Qrtzgeotherm: An ActiveX component for the quartz solubility geothermometer
2008; Elsevier BV; Volume: 34; Issue: 12 Linguagem: Inglês
10.1016/j.cageo.2008.01.008
ISSN1873-7803
Autores Tópico(s)Phase Equilibria and Thermodynamics
ResumoAn ActiveX component, QrtzGeotherm, to calculate temperature and vapor fraction in a geothermal reservoir using quartz solubility geothermometry was written in Visual Basic 6.0. Four quartz solubility equations along the liquid-vapor saturation curve: (i) a quadratic equation of 1/T and pressure, (ii) a linear equation relating logSiO2 to the inverse of absolute temperature (T), (iii) a polynomial of T including logarithmic terms and (iv) temperature as a polynomial of SiO2 including logarithmic terms are programmed. The QrtzGeotherm has input parameters: (i) HRes-the reservoir enthalpy (kJ/kg), (ii) SiO2TD-silica concentration in total discharge (ppm), (iii) GeoEq-number of quartz solubility equation and (iv) TempGuess-a guess value of the reservoir temperature (^oC). The reservoir enthalpy Hres is assumed to be the same as the total discharge enthalpy HR. The output parameters are (i) TempRes-reservoir temperature (^oC) and (ii) VapRes-reservoir vapor fraction. The first step is to calculate the total discharge concentration of silica SiO2TD from the concentration of silica SiO2Col of separated water, sampled after N-separations of vapor and water. To use QrtzGeotherm in MS-Excel, three functions SiO2TD, GeoResTemp and GeoResVap for an N-stage separation of geothermal reservoir fluid are written in Visual Basic for Application (VBA). Similarly, a demonstration program, QrtzGeothrm, is written in Visual Basic 6.0.
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