Journal articles on the topic 'Bedrock wells'
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1
Fuad Gafarlı, Fuad Gafarlı, and Südabə Novruzov Südabə Novruzov. "PREVENTION OF SAND CLOGGING IN WELLS." PAHTEI-Procedings of Azerbaijan High Technical Educational Institutions 16, no. 05 (April 25, 2022): 101–6. http://dx.doi.org/10.36962/pahtei16052022-101.
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A brief analysis of the prevention of sand blockage in wells is considered. One of the most common complications during the operation of wells in Azerbaijani oil fields is sand formation. During sand formation, wells are stopped for a while, their repair takes a long time, and as a result, significant well product losses occur. The sand that comes with the fluid entering the wellbore destroys the equipment and at the same time forms a blockage in the wellbore. The removal of the sand plug requires heavy labor, but sometimes leads to oil losses in many wells and leads to the collapse of rocks in the wellbore zone and the deformation of the production pipeline. The collapse of the bedrock and the prevention of sand congestion are still one of the most pressing issues in the oil industry. Despite numerous scientific studies and mining experiments on the mechanism of sand formation prevention, no universal method has been found to combat sand formation. The collapse of the bedrock and the prevention of sand congestion are still one of the most pressing issues in the oil industry. Keywords: sand plug, well, sand plug removal, well bottom filter, surface filter, well bottom zone
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Gaut, Sylvi, Lucy Robertson, Bjørn Gjerde, Atle Dagestad, and Bjørge Brattli. "Occurrence of Cryptosporidium oocysts and Giardia cysts in Norwegian groundwater wells in bedrock." Journal of Water and Health 6, no. 3 (March 1, 2008): 383–88. http://dx.doi.org/10.2166/wh.2008.046.
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The occurrence of Cryptosporidium oocysts and Giardia cysts in Norwegian groundwater wells in bedrock has been investigated for the first time. Wells close to risk areas such as farming and septic tanks were chosen. In all, 20 water samples from 20 different waterworks were collected. The samples were analysed for Cryptosporidium and Giardia, using US EPA Method 1623. Turbidity was also measured. Water samples from 10 of the waterworks were also analysed for Clostridium perfringens by membrane filtration. Cryptosporidium was detected in the groundwater samples from 3 of the waterworks. Giardia and Clostridium perfringens were not detected. Too few samples were analysed to verify whether Giardia is indeed absent from bedrock wells, and further studies are recommended to give more reliable data.
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Gernand, Jeff, Bruce Rundell, and Chen-yu Yen. "Practical Bedrock Aquifer Characterization Using Borehole Geophysics and Multilevel Wells." Practice Periodical of Hazardous, Toxic, and Radioactive Waste Management 5, no. 2 (April 2001): 111–18. http://dx.doi.org/10.1061/(asce)1090-025x(2001)5:2(111).
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Brainerd, Richard J., and Gary A. Robbins. "A Tracer Dilution Method for Fracture Characterization in Bedrock Wells." Ground Water 42, no. 5 (September 2004): 774–80. http://dx.doi.org/10.1111/j.1745-6584.2004.tb02731.x.
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Akingboye, Adedibu Sunny, Isaac Babatunde Osazuwa, and Muraina Zaid Mohammed. "Electrical Resistivity Tomography for Sustainable Groundwater Development in a Complex Geological Area." Materials and Geoenvironment 66, no. 2 (June 1, 2019): 121–28. http://dx.doi.org/10.2478/rmzmag-2019-0004.
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AbstractElectrical resistivity tomography (ERT) was used for delineating significant subsurface hydrogeological features for sustainable groundwater development in Etioro-Akoko area, Southwestern Nigeria. This study was necessitated by challenges posed on groundwater supplies from wells and boreholes in Etioro-Akoko and the neighbouring fast growing towns and villages. Field data were acquired over the area with ABEM Lund Resistivity Imaging System and were subsequently processed and inverted through RES2DINVx64 software. Results showed four distinct subsurface layers: topsoil, weathered layer, fractured bedrock and fresh bedrock (basal unit). Localised bedrock depressions occasioned by fracturing and deep weathering of less stable bedrock minerals were delineated with resistivity and thickness values ranging from 50 to 650 Ωm and 12 to ---gt--- 25 m, respectively. The localised depressions mirrored uneven bedrock topography and served as the preferential groundwater storage and hydrogeological zones in the area. The two hydrogeological zones significant for groundwater development included overburden-dependent aquifers and fractured dependent bedrock aquifers. It was, therefore, concluded that groundwater storage potential was depended on hydrogeological zones particularly at major localised bedrock depressions where fractures and groundwater recharges/discharges were evident. Wells and boreholes were proposed at bedrock depressions with thickness value not less than 12 and ---gt--- 25 m, respectively, for enhanced groundwater sustainability and quality assurance in the area.
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Miller, Richard D., Don W. Steeples, and Michael Brannan. "Mapping a bedrock surface under dry alluvium with shallow seismic reflections." GEOPHYSICS 54, no. 12 (December 1989): 1528–34. http://dx.doi.org/10.1190/1.1442620.
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Shallow seismic‐reflection techniques were used to image the bedrock‐alluvial interface, near a chemical evaporation pond in the Texas Panhandle, allowing optimum placement of water‐quality monitor wells. The seismic data showed bedrock valleys as shallow as 4 m and accurate to within 1 m horizontally and vertically. The normal‐moveout velocity within the near‐surface alluvium varies from 225 m/s to 400 m/s. All monitor‐well borings near the evaporation pond penetrated unsaturated alluvial material. On most of the data, the wavelet reflected from the bedrock‐alluvium interface has a dominant frequency of around 170 Hz. Low‐cut filtering at 24 dB/octave below 220 Hz prior to analog‐to‐digital conversion enhanced the amplitude of the desired bedrock reflection relative to the amplitude of the unwanted ground roll. The final bedrock contour map derived from drilling and seismic‐reflection data possesses improved resolution and shows a bedrock valley not interpretable from drill data alone.
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Pociecha, Agnieszka, Maciej Karpowicz, Tadeusz Namiotko, Elżbieta Dumnicka, and Joanna Galas. "Diversity of Groundwater Crustaceans in Wells in Various Geologic Formations of Southern Poland." Water 13, no. 16 (August 11, 2021): 2193. http://dx.doi.org/10.3390/w13162193.
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Data on Crustacea from underground waters accessed through wells are limited in Poland. A recent study was undertaken to determine diversity and factors influencing the crustacean communities inhabiting wells drilled in three bedrocks, Jurassic limestone, Cretaceous marls and flysch. A total of 23 crustacean species and subspecies were recorded belonging to Copepoda, Ostracoda, Amphipoda and Bathynellacea. Only four species of low abundance, however, were stygobionts. Our studies showed that abundance and species number of Copepoda and Ostracoda were affected by bedrock geology (with higher abundances and species richness in wells of Cretaceous marls), and in the case of copepods, also by sampling season. Furthermore, this paper lists all species of Crustacea recorded from inland groundwater habitats of Poland based published over the last 133 years. The most species-rich group was Copepoda with 43 representatives (four stygobites), followed by Ostracoda and Amphipoda with a total of 37 and 12 species, respectively (each with nine stygobites). In addition, two species of Isopoda (one stygobite) and one Bathynellid appear in the checklist. The checklist identifies geographical (and environmental) gaps which require further research.
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Bailey, Brooks, Weston Drip, and Suresh Muthukrishnan. "Spatial Analysis of Hydrological Productivity in Fractured Bedrock Terrains of the Piedmont of Northwestern South Carolina." Journal of South Carolina Water Resources, no. 5 (June 1, 2018): 25–33. http://dx.doi.org/10.34068/jscwr.05.02.
