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  • Blackwell Publishing Ltd  (8)
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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 34 (1996), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: It is a general belief that useful estimates of total dissolved solids concentrations of ground water cannot be made from borehole geophysical logs. A case study of estimating total dissolved solids concentration of ground water in the local area using the ratio method yielded estimates with an average error of less than 25 percent. The results do not support the hypothesis that useful estimates of total dissolved solids concentration cannot be made from borehole geophysical logs.The case study included a comparison of estimates of total dissolved solids concentration utilizing a resistivity of the mud input versus using resistivity of the mud filtrate input. Estimates made using resistivity of mud had a correlation coefficient of 0.97 whereas estimates using resistivity of mud filtrate had a correlation coefficient of only 0.27. The results from the case study suggest that at least in some cases the resistivity of the mud (Rm) may produce a better estimate of the resistivity of water (Rw) in the fully flushed zone than an estimate using the resistivity of the mud filtrate Rmf.The ratio method can be easily used to estimate ground-water resistivity and total dissolved solids concentration of the formation water based only on data from resistivity logs. The advantage of the method is that data on porosity, cementation exponent, temperature, and volume of clay are not required. The method, which has been used by the oil industry to crudely estimate water resistivity, is based in part on the ratio of the resistivity of a fully water-saturated formation to the resistivity of the fully flushed zone adjacent to the annulus in a mud-filled borehole. The method, which is very robust, requires only an estimate of the resistivity of a fully water-saturated formation from a deep looking induction or resistivity log, an estimate of the resistivity of the fully flushed zone from a microresistivity or short normal log, and a measurement of resistivity of the mud or mud filtrate and its temperature.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    ISSN: 1745-6592
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: Borehole-geophysical logs can be used to estimate geohydrologic properties based on in situ measurement of rock and water properties. Estimates of properties of both formation and water, such as coefficient of diffusion, formation factor, cementation exponent, hydraulic conductivity, irreducible water content and specific yield can be assessed from borehole-geophysical data and selected algorithms and graphs.Water properties, such as resistivity, sodium chloride concentration, viscosity and density, can also be estimated using data from borehole-geophysical logs. Water resistivity using the spontaneous-potential method can be estimated if an empirical correction for fresh water is applied.Estimates of formation properties, such as porosity and permeability, can also be made using borehole-geophysical data.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 7 (1969), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: A well-designed and calibrated orifice meter is an accurate and inexpensive measuring device for flow. Endline orifices can be calibrated at work sites by solving an equation that interrelates easily measured dimensions of the orifice and outflow.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 6 (1968), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: An aquifer test and analyses of water samples, showed that the anomalous water quality of a municipal well was caused by leakage from a nearby abandoned well tapping another aquifer.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 33 (1995), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: A research borehole-geophysical logging program was implemented to assess specific yield, aquifer mineralogy, and water resistivity more accurately and economically than can be done using conventional aquifer testing and coring procedures. The logging program was part of the Ground-Water Research Project for Abu Dhabi Emirate.A method of determining specific yield using data from a thermal decay-time (TDT) log was developed and tested. This technique relates the capture cross section of the fluid in the invaded zone to specific yield. A second new method uses data from density and neutron logs in a program “LOGAN2” to determine specific yield. Results from both methods were compared to the specific yield derived from the neutron log as well as a specific yield determined by a complex analysis of data from a set of research borehole-geophysical logs, including a gamma-gamma log for density, neutron, sonic, gamma-ray, induction, microresistivity, photoelectric, caliper, and spontaneous-potential logs. The agreement was good.A method of computer-assisted interpretation of mineralogy was developed by correlating results of direct examination of the mineralogy of sidewall cores with data from a nuclear activated spectral-gamma log (GLT). The GLT log allows the mineralogy to be assessed in a comprehensive manner. These computer interpreted results were used to develop another method of computer-assisted interpretation of holes logged not using the GLT. The second method was applied to the more than 50 other test holes that did not include GLT and TDT logs.Resistivity of the water in the formation was conceptualized using a dual-water model, which is especially suited for clayey aquifers. Water resistivities were calculated by two methods—first using data from the suite of logs without the GLT and again using the data from the research suite of logs, which included the GLT. The agreement of calculated water resistivities was excellent
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 19 (1981), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: The major water-bearing units in the Houston district are the Chicot and Evangeline aquifer systems. Both systems consist of discontinuous layers of unconsolidated sand (aquifers) separated by clay layers.Extensive pumping has caused large declines of potentiometric surfaces in and around Houston. The declines have caused both the compaction of clay layers, which has resulted in land-surface subsidence, and the movement of salt water towards Houston.During the early 1960's, an electric analog model of the district was made. The model simulated water-level declines; but more importantly, the model indicated that the available data and conceptual model of the hydrologic system, consisting of two aquifers, were not totally adequate to allow simulation of the ground-water systems.During the early 1970's, a second electric analog was built. The second model used new data and a conceptual model consisting of two aquifer systems simulated water-level declines quite accurately, but the model was unable to accurately simulate the spatial distribution of water yielded from clay storage.A digital model was then developed during 1979 to simulate the hydrology of the district. The digital model used five layers and accurately simulated the hydraulic heads in both aquifer systems and land-surface subsidence.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1745-6592
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : The Dakota aquifer, composed of the Dakota Sandstone and stratigraphically equivalent sandstone units of Cretaceous age, is the upper-most regional aquifer underlying the extensively developed High Plains aquifer of the midwestern United States. The concentration of dissolved solids in ground water of the Dakota aquifer ranges from less than 500 milligrams per liter in calcium bicarbonate type water in the eastern outcrop area to more than 100,000 milligrams per liter in sodium chloride type oilfield brine in the Denver Basin to the west. Preliminary maps showing the distribution of dissolved solids confirm the complex nature of the Dakota aquifer as inferred from stratigraphic and hydraulic evidence. Extensive vertical leakage through confining layers, local recharge at the truncated eastern boundary, and a barrier to recharge along the western edge of the Denver Basin are consistent with the distribution of hydraulic head and dissolved solids.
    Type of Medium: Electronic Resource
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