising long-term carbon dioxide management strategies. Possible reservoir formations include limestones, chalks and carbonate- cemented sandstones. To evaluate possible CO2 escape scenarios, and to model the long- term behavior of such reservoirs, data concerning the response of carbonate rocks to carbon dioxide introduction are needed.
Proceedings 76th EAGE Conference and Exhibition 2014, 2014
ABSTRACT As part of a study to investigate methods to enhance pore/crack connectivity between the... more ABSTRACT As part of a study to investigate methods to enhance pore/crack connectivity between the shale matrix and the induced fractures, we have investigated the matrix microstructure of an exposed analogue of the Jurassic Posidonia shales in the Dutch sub-surface. A combination of Precision-Ion-Polishing and Scanning Electron Microscopy has been used to image the in-situ porosity and mineralogy in shale samples from Whitby (UK), which are an analogue for the Dutch Posidonia shale. First results show a fine-grained mudstone with cm-sub-mm scale stratification. The section at Whitby can be divided into a clay matrix dominated upper half and a coarser grained, calcite-rich, lower half of the section. Commonly occurring minerals are pyrite, calcite (fossils, grains and cement), quartz, mica and dolomite. Organic matter content varies from 0 – 2 % in the calcite dominated layers to 5 – 18% in the clay matrix dominated layers. The most porous phases are the clay matrix and calcite fossils. This microstructural study shows which intervals within Posidonia shale contain the largest porosity and organic matter contents for sweet spot analyses and forms a basis for future research on enhancing connectivity between the pores and induced fractures
Phyllosilicates are common constituents of mid-crustal fault zones and are widely believed to exe... more Phyllosilicates are common constituents of mid-crustal fault zones and are widely believed to exert a strong influence on the strength of fault rocks, in particular around the brittle-ductile transition. The present study aims to experimentally determine the mechanical strength and frictional behaviour of muscovite gouge, in order to establish whether the presence of muscovite might contribute to the long term weakness often inferred to hold for large scale crustal fault zones. Rotary shear experiments in the temperature range 20-700°C, at 100 MPa fluid pressure, have been performed on synthetic muscovite gouges (average grain size 13 mum, < 10% quartz). The effects of sliding velocity, normal stress and shear strain on the frictional behavior of the muscovite gouges have been studied. Microstructural analysis of the experimentally deformed samples has been done using SEM and XED in order to obtain insight in the operating microphysical processes. The mechanical behavior under th...
Carbon dioxide sequestration in depleted oil/gas reservoirs and saline aquifers is one of the mos... more Carbon dioxide sequestration in depleted oil/gas reservoirs and saline aquifers is one of the most promising long-term carbon dioxide management strategies. Possible reservoir formations include limestones, chalks and carbonate- cemented sandstones. To evaluate possible CO2 escape scenarios, and to model the long- term behavior of such reservoirs, data concerning the response of carbonate rocks to carbon dioxide introduction are needed.
Major continental fault zones typically contain phyllosilicates and have long been recognised as ... more Major continental fault zones typically contain phyllosilicates and have long been recognised as zones of persistent weakness. To establish whether the presence of micas can explain this weakness, we studied the frictional behaviour of simulated muscovite fault ...
A hypothesis is advanced that dynamic recrystallization of Earth materials undergoing solid state... more A hypothesis is advanced that dynamic recrystallization of Earth materials undergoing solid state flow may represent a balance between grain size reduction and grain growth processes occurring directly in the boundary between the dislocation and diffusion creep fields. Accordingly, the recrystallized grain size (D) and flow stress (o) at steady state will be related by the equation delineating the field boundary, which in general is temperature dependent. Creep experiments on a metallic rock analogue, Magnox, yielded D-101-12exp[29.3/RT]o-1-23 and demonstrated that D (• tm) decreases with increasing o (MPa) and increasing temperature (T) in a manner which is in agreement with the field botlndary hypothesis. If the model applies to rocks, the widely accepted idea that dynamic recrystallization can lead to major rheological weakening in the Earth may not hold. Moreover, empirical Do relations, used in paleo-piezometry, will need to be modified to account for temperature effects.
Carbon dioxide sequestration in depleted oil/gas reservoirs and saline aquifers is one of the mos... more Carbon dioxide sequestration in depleted oil/gas reservoirs and saline aquifers is one of the most promising long-term carbon dioxide management strategies. Possible reservoir formations include limestones, chalks and carbonate- cemented sandstones. To evaluate possible CO2 escape scenarios, and to model the long- term behavior of such reservoirs, data concerning the response of carbonate rocks to carbon dioxide introduction are needed.
Proceedings 76th EAGE Conference and Exhibition 2014, 2014
ABSTRACT As part of a study to investigate methods to enhance pore/crack connectivity between the... more ABSTRACT As part of a study to investigate methods to enhance pore/crack connectivity between the shale matrix and the induced fractures, we have investigated the matrix microstructure of an exposed analogue of the Jurassic Posidonia shales in the Dutch sub-surface. A combination of Precision-Ion-Polishing and Scanning Electron Microscopy has been used to image the in-situ porosity and mineralogy in shale samples from Whitby (UK), which are an analogue for the Dutch Posidonia shale. First results show a fine-grained mudstone with cm-sub-mm scale stratification. The section at Whitby can be divided into a clay matrix dominated upper half and a coarser grained, calcite-rich, lower half of the section. Commonly occurring minerals are pyrite, calcite (fossils, grains and cement), quartz, mica and dolomite. Organic matter content varies from 0 – 2 % in the calcite dominated layers to 5 – 18% in the clay matrix dominated layers. The most porous phases are the clay matrix and calcite fossils. This microstructural study shows which intervals within Posidonia shale contain the largest porosity and organic matter contents for sweet spot analyses and forms a basis for future research on enhancing connectivity between the pores and induced fractures
Phyllosilicates are common constituents of mid-crustal fault zones and are widely believed to exe... more Phyllosilicates are common constituents of mid-crustal fault zones and are widely believed to exert a strong influence on the strength of fault rocks, in particular around the brittle-ductile transition. The present study aims to experimentally determine the mechanical strength and frictional behaviour of muscovite gouge, in order to establish whether the presence of muscovite might contribute to the long term weakness often inferred to hold for large scale crustal fault zones. Rotary shear experiments in the temperature range 20-700°C, at 100 MPa fluid pressure, have been performed on synthetic muscovite gouges (average grain size 13 mum, < 10% quartz). The effects of sliding velocity, normal stress and shear strain on the frictional behavior of the muscovite gouges have been studied. Microstructural analysis of the experimentally deformed samples has been done using SEM and XED in order to obtain insight in the operating microphysical processes. The mechanical behavior under th...
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