The upper continental crust, an aquifer and its fluid: hydaulic and chemical data from 4 km depth in fractured crystalline basement rocks at the KTB test site
Tóm tắt
Detailed information on the hydrogeologic and hydraulic properties of the deeper parts of the upper continental crust is scarce. The pilot hole of the deep research drillhole (KTB) in crystalline basement of central Germany provided access to the crust for an exceptional pumping experiment of 1‐year duration. The hydraulic properties of fractured crystalline rocks at 4 km depth were derived from the well test and a total of 23100 m3 of saline fluid was pumped from the crustal reservoir. The experiment shows that the water‐saturated fracture pore space of the brittle upper crust is highly connected, hence, the continental upper crust is an aquifer. The pressure–time data from the well tests showed three distinct flow periods: the first period relates to wellbore storage and skin effects, the second flow period shows the typical characteristics of the homogeneous isotropic basement rock aquifer and the third flow period relates to the influence of a distant hydraulic border, probably an effect of the Franconian lineament, a steep dipping major thrust fault known from surface geology. The data analysis provided a transmissivity of the pumped aquifer
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Tài liệu tham khảo
Boonstra J, 1989, SATEM: Selected Aquifer Test Evaluation Methods, a Microcomputer Program, 80
Emmermann R, 1995, KTB Hauptbohrung Results of Geoscientific Investigation in the KTB Field Laborarory, Final Report: 0‐9101 m
Frape SK, 1987, Saline Water and Gases in Crystalline Rocks, 19
Frape SK, 2004, Surface and Ground Water, Weathering, and Soils, 541
Gale J, 1987, Hydrogeological Characterization of the Stripa Site, 126
Horner DR, 1951, Pressure build‐up in wells, Engineer Journal Bulletin, 3, 503
Ingebritsen SE, 1998, Groundwater in Geologic Processes
Krusemann GP, 1991, Analysis and Evaluation of Pumping Test Data, 377
Miller CC, 1950, The estimation of permeability and reservoir pressure from bottom hole pressure builtup characteristics, Petroleum Transactions AIME, 189, 91
Nagra, 2002, Projekt Opalinuston, Synthese der geowissenschaftlichen Untersuchungsergebnisse, 659
Parkhurst DL, 1980, PHREEQE – A Computer Program for Geochemical Calculations, 210
Patzak M, 1991, Die Metabasite der KTB‐Vorbohrung, Oberpfalz (NE‐Bayern), 103
Stober I, 1986, Strömungsverhalten in Festgesteinsaquiferen mit Hilfe von Pump‐ und Injektionsversuchen, Geologisches Jahrbuch, 42, 204