Small Diameter Natural Gamma Well Logging Tool Based on Position Sensitive Detector

Abstract

Summary With hydrocarbon exploration shifting to thin-bedded strata, the measurement of thin beds becomes a challenge faced by the well-logging industry. We propose to replace conventional detectors with position sensitive detectors(PSD), which is available for recording the position of particle enters crystal. By its property of recording position and energy, the whole section of the detector is considered as a multi-section short detector instead of the traditional multi-detector scheme to achieve and increase the vertical resolution of the logging instrument. In simulation, tool with PSD has a higher count than the traditional tool. And it is capable of identifying thin beds of 5cm, while the traditional tool is not. Our experiments also proved that, the tool with a PSD has a better vertical resolution than the traditional tool. It is worth noting that the PSD proposed in this work not only is limited to be used in natural gamma logging tools but may also be a promising detector candidate in other nuclear well-logging tools that measure gamma-ray flux and even energy spectrum.