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Fractured bedrock aquifers are structurally complex groundwater systems. Groundwater flow is limited to secondary porosity features such as faults and fractures on account of the low primary porosity and permeability of the native bedrock. The hydrologic productivity of wells drilled within these systems is spatially and vertically variable because of limited interconnectivity among these features. The purpose of this study was to assess potential correlations between driller-estimated well yields and the mapped lithology and structural features of the fractured bedrock aquifers of the Piedmont of northwestern South Carolina. Groundwater well data (e.g., well depth, well yields, static water level) of 1,069 wells, geologic data (e.g., lithology, mapped structural features), and topographic data (e.g., surface elevation, slope) were integrated within a geographic information system database for a spatial analysis of well yield distribution. Wells drilled in alluvium had the highest median yield (15 gal/min), whereas those drilled in schist, amphibolite, and gneisses had lower median yields (9, 8.5, and 8 gal/min, respectively). Nonparametric statistical analyses indicated that no geologic or topographic variables considered were strongly or moderately correlated with reported well yields. Spearman’s correlation coefficients for well depth (0.24), static water level (0.19), proximity to water bodies (–0.10), and proximity to lithologic contacts (–0.08) were statistically significant (at the 0.05 confidence level) but only weakly correlated with well yield. Topographic variables and proximity to mapped faults were not statistically significant. Wells drilled in alluvium had the highest yields due to the higher porosity and permeability compared to the bedrock. However, alluvium makes up less than 5% of the study area surface, and so opportunities to further tap this unit are limited and spatially constrained. The lower median yields of other lithologies are attributed to the lack of fracture development in amphibolite and the low degree of weathering within gneiss foliation planes. To maximize yields, wells should be drilled in alluvium close to water bodies and lithologic contacts where possible.
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Lukas, William G., Don J. DeGroot, David W. Ostendorf, and Erich S. Hinlein. "Multi-scale hydrogeologic characterization of a leaky till–mantled fractured bedrock aquifer system." Canadian Geotechnical Journal 52, no. 12 (December 2015): 1945–55. http://dx.doi.org/10.1139/cgj-2014-0296.
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The paper presents hydrogeologic properties for a leaky till–mantled fractured bedrock aquifer system based on geophysical and hydraulic tests performed at a drumlin located in northeastern Massachusetts, USA. The site profile consists of a fractured bedrock aquifer overlain by a 30 m thick unweathered, coarse-grained till aquitard. Steady state, decadal scale, hydraulics varied little until seasonal irrigation pumping was initiated in recent years, causing a substantial annual drawdown in the aquifer and leakage from the overlying till. High frequency hydraulic head data sets collected in monitoring wells record the hydraulic response to the irrigation pumping. These data sets, together with results from small scale slug and purge tests performed in monitoring wells, are used to characterize the hydrogeologic behavior of this groundwater system. Geophysical logging performed in bedrock wells confirmed the presence of numerous flowing fractures. The large-scale continuum analysis of the fractured bedrock aquifer response to the irrigation pumping yields transmissivity values consistent with those determined from the small-scale, short-term purge test results. The low hydraulic conductivity till has a significant impact on the drawdown behavior of the fractured bedrock aquifer. Calibrated values from the collective data sets and analyses result in the following properties for the 30 m thick unweathered till: hydraulic conductivity K′ = 7.2 × 10−9 m/s, transmissivity T′ = 2.3 × 10−8 m2/s, and storativity S′ = 2.7 × 10−4, and for the underlying fractured bedrock aquifer: T = 6.5 × 10−6 m2/s with an average fracture aperture of 46 μm and hydraulic conductivity Kf = 1.3 × 10−3 m/s. These results should describe similar unweathered coarse-grained till–mantled fractured bedrock aquifer systems and provide useful data for preliminary analyses prior to any site-specific investigations.
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Libby, Jill L., and Gary A. Robbins. "An Unsteady State Tracer Method for Characterizing Fractures in Bedrock Wells." Groundwater 52, no. 1 (March 29, 2013): 136–44. http://dx.doi.org/10.1111/gwat.12045.
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Chlebica, Dariusz W., and Gary A. Robbins. "Altering Dissolved Oxygen to Determine Flow Conditions in Fractured Bedrock Wells." Groundwater Monitoring & Remediation 33, no. 4 (July 10, 2013): 100–107. http://dx.doi.org/10.1111/gwmr.12019.
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Metcalf, Meredith J., and Gary A. Robbins. "Evaluating groundwater sustainability for fractured crystalline bedrock." Water Supply 14, no. 1 (September 12, 2013): 127–34. http://dx.doi.org/10.2166/ws.2013.179.
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Water sustainability is an important concern for communities that rely on groundwater in fractured rock; yet the complexity of the fracture system and the unknown rate of recharge make quantifying groundwater availability difficult, if not impossible, using conventional water balance calculations. This study provides a new approach for estimating groundwater sustainability in fractured rock that entails synthesis of pre-existing well data into a comprehensive database that permits defining bedrock groundwater drainage basins and flow for use in estimating recharge and usage. The method was tested in the Coventry Quadrangle, Connecticut and entailed the use of more than 2,500 wells. Groundwater recharge and usage were estimated for each drainage basin and the sustainability of each basin was determined by taking the difference between these estimates. Additionally, temporal analysis of well parameters indicated a decrease in well yield by approximately 20% and the depth to water declined. The method demonstrated here provides a means to allow the consideration of groundwater sustainability in land use planning and decision-making.
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M. Isam Salih, M., H. B. L. Pettersson, and E. Lund. "Uranium and Thorium Series Radionuclides in Drinking Water from Drilled Bedrock Wells: Correlation to Geology and Bedrock Radioactivity and Dose Estimation." Radiation Protection Dosimetry 102, no. 3 (November 1, 2002): 249–58. http://dx.doi.org/10.1093/oxfordjournals.rpd.a006093.
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Betcher, R. N., M. Gascoyne, and D. Brown. "Uranium in groundwaters of southeastern Manitoba, Canada." Canadian Journal of Earth Sciences 25, no. 12 (December 1, 1988): 2089–103. http://dx.doi.org/10.1139/e88-193.
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Anomalously high levels of naturally derived uranium have been found in groundwater samples from wells completed in overburden and bedrock aquifers in southeastern Manitoba. Uranium analyses were carried out on groundwater samples collected from 287 individual wells in a 15 500 km2 area. The mean U concentration in all samples was 58.3 μg/L; the maximum value was 2020 μg/L. Uranium concentrations were highest in samples from Precambrian rock aquifers, averaging 115.6 μg/L, and were lowest in samples from Paleozoic sedimentary rock aquifers, averaging 3.5 μg/L.Uranium concentrations up to 250 μg/L were found in groundwaters in or associated with Lake Agassiz clay deposits. These high concentrations are thought to result principally from release of U from the organic component of the clays, either by oxidation or desorption. Leakage of uraniferous groundwater from the clays appears to provide a significant source of U to underlying sand and gravel aquifers and to the Precambrian bedrock aquifer. Uranium within the bedrock is also being released to solution by oxidation of uraniferous hematite found as mineral coatings and fracture fillings in highly weathered zones. Uranium solubility in many Precambrian bedrock groundwaters is increased by recharge of these aquifers by ground waters from overburden materials that contain high [Formula: see text] concentrations.
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Cho, Byong-Wook, Dong-Soo Kim, Moon-Su Kim, Jae-Hong Hwang, and Chang-Oh Choo. "Hydrogeochemical Characteristics of Uranium and Radon in Groundwater from the Goesan Area of the Ogcheon Metamorphic Belt (OMB), Korea." Sustainability 13, no. 20 (October 13, 2021): 11261. http://dx.doi.org/10.3390/su132011261.
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Uranium and radon concentrations in groundwater from the Goesan area of the Ogcheon Metamorphic Belt (OMB), central Korea, whose bedrock is known to contain the highest uranium levels in Korea, were analyzed from 200 wells. We also measured the uranium concentrations in the bedrock near the investigated wells to infer a relationship between the bedrock geology and the groundwater. The five geologic bedrock units in the Goesan area consist of Cretaceous granite (Kgr), Jurassic granite (Jgr) and three types of metasedimentary rocks (og1, og2, and og3). The percentages of the groundwater samples over 30 μg/L (maximum contaminant level, MCL of US EPA) were 2.0% of the 200 groundwater samples; 12% of Kgr and 1.8% of Jgr exceeded the MCL, respectively. Overall, 16.5% of the 200 groundwater samples exceeded 148 Bq/L (alternative maximum contaminant level, AMCL of US EPA); 60.0% of Kgr and 25.0% of Jgr exceeded the AMCL, but only 0% of og1, 7.9% of og2, and 2.6% of og3 exceeded the value, respectively. No direct correlation was found between uranium concentration and radon concentration in water samples. Radon has a slightly linear correlation with Na (0.31), Mg (−0.30), and F (0.36). However, uranium behavior in groundwater was independent of other components. Based on thermodynamic calculation, uranium chemical speciation was dominated by carbonate complexes, namely the Ca2UO2(CO3)3(aq) and CaUO2(CO3)32− species. Although uraniferous mineral phases designated as saturation indices were greatly undersaturated, uranium hydroxides such as schoepite, UO2(OH)2 and U(OH)3 became possible phases. Uranium-containing bedrock in OMB did not significantly affect radioactive levels in the groundwater, possibly due to adsorption effects related to organic matter and geochemical reduction. Nevertheless, oxidation prevention of uranium-containing bedrock needs to be systematically managed for monitoring the possible migration of uranium into groundwater.
