Horizontal drilling

Directional drilling can reduce oil and gas wells’ surface impacts while also improving production.

Also called horizontal drilling or deviated drilling, directional drilling involves deliberately shifting a well’s path from the vertical. Wells can be deviated until they are running horizontally.

In coal seam gas projects, directional drilling isused to expose more of the reservoir to the wellbore and to exploit naturally occurring fractures – or “cleats” – in the coal seams.

Cleats tend to run in the same direction and directional drilling can be used to align the wellbore so that it runs perpendicular to as many cleats as possible, which improves gas drainage.

Other reasons for directional drilling include:

  • To avoid using a surface site that is operationally difficult or environmentally sensitive
  • Drilling an offshore well from an onshore site
  • Reducing costs or surface impact by drilling several wells in different directions from the one surface location.

To steer the well path, rotary steerable equipment is mounted on the drill pipe just behind the drill bit. These systems can be remotely steered from the surface to redirect the drill bit to deviate the well on any desired path.

Directional drilling can be very precise. Even in wells that are several kilometres deep – many times deeper than CSG wells – the drillhead can be directed to within centimetres of the targets.