ABSTRACT This paper reports the CO2SINK drilling and permanent monitoring completions, as well as... more ABSTRACT This paper reports the CO2SINK drilling and permanent monitoring completions, as well as the well testing techniques applied in Europe's first scientific carbon dioxide onshore storage test in a saline aquifer near the town of Ketzin, 40 km east of Berlin/Germany. Three boreholes, one injection and two observation wells have been drilled in 2007 to a total depth of about 800 m. The wells were completed as "smart" wells containing a variety of permanently installed down-hole sensors, which have successfully proven their functionality during over their first injection year and are the key instruments for the continuous monitoring of the CO2 inside the reservoir during the storage phase. Constructing three wells in close proximity of 50 to 100m distance to each other with a dense sensor and monitoring cable population requires detailed planning and employment of high-end project management tools. All wells were cased with stainless final casings equipped with pre-perforated sand filters in the pay-zone and wired on the outside with two fibre-optical, one multi-conductor copper, and a PU-heating cable to the surface. The reservoir casing section is externally coated with a fibre-glass-resin wrap for electrical insulation of the 15 geo-electrical toroid antennas in the open hole section. A staged cementation program was selected in combination with the application of a newly developed swellable rubber packer technology and specialized cementation down-hole tools. This technology was given preference over perforation work inside the final casing at the reservoir face, which would have created unmanageable risks of potential damage of the outside casing cables. Prior to the start of the injection phase, an extensive production and injection well test program as well as well-to-well interference tests were performed in order to determine the optimum CO2 injection regime.
Proceedings of the SPE/AAPG/SEG Asia Pacific Unconventional Resources Technology Conference, 2019
Coal Seam Gas (CSG) is a significant resource; it makes up 90% of the gas production in Queenslan... more Coal Seam Gas (CSG) is a significant resource; it makes up 90% of the gas production in Queensland, Australia, most of it from the Surat Basin Walloon Coal Measures, (WCM). However, coal connectivity and distribution are poorly understood resulting in production and modelling challenges. Simplistic, homogeneous models cannot adequately explain volumes or flow rates of gas and water. Initially, the focus of the industry was on optimizing drilling, often without the aid of seismic data, relying on correlations based on wireline logs and cores alone. Those correlations were often based on lithology, and connected sand with sand and coal with coal. Those models seem to overestimate flow between wells and volumes of hydrocarbons or water (Cardwell, 2018). Here, log interpretation is integrated with 3D seismic using a sequence stratigraphic framework. Special attention is placed on the architecture of the WCM revealed by seismic. Seismic mapping of individual coal seams in the Springbok S...
Geothermal resources for most European countries are assembled in the recently completed Atlas of... more Geothermal resources for most European countries are assembled in the recently completed Atlas of Geothermal Resources in Europe. The participating countries are: Albania, Austria, Belgium, Bulgaria, Czech Republic, Denmark, Estonia, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, The Netherlands, Poland, Portugal, Romania, Russia, Slovakia, Slovenia, Spain, Sweden, Switzerland, and the United Kingdom. A volumetric heat content model for porous reservoirs assuming exploitation of geothermal energy by a doublet (production and injection wells) or a singlet (production well only) system is the basis of the resource calculation. Maps of depth, thickness, temperature and resources characterize the geothermal reservoir. The assessment methodology is simple and relies on a small number of parameters. In that way, assessments are also possible in regions of very limited data coverage. An illustrative example in the eastern North German Basin is discussed. This atlas does not re...
At the Ketzin test site significant differences of wellhead pressures and temperature anomalies h... more At the Ketzin test site significant differences of wellhead pressures and temperature anomalies have been recorded at two observation wells after the arrival of CO2. Analysis of the measured well temperature and pressure data, and the deduced fluid density data shows that two-phase fluid conditions are prevailing in the upper 400 m of the wells. Implications on reservoir monitoring and well
Stress-dependent permeability in coal seam gas (CSG) reservoirs can challenge the development of ... more Stress-dependent permeability in coal seam gas (CSG) reservoirs can challenge the development of coal fields with lower initial permeabilities. Thus, advanced well stimulation techniques become essential. This work evaluates the performance of novel graded proppant injection (GPI) technique for CSG reservoir stimulation using reservoir simulation models. A simplified model for steady-state incompressible fluid flow during the early dewatering stage of production is validated by the analytical model results. A general model is then developed for GPI process during unsteady-state compressible two-phase flow in coal, accounting for gas desorption, matrix shrinkage, heterogeneous permeability distribution, and cross-flow. Fractured porous medium is modelled by a dual-porosity radial model. Stress-dependent permeability and matrix shrinkage effects are modelled using the Palmer-Mansoori equation. Under the incompressible fluid flow condition, the productivity index after well stimulation...