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Williams, John H., and Randall W. Conger. "Preliminary Delineation of Contaminated Water-Bearing Fractures Intersected by Open-Hole Bedrock Wells." Groundwater Monitoring & Remediation 10, no. 4 (November 1990): 118–26. http://dx.doi.org/10.1111/j.1745-6592.1990.tb00028.x.
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Vitale, Sarah A., and Gary A. Robbins. "Measuring Flow Rate in Crystalline Bedrock Wells Using the Dissolved Oxygen Alteration Method." Groundwater 55, no. 4 (March 22, 2017): 588–92. http://dx.doi.org/10.1111/gwat.12512.
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Flahive, Neil A., and Gary A. Robbins. "A Single Packer Method for Characterizing Water Contributing Fractures in Crystalline Bedrock Wells." Groundwater Monitoring & Remediation 40, no. 1 (January 2020): 65–73. http://dx.doi.org/10.1111/gwmr.12365.
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Lahermo, Pertti W. "Atmospheric, Geological, Marine and Anthropogenic Effects on Groundwater Quality in Finland." Water Science and Technology 20, no. 3 (March 1, 1988): 33–39. http://dx.doi.org/10.2166/wst.1988.0078.
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The atmospheric, geological, marine and anthropogenic factors affecting the chemical quality of groundwater are evaluated. Sulphates and nitrates derive mainly from the atmosphere as wet or dry deposition in weakly mineralized shallow groundwater in natural uncontaminated surficial aquifers. The texture, structure and lithologic composition of aquifer material have an impact on water chemistry although marine influence and anthropogenic pollution generally outweigh the geological influence. Relict seawater trapped in deeper parts of confined aquifers and in bedrock covered by clay deposits has a marked effect on the quality of groundwater drawn from wells drilled into bedrock in the broad coastal belt. Brackish or saline groundwater is encountered all over the country in holes drilled in crystalline bedrock to a depth of more than 500 to 1000 metres. The lithologic environment affects the quality of deep bedrock groundwater which tends to change from Na-Cl type towards Ca-Na-Cl type with increasing salinity and depth of occurrence. Anthropogenic pollution is reflected in elevated amounts of all major dissolved components, although the most sensitive indicators of contamination are nitrates, chlorides and potassium. Nation-wide hydrogeochemical mapping of rural water sources revealed that shallow wells dug into glacial till deposits had the highest median NO3 contents, and that spring water discharging from glaciofluvial sand deposits had the lowest. The quality of groundwater distributed by public waterworks is generally good.
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Ha, Kyoochul, Hyowon An, Eunhee Lee, Sujeong Lee, Hyoung Chan Kim, and Kyung-Seok Ko. "Evaluation of Well Improvement and Water Quality Change before and after Air Surging in Bedrock Aquifers." Water 14, no. 14 (July 15, 2022): 2233. http://dx.doi.org/10.3390/w14142233.
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When a drought occurs, drought response is mainly focused on the development of new wells. However, it is inefficient to respond to droughts by developing additional new wells in areas where many existing groundwater wells have been developed. Rather, it is necessary to find a way to use the existing wells efficiently and, if possible, increase the amount of groundwater that can be pumped. In this study, a pumping test and analysis method were used to evaluate the effect of air surging on improving existing wells. Drawdowns were reduced in the test wells, and, accordingly, the average specific discharges and transmissivities were increased. Since many factors in bedrock aquifers must be considered in order to calculate the well efficiency for the evaluation of the well performance, it seems better to compare the pumping rate and drawdown based on a reference time calculated by an adjusted time. Such factors could be the uncertainty of the aquifer model, aquifer inhomogeneity, and a hydrogeologic boundary. Additionally, in this process, the changes in groundwater quality were investigated, as well as the substances that caused the degradation of the well performance in bedrock aquifers. According to the results of the groundwater quality analysis conducted during the surging process and the step drawdown tests, there was no significant groundwater quality change before and after surging, but it appeared that there was an inflow of contaminants from the upper shallow strata close to the surface. According to the results of the XRD, XRF, and SEM-EDS analyses for the substances collected during surging and the substances deposited inside the well pipe, most of the substances were Fe-related amorphous components. Additionally, Fe coexisted with components such as As, V, and Zn, which formed the well casing together with Fe and were eluted in the surging process and step drawdown tests.
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Lee, Jeong-Hwan, Se-Yeong Hamm, Suk-Jong Han, Soon-Il Ok, Eun-Jee Cha, Heuy-Nam Cho, Chang-Oh Choo, and Moo-Jin Kim. "Verifying Rehabilitation and Evaluation of Bedrock Wells using Air-brush Surging and Explosive Methods." Journal of Engineering Geology 21, no. 4 (December 30, 2011): 369–79. http://dx.doi.org/10.9720/kseg.2011.21.4.369.
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Purkamo, Lotta, Riikka Kietäväinen, Maija Nuppunen-Puputti, Malin Bomberg, and Claire Cousins. "Ultradeep Microbial Communities at 4.4 km within Crystalline Bedrock: Implications for Habitability in a Planetary Context." Life 10, no. 1 (January 4, 2020): 2. http://dx.doi.org/10.3390/life10010002.
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The deep bedrock surroundings are an analog for extraterrestrial habitats for life. In this study, we investigated microbial life within anoxic ultradeep boreholes in Precambrian bedrock, including the adaptation to environmental conditions and lifestyle of these organisms. Samples were collected from Pyhäsalmi mine environment in central Finland and from geothermal drilling wells in Otaniemi, Espoo, in southern Finland. Microbial communities inhabiting the up to 4.4 km deep bedrock were characterized with phylogenetic marker gene (16S rRNA genes and fungal ITS region) amplicon and DNA and cDNA metagenomic sequencing. Functional marker genes (dsrB, mcrA, narG) were quantified with qPCR. Results showed that although crystalline bedrock provides very limited substrates for life, the microbial communities are diverse. Gammaproteobacterial phylotypes were most dominant in both studied sites. Alkanindiges -affiliating OTU was dominating in Pyhäsalmi fluids, while different depths of Otaniemi samples were dominated by Pseudomonas. One of the most common OTUs detected from Otaniemi could only be classified to phylum level, highlighting the uncharacterized nature of the deep biosphere in bedrock. Chemoheterotrophy, fermentation and nitrogen cycling are potentially significant metabolisms in these ultradeep environments. To conclude, this study provides information on microbial ecology of low biomass, carbon-depleted and energy-deprived deep subsurface environment. This information is useful in the prospect of finding life in other planetary bodies.
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Abbott, Robert E., and John N. Louie. "Depth to bedrock using gravimetry in the Reno and Carson City, Nevada, area basins." GEOPHYSICS 65, no. 2 (March 2000): 340–50. http://dx.doi.org/10.1190/1.1444730.
