Subsurface geologic storage of carbon dioxide calls for sophisticated monitoring tools with respect to long-term safety and environmental impact issues. Despite extensive research, many factors governing the fate of injected carbon dioxide (CO2) remain unclear. To identify possible risks through leakage of the CO2 storage reservoir, a program for monitoring of the CO2 flux at the surface was started at the Ketzin test site, which allows to distinguish between natural temporal and spatial flux variations and a potential leakage. To gain adequate long-term baseline data on the local background CO2 flux variations, CO2 soil gas flux, soil moisture, and temperature measurements were conducted once a month during a 6-yr period. Furthermore, soil samples were analyzed for their organic carbon and total nitrogen contents. The mean flux of all sampling sites before the CO2 injection (2005–2007) was 2.8 mol m2 s1 (ranging from 2.4 to 3.5), with a Q10 factor of 2.4, and in the years after commencing injection (2009–2010), 2.4 mol m2 s1 (ranging from 2.2 to 2.5), with the same Q10 factor. The CO2 flux rate is mainly controlled by the soil temperature. A significant influence of diurnal temperature variation and soil moisture was not detected. The spatial variability of the CO2 flux among the 20 sampling locations ranges from 1.0 to 4.5 mol m2 s1, depending on the organic carbon and total nitrogen content of the soil. Through comparison with the long-term measurements, unusual high CO2 fluxes can theoretically be distinguished from natural variations.
{"title":"Long-term surface carbon dioxide flux monitoring at the Ketzin carbon dioxide storage test site","authors":"M. Zimmer, P. Pilz, J. Erzinger","doi":"10.1306/EG.11181010017","DOIUrl":"https://doi.org/10.1306/EG.11181010017","url":null,"abstract":"Subsurface geologic storage of carbon dioxide calls for sophisticated monitoring tools with respect to long-term safety and environmental impact issues. Despite extensive research, many factors governing the fate of injected carbon dioxide (CO2) remain unclear. To identify possible risks through leakage of the CO2 storage reservoir, a program for monitoring of the CO2 flux at the surface was started at the Ketzin test site, which allows to distinguish between natural temporal and spatial flux variations and a potential leakage. To gain adequate long-term baseline data on the local background CO2 flux variations, CO2 soil gas flux, soil moisture, and temperature measurements were conducted once a month during a 6-yr period. Furthermore, soil samples were analyzed for their organic carbon and total nitrogen contents. The mean flux of all sampling sites before the CO2 injection (2005–2007) was 2.8 mol m2 s1 (ranging from 2.4 to 3.5), with a Q10 factor of 2.4, and in the years after commencing injection (2009–2010), 2.4 mol m2 s1 (ranging from 2.2 to 2.5), with the same Q10 factor. The CO2 flux rate is mainly controlled by the soil temperature. A significant influence of diurnal temperature variation and soil moisture was not detected. The spatial variability of the CO2 flux among the 20 sampling locations ranges from 1.0 to 4.5 mol m2 s1, depending on the organic carbon and total nitrogen content of the soil. Through comparison with the long-term measurements, unusual high CO2 fluxes can theoretically be distinguished from natural variations.","PeriodicalId":11706,"journal":{"name":"Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1306/EG.11181010017","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66169269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Engineered landfill liner systems are expensive to install and represent a challenge to several developing countries. Alternatively, native soils, preferentially clays, can be used as cost-effective bottom liners. The purpose of this work is to justify the reliance on the ability of the clays at the Kharga-Dakhla land stretch, Western Desert, Egypt, to act as a containment and barrier for pollutants that might be generated in a landfill leachate. This is particularly valid in hyperarid regions where many environmental requirements for landfill liner design are relaxed, as precipitation is rare and percolation to buried wastes is practically absent. The availability of native clays and clay-bearing sediments in the study area, both on surface and subsurface, makes it a potential landfill site. Collaborating techniques have been used to determine the mineralogical, geochemical, and geotechnical characteristics of the sediments constituting the Quseir Formation (Upper Cretaceous). These techniques include x-ray diffraction analysis, differential thermal analysis, cation exchange capacity (CEC), swelling properties, Atterberg limits, porosity, and hydraulic conductivity. The obtained results indicate that the investigated clayey sediments are dense and compact. They have low hydraulic conductivity that ranges from 1 1010 to 4.96 1011 cm/s, with moisture content that does not exceed 7%. The swelling values of samples containing smectite range between 250 and 500%. The plasticity limit of the red clay (floor of the Dakhla Oasis) ranges between 11 and 18%, which indicates its suitability as a landfill lining material. Values for CEC are generally high and increase with increasing smectite content. It reaches as much as 69 meq/100-g sample, indicating enhanced ability for natural attenuation and can act within the containment system for metal pollutants. The obtained mineralogical, geochemical, and geotechnical data suggest that the studied clays can be used, effectively, as a viable alternative liner system for solid waste and/or secured landfills, replacing the costly state of the art liner systems. Satisfying siting criteria, the availability of the clays, and the easy way and their low cost of extraction provide a cost-effective solution to the problem of landfill lining in developing countries.
