LONG FIBER-OPTIC REMOTE SENSOR FOR DETECTION AND IDENTIFICATION OF CHEMICAL SPECIES IN GEOTHERMAL WELLS

A LONG-LENGTH REMOTE SENSOR THAT WILL ACT AS BOTH A GAS SPECIES DETECTION, IDENTIFICATION, AND QUANTIFICATION SYSTEM (GSDIQS), AND A TEMPERATURE MEASURING SYSTEM (TMS) IS BEING DEVELOPED. PARTICULARLY FOR USE IN DOWNHOLE GEOTHERMAL WELL LOGGING, THE GSDIQS USES RAMAN SCATTERING AS THE OPTICAL METHOD TO MEASURE SPECIES SUCH AS CO2 AND H2O VAPOR. PROBLEMS OF FIBER BACKGROUND HAVE BEEN SOLVED THROUGH THE USE OF HOLOGRAPHIC AND DIELECTRIC FILTERS, AND THE USE OF A LASER DIODE SOURCE AND TELECOMMUNICATION FIBER-OPTICS EXTENDS THE SENSOR LENGTHS TO 10 KM. THE TMS USES THE SAME GRADED-INDEX, FIBER-OPTIC, AND DIODE SOURCE, AND USES THE FLUORESCENCE AMPLITUDE DEPENDENCE OF ER-GLASS WITH TEMPERATURE (OR OTHER MATERIAL) AS THE NEAR-IR TEMPERATURE SENSING MECHAISM.