TRACER TEST ANALYSIS FOR CHARACTERIZATION OF LAUGALAND GEOTHERMAL FIELD
This paper presents the tracer data analysis obtained from the single-phase, conservative tracer experiments conducted during a two-year reinjection project at Laugaland geothermal field in N. Iceland. Three tracer tests were conducted during the two-year period (1997-1999). The tracers injected were sodium fluorescein in Test 1 and Test 3 and potassium iodide in Test 2. We concentrated on Test 1 only, the reasons for which are explained in the paper. Axelsson et al. (2000; 2001) have conducted a comprehensive analysis of the Laugaland reinjection project tracer test data, including both qualitative and quantitative aspects using multi-flow-channel models. In this study, we focus only on the quantitative analysis of tracer test data using analytical interpretation methods . It has been proved extensively that the first temporal moment analysis leads to an estimation of the tracer swept pore volume in a closed boundary with a balanced injection/production rate scenario. But in this paper, we prove that the first temporal moment does give the swept pore volume, even for open boundaries with an unbalanced rate scenario such as existed at the Laugaland geothermal field. The produced tracer concentration history was used to estimate the interwell reservoir relative flow capacity versus storage capacity (F-C plot). The F-C plot is a simple and powerful semi-quantitative tool to evaluate the conceptual model’s relative flow and storage geometries. The relative flow and storage capacities calculated from the flow channel geometry obtained from multi-flow-channel modeling (Axelsson et al. 2001) for one production well LN-12 agreed well with the continuous F-C plot obtained from the tracer return data. The second temporal moment of tracer production history was used to derive an equivalent dispersion coefficient. The reservoir interwell heterogeneity was characterized using the Lorenz coefficient derived from the F-C plot. The Lorenz coefficient for well pair LJ-08/LN-12 was 0.509, indicating that it is moderately heterogenous. Reservoir information was obtained for interwell LJ-08/LN-12 and, to some extent, LJ-08/TN-04. The tracer data for other wells could not be analyzed, since the streamlines were not constant, and deconvolution techniques need to be developed to do meaningful interpretation. Recommendations for possible future Laugaland reservoir modeling are offered in order to obtain a better description of the reservoir.
Demonstration of improved energy extraction from a fractured geothermal reservoir : final report for Thermie Project GE-0060/96
Hofundar: Guðni Axelsson, Arnar Hjartarson, Steinunn Hauksdottir, Olafur G. Flovens, Guðrun Sverrisdottir, Franz Arnason, Magnus Finnsson, Arni Arnason og Reynir Boðvarsson.
Endodontic regeneration: hard shell, soft core
A loss of organs or the destruction of tissue leaves wounds to which organisms and living things react differently. Their response depends on the extent of damage, the functional impairment and the biological potential of the organism. Some can completely regenerate lost body parts or tissues, whereas others react by forming scars in the sense of a tissue repair. Overall, the regenerative capacities of the human body are limited and only a few tissues are fully restored when injured. Dental tissues may suffer severe damage due to various influences such as caries or trauma; however, dental care aims at preserving unharmed structures and, thus, the functionality of the teeth. The dentin–pulp complex, a vital compound tissue that is enclosed by enamel, holds many important functions and is particularly worth protecting. It reacts physiologically to deleterious impacts with an interplay of regenerative and reparative processes to ensure its functionality and facilitate healing. While there were initially no biological treatment options available for the irreversible destruction of dentin or pulp, many promising approaches for endodontic regeneration based on the principles of tissue engineering have been developed in recent years. This review describes the regenerative and reparative processes of the dentin–pulp complex as well as the morphological criteria of possible healing results. Furthermore, it summarizes the current knowledge on tissue engineering of dentin and pulp, and potential future developments in this thriving field.