{"title":"Potentiality of clays in the Kharga-Dakhla land stretch as a natural landfill liner in a hyperarid region","authors":"A. E. Maghraby, A. E. Kammar, M. Mabrouk","doi":"10.1306/EG.09091010016","DOIUrl":"https://doi.org/10.1306/EG.09091010016","url":null,"abstract":"Engineered landfill liner systems are expensive to install and represent a challenge to several developing countries. Alternatively, native soils, preferentially clays, can be used as cost-effective bottom liners. The purpose of this work is to justify the reliance on the ability of the clays at the Kharga-Dakhla land stretch, Western Desert, Egypt, to act as a containment and barrier for pollutants that might be generated in a landfill leachate. This is particularly valid in hyperarid regions where many environmental requirements for landfill liner design are relaxed, as precipitation is rare and percolation to buried wastes is practically absent. The availability of native clays and clay-bearing sediments in the study area, both on surface and subsurface, makes it a potential landfill site. Collaborating techniques have been used to determine the mineralogical, geochemical, and geotechnical characteristics of the sediments constituting the Quseir Formation (Upper Cretaceous). These techniques include x-ray diffraction analysis, differential thermal analysis, cation exchange capacity (CEC), swelling properties, Atterberg limits, porosity, and hydraulic conductivity. The obtained results indicate that the investigated clayey sediments are dense and compact. They have low hydraulic conductivity that ranges from 1 1010 to 4.96 1011 cm/s, with moisture content that does not exceed 7%. The swelling values of samples containing smectite range between 250 and 500%. The plasticity limit of the red clay (floor of the Dakhla Oasis) ranges between 11 and 18%, which indicates its suitability as a landfill lining material. Values for CEC are generally high and increase with increasing smectite content. It reaches as much as 69 meq/100-g sample, indicating enhanced ability for natural attenuation and can act within the containment system for metal pollutants. The obtained mineralogical, geochemical, and geotechnical data suggest that the studied clays can be used, effectively, as a viable alternative liner system for solid waste and/or secured landfills, replacing the costly state of the art liner systems. Satisfying siting criteria, the availability of the clays, and the easy way and their low cost of extraction provide a cost-effective solution to the problem of landfill lining in developing countries.","PeriodicalId":11706,"journal":{"name":"Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1306/EG.09091010016","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66166878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
At Cranfield field, Mississippi, a monitored carbon dioxide (CO2) sequestration and enhanced oil recovery project provides a unique opportunity to study sealing properties of a marine shale as a CO2-confining zone. The reservoir is in the amalgamated fluvial basal sandstone of the lower Tuscaloosa Formation at depths of more than 3000 m (9843 ft). The marine mudstone of the middle Tuscaloosa forms a continuous regional confining system of approximately 75 m (246 ft).A 6-m (20-ft) core was retrieved from the middle Tuscaloosa marine mudstone approximately 70 m (230 ft) above the CO2 injection zone. We conducted a series of characterizing analyses on the core that would enable us to assess with high confidence seal performance over geologic time. The core displays considerable heterogeneity at centimeter to decimeter scales, with lithology varying from silt-bearing clay-rich mudstone to siltstone and very fine grained sandstone. In total, nine microfacies are recognized in the core. Petrographic, mineralogical, and chemical analyses (scanning electron microscopy, x-ray diffraction, and x-ray fluorescence) show that calcite cements preferentially form in coarser grained beds and have greatly reduced porosity and permeability, making silty and sandy beds less permeable than mudstone. Mercury intrusion capillary pressure tests show desirable sealing capacity for all samples capable of retaining a CO2 column of 49 to 237 m (161–778 ft) at 100% water saturation. Permeability and porosity of all facies are less than 0.0001 md and 4%, respectively. Pores in the samples are at nanometer scales, with modal pore-throat sizes less than 20 nm. Scanning electron microscopic imaging on ion-milled surfaces confirms that nanopores are scarce and generally isolated.
