Description

The NGR 200 instrument performs both total and spectral analysis of the natural gamma radiations emitted from recuperated reservoir core samples. The device has the ability to report Potassium (K), Uranium (U) and Thorium (Th) concentrations. The most immediate virtue of the NGR200 is its ability to adjust the estimated original depth of a rock sample or cutting by matching the experimental results to a Gamma Ray log obtained during MWD/LWD (Measurement While Drilling/Logging While Drilling) or wireline logging operations. The apparatus consists of a highly sensitive, strategically placed gamma ray detector, a four meter long linear belt conveyer to displace the core along the detector, and heavy lead shielding to eliminate background gamma radiation. The detector system consists of a shielded scintillation crystal coupled with a photo multiplier. Signals from the detector are processed using a multi-channel spectrum analyzer and a dedicated analytical software. The total gamma ray radiation is reported but more importantly, gamma ray events are energy-sorted and counted over three energy windows K, U and Th. Core samples can be either fully exposed or contained in a barrel. The core is scanned longitudinally from bottom to top, thereby simulating a MWD, LWD or wire-line logging operation. Logging speed is adjustable to suit the nature of the core and data requirements.