Lines of derricks and pumps like a forest of steel – that was how oilfields looked years ago and there was a simple reason. A well sunk using traditional drilling techniques was more or less a vertical hole. If a borehole struck oil or gas, the drilling engineers had no choice but to sink another well right next to the first one if they wanted to maximise production from the field. So rows and rows of derricks were the result. Deutsche Erdoel´s drilling specialists said farewell to this method of producing oil and gas long ago.
Roads through the interior of the rock
Today, using directional drilling technology, boreholes are drilled following winding routes through underground rock formations and, thanks to this technology which enables bends and straights to be drilled as required, we now reach the precise target formations where hydrocarbons are suspected. From a single drilling rig we can now drill numerous boreholes in different directions and thus develop several fields.
Rotary motion is transmitted from ground level to underground
A drilling technique that is now commonplace has existed for more than a century - rotary drilling. A drill string made up of 9-metre threaded pipes screwed together is rotated at ground level and transmits this rotational motion to the bit. The traditional roller bit drills deeper and deeper by breaking up the bottomhole rock. Heavy drill collars mounted above the bit ensure that the bit drills with the required pressure.
To drill around a bend, engineers previously needed to stop the drill string rotating and drive the bit using a hydraulic motor or a turbine at the bottom of the string. But now, as the drill string can now continue rotating, even in deviated horizontal wells, wells can be drilled at maximum speed irrespective of whether the bit is driving straight ahead or going around a bend.