{"title":"Diagenesis and sealing capacity of the middle Tuscaloosa mudstone at the Cranfield carbon dioxide injection site, Mississippi, U.S.A.","authors":"Jiemin Lu, K. Milliken, R. Reed, S. Hovorka","doi":"10.1306/EG.09091010015","DOIUrl":"https://doi.org/10.1306/EG.09091010015","url":null,"abstract":"At Cranfield field, Mississippi, a monitored carbon dioxide (CO2) sequestration and enhanced oil recovery project provides a unique opportunity to study sealing properties of a marine shale as a CO2-confining zone. The reservoir is in the amalgamated fluvial basal sandstone of the lower Tuscaloosa Formation at depths of more than 3000 m (9843 ft). The marine mudstone of the middle Tuscaloosa forms a continuous regional confining system of approximately 75 m (246 ft).A 6-m (20-ft) core was retrieved from the middle Tuscaloosa marine mudstone approximately 70 m (230 ft) above the CO2 injection zone. We conducted a series of characterizing analyses on the core that would enable us to assess with high confidence seal performance over geologic time. The core displays considerable heterogeneity at centimeter to decimeter scales, with lithology varying from silt-bearing clay-rich mudstone to siltstone and very fine grained sandstone. In total, nine microfacies are recognized in the core. Petrographic, mineralogical, and chemical analyses (scanning electron microscopy, x-ray diffraction, and x-ray fluorescence) show that calcite cements preferentially form in coarser grained beds and have greatly reduced porosity and permeability, making silty and sandy beds less permeable than mudstone. Mercury intrusion capillary pressure tests show desirable sealing capacity for all samples capable of retaining a CO2 column of 49 to 237 m (161–778 ft) at 100% water saturation. Permeability and porosity of all facies are less than 0.0001 md and 4%, respectively. Pores in the samples are at nanometer scales, with modal pore-throat sizes less than 20 nm. Scanning electron microscopic imaging on ion-milled surfaces confirms that nanopores are scarce and generally isolated.","PeriodicalId":11706,"journal":{"name":"Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1306/EG.09091010015","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66167253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Castle and Rodgers (2009) propose that toxins produced by photosynthetic microbes (“algae”) were factors in the five major Phanerozoic mass extinctions. Although toxins have undoubtedly caused metazoan mortality throughout the Phanerozoic, the data presented by Castle and Rodgers (2009) do not constrain the timing, scale, impact, or longevity of any such events and do not support the suggestion that microbially produced toxins significantly affect extinction rate. To demonstrate a causal relationship between the production of toxins and extinction events, a reliable high-resolution proxy for toxin production is required; such a proxy must indicate an increase in toxin production at, or immediately before, each mass extinction. Castle and Rodgers (2009) propose stromatolite abundance as such a proxy. Unfortunately, its accuracy as a measure of algal abundance is questionable. The increased abundance of certain algae inhibits, rather than promotes, stromatolite growth (Macintyre et al., 1996). Furthermore, the link between toxin production and stromatolitic organisms is only tentatively supported (Burns et …