In 2006, the CO2ReMoVe project funded by the European Commission was launched with the objectives... more In 2006, the CO2ReMoVe project funded by the European Commission was launched with the objectives of developing new and common methodologies and technologies to improve site based R&D for the monitoring, measurement and verification of the injection and storage of CO2 at multiple sites. The In Salah Gas Krechba Field Joint Industry Project has been in operation since 2004 when gas from several fields was put on production. To comply with export regulations, the high content of carbon dioxide (CO2), 1–10% in the produced gas is removed and re-injected down dip from the producing gas horizon, through three horizontal injection wells at approximately 1800 m below surface. Within the framework of CO2ReMoVe, this paper discusses the site characterization and the short term system performance for the In Salah Krechba field. Prior to the injection, the reservoir unit and the seals were characterized. The resulting geological (static) model is consistent with the information obtained from t...
Since the end of June 2008, carbon dioxide (CO 2 ) is being injected in the Stuttgart Formation a... more Since the end of June 2008, carbon dioxide (CO 2 ) is being injected in the Stuttgart Formation at Ketzin, Germany as part o f the European Union’s CO2SINK project. The injection well (Ktzi 201) is roughly 50 and 100 m away from observation wells Ktzi 200 and Ktzi 202, respectively. CO 2 was detected at the closest observation well on the 15th of July 2008, approximately 20 days after injection commenced. Breakthrough at the Ktzi 202 well was recorded on March 21, more than 8 months after injection was initiated. Dynamic simulations of the injection and flow of CO 2 into the subsurface at Ketzin will be described. The three dimensional (3D) geological model was built based on a 3D seismic survey as well as logging and core analysis data. The formation consists of fluvial sandstone channels within a muddy flood plain at mean depth of 650 m within an anticlinal structure. The geological model uses a cell size of 20×20 m and a layer thickness of 0.5 m, resulting in a total of ∼7 millio...
In coal-seam-gas (CSG) fields, where single wells tap multiple seams, it is likely that some of t... more In coal-seam-gas (CSG) fields, where single wells tap multiple seams, it is likely that some of the individual seams hardly contribute to gas recovery. This study aims to examine the contribution of individual seams to the total gas and water production considering that each seam can have different properties and dimensions. A sensitivity analysis using reservoir simulation investigates the effects of individual seam properties on production profiles. A radial model simulates the production of a single CSG well consisting of a stack of two seams with a range of properties for permeability, thickness, seam extent, initial reservoir pressure, coal compressibility and porosity. The stress dependency of permeability obeys the Palmer and Mansoori (1998) model. A time coefficient (α) relates seam radius, viscosity, porosity, fracture compressibility, and permeability. It is used to aid interpretation of the sensitivity study. Finally, two hypothetical simulation scenarios with five seams ...
In coal seam gas (CSG) fields, where single wells tap multiple seams, it is likely that some of t... more In coal seam gas (CSG) fields, where single wells tap multiple seams, it is likely that some of the individual seams hardly contribute to gas recovery. This study aims to examine the contribution of individual seams to the total gas and water production considering that each seam may have different properties and dimensions. A sensitivity analysis using reservoir simulation investigates the effects of individual seam properties on production profiles. A radial model simulates the production of a single CSG well consisting of a stack of 2 seams with a range of properties for permeability, thickness, seam extent, initial reservoir pressure, compressibility and porosity. The stress-dependency of permeability obeys the Palmer and Mansoori (1998) model. A coefficient (α) relates seam radius, thickness, porosity, compressibility, permeability, and initial pressure. It is used to aid interpretation of the sensitivity study. Finally, a case study is modelled with 5 seams of different thickn...
Temperatures of 100°C are measured at 3 km depth in a well located on the resurgent dome in the c... more Temperatures of 100°C are measured at 3 km depth in a well located on the resurgent dome in the center of Long Valley Caldera, California, despite an assumed >800°C magma chamber at 6–8 km depth. Local downflow of cold meteoric water as a process for cooling the resurgent dome is ruled out by a Peclet-number analysis of temperature logs. These analyses reveal zones with fluid circulation at the upper and lower boundaries of the Bishop Tuff, and an upflow zone in the metasedimentary rocks. Vertical Darcy velocities range from 10 to 70 cm a −1 . A 21-km-long geoelectrical profile across the caldera provides resistivity values to the order of 10 0 to >10 3 Ωm down to a depth of 6 km, as well as variations of self-potential. Interpretation of the electrical data with respect to hydrothermal fluid movement confirms that there is no downflow beneath the resurgent dome. To explain the unexpectedly low temperatures in the resurgent dome, we challenge the common view that the caldera a...
