What is a Wellbore

A wellbore is a hole that is drilled to aid in the exploration and recovery of natural resources including oil, gas or water. A wellbore is the actual hole that forms the well. A wellbore can be encased by materials such as steel and cement, or it may be uncased.


A wellbore provides access to the natural resources that are sought, such as oil and gas. A wellbore is typically a straight vertical shaft that "bores" into the ground to allow the recovery of natural resources. Specialized equipment is needed to drill wellbores.

The following is a diagram of an oil wellbore encased in steel and cement. The wellbore is the actual drilled hole, including the open hole or uncased portion of the well. The drilled hole may refer to the inside diameter of the wellbore wall, the rock face that bounds the drilled hole. The wellbore can then be cased with materials to improve its stability and improve operation and resource recovery.

Wellbore encased in steel and cement