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Sedimentary basins can trap earthquake surface waves and amplify the magnitude and lengthen the duration of seismic shaking at the surface. Poor existing gravity and well‐data coverage of the basins below the rapidly growing Reno and Carson City urban areas of western Nevada prompted us to collect 200 new gravity measurements. By classifying all new and existing gravity locations as on seismic bedrock or in a basin, we separate the basins’ gravity signature from variable background bedrock gravity fields. We find an unexpected 1.2-km maximum depth trough below the western side of Reno; basin enhancement of the seismic shaking hazard would be greatest in this area. Depths throughout most of the rest of the Truckee Meadows basin below Reno are less than 0.5 km. The Eagle Valley basin below Carson City has a 0.53-km maximum depth. Basin depth estimates in Reno are consistent with depths to bedrock in the few available records of geothermal wells and in one wildcat oil well. Depths in Carson City are consistent with depths from existing seismic reflection soundings. The well and seismic correlations allow us to refine our assumed density contrasts. The basin to bedrock density contrast in Reno and Carson City may be as low as −0.33 g/cm3. The log of the oil well, on the deepest Reno subbasin, indicates that Quaternary deposits are not unusually thick there and suggests that the subbasin formed entirely before the middle Pliocene. Thickness of Quaternary fill, also of importance for determining seismic hazard below Reno and Carson City may only rarely exceed 200 m.
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Paillet, Frederick, and Russell Duncanson. "Comparison of Drilling Reports and Detailed Geophysical Analysis of Ground-Water Production in Bedrock Wells." Ground Water 32, no. 2 (March 1994): 200–206. http://dx.doi.org/10.1111/j.1745-6584.1994.tb00634.x.
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Vieira, Yesus Emmanuel Medeiros, Renata Albergaria de Mello Bandeira, and Orivalde Soares da Silva Junior. "Application of a Logit Model for Water well site location in fractured-bedrock aquifers in northeastern Brazil." International Journal for Innovation Education and Research 10, no. 8 (July 19, 2022): 33–52. http://dx.doi.org/10.31686/ijier.vol10.iss8.3854.
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Wells drilling process in fractured-bedrock aquifers is a difficult task. Extreme variations in lithology and structure features, as well productive water zones sited at preferential points make geological and geophysical investigations difficult. To contribute to the understanding of the process of groundwater zones occurrence in fractured-bedrock aquifers, this paper develops a drilling prospective model by using regression analysis, whose parameters were calibrated according to the photogeological and cartographic analysis of 113 drilling points in the states of Rio Grande do Norte, Paraíba, and Ceará. The effectiveness of the resulting model was assessed through a sample of 43 additional drillings, which were carried out aiming at the distribution of water to the communities in the semiarid region of Brazil. The obtained results indicate the model as an important tool in the drilling process, with direct implications on the logistics costs of water well site location and consequent attendance to the population that needs the water.
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Drew, Lawrence J., John H. Schuenemeyer, Thomas R. Armstrong, and David M. Sutphin. "Initial Yield to Depth Relation for Water Wells Drilled into Crystalline Bedrock-Pinardville Quadrangle, New Hampshire." Ground Water 39, no. 5 (September 2001): 676–84. http://dx.doi.org/10.1111/j.1745-6584.2001.tb02357.x.
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Hughes, Larry J. "Mapping contaminant-transport structures in karst bedrock with ground-penetrating radar." GEOPHYSICS 74, no. 6 (November 2009): B197—B208. http://dx.doi.org/10.1190/1.3223312.
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Ammonium perchlorate, a risk to human health, was used formerly to manufacture rocket fuel at the Naval Weapons Industrial Reserve Plant (NWIRP) McGregor, McLennon County, Texas. Perchlorate exists in several groundwater contaminant plumes, whose geometries were suspected to be influenced by transmissive bedrock structures. To identify these possible contaminant-transport pathways, a towed-array ground-penetrating radar (GPR) system was used to acquire 118 line-km of data across [Formula: see text] of the property. The shallow geology consists of bedrock limestone overlain by [Formula: see text] of clay soil. For the [Formula: see text] antennas used, the conductive clay limits depth penetration to less than [Formula: see text] and yields a [Formula: see text] wavelength, reducing lateral and vertical resolution. Nevertheless, GPR data resolved the top of bedrock in many areas. Linear discontinuities in bedrock were interpreted as weathered fracture zones, and linear areas of signal loss were attributed to deeper clay weathering along fracture zones. GPR-interpreted fractures have orientations corresponding to known lineament and fault trends, appear to control plume geometries, and tend to have higher hydraulic transmissivities. GPR results led to a more complete contaminant-transport model and were used to optimize the positions of monitoring wells needed to define the extent of contamination. This reduced the cost and time required for an environmental investigation at the site. GPR was helpful also in positioning remedial trenches across contaminated structures, resulting in plume containment at the property boundaries.
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Zhao, Sihan, Hongchang Hu, Ciaran Harman, Fuqiang Tian, Qiang Tie, Yaping Liu, and Zhenyang Peng. "Understanding of Storm Runoff Generation in a Weathered, Fractured Granitoid Headwater Catchment in Northern China." Water 11, no. 1 (January 11, 2019): 123. http://dx.doi.org/10.3390/w11010123.
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Few of the classical field studies of streamflow generation in headwater watersheds have been conducted in catchments with thin soils and deeply weathered crystalline silicate bedrock. As such, the role of the (potentially very large) storage capacity of weathered, fractured rock in baseflow and storm event discharge remains poorly characterized. Here we present a study of streamflow generation in an upland semi-humid watershed (Xitaizi Experimental Watershed, XEW, 4.22 km2) dominated by baseflow feeding one of the main water supply reservoirs for the city of Beijing, China. This catchment is relatively dry (625 mm/yr precipitation, 480 mm/yr Evapotranspiration), but has strongly seasonal precipitation that varies in phase with strongly seasonal potential evapotranspiration. The catchment was instrumented with four weather stations and precipitation collectors, 11 deep wells drilled into the bedrock along three hillslopes, and additional soil moisture sensors and water samplers along one hillslope. In six storm events over two years, samples of rainfall, soil water (10–80 cm depth), groundwater, and stream water were collected with high frequency and analyzed for stable water isotopes (δ18O and δ2H). Tracer-based hydrograph separation showed that event water (precipitation) makes up the majority of the hydrograph peak above baseflow, and pre-event water contributions (on average) simply represent the steady release of groundwater. The quantity of event water corresponded to a very small effective contributing area (<0.2% of the catchment) that nevertheless showed a clear dependence on catchment wetness as measured by the streamflow. The streamflow itself was isotopically identical to the deep groundwater in wells. This suggests that the fractured, weathered, bedrock system dominates the production of streamflow in this catchment.
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Moore, J. P., and J. J. Walsh. "Quantitative analysis of Cenozoic faults and fractures and their impact on groundwater flow in the bedrock aquifers of Ireland." Hydrogeology Journal 29, no. 8 (October 5, 2021): 2613–32. http://dx.doi.org/10.1007/s10040-021-02395-z.
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AbstractFaults and fractures are a critical store and pathway for groundwater in Ireland’s limestone bedrock aquifers either directly as conductive structures or indirectly as the locus for the development of karst conduits. From the quantitative analysis of post-Devonian faults and fractures in a range of lithological sequences, this report describes the principal characteristics of Cenozoic strike-slip faults and joints, the youngest and the most intrinsically conductive fractures within Irish bedrock. Analysis of these structures in more than 120 outcrop, quarry, mine and cave locations in a range of bedrock types, provides a basis for: (1) definition of quantitative models for their depth dependency, lithological control, scaling systematics and links to preexisting structure, (2) conceptualisation of their impact on groundwater behaviour, and (3) estimation of groundwater flow parameters. The quantitative models provide constraints on fracture-controlled flow connectivity. Commonly observed decreases in sustainable flows and water strike interceptions with depth are attributed to increasing confinement and decreasing fracture connectivity and dissolution. Faults and joints have quite different end member geometries, with faults having strongly heterogeneous scale-independent properties and joints more often showing scale-dependent stratabound properties. The highest and most sustainable groundwater flows are usually associated with the complexity of structure of Cenozoic faults and of preexisting Carboniferous structures (on which conductive fracturing localises), enhanced by karstification and strongly jointed limestone bedrock particularly in the near-surface. Increased groundwater flow is promoted within bedded, rather than massive (i.e. unbedded), limestone sequences, characterised by bedding-parallel fractures and karst connecting otherwise subvertical fractures and subvertical wells.