CO2 geo-sequestration can significantly contribute to the reduction of greenhouse gas emissions. ... more CO2 geo-sequestration can significantly contribute to the reduction of greenhouse gas emissions. Out of all geological CO2 storage sites, mature oil fields are often considered primary targets for CO2 sequestration as one of Carbon Capture, Utilisation and Storage (CCUS) approaches where the operation cost can be offset by enhancing oil recovery and utilising the existing facilities. However, a geological formation with large volumetric capacity (pore volume) is not necessarily an appropriate candidate for CO2 storage and CO2 injectivity plays equally an important role for site selection to store CO2. Therefore, evaluation of CO2 dynamic storage capacity (injectivity) and ultimate CO2 enhanced oil recovery (EOR) are key elements for a successful CO2 storage – EOR project. CO2 EOR was considered as a suitable tertiary oil recovery approach after very short and inefficient primary and secondary oil recoveries in Yanchang oil field, the second largest tight oil field in China, located ...
Carbonated water injection (CWI) is described as a chemical-enhanced oil recovery method in which... more Carbonated water injection (CWI) is described as a chemical-enhanced oil recovery method in which CO2-enriched water is injected into oil reservoirs as a displacing fluid. Although confirmed by many that a considerable amount of recovery improvement is attainable through CWI in both lab and field scales, the interaction of salinity on the performance of CWI and its potential fines migration is not very well understood. This study examines the efficiency of oil recovery improvement during low-salinity carbonated water injection (LSCWI) in a sandstone reservoir, while total dissolved salt concentration varies. To this end, a series of coreflooding experiments were performed on homogeneous sandstone cores at 80°C and 2000psi, and the amount of oil recovery was measured. From the experiments, it was observed that CWI could extract more crude oil than conventional water flooding in all salinities. In particular, the highest oil recovery was observed in the lowest salinity (61.2% in CWI a...
ABSTRACT This paper reports the CO2SINK drilling and permanent monitoring completions, as well as... more ABSTRACT This paper reports the CO2SINK drilling and permanent monitoring completions, as well as the well testing techniques applied in Europe's first scientific carbon dioxide onshore storage test in a saline aquifer near the town of Ketzin, 40 km east of Berlin/Germany. Three boreholes, one injection and two observation wells have been drilled in 2007 to a total depth of about 800 m. The wells were completed as "smart" wells containing a variety of permanently installed down-hole sensors, which have successfully proven their functionality during over their first injection year and are the key instruments for the continuous monitoring of the CO2 inside the reservoir during the storage phase. Constructing three wells in close proximity of 50 to 100m distance to each other with a dense sensor and monitoring cable population requires detailed planning and employment of high-end project management tools. All wells were cased with stainless final casings equipped with pre-perforated sand filters in the pay-zone and wired on the outside with two fibre-optical, one multi-conductor copper, and a PU-heating cable to the surface. The reservoir casing section is externally coated with a fibre-glass-resin wrap for electrical insulation of the 15 geo-electrical toroid antennas in the open hole section. A staged cementation program was selected in combination with the application of a newly developed swellable rubber packer technology and specialized cementation down-hole tools. This technology was given preference over perforation work inside the final casing at the reservoir face, which would have created unmanageable risks of potential damage of the outside casing cables. Prior to the start of the injection phase, an extensive production and injection well test program as well as well-to-well interference tests were performed in order to determine the optimum CO2 injection regime.
Proceedings of the SPE/AAPG/SEG Asia Pacific Unconventional Resources Technology Conference, 2019
Coal Seam Gas (CSG) is a significant resource; it makes up 90% of the gas production in Queenslan... more Coal Seam Gas (CSG) is a significant resource; it makes up 90% of the gas production in Queensland, Australia, most of it from the Surat Basin Walloon Coal Measures, (WCM). However, coal connectivity and distribution are poorly understood resulting in production and modelling challenges. Simplistic, homogeneous models cannot adequately explain volumes or flow rates of gas and water. Initially, the focus of the industry was on optimizing drilling, often without the aid of seismic data, relying on correlations based on wireline logs and cores alone. Those correlations were often based on lithology, and connected sand with sand and coal with coal. Those models seem to overestimate flow between wells and volumes of hydrocarbons or water (Cardwell, 2018). Here, log interpretation is integrated with 3D seismic using a sequence stratigraphic framework. Special attention is placed on the architecture of the WCM revealed by seismic. Seismic mapping of individual coal seams in the Springbok S...
