Core Gamma Logger
Information about cored formations can quickly be revealed by measuring naturally emitted gamma ray radiation from the recovered core at well-site.
This can easily be achieved with our core gamma logging service. ALS core gamma logging unit is a hand held source-less spectral device which records Uranium, Thorium, Potassium and Total gamma radiation counts emitted from recovered cores.
To gamma log a core, the inner barrel is typically laid in a horizontal position while still in its core laydown cradle to maintain core integrity. The operator will then mark depth intervals, typically 1 ft or 1 meter apart on the inner barrel. The wellsite geologist will specify the distance at which gamma readings will take place (e.g. every foot, every 10cm etc.) The operator will then mark up the inner tube at the desired intervals. The inner barrel is now ready for logging.
The core gamma logging tool will take radiation readings at each of the desired depth intervals for 10 seconds. In the presence of steel inner tubes, a longer sampling time is required.
Following the logging operation, the gamma ray counts and their respective depth readings are processed on a portable computer. This data is then used to plot and print a finished graph of gamma ray counts versus depth, similar to those produced by core logging companies. Clear trends can be seen between sandstone and claystone. The Core Gamma unit distinguishes any sand, shale and clay intervals in the core sample. It can be subsequently used to cross reference with wireline logs upon completion of the drilled section.