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Grasby, Stephen E., Zhuoheng Chen, Anthony P. Hamblin, Paul R. J. Wozniak, and Arthur R. Sweet. "Regional characterization of the Paskapoo bedrock aquifer system, southern AlbertaGeological Survey of Canada Contribution 2008-0479." Canadian Journal of Earth Sciences 45, no. 12 (December 2008): 1501–16. http://dx.doi.org/10.1139/e08-069.
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The Paskapoo Formation of southern Alberta supports more groundwater wells than any other aquifer system in the Canadian Prairies. Located in a region of rapid population growth and straddling watersheds where no new surface water licenses are available, this aquifer system is under increasing pressure to provide water supply. The Paskapoo Formation represents a foreland deposit of a siltstone- and mudstone-dominated fluvial system. The system is highly heterogeneous with broad ranges in physical properties that impact groundwater production. High-porosity coarse-grained channel sandstone can provide productive wells, whereas thin and fractured sands and siltstones are low producers. The basal Haynes Member and western portion of the Paskpaoo Formation have higher sandstone volumes than other portions of the system. Fracture density shows a strong inverse relationship to bed thickness, such that fracture flow becomes more important for thinner sandstone beds. There is no regional-scale flow system associated with the Paskapoo Formation; rather it is dominated by local-scale recharge processes. The geochemistry of Paskapoo Formation groundwater is largely controlled by the variable composition of immediately overlying glacial deposits.
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Barth-Naftilan, E., J. Sohng, and J. E. Saiers. "Methane in groundwater before, during, and after hydraulic fracturing of the Marcellus Shale." Proceedings of the National Academy of Sciences 115, no. 27 (June 18, 2018): 6970–75. http://dx.doi.org/10.1073/pnas.1720898115.
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Concern persists over the potential for unconventional oil and gas development to contaminate groundwater with methane and other chemicals. These concerns motivated our 2-year prospective study of groundwater quality within the Marcellus Shale. We installed eight multilevel monitoring wells within bedrock aquifers of a 25-km2 area targeted for shale gas development (SGD). Twenty-four isolated intervals within these wells were sampled monthly over 2 years and groundwater pressures were recorded before, during, and after seven shale gas wells were drilled, hydraulically fractured, and placed into production. Perturbations in groundwater pressures were detected at hilltop monitoring wells during drilling of nearby gas wells and during a gas well casing breach. In both instances, pressure changes were ephemeral (<24 hours) and no lasting impact on groundwater quality was observed. Overall, methane concentrations ([CH4]) ranged from detection limit to 70 mg/L, increased with aquifer depth, and, at several sites, exhibited considerable temporal variability. Methane concentrations in valley monitoring wells located above gas well laterals increased in conjunction with SGD, but CH4 isotopic composition and hydrocarbon composition (CH4/C2H6) are inconsistent with Marcellus origins for this gas. Further, salinity increased concurrently with [CH4], which rules out contamination by gas phase migration of fugitive methane from structurally compromised gas wells. Collectively, our observations suggest that SGD was an unlikely source of methane in our valley wells, and that naturally occurring methane in valley settings, where regional flow systems interact with local flow systems, is more variable in concentration and composition both temporally and spatially than previously understood.
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Sinha, Ajit K. "Stratigraphic mapping of sedimentary formations in southern Ontario by ground electromagnetic methods." GEOPHYSICS 55, no. 9 (September 1990): 1148–57. http://dx.doi.org/10.1190/1.1442931.
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Multifrequency and transient electromagnetic (EM) soundings were done at several locations in southern Ontario to evaluate the possibility of stratigraphic mapping of gently dipping sedimentary formations by ground EM techniques. The possibility of detecting structural features such as folds, faults, and grabens in the formations was also explored. The two EM techniques were used to map a buried river valley near the village of Copetown, about 75 km southwest of Toronto. The valley, buried under fairly resistive glacial till and dolomite formations was mapped at depths ranging from 100 to 200 m. The interpreted shape and depth of the valley agreed well with information from a high resolution seismic reflection survey and data from wells penetrating the bedrock. Transient EM (TEM) data, using square transmitter loops with side dimensions comparable to the transmitter‐receiver separation for the multifrequency system, was found to be less affected by the presence of shallow conductors and lateral inhomogeneities than the multifrequency data, and had greater depth of investigation. TEM soundings were made on five additional profiles in the area. Lithologic logs from old oil and gas wells located near the profiles provided information for comparison with EM sounding interpretations. The depths to various dolomite, shale, and limestone formations interpreted from EM data agreed well with drillhole information. The EM soundings also detected structures in the Paleozoic formations such as faults and folds that were not previously known. The soundings confirmed the existence of a graben at one site at a depth of 100 m, which was postulated from logs from a cluster of closely spaced drillholes by geologists. The survey results indicated that EM sounding methods can be used for stratigraphic mapping in areas where detailed geological information is unavailable either because the bedrock is concealed by overburden, or when drillholes are sparsely distributed.
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Kennedy, Gavin W., and John M. Drage. "Assessing patterns of dissolved methane in shallow aquifers related to Carboniferous and Triassic sedimentary basins, Nova Scotia, Canada." Atlantic Geology 51, no. 1 (December 9, 2015): 233. http://dx.doi.org/10.4138/atlgeol.2015.009.
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<p>The study examines patterns of groundwater methane in shallow aquifers located in Carboniferous and Triassic sedimentary basins in Nova Scotia to improve our understanding of the factors influencing the observed distribution. A combined total of over 800 dissolved methane samples were collected from water wells during surveys conducted in 1975 and 2013. Statistical analyses of the methane data did not detect a significant difference between groupings of methane concentrations for aquifer type, bedrock group, and distance to wetlands. A significant difference, however, was observed between sedimentary basins and bedrock formations, which was largely attributed to localized higher methane concentrations found in the Stellarton Formation/basin compared to other on-shore sedimentary basins of the province. A significant difference was also found between groupings of methane data based on the distance to major stream systems, which was used to indicate topographic position (i.e., valley vs. upslope). The low sample density and percentage of detectable methane concentrations, and the multiple sources of dissolved methane in shallow groundwater in sedimentary basins made it difficult to detect and interpret statistical and spatial trends. Geochemical classification indicates that elevated dissolved methane in well water is associated with sodium dominated groundwater.</p>
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Gilmer, Jess H., and Troy Keller. "Groundwater chemistry and soils have limited influence on the habitat-scale distribution of Cambarus harti Hobbs." Freshwater Crayfish 21, no. 1 (December 31, 2015): 43–50. http://dx.doi.org/10.5869/fc.2015.v21-1.43.
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Abstract Primary burrowing crayfish constitute 32% of crayfish considered imperiled, yet little is known about their autecology. To advance our knowledge about burrowing crayfish, groundwater chemistry and soils were assessed at sites containing the state-listed, endangered Cambarus harti Hobbs. Water chemistry was collected and analyzed every one to four weeks from January 2014 – August 2014 from wells (< 2 m deep) at four sites in Meriwether County (GA). Water samples were collected from wells near active burrows, wells without burrows, and burrows showing activity. To assess crayfish soil preferences, three soil cores were collected within ten meters of each well and dry sieved to determine percent sand and silt/clay. Water from wells (with/without crayfish) and burrows showed no differences in potassium, iron, manganese, and silica concentrations. Burrow water showed elevated chloride concentrations. Soils were sand-rich and contained only minor amounts of silt/clay. Soils differed slightly among sites but showed no difference between locations with and without burrows. Thus, bedrock and soils appear to be relatively homogeneous over the spatial scales studied. It is unclear if crayfish activity elevates chloride concentrations in burrows. These results corroborate previous research suggesting groundwater chemistry and soil texture are not the exclusive environmental factors controlling the distribution of primary burrowing crayfish.
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Gerber, Gloria E., Robin W. Tweedie, Stephen M. Bean, Stan Thomson, and Zdenek Eisenstein. "Stability of the north slope and portal at the Edmonton light rail transit crossing of the North Saskatchewan River." Canadian Geotechnical Journal 30, no. 1 (February 1, 1993): 12–21. http://dx.doi.org/10.1139/t93-002.