Geothermal resources for most European countries are assembled in the recently completed Atlas of... more Geothermal resources for most European countries are assembled in the recently completed Atlas of Geothermal Resources in Europe. The participating countries are: Albania, Austria, Belgium, Bulgaria, Czech Republic, Denmark, Estonia, France, Germany, Greece, Hungary, Italy, Latvia, Lithuania, The Netherlands, Poland, Portugal, Romania, Russia, Slovakia, Slovenia, Spain, Sweden, Switzerland, and the United Kingdom. A volumetric heat content model for porous reservoirs assuming exploitation of geothermal energy by a doublet (production and injection wells) or a singlet (production well only) system is the basis of the resource calculation. Maps of depth, thickness, temperature and resources characterize the geothermal reservoir. The assessment methodology is simple and relies on a small number of parameters. In that way, assessments are also possible in regions of very limited data coverage. An illustrative example in the eastern North German Basin is discussed. This atlas does not re...
At the Ketzin test site significant differences of wellhead pressures and temperature anomalies h... more At the Ketzin test site significant differences of wellhead pressures and temperature anomalies have been recorded at two observation wells after the arrival of CO2. Analysis of the measured well temperature and pressure data, and the deduced fluid density data shows that two-phase fluid conditions are prevailing in the upper 400 m of the wells. Implications on reservoir monitoring and well
Stress-dependent permeability in coal seam gas (CSG) reservoirs can challenge the development of ... more Stress-dependent permeability in coal seam gas (CSG) reservoirs can challenge the development of coal fields with lower initial permeabilities. Thus, advanced well stimulation techniques become essential. This work evaluates the performance of novel graded proppant injection (GPI) technique for CSG reservoir stimulation using reservoir simulation models. A simplified model for steady-state incompressible fluid flow during the early dewatering stage of production is validated by the analytical model results. A general model is then developed for GPI process during unsteady-state compressible two-phase flow in coal, accounting for gas desorption, matrix shrinkage, heterogeneous permeability distribution, and cross-flow. Fractured porous medium is modelled by a dual-porosity radial model. Stress-dependent permeability and matrix shrinkage effects are modelled using the Palmer-Mansoori equation. Under the incompressible fluid flow condition, the productivity index after well stimulation...
In 2006, the CO2ReMoVe project funded by the European Commission was launched with the objectives... more In 2006, the CO2ReMoVe project funded by the European Commission was launched with the objectives of developing new and common methodologies and technologies to improve site based R&D for the monitoring, measurement and verification of the injection and storage of CO2 at multiple sites. The In Salah Gas Krechba Field Joint Industry Project has been in operation since 2004 when gas from several fields was put on production. To comply with export regulations, the high content of carbon dioxide (CO2), 1–10% in the produced gas is removed and re-injected down dip from the producing gas horizon, through three horizontal injection wells at approximately 1800 m below surface. Within the framework of CO2ReMoVe, this paper discusses the site characterization and the short term system performance for the In Salah Krechba field. Prior to the injection, the reservoir unit and the seals were characterized. The resulting geological (static) model is consistent with the information obtained from t...
Since the end of June 2008, carbon dioxide (CO 2 ) is being injected in the Stuttgart Formation a... more Since the end of June 2008, carbon dioxide (CO 2 ) is being injected in the Stuttgart Formation at Ketzin, Germany as part o f the European Union’s CO2SINK project. The injection well (Ktzi 201) is roughly 50 and 100 m away from observation wells Ktzi 200 and Ktzi 202, respectively. CO 2 was detected at the closest observation well on the 15th of July 2008, approximately 20 days after injection commenced. Breakthrough at the Ktzi 202 well was recorded on March 21, more than 8 months after injection was initiated. Dynamic simulations of the injection and flow of CO 2 into the subsurface at Ketzin will be described. The three dimensional (3D) geological model was built based on a 3D seismic survey as well as logging and core analysis data. The formation consists of fluvial sandstone channels within a muddy flood plain at mean depth of 650 m within an anticlinal structure. The geological model uses a cell size of 20×20 m and a layer thickness of 0.5 m, resulting in a total of ∼7 millio...
