AN ULTRA FAST SCINTILLATOR FOR WELL LOGGING APPLICATIONS

BECAUSE OF THEIR LONG DECAY TIMES, SCINTILLATORS IN NEUTRON LOGGING TOOLS ARE RESPONSIVE PRIMARILY TO THE GAMMA RADIATION FROM THE NEUTRON CAPTURE SPECTUM. THIS INHIBITS POROSITY MEASUREMENTS IN GAS-FILLED ZONES AND SUBSTANTIALLY LIMITS THE ELEMENTAL INFORMATION ON THE STRATA WHICH CAN BE ACQUIRED. ADVANCES IN NEUTRON LOGGING TOOLS REQUIRE A NEW SCINTILLATOR MATERIAL CAPABLE OF MAKING PRECISION MEASUREMENTS IN THE INELASTIC SCATTERING REGIME WHERE ELEMENTAL INFORMATION CAN BE ACQUIRED. A NEW POLYMERIC MATERIAL HAS BEEN FORMULATED WHICH COMBINES AN EXTREMELY FAST DECAY TIME WITH THE HIGH LIGHT YIELDS NORMALLY ASSOCIATED WITH AN INORGANIC SCINTILLATOR MATERIAL. THE RESULT IS A FIGURE OF MERIT THAT IS THREE ORDERS OF MAGNITUDE GREATER FOR SCINTILLATOR APPLICATIONS THAN THE SODIUM IODIDE DETECTORS CURRENTLY EMPLOYED IN LOGGING TOOLS. THIS SHOULD PROVIDE THE CAPABILITY TO DO EXTENSIVE ELEMENTAL ANALYSIS BASED ON INELASTIC SCATTERING GAMMA RADIATION. SPECTROSCOPY AND PHOTOPHYSICS CHARACTERIZATION OF ONE SCINTILLATOR SOLVENT AND FLUOR WILL BE ACCOMPLISHED. THE RESPONSE TO IONIZING RADIATION WILL BE MEASURED. A PROTOTYPE SCINTILLATOR WILL BE FABRICATED AND INTEGRATED WITH A COMMERCIAL NEUTRON LOGGING TOOL. COMPARATIVE PERFORMANCE DATA WILL BE OBTAINED IN THE API NEUTRON LOGGING TEST PIT.