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The North Portal for the Edmonton South Light Rail Transit (SLRT) extension is located on the north slope of the North Saskatchewan River Valley west of the High Level Bridge. There was no evidence that the north slope at this location had experienced major, deep-seated slope movements prior to SLRT construction. Since commencement of the North Portal construction, translational slope movements along near-horizontal bentonite layers within the bedrock have developed. Initiation and acceleration of slope movement are believed to be due to the earthwork activities, coupled with precipitation and associated rise in groundwater table. As an interim measure, four deep wells were installed close to the toe of the upper slope in May 1989. The piezometric levels observed after installation of the wells suggest that the drilling of the wells hydraulically connected the various coal–bentonite layers and effectively lowered the higher perched water in the upper coal?bentonite layer. Subsequent slope inclinometer measurements indicate negligible slope movements since the well installations. This paper describes the detailed geotechnical investigations, slope stability assessments, instrumentation, and monitoring records over a 5-year period during and after construction. The paper also describes the implementation of the stabilizing measures and their effects on slope stability. Key words : South Light Rail Transit, North Saskatchewan River Valley, coal–bentonite layers, slope stability, vertical wells.
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Bondu, Raphaël, Vincent Cloutier, and Eric Rosa. "Occurrence of geogenic contaminants in private wells from a crystalline bedrock aquifer in western Quebec, Canada: Geochemical sources and health risks." Journal of Hydrology 559 (April 2018): 627–37. http://dx.doi.org/10.1016/j.jhydrol.2018.02.042.
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Eger, Charles K., Wen-Jei Fang, Jon Maybriar, and Keith Sims. "IMPLEMENTATION OF FIELD TECHNIQUES TO STABILIZE ABANDONED OIL WELLS—BOYD'S CREEK, KENTUCKY1." International Oil Spill Conference Proceedings 1993, no. 1 (March 1, 1993): 83–88. http://dx.doi.org/10.7901/2169-3358-1993-1-83.
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ABSTRACT Boyd's Creek, situated in Barren County, is recognized as the birthplace of the oil industry in the Commonwealth of Kentucky. Naturally occurring oil seeps were identified as early as the 1820s. Commercial crude-oil drilling production began in the early 1860s.3 From the early days to present, countless unrecorded exploration wells were drilled and many of these wells have been found to be improperly abandoned. The Corniferous limestone is the first oil producing interval and is situated at an average subsurface depth of 135 feet. The potential for impacting natural resources is high because of the shallow depth(s) of the Corniferous limestone and the presence of overlying artesian sulfur-water zones which routinely mix with brine and oil in uncased boreholes. The occurrence of limestone related (karstic) features, such as fractures and dissolution cavities, and the close proximity of the Boyd's Creek oil field to nearby surface streams are also of concern. Initially, two abandoned wells were identified as flowing into nearby streams. Pursuant to federal removal authority provided by Subsection (c) of Section 311 of the Federal Water Pollution Control Act in accordance with Subtitle ? of the Oil Pollution Act of 1990 and the National Contingency Plan, the Environmental Protection Agency has initiated cleanup operations within properties nearest to Boyd's Creek. Most wells are difficult to identify because they lack any casing strings and/or they have been buried with soil to hide uncontrolled flows at the surface. Field operations have included the utilization of multiple geophysical techniques to identify anomaly areas thought to represent buried unplugged wells. These include the excavation of surface soils down to the underlying limestone bedrock to search for cable tool and rotary boreholes, the drilling out of old wells using conventional industry technology and standards to plug them permanently with cement, the construction of temporary underflow dams downgradient from identified oil spills to minimize impacts on Boyd's Creek and its adjoining tributaries, and the burning of spilled product in temporary holding pits to minimize associated cleanup cost. In undertaking these actions, the agency is eliminating potential sources of petroleum related contamination.
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Cardace, D., T. Hoehler, T. McCollom, M. Schrenk, D. Carnevale, M. Kubo, and K. Twing. "Establishment of the Coast Range ophiolite microbial observatory (CROMO): drilling objectives and preliminary outcomes." Scientific Drilling 16 (November 5, 2013): 45–55. http://dx.doi.org/10.5194/sd-16-45-2013.
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Abstract. This project aimed to establish a subsurface microbial observatory in ultramafic rocks, by drilling into an actively serpentinizing peridotite body, characterizing cored rocks, and outfitting the boreholes for a program of long-term observation and experimentation to resolve the serpentinite-hosted subsurface biosphere. We completed drilling in August 2011, drilling two boreholes with core recovery and possibility for down-hole experimentation, and six smaller-diameter monitoring wells arrayed around the two primary holes, in the Coast Range ophiolite (CRO) locality in the UC-Davis McLaughlin Natural Reserve, Lower Lake, CA. Every effort was made during drilling to keep the cores and wells as free of drilling-induced contamination as possible: clean, purified water was used as drilling fluid, fluorescent microbead tracers were suspended in that water for quantification of drilling fluid penetration into the cores, and high resolution next generation sequencing approaches were used to characterize the microbial populations in the drill fluids and core materials. In December 2011, we completed installation of well pumps (slow flow bladder pumps) in the monitoring wells, and have deployed a set of in situ incubation experiments in the two uncased boreholes. Preliminary findings illustrate natural variability in actively serpentinizing strata, and confirm distinct groundwater flow regimes and microbial ecosystems in (a) shallow, surface-impacted soil water horizons and (b) deeper, ultramafic bedrock-sourced formation fluids.
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Nugroho, Muchamad Ocky Bayu, Carolus Prasetyadi, and Teguh Jatmiko. "Pemodelan Intensitas Rekahan pada Fractured Basement Reservoir dengan Pendekatan Konsep Geologi Menggunakan Analisis Kualitatif di Cekungan Sumatra Tengah." Jurnal Offshore: Oil, Production Facilities and Renewable Energy 2, no. 1 (July 4, 2018): 1. http://dx.doi.org/10.30588/jo.v2i1.347.
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<p>Lokasi Penelitian terletak di Selat Malaka dan termasuk dalam Cekungan Sumatra Tengah. Secara stratigrafi, Batuan Dasar Cekungan Sumatra Tengah berumur Pra Tersier dengan litologi batuan sedimen yang termalihkan atau metasedimen. Berdasarkan data sumur pemboran, batuan dasar di lokasi penelitian secara umum berupa kuarsit dan filit. Rekahan pada batuan dasar dikontrol oleh periode tektonik regional yang mempengaruhi Sumatra. Sesar-sesar yang terbentuk berarah umum Utara Barat Laut – Selatan Tenggara (NNW – SSE), hasil dari fase tektonik selama Paleogen hingga Neogen yang menghasilkan morfologi batuan dasar beragam akibat adanya horst graben dan half graben. Morfologi tinggian adalah yang berpotensi menjadi reservoir karena batuan induk yang terletak lebih rendah akan memungkinkan migrasi hidrokarbon. Identifikasi rekahan batuan dasar dianalisa berdasarkan data pemboran sumur dan seismik. Intensitas rekahan dibangun berdasarkan model dengan pendekatan 4 parameter geologi yaitu intensitas rekahan dengan jarak dari bidang sesar, intensitas rekahan dengan pucak antiklin, intensitas rekahan dengan jarak dari permukaan batuan dan dibantu dengan atribut seismik. Nilai intensitas yang memungkinkan terbentuk rekahan adalah 0,3-1.</p><p><em>The research site is located in the Malacca Strait and is included in the Central Sumatra Basin. Stratigraphically, the basement of the Central Sumatra Basin is Pre-Tertiary with thermal sedimentary or metasediment lithology. Based on data from drilling wells, bedrock in the study site generally consists of quartzite and filite. Fractures in bedrock are controlled by regional tectonic periods affecting Sumatra. Faults that form are generally north-north-south-south (NNW-SSE), resulting from tectonic phases during Paleogene to Neogene which produce various bedrock morphologies due to horst graben and half graben. Height morphology is the potential to be a reservoir because the source rock which is located lower will allow hydrocarbon migration. Identification of basement fractures was analyzed based on well and seismic drilling data. The fracture intensity was built based on the model with a 4 geological parameter approach, namely fracture intensity with distance from the fault plane, fracture intensity with anticline peaks, fracture intensity with distance from the rock surface and assisted with seismic attributes. The intensity value that allows the fracture to form is 0.3-1.</em></p>
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Turtiainen, Tuukka, and Laina Salonen. "Prevention measures against radiation exposure to radon in well waters: analysis of the present situation in Finland." Journal of Water and Health 8, no. 3 (December 4, 2009): 500–512. http://dx.doi.org/10.2166/wh.2009.067.
