Conventional drilling technology produces boreholes that start with a wide diameter and become progressively narrower the deeper they go – like a telescope. This is because at certain intervals, the drill string is pulled back up and casings lowered into the borehole to stabilise it. The result is that we work with a smaller and smaller bit the deeper we go.
Deformable tubes for borehole with constant diameter
To keep the diameter of the borehole as wide as possible (also for subsequent production purposes) we try to expand the casing using special deformable tubes. Immediately after installation, these tubes are expanded by hydraulic pressure using a funnel-shaped cone. The outcome is a so-called monobore construction – a borehole of the same diameter from top to bottom.