Statistical Interpretation Of Chemical Results From Drillholes As An Aid To Geothermal Prospecting And Exploitation

Jump to: navigation, search


OpenEI Reference LibraryAdd to library

Journal Article: Statistical Interpretation Of Chemical Results From Drillholes As An Aid To Geothermal Prospecting And Exploitation

Abstract
In prospecting a geothermal field, it will be necessary to allow a number of wells to discharge freely to test the potential of the field. It is suggested that determinations of the concentrations of chloride and silica on water separated from the discharge at atmospheric pressure can be used to give information about the uniformity of the underground water. For this purpose, E/639-E) (E, enthalpy, in cal/g) should be plotted against chloride concentration, on paper with lines showing the effects on enthalpy and chloride of loss of steam, dilution, and loss of heat by conduction. Samples of steam for gas content have to be taken at high pressure, e.g. 12-17 kg/cm2, and calculations by computer are suggested to find the contents of gaseous constituents at an average pressure of, say, 14 kg/cm2 (gauge). The adjusted values would then be plotted against E/(E-201), again with a grid of lines to show the effects of loss of steam in various ways from the underground water. When production wells are delivering separated steam to a steam line to the power station, samples of water separated at atmospheric pressure will continue to be analysed to give information on changes in the underground water supplies to the drillholes. The author has published work to show that statistical studies with computer calculation, of changes of chloride with time for groups of wells, can give average yearly changes of enthalpy, which, from calculations of standard error, are much more accurate than changes found from direct enthalpy determinations, and also give indications of the reasons for the changes. Further programmes of computer calculations are suggested for use on determinations of silica, Na/K ratios, CO2 content to indicate average yearly changes of temperature, enthalpy or steam loss, and also to give average ratios of chloride to bicarbonate or pH values.

Author 
S. H. Wilson








Published Journal 
Geothermics, 1970





DOI 
10.1016/0375-6505(70)90450-5


 

Citation

S. H. Wilson. 1970. Statistical Interpretation Of Chemical Results From Drillholes As An Aid To Geothermal Prospecting And Exploitation. Geothermics. (!) .