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Naturally occurring radioactive elements are found in all groundwaters, especially in bedrock waters. Exposure to these radioactive elements increases the risk of cancer. The most significant of these elements is radon which, as a gas, is mobile and dissolves in groundwater. In Finland, water supply plants are obliged to carry out statutory monitoring of the water quality, including radon. Monitoring of private wells, however, is often neglected. In this paper, we outline the problem by reviewing the outcomes of the studies conducted in Finland since the 1960s. We also summarise the development of legislation, regulations and political decisions made so far that have affected the amount of public exposure to radon in drinking water. A review of the studies on radon removal techniques is provided, together with newly obtained results. New data on the transfer of radon from water into indoor air are presented. The new assessments also take into account the expanding use of domestic radionuclide removal units by Finnish households.
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Chen, Qiang, Sheng Zhang, Suoliang Chang, Bo Liu, Jun Liu, and Jianhui Long. "Geophysical Interpretation of a Subsurface Landslide in the Southern Qinshui Basin." Journal of Environmental and Engineering Geophysics 24, no. 3 (September 2019): 433–49. http://dx.doi.org/10.2113/jeeg24.3.433.
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A subsurface landslide is the key problem to a large affordable home program in the southern Qinshui Basin, China. A geophysical survey integrated with seismic refraction tomography (SRT), seismic scattered wave imaging (SSI), and electrical resistivity tomography (ERT) was performed along five profiles over the landslide body. The bedrock surface was a crucial interface, represented by a relatively high velocity, high density, and high resistivity in contrast to the unconsolidated soil and landslide material above it. Based on the most comparable geophysical features, several problems were uncovered such as a “sandwich velocity structure” in the SRT results, velocity trap in the SSI results, and rapid variations in the local topography in all three methods. Aiming to improve the comprehensive interpretation of the ERT, SRT, SSI data, the vertical gradient extremum in the ERT and SRT data and tracing the target wave group according to the velocity sensitivity in the SSI data were analyzed. Moreover, a joint interpretation of the three geophysical survey datasets as well as 32 geological wells and 73 geotechnical boreholes helped to determine one undulating bedrock surface, delineate two types of failure surface geometry (landslide surface and collapse surface), and identify three external shapes in the ex situ body (ancient river channel, landslide body and collapse body). The results showed that the integrated geophysical survey not only provided detailed evidence for the existing of landslide but also presented meaningful evidence for the sliding mechanism. These results were difficult to fully describe and to apply to understanding landslide processes. Furthermore, for near-surface landslide events, the joint interpretation of geologic, geotechnical and geophysical data was necessary to reduce problems with any single geophysical survey.
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Macheret, Yu Ya, A. F. Glazovsky, I. I. Lavrentiev, and I. O. Marchuk. "Distribution of cold and temperate ice in glaciers on the Nordenskiold Land, Spitsbergen, from ground-based radio-echo sounding." Ice and Snow 59, no. 2 (June 11, 2019): 149–66. http://dx.doi.org/10.15356/20766734-2019-2-430.
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Data of ground-based radio-echo sounding of 16 glaciers located on the Nordenskiold Land, Spitsbergen, carried out in springs of 1999, 2007 and 2010–2013, allowed defining five glaciers as of the cold thermal type while other eleven ones were polythermal glaciers. In the last ones (polythermal) the average thickness of the upper layer of cold ice and the bottom layer of temperate ice was equal to 11-66 m and 15-96 m, respectively. The ratio of these thicknesses varies from 0.32 to 2.28, and the volume fraction of temperate ice in the total volume of the glaciers varies from 1 to 74% and changes from 0 to 50% in the ablation zone up to 80% in the accumulation zone. Thickness of cold ice was determined by measured delay time of radar reflections from cold-temperate surface (CTS) while thickness of temperate ice was derived as a difference between the total thickness of the glacier and the thickness of its cold ice. For interpretation of radar reflections from CTS we used the noticeable distinction in character of the radar reflections from the upper and lower thicknesses of glacier: absence of internal reflections (excluding reflections from buried crevasses and glacier wells) from upper cold ice layer and a great number of reflections of hyperbolic form from the lower layer related to strong scattering of radio waves by water inclusions in the temperate ice. According to the measurements, relative power of the radar reflections from CTS is by 5,5–14,2 dB smaller than those from the bedrock, that can be considered as an indicator of smaller water content at CTS; so, the repeated measurements of their relative power can be used for estimation of temporal changes in the water content at these boundaries. In layers of the temperate ice, the series of vertical hyperbolic reflections penetrating the cold ice down to CTS and further to the bedrock were detected. Such reflections are related to buried crevasses and/or the glacier wells and can serve as sources of the water permeating during the melt periods from the glacier surface down to CTS and bedrock and, thus, influencing on the ice viscosity and fluidity as well as on velocity of the bottom sliding in the polythermal glaciers. Repeated measurements of relative power of reflections from buried crevasses and wells can also be used to study processes of freezing them through and emptying during the period before start of the surface melting. Relation between volume of temperate ice and area of 16 studied glaciers was used to estimate the probability of existence of polythermal glaciers with a temperate ice core in all 202 glaciers in the Nordenskiold Land. 72 glaciers with areas exceeding 1.79 km2 may be referred to the polythermal type. The probable total volume of temperate ice in these glaciers amounts roughly to 10 km3, and with the 95% confidence it is within the interval from 8 to 33 km3. Almost 80% of the whole temperate ice may be concentrated in only five glaciers with area more than 17 km2, that makes up 2.5% of the total number of glaciers and about 30% of their total area. Data presented in this paper demonstrate more sophisticated pattern of the cold and temperate ice distribution within the glaciers than it was earlier known that should be taken into consideration when modeling and forecasting dynamics of the polythermal glaciers and investigating internal processes of the temperate ice formation in such glaciers.
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Turtiainen, T. "Radon removal by aeration: observations on testing, installation and maintenance of domestic treatment units." Water Supply 9, no. 4 (October 1, 2009): 469–75. http://dx.doi.org/10.2166/ws.2009.449.
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Radon is one of the contaminants that sometimes impair the water quality of wells, especially those drilled in bedrock. Domestic radon removal units based on aeration have been commercially available for more than ten years. In order to determine how effectively these units remove radon a new test protocol applying frequent sampling while letting 100 litres of water flow, was developed. This way, removal efficiencies can be more accurately calculated and possible malfunctions detected. Seven models of domestic aerators designed for removing radon from household water were tested. The aerators were based on diffused bubble aeration, spray aeration or jet aeration. The average removal efficiencies for 100 litres with a medium flow rate were 86–100% except for a unit that circulated the aerated water back to the well that had removal efficiency of 80% at the maximum. By conducting a questionnaire study usual problems related to the aeration units were localized and recommendations on maintenance and installation are given accordingly.
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Kvitsand, Hanne M. L., and Liv Fiksdal. "Waterborne disease in Norway: emphasizing outbreaks in groundwater systems." Water Science and Technology 61, no. 3 (February 1, 2010): 563–71. http://dx.doi.org/10.2166/wst.2010.863.
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In this study, we compiled and examined available data on waterborne disease outbreaks (1984–2007) in Norway, with emphasis on groundwater systems. A total of 102 waterborne outbreaks and 17 243 disease cases were reported during the period 1984–2007. The proportion of outbreaks related to groundwater reflected the proportion of groundwater works in Norway (40%). The proportion of disease cases corresponded to the proportion of persons supplied by groundwater (15%). Norovirus was identified as the most important disease causing agent in groundwater systems. No clear seasonal correlation was observed for Norovirus outbreaks in groundwater, but the largest outbreaks occurred during winter season. All outbreaks of campylobacteriosis occurred during March to November, with a peak in July–September, which correlates with the occurrence of coliforms in Norwegian groundwater in bedrock wells.
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Maxe, Lena. "Sources of Major Chemical Constituents in Surface Water and Groundwater of Southern Sweden." Hydrology Research 32, no. 2 (April 1, 2001): 115–34. http://dx.doi.org/10.2166/nh.2001.0008.
