Coreliners are rigid, transparent PVC tubes with a wall thickness of approximately 1 mm, that fit snugly inside the core barrel inner tube.
Coreliner was introduced into the UK in 1986 to provide a much improved handling system for rapid extrusion of sticky, broken and soft formation cores. Since then, the advantages of reduced handling time and improved presentation has made the Coreliner system an industry standard in exploration drilling.
Coreliners can be supplied to fit most types and sizes of core barrel – metric, DCDMA and wireline. It is normally supplied in standard 10ft lengths, with or without plastic end caps. After sliding the coreliner tube into the inner tube it is trimmed to length with a hacksaw to allow a small gap between its lower end and the lifter case.
In T series core barrels, the coreliner tube is extracted by removing the core bit and extension tube. The core-filled liner can then be simply pulled out by hand. In WF series core barrels, a special inner tube can be supplied with two slots milled across its lower end. This enables the core-filled liner to be gripped with pliers and pulled straight out.
To use the coreliner system a modified Core Bit and Corelifter is required with reduced internal diameter (see Table for details). This is to ensure that there is adequate clearance for the core to fit into the plastic coreliner tube. Such “coreliner set” bits and corelifters are available on request.
|Core Barrel Designation||Standard I.D. of Core Bit(mm)||Reduced I.D. of Mylar Bit (mm)|
|TT T2 T6 & W/L series||see data tables||3 mm smaller than standard|