Castle和Rodgers(2009)提出光合微生物(“藻类”)产生的毒素是显生宙五次大灭绝的因素。尽管毒素无疑在显生宙造成了后生动物的死亡，但Castle和Rodgers(2009)提供的数据并没有限制任何此类事件的时间、规模、影响或持续时间，也不支持微生物产生的毒素显著影响灭绝速度的说法。为了证明毒素产生和灭绝事件之间的因果关系，需要一个可靠的高分辨率毒素产生代理;这样的代用物必须表明在每次大灭绝时或之前毒素产量的增加。Castle和Rodgers(2009)提出叠层石丰度作为这样一个代理。不幸的是，它作为衡量藻类丰度的准确性值得怀疑。某些藻类丰度的增加抑制而不是促进叠层石的生长(Macintyre et al.， 1996)。此外，毒素产生和叠层生物之间的联系只是暂时得到支持(Burns等…
{"title":"Comment on the Hypothesis for the role of toxin-producing algae in Phanerozoic mass extinctions based on evidence from the geologic record and modern environments","authors":"Martin R. Smith","doi":"10.1306/EG.03231010006","DOIUrl":"https://doi.org/10.1306/EG.03231010006","url":null,"abstract":"Castle and Rodgers (2009) propose that toxins produced by photosynthetic microbes (“algae”) were factors in the five major Phanerozoic mass extinctions.\u0000\u0000Although toxins have undoubtedly caused metazoan mortality throughout the Phanerozoic, the data presented by Castle and Rodgers (2009) do not constrain the timing, scale, impact, or longevity of any such events and do not support the suggestion that microbially produced toxins significantly affect extinction rate.\u0000\u0000To demonstrate a causal relationship between the production of toxins and extinction events, a reliable high-resolution proxy for toxin production is required; such a proxy must indicate an increase in toxin production at, or immediately before, each mass extinction.\u0000\u0000Castle and Rodgers (2009) propose stromatolite abundance as such a proxy. Unfortunately, its accuracy as a measure of algal abundance is questionable. The increased abundance of certain algae inhibits, rather than promotes, stromatolite growth (Macintyre et al., 1996). Furthermore, the link between toxin production and stromatolitic organisms is only tentatively supported (Burns et …","PeriodicalId":11706,"journal":{"name":"Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1306/EG.03231010006","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66164312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We evaluated the pore volume available for a specific potential geologic carbon dioxide (CO2) storage site in the Upper Ordovician Queenston Formation near the AES Corporation Cayuga coal-fired power plant in Tompkins County, New York. Core data collected 25 mi (40 km) from the plant reveal that the Queenston Formation is a relatively homogeneous fine- to medium-grained sandstone with hematite cement. Seismic and core data indicate that the formation was deposited in a fluvial system with mobile channels and has thickness maxima that trend north-northwest. Porosity is a major factor affecting geologic CO2 storage potential, and it is important to understand discrepancies among porosity measured from core plug, neutron porosity, density-derived porosity, and thin-section point count values. Relative to core plug–derived porosity values, the neutron porosity log is more reliable than the electron density porosity values. Thin sections reveal that hematite cement is the primary factor affecting porosity variability. Seismic, core, and well-log data suggest that in a 25-mi2 (65-km2) area surrounding this power plant, the Queenston Formation can sequester 18 million metric tons (11 million metric tons) of CO2 emission from the Cayuga power plant (8 yr of CO2 output, with a range of 3–12 yr), although many uncertainties must be better constrained to obtain a more accurate estimate. Because the Queenston Formation near the Cayuga power plant is relatively homogeneous, most of the formation at this location offers the potential for CO2 storage in its pore space.