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The chemistry of groundwater has been altered to a large degree through the influence of human activities. Addition of acids through precipitation and dry deposition, nitrogen from agriculture and sewage systems, and chloride from deicing are quantitatively the most important sources. In this paper the chemical characteristics of groundwater are discussed for a crystalline bedrock area located above the highest marine shoreline in southern Sweden. The aim of the study is to establish the background levels for the main chemical constituents in these waters. Focusing on sulphate and chloride, contributions from deposition are evaluated and a comparison with surface water chemistry is performed. Approximately 50% of the base cations in the lakes with extremely low alkalinity originate directly from deposition, while the corresponding figure for lakes with higher, though still low alkalinity, is approximately 39%, and for shallow wells the figure is 36%. There is evidence that the lakes receive water from a shallower depth than the shallow wells, but both groups receive the base cations mostly from the exchange store, or from weathering where the alkalinity produced is consumed by acid inputs. Deposition levels of sulphate and chloride are better approximated by lake water than by groundwater.
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Valdez, Benjamin, Michael Schorr, and Jose M. Bastidas. "The natural gas industry: equipment, materials, and corrosion." Corrosion Reviews 33, no. 3-4 (July 1, 2015): 175–85. http://dx.doi.org/10.1515/corrrev-2015-0012.
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AbstractCorrosion is a crucial worldwide problem that strongly affects the oil and gas industry. Natural gas (NG) is a source of energy used in industrial, residential, commercial, and electric applications. The abundance of NG in many countries augurs a profitable situation for the vast energy industry. NG is considered friendlier to the environment and has lesser greenhouse gas emissions compared with other fossil fuels. In the last years, shale gas is increasingly exploited in the USA and in Europe, using a hydraulic fracturing (fracking) technique for releasing gas from the bedrock by injection of saline water, acidic chemicals, and sand to the wells. Various critical sectors of the NG industry infrastructure suffer from several types of corrosion: steel casings of production wells and their drilling equipment, gas-conveying pipelines including pumps and valves, plants for regasification of liquefied NG, and municipal networks of NG distribution to the consumers. Practical technologies that minimize or prevent corrosion include selection of corrosion-resistant engineering materials, cathodic protection, use of corrosion inhibitors, and application of external and internal paints, coatings, and linings. Typical cases of corrosion management in the NG industry are presented based on the authors’ experience and knowledge.
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Veeger, Anne I., Daniel P. Murray, O. Don Hermes, Jon C. Boothroyd, and Nasir Hamidzada. "Geographic Information System-Based Digital Catalog for Managing Subsurface Geotechnical and Geologic Data." Transportation Research Record: Journal of the Transportation Research Board 1821, no. 1 (January 2003): 90–96. http://dx.doi.org/10.3141/1821-11.
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Knowledge of surface and subsurface geology and geotechnical properties is fundamental to planning, developing, and modernizing transportation systems. Through dynamic coupling of readily available areal geographic information system coverages and subsurface borehole data stored in a relational database, a spatially referenced digital catalog of borehole data was created for two pilot areas in Rhode Island. The borehole database was populated with data derived from Rhode Island Department of Transportation geotechnical reports and supplemental data from the U.S. Geological Survey groundwater site inventory system and local storm water and sewer projects. Most of these data were previously maintained in paper format, making historical or interproject data comparisons virtually impossible. Unification of these data in a single relational database yields two primary benefits: ( a) historical data are readily accessible for review and therefore can be incorporated easily into the planning stages of new projects and ( b) sophisticated analysis of the region becomes possible with access to data from multiple projects with both spatial and temporal coverage. Geologic data include bedrock geology, surface outcrops, unconsolidated materials, soil type, topographic and orthophotographic base maps, and location of boreholes and wells. Subsurface data include land surface elevation, depth to water table, depth to bedrock, presence of fill, high and low blow-count zones, and organic sediment. The digital catalog is distributed on a CD-ROM that includes ArcView project files and an Access relational database. The borehole data are also accessible through the Internet, with retrieval access for all users and data entry privileges for registered users.
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Zhang, Shuo, Gang Chen, Cheng Hu, and Long Zhang. "Analysis of the Influential Factors of Waterlogging Caused by a Reservoir Impoundment and Evaluation of the Related Solutions." Advanced Materials Research 726-731 (August 2013): 3222–28. http://dx.doi.org/10.4028/www.scientific.net/amr.726-731.3222.
Full textAbstract:
After the impoundment of large reservoirs, the cut-off wall, originally built into the bedrock to cope with the immersion effects, can block the river backwater zone and minimize the risk of the consequential submergence. However, it also hinders the groundwater at the reservoir bank from flowing into the river, resulting in some sort of waterlogging disasters and causing some impact on the crops and buildings alongshore. This paper mainly focuses on the following three factors, i.e. the water table of the backwater zone, the rising height of capillary water and the characteristics of infiltration and evaporation. All of them are the most straightforward factors of the waterlogging of a reservoir. To tackle the issue, the paper has proposed a solution that combines the relief wells and drainage channels on the basis of the numerical simulation methods.
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Metcalf, Meredith J., and Gary A. Robbins. "Domestic well database development and integration into a GIS: an approach for managing ground water resources." Water Supply 13, no. 4 (August 1, 2013): 993–1006. http://dx.doi.org/10.2166/ws.2013.081.
Full textAbstract:
Connecticut is dominated by rural communities which rely upon individual domestic wells in fractured crystalline bedrock for water supply. The individualized nature of ground water usage has made ground water resource planning on a regional or townwide basis non-existent. In recent years there has been increased development and concerns expressed regarding the sustainability of the fractured crystalline rock water supply and its quality, and the need for ground water resource planning. In this study, using a rural quadrangle in eastern Connecticut, we have developed a database system that is tied to a geographic information system that can be used to help manage and assess ground water conditions. The data in the database were derived using available water completion reports and water quality reports. Data query schemes were developed to screen for data entry and reporting errors. The information maintained in the database has been analyzed to derive products on well yield, well depth, and water elevation. These products are beneficial to town planners, local sanitarians, developers, homeowners, and drillers. They can improve and facilitate decision-making concerning future rural development to ensure ground water sustainability.
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Hesselbrandt, Max, Mikael Erlström, Daniel Sopher, and Jose Acuna. "Multidisciplinary Approaches for Assessing a High Temperature Borehole Thermal Energy Storage Facility at Linköping, Sweden." Energies 14, no. 14 (July 20, 2021): 4379. http://dx.doi.org/10.3390/en14144379.
Full textAbstract:
Assessing the optimal placement and design of a large-scale high temperature energy storage system in crystalline bedrock is a challenging task. This study applies and evaluates various methods and strategies for pre-site investigation for a potential high temperature borehole thermal energy storage (HT-BTES) system at Linköping in Sweden. The storage is required to shift approximately 70 GWh of excess heat generated from a waste incineration plant during the summer to the winter season. Ideally, the site for the HT-BTES system should be able to accommodate up to 1400 wells to 300 m depth. The presence of major fracture zones, high groundwater flow, anisotropic thermal properties, and thick Quaternary overburden are all factors that play an important role in the performance of an HT-BTES system. Inadequate input data to the modeling and design increases the risk of unsatisfactory performance, unwanted thermal impact on the surroundings, and suboptimal placement of the HT-BTES system, especially in a complex crystalline bedrock setting. Hence, it is crucial that the subsurface geological conditions and associated thermal properties are suitably characterized as part of pre-investigation work. In this study, we utilize a range of methods for pre-site investigation in the greater Distorp area, in the vicinity of Linköping. Ground geophysical methods, including magnetic and Very Low-Frequency (VLF) measurements, are collected across the study area together with outcrop observations and lab analysis on rock samples. Borehole investigations are conducted, including Thermal Response Test (TRT) and Distributed Thermal Response Test (DTRT) measurements, as well as geophysical wireline logging. Drone-based photogrammetry is also applied to characterize the fracture distribution and orientation in outcrops. In the case of the Distorp site, these methods have proven to give useful information to optimize the placement of the HT-BTES system and to inform design and modeling work. Furthermore, many of the methods applied in the study have proven to require only a fraction of the resources required to drill a single well, and hence, can be considered relatively efficient.