Definition - What does Wellbore Excavation mean?
Wellbore excavation is the process of excavating a borehole beneath the earth's surface for the purpose of extracting natural resources such as oil, gas and water. Wellbores are usually vertical and but if the location of the reserve isn't accessible vertically, directional drilling is utilized to excavate the hole and access the reserve.
Special rigs are used for drilling wells either on land or offshore on oil rig platforms.
Trenchlesspedia explains Wellbore Excavation
Wellbore excavation is carried out using drilling equipment installed on the surface. Durable steel pipes called drill pipes transfer the rotating force to the drill bit which in turn cuts into the rock till the intended reserve is reached. Drill mud is allowed to circulate around the drill string that helps in lubricating the drill bit, carrying the cuttings out of the well bore and stabilizing the wellbore. Casings are used to line the wellbore so that the drilling mud does not contaminate the surrounding soil and also keeps the hole from collapsing and failing.
The drill string is withdrawn at regular intervals during the excavation and the wellbore is lined with casing. Once the drilling process is complete, the tubing for retrieval of the natural resource is installed.