How it works
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 0.5mm. 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 such as those for magnetic susceptibility. Continuous core logging means exactly what it says: a continuous, automated and uninterrupted process.
Recently, Geotek has been supplying more MSCL systems to users with unlined rock cores. To overcome the problems of fractured core, fibreglass boats are used to carry core through the sensors. An extra motor is supplied so the P-wave transducers move against the core to take a measurement and out again as the core moves past the sensors. A third motor is used to move the split core sensor arm, if fitted.
Geotek has also made moving sensor/stationary core systems for specialist applications in the oil industry. Equally, vertical tracking systems (MSCL-V) have been built for samples that must be held upright. Systems that accept multiple sections at once (MSCL-XYZ) can also be produced for certain sensor configurations.
Basic range of sensors available