This core scanner is a variation of the standard MSCL-S multisensor core scanner with similar parameters and operating principle. The MSCL-NG Dedicated Scanner is a stand-alone natural gamma activity measurement system designed to obtain both absolute and total spectral natural gamma activity. The system can be equipped with four NaI (TI) detectors to obtain high quality spectral data from sedimentary rocks with high resolution.
The sensor comprises two to four 3” x 3” NaI(Tl) detectors housed in 6” diameter lead shields. Each detector uses a NaI(Tl) crystal optically coupled to a photomultiplier tube and a Multi-Channel Analyser (MCA). Each of the detectors has a resolution of 6-8% specified at the 0.662 MeV peak of 137Cs. The data are collected by the MCAs over the energy range 0-3 MeV.
The detectors make measurements over 1024 channels calibrated to correspond to 0-3 MeV energy range. In the full spectral mode the relative elemental yields of K, U and Th can be obtained if a suitable core standard (with known concentrations of K, U and Th) is available. Three check standards are provided for energy calibration of the detectors. These can be used for energy calibration and subsequent collection of stabilised spectra.
The complete system is controlled through custom-designed Geotek MSCL software, which enables either multi-channel spectral measurements or simply total counts to be recorded. The software gives the user full control of sampling positions and intervals down the core and control of count times. All the electronics are supplied in a single integrated 19” rack unit that contains of all the necessary external electronics including the motor control unit, the microprocessor and rack mounted PC.
For the highest quality measurements, the detectors are mounted in purpose-built housings to fit specific core sizes. This helps to eliminate down-core and background gamma noise from entering the data.
Any core collected for a science or engineering application can benefit from the high resolution, continuous, non-destructive core analysis offered by the MSCL. Measurements are used by scientists and engineers both intrinsically, for their actual values, or as proxies for changes in lithology or depositional environment. The MSCL-NG system allows the user to easily compare micro- and macroscale properties of the core and allows solving various geological problems:
- Correlation and binding of core data to logging results;
- Analysis of core heterogeneity;
- Determination of lithology and depth of occurrence of rocks in a well;
- Allocation and assessment of mineral reserves (oil, gas, water, coal, ores, building materials);
- Detection of downhole conditions;
- Control of the development of oil and gas fields.
Geotek MSCL-NG multisensor core scanner parameters:
- System dimensions (LxWxH, cm): 275 x 150 x 150 (depending on the end-user core sizes);
- System weight (kg): 350 (depending on the end-user core sizes);
- Sample parameters: length up to 155 cm, diameter 5-15 cm;
- Sensor movement: fully automated and software controlled (linear accuracy 0.1 mm);
- Data output: ASCII files containing all measured parameters associated with depth;
- Multi-channel analyser: 1024 channels at 0-3 MeV;
- Resolution: detectors (6-8% specified at the 0.662 MeV peak of 137Cs), downcore 10 cm.
Each core section is pushed past the sensors, which scan the core as it passes. The active pushing element is connected to a ball screw, driven by a stepper motor which can position a core to an accuracy of better than 0.1 mm. The computer controlling the stepper motor also controls the sensors, so that all the data are automatically correlated. The computer also measures the length of each core section and can automatically subtract the thickness of the end caps. This allows the sections to follow sequentially, producing an unbroken stream of data. Such a system not only saves time, but by ensuring that the core sections butt up against each other, the data are not corrupted by the air gaps which normally spoil measurements. Continuous core logging means exactly what it says: a continuous, automated and uninterrupted process.
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- General product brochure MSCL-NG