{"title":"Carbon dioxide storage potential for the Queenston Formation near the AES Cayuga coal-fired power plant in Tompkins County, New York","authors":"K. Tamulonis, T. Jordan, Brian E. Slater","doi":"10.1306/EG.05191010005","DOIUrl":"https://doi.org/10.1306/EG.05191010005","url":null,"abstract":"We evaluated the pore volume available for a specific potential geologic carbon dioxide (CO2) storage site in the Upper Ordovician Queenston Formation near the AES Corporation Cayuga coal-fired power plant in Tompkins County, New York. Core data collected 25 mi (40 km) from the plant reveal that the Queenston Formation is a relatively homogeneous fine- to medium-grained sandstone with hematite cement. Seismic and core data indicate that the formation was deposited in a fluvial system with mobile channels and has thickness maxima that trend north-northwest. Porosity is a major factor affecting geologic CO2 storage potential, and it is important to understand discrepancies among porosity measured from core plug, neutron porosity, density-derived porosity, and thin-section point count values. Relative to core plug–derived porosity values, the neutron porosity log is more reliable than the electron density porosity values. Thin sections reveal that hematite cement is the primary factor affecting porosity variability. Seismic, core, and well-log data suggest that in a 25-mi2 (65-km2) area surrounding this power plant, the Queenston Formation can sequester 18 million metric tons (11 million metric tons) of CO2 emission from the Cayuga power plant (8 yr of CO2 output, with a range of 3–12 yr), although many uncertainties must be better constrained to obtain a more accurate estimate. Because the Queenston Formation near the Cayuga power plant is relatively homogeneous, most of the formation at this location offers the potential for CO2 storage in its pore space.","PeriodicalId":11706,"journal":{"name":"Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1306/EG.05191010005","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66164862","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Plasynski, J. Litynski, H. Mcilvried, Derek M. Vikara, R. Srivastava
A growing concern that increasing levels of greenhouse gases in the atmosphere are contributing to global climate change has led to a search for economical and environmentally sound ways to reduce carbon dioxide (CO2) emissions. One promising approach is CO2 capture and permanent storage in deep geologic formations, such as depleted oil and gas reservoirs, unminable coal seams, and deep brine-containing (saline) formations. However, successful implementation of geologic storage projects will require robust monitoring, verification, and accounting (MVA) tools. This article deals with all aspects of MVA activities associated with such geologic CO2 storage projects, including site characterization, CO2 plume tracking, CO2 flow rate and injection pressure monitoring, leak detection, cap-rock integrity analysis, and long-term postinjection monitoring. Improved detailed decision tree diagrams are presented covering the five stages of a geologic storage project. These diagrams provide guidance from the point of site selection through construction and operations to closure and postclosure monitoring. Monitoring, verification, and accounting techniques (both well-established and promising new developments) appropriate for various project stages are discussed. Accomplishments of the Department of Energy (DOE) Regional Carbon Sequestration Partnerships field projects serve as examples of the development and application to geologic storage of MVA tools, such as two-dimensional and three-dimensional seismic and microseismic, as well as the testing of new cost-effective monitoring technologies. Although it is important that MVA and computer simulation efforts be carefully integrated to ensure long-term success of geologic storage projects, this article is limited to a discussion of MVA activities. This article is an extension of a report published in 2009 by the DOE National Energy Technology Laboratory titled, “Best Practices for Monitoring, Verification, and Accounting of CO2 Stored in Deep Geologic Formations,” to which interested readers are referred for more details on MVA tools. Ultimately, a robust MVA program will be critical for establishing carbon capture and storage as a viable greenhouse gas mitigation strategy.
