Definition - What does Directional Well mean?
A directional well, in the context of horizontal directional drilling (HDD), is defined as a borehole that deviates at an angle from a horizontally straight path. Directional drilling is related to this term and is applied in trenchless technology to guide boreholes in order to avoid passing through other pipelines or underground installations. This process also serves to determine the existence of soil conditions that may not be appropriate for drilling.
Also known as a horizontal directional well in trenchless construction.
Trenchlesspedia explains Directional Well
During the process of drilling, changing the direction of the well is achieved by using a non-rotating drill string which keeps the steering mechanism in place and an asymmetrical leading edge which acts as a steering bias. The asymmetry of the leading edge can be achieved by using a bent motor housing. A jet nozzle is used in soft soils and can be maneuvered using the drill string and by blocking some nozzles. When changing direction, the drill string is rolled so that the bias is directed toward the change in direction.