In coal-seam-gas (CSG) fields, where single wells tap multiple seams, it is likely that some of t... more In coal-seam-gas (CSG) fields, where single wells tap multiple seams, it is likely that some of the individual seams hardly contribute to gas recovery. This study aims to examine the contribution of individual seams to the total gas and water production considering that each seam can have different properties and dimensions. A sensitivity analysis using reservoir simulation investigates the effects of individual seam properties on production profiles. A radial model simulates the production of a single CSG well consisting of a stack of two seams with a range of properties for permeability, thickness, seam extent, initial reservoir pressure, coal compressibility and porosity. The stress dependency of permeability obeys the Palmer and Mansoori (1998) model. A time coefficient (α) relates seam radius, viscosity, porosity, fracture compressibility, and permeability. It is used to aid interpretation of the sensitivity study. Finally, two hypothetical simulation scenarios with five seams ...
In coal seam gas (CSG) fields, where single wells tap multiple seams, it is likely that some of t... more In coal seam gas (CSG) fields, where single wells tap multiple seams, it is likely that some of the individual seams hardly contribute to gas recovery. This study aims to examine the contribution of individual seams to the total gas and water production considering that each seam may have different properties and dimensions. A sensitivity analysis using reservoir simulation investigates the effects of individual seam properties on production profiles. A radial model simulates the production of a single CSG well consisting of a stack of 2 seams with a range of properties for permeability, thickness, seam extent, initial reservoir pressure, compressibility and porosity. The stress-dependency of permeability obeys the Palmer and Mansoori (1998) model. A coefficient (α) relates seam radius, thickness, porosity, compressibility, permeability, and initial pressure. It is used to aid interpretation of the sensitivity study. Finally, a case study is modelled with 5 seams of different thickn...
Temperatures of 100°C are measured at 3 km depth in a well located on the resurgent dome in the c... more Temperatures of 100°C are measured at 3 km depth in a well located on the resurgent dome in the center of Long Valley Caldera, California, despite an assumed >800°C magma chamber at 6–8 km depth. Local downflow of cold meteoric water as a process for cooling the resurgent dome is ruled out by a Peclet-number analysis of temperature logs. These analyses reveal zones with fluid circulation at the upper and lower boundaries of the Bishop Tuff, and an upflow zone in the metasedimentary rocks. Vertical Darcy velocities range from 10 to 70 cm a −1 . A 21-km-long geoelectrical profile across the caldera provides resistivity values to the order of 10 0 to >10 3 Ωm down to a depth of 6 km, as well as variations of self-potential. Interpretation of the electrical data with respect to hydrothermal fluid movement confirms that there is no downflow beneath the resurgent dome. To explain the unexpectedly low temperatures in the resurgent dome, we challenge the common view that the caldera a...
CO2 geo-sequestration can significantly contribute to the reduction of greenhouse gas emissions. ... more CO2 geo-sequestration can significantly contribute to the reduction of greenhouse gas emissions. Out of all geological CO2 storage sites, mature oil fields are often considered primary targets for CO2 sequestration as one of Carbon Capture, Utilisation and Storage (CCUS) approaches where the operation cost can be offset by enhancing oil recovery and utilising the existing facilities. However, a geological formation with large volumetric capacity (pore volume) is not necessarily an appropriate candidate for CO2 storage and CO2 injectivity plays equally an important role for site selection to store CO2. Therefore, evaluation of CO2 dynamic storage capacity (injectivity) and ultimate CO2 enhanced oil recovery (EOR) are key elements for a successful CO2 storage – EOR project. CO2 EOR was considered as a suitable tertiary oil recovery approach after very short and inefficient primary and secondary oil recoveries in Yanchang oil field, the second largest tight oil field in China, located ...
Carbonated water injection (CWI) is described as a chemical-enhanced oil recovery method in which... more Carbonated water injection (CWI) is described as a chemical-enhanced oil recovery method in which CO2-enriched water is injected into oil reservoirs as a displacing fluid. Although confirmed by many that a considerable amount of recovery improvement is attainable through CWI in both lab and field scales, the interaction of salinity on the performance of CWI and its potential fines migration is not very well understood. This study examines the efficiency of oil recovery improvement during low-salinity carbonated water injection (LSCWI) in a sandstone reservoir, while total dissolved salt concentration varies. To this end, a series of coreflooding experiments were performed on homogeneous sandstone cores at 80°C and 2000psi, and the amount of oil recovery was measured. From the experiments, it was observed that CWI could extract more crude oil than conventional water flooding in all salinities. In particular, the highest oil recovery was observed in the lowest salinity (61.2% in CWI a...
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Papers by Suzanne Hurter