{"title":"The critical role of monitoring, verification, and accounting for geologic carbon dioxide storage projects","authors":"S. Plasynski, J. Litynski, H. Mcilvried, Derek M. Vikara, R. Srivastava","doi":"10.1306/EG.06231010008","DOIUrl":"https://doi.org/10.1306/EG.06231010008","url":null,"abstract":"A growing concern that increasing levels of greenhouse gases in the atmosphere are contributing to global climate change has led to a search for economical and environmentally sound ways to reduce carbon dioxide (CO2) emissions. One promising approach is CO2 capture and permanent storage in deep geologic formations, such as depleted oil and gas reservoirs, unminable coal seams, and deep brine-containing (saline) formations. However, successful implementation of geologic storage projects will require robust monitoring, verification, and accounting (MVA) tools. This article deals with all aspects of MVA activities associated with such geologic CO2 storage projects, including site characterization, CO2 plume tracking, CO2 flow rate and injection pressure monitoring, leak detection, cap-rock integrity analysis, and long-term postinjection monitoring. Improved detailed decision tree diagrams are presented covering the five stages of a geologic storage project. These diagrams provide guidance from the point of site selection through construction and operations to closure and postclosure monitoring. Monitoring, verification, and accounting techniques (both well-established and promising new developments) appropriate for various project stages are discussed. Accomplishments of the Department of Energy (DOE) Regional Carbon Sequestration Partnerships field projects serve as examples of the development and application to geologic storage of MVA tools, such as two-dimensional and three-dimensional seismic and microseismic, as well as the testing of new cost-effective monitoring technologies. Although it is important that MVA and computer simulation efforts be carefully integrated to ensure long-term success of geologic storage projects, this article is limited to a discussion of MVA activities. This article is an extension of a report published in 2009 by the DOE National Energy Technology Laboratory titled, “Best Practices for Monitoring, Verification, and Accounting of CO2 Stored in Deep Geologic Formations,” to which interested readers are referred for more details on MVA tools. Ultimately, a robust MVA program will be critical for establishing carbon capture and storage as a viable greenhouse gas mitigation strategy.","PeriodicalId":11706,"journal":{"name":"Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2011-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1306/EG.06231010008","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66166095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Geophysical methods have been adopted to characterize a site whose soils and groundwater had been contaminated by nonaqueous-phase liquid (NAPL); the hydrocarbons were found in both residual form and as a free phase above the water table. The geophysical survey was aimed at improving the knowledge of the hydrogeological setting of the site; we wanted to estimate the soil heterogeneity and the hydrogeological parameters (porosity, water content, and hydraulic conductivity). We also wanted to assess the effect of the water table fluctuations on the interaction between the groundwater and the residual NAPL. The geophysical investigation was conducted using geoelectrical, electromagnetic (frequency domain), and georadar methods; data calibration was conducted using borehole geochemical logs. The presence of residual NAPL in the silty and sandy material was confirmed by a remarkable increase of the attenuation in the georadar energy and by peak of induced polarization response. The hydrocarbons have been detected in concentrations of more than 1000 mg/kg (1000 ppm) at a depth of 5 m (15 ft) and in concentrations of 3000 mg/kg (3000 ppm) at a depth of 6 to 8 m (18–24 ft).
{"title":"Geophysical characterization of a nonaqueous-phase liquid–contaminated site","authors":"A. Godio, A. Arato, S. Stocco","doi":"10.1306/EG.04261010003","DOIUrl":"https://doi.org/10.1306/EG.04261010003","url":null,"abstract":"Geophysical methods have been adopted to characterize a site whose soils and groundwater had been contaminated by nonaqueous-phase liquid (NAPL); the hydrocarbons were found in both residual form and as a free phase above the water table. The geophysical survey was aimed at improving the knowledge of the hydrogeological setting of the site; we wanted to estimate the soil heterogeneity and the hydrogeological parameters (porosity, water content, and hydraulic conductivity). We also wanted to assess the effect of the water table fluctuations on the interaction between the groundwater and the residual NAPL. The geophysical investigation was conducted using geoelectrical, electromagnetic (frequency domain), and georadar methods; data calibration was conducted using borehole geochemical logs. The presence of residual NAPL in the silty and sandy material was confirmed by a remarkable increase of the attenuation in the georadar energy and by peak of induced polarization response. The hydrocarbons have been detected in concentrations of more than 1000 mg/kg (1000 ppm) at a depth of 5 m (15 ft) and in concentrations of 3000 mg/kg (3000 ppm) at a depth of 6 to 8 m (18–24 ft).","PeriodicalId":11706,"journal":{"name":"Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1306/EG.04261010003","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66164824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Many bedrock units contain joint sets that commonly act as preferred paths for the movement of water, electrical charge, and possible contaminants associated with production or transit of crude oil or refined products. To facilitate the development of remediation programs, a need exists to reliably determine regional-scale properties of these joint sets: azimuth of transmissivity ellipse, dominant set, and trend(s). The surface azimuthal electrical resistivity survey method used for local in situ studies can be a noninvasive, reliable, efficient, and relatively cost-effective method for regional studies. The azimuthal resistivity survey method combines the use of standard resistivity equipment with a Wenner array rotated about a fixed center point, at selected degree intervals, which yields an apparent resistivity ellipse from which joint-set orientation can be determined. Regional application of the azimuthal survey method was tested at 17 sites in an approximately 500 km2 (193 mi2) area around Milwaukee, Wisconsin, with less than 15 m (50 ft) overburden above the dolomite. Results of 26 azimuthal surveys were compared and determined to be consistent with the results of two other methods: direct observation of joint-set orientation and transmissivity ellipses from multiple-well-aquifer tests. The average of joint-set trend determined by azimuthal surveys is within 2.5 of the average of joint-set trend determined by direct observation of major joint sets at 24 sites. The average of maximum of transmissivity trend determined by azimuthal surveys is within 5.7 of the average of maximum of transmissivity trend determined for 14 multiple-well-aquifer tests.
{"title":"Use of the azimuthal resistivity technique for determination of regional azimuth of transmissivity","authors":"D. Carlson","doi":"10.1306/EG.05071010004","DOIUrl":"https://doi.org/10.1306/EG.05071010004","url":null,"abstract":"Many bedrock units contain joint sets that commonly act as preferred paths for the movement of water, electrical charge, and possible contaminants associated with production or transit of crude oil or refined products. To facilitate the development of remediation programs, a need exists to reliably determine regional-scale properties of these joint sets: azimuth of transmissivity ellipse, dominant set, and trend(s). The surface azimuthal electrical resistivity survey method used for local in situ studies can be a noninvasive, reliable, efficient, and relatively cost-effective method for regional studies. The azimuthal resistivity survey method combines the use of standard resistivity equipment with a Wenner array rotated about a fixed center point, at selected degree intervals, which yields an apparent resistivity ellipse from which joint-set orientation can be determined. Regional application of the azimuthal survey method was tested at 17 sites in an approximately 500 km2 (193 mi2) area around Milwaukee, Wisconsin, with less than 15 m (50 ft) overburden above the dolomite. Results of 26 azimuthal surveys were compared and determined to be consistent with the results of two other methods: direct observation of joint-set orientation and transmissivity ellipses from multiple-well-aquifer tests. The average of joint-set trend determined by azimuthal surveys is within 2.5 of the average of joint-set trend determined by direct observation of major joint sets at 24 sites. The average of maximum of transmissivity trend determined by azimuthal surveys is within 5.7 of the average of maximum of transmissivity trend determined for 14 multiple-well-aquifer tests.","PeriodicalId":11706,"journal":{"name":"Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1306/EG.05071010004","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66164479","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Multidisciplinary investigations of natural and oil field salinization along the upper Colorado River, Texas, present an opportunity to integrate results from a stream-axis airborne geophysical survey, ground and borehole geophysical surveys, and well drilling and sampling. Airborne electromagnetic (EM) induction measurements along 437 km (272 mi) of river and tributary stream axes identified discrete salinized streambed segments, including several near oil fields. Identification of these salinized streambed segments allowed more intensive and invasive investigations to be focused on the most significant near-river sources of salinity. One of these streambed segments lies adjacent to an oil field, where production began in the 1950s before discharge of coproduced brine into surface pits was prohibited in Texas. Monitor wells drilled after the airborne survey verified groundwater salinization in the oil field but did not adequately delineate salinization nor identify specific salinity source areas. Subsequent ground and borehole geophysical surveys complemented airborne EM induction and well data by establishing lateral and vertical salinization bounds in the oil field, discovering possible salinity source areas, and determining optimal locations for additional wells.
{"title":"Characterizing oil field salinization using airborne, surface, and borehole geophysics: An example from the Upper Colorado River Basin, Texas","authors":"J. G. Paine, E. Collins","doi":"10.1306/EG.06231010011","DOIUrl":"https://doi.org/10.1306/EG.06231010011","url":null,"abstract":"Multidisciplinary investigations of natural and oil field salinization along the upper Colorado River, Texas, present an opportunity to integrate results from a stream-axis airborne geophysical survey, ground and borehole geophysical surveys, and well drilling and sampling. Airborne electromagnetic (EM) induction measurements along 437 km (272 mi) of river and tributary stream axes identified discrete salinized streambed segments, including several near oil fields. Identification of these salinized streambed segments allowed more intensive and invasive investigations to be focused on the most significant near-river sources of salinity. One of these streambed segments lies adjacent to an oil field, where production began in the 1950s before discharge of coproduced brine into surface pits was prohibited in Texas. Monitor wells drilled after the airborne survey verified groundwater salinization in the oil field but did not adequately delineate salinization nor identify specific salinity source areas. Subsequent ground and borehole geophysical surveys complemented airborne EM induction and well data by establishing lateral and vertical salinization bounds in the oil field, discovering possible salinity source areas, and determining optimal locations for additional wells.","PeriodicalId":11706,"journal":{"name":"Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1306/EG.06231010011","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66166151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Joints within unconsolidated material such as glacial till can be primary avenues for the flow of electrical charge, water, and contaminants. To facilitate the siting and design of remediation programs, a need exists to map anisotropic distribution of such pathways within glacial tills by determining the azimuth of the dominant joint set. The azimuthal survey method uses standard resistivity equipment with a Wenner array rotated about a fixed center point at selected degree intervals that yields an apparent resistivity ellipse. From this ellipse, joint set orientation can be determined. Azimuthal surveys were conducted at 21 sites in a 500-km2 (193 mi2) area around Milwaukee, Wisconsin, and more specifically, at sites having more than 30 m (98 ft) of glacial till (to minimize the influence of underlying bedrock joints). The 26 azimuthal surveys revealed a systematic pattern to the trend of the dominant joint set within the tills, which is approximately parallel to ice flow direction during till deposition. The average orientation of the joint set parallel with the ice flow direction is N77E and N37E for the Oak Creek and Ozaukee tills, respectively. The mean difference between average direct observation of joint set orientations and average azimuthal resistivity results is 8, which is one fifth of the difference of ice flow direction between the Ozaukee and Oak Creek tills. The results of this study suggest that the surface azimuthal electrical resistivity survey method used for local in situ studies can be a useful noninvasive method for delineating joint sets within shallow geologic material for regional studies.
{"title":"Application of the surface azimuthal electrical resistivity survey method to determine patterns of regional joint orientation in glacial tills","authors":"D. Carlson","doi":"10.1306/EG.04061010002","DOIUrl":"https://doi.org/10.1306/EG.04061010002","url":null,"abstract":"Joints within unconsolidated material such as glacial till can be primary avenues for the flow of electrical charge, water, and contaminants. To facilitate the siting and design of remediation programs, a need exists to map anisotropic distribution of such pathways within glacial tills by determining the azimuth of the dominant joint set. The azimuthal survey method uses standard resistivity equipment with a Wenner array rotated about a fixed center point at selected degree intervals that yields an apparent resistivity ellipse. From this ellipse, joint set orientation can be determined. Azimuthal surveys were conducted at 21 sites in a 500-km2 (193 mi2) area around Milwaukee, Wisconsin, and more specifically, at sites having more than 30 m (98 ft) of glacial till (to minimize the influence of underlying bedrock joints). The 26 azimuthal surveys revealed a systematic pattern to the trend of the dominant joint set within the tills, which is approximately parallel to ice flow direction during till deposition. The average orientation of the joint set parallel with the ice flow direction is N77E and N37E for the Oak Creek and Ozaukee tills, respectively. The mean difference between average direct observation of joint set orientations and average azimuthal resistivity results is 8, which is one fifth of the difference of ice flow direction between the Ozaukee and Oak Creek tills. The results of this study suggest that the surface azimuthal electrical resistivity survey method used for local in situ studies can be a useful noninvasive method for delineating joint sets within shallow geologic material for regional studies.","PeriodicalId":11706,"journal":{"name":"Environmental Geosciences","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2010-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1306/EG.04061010002","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66164120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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