Directional drilling is a specialised technique used to create boreholes that deviate from a vertical path. It’s a versatile and essential tool in a variety of industries, including:
- Oil and gas exploration and production
- Pipeline installation for water, sewer, and utilities
- Telecommunications cable installation
- Environmental remediation
- Civil engineering projects
There are several advantages to using directional drilling over traditional vertical drilling methods. Here are a few key benefits:
- Reduced surface disruption: Directional drilling allows you to drill beneath existing infrastructure, such as roads, buildings, and rivers, minimising the need for excavation and environmental impact.
- Reaches inaccessible locations: Directional drilling can be used to reach targets that would be difficult or impossible to reach with vertical drilling, such as those beneath buildings or in environmentally sensitive areas.
- Increased accuracy: Directional drilling allows for highly precise placement of boreholes, which is essential for many applications, such as installing pipelines and utilities.
How Directional Drilling Works
The basic process of directional drilling involves the following steps:
- Planning: The first step is to carefully plan the drilling path. This involves considering the target location, any obstacles that need to be avoided, and the geological conditions of the ground.
- Pilot hole: A small diameter pilot hole is drilled along the planned path. This hole is typically guided by a downhole navigation system that uses sensors to track the drill bit’s location and inclination.
- Reaming: Once the pilot hole is complete, the borehole is widened to the required diameter using a process called reaming. This may involve multiple passes with progressively larger drilling tools.
- Completion: Once the borehole is at the desired size, it can be completed with casing, pipeline, or other necessary elements.
Different Types of Directional Drilling Techniques
There are several different directional drilling techniques available, each with its own advantages and limitations. Some of the most common methods include:
- Rotary steerable drilling: This method uses a downhole tool that can be rotated to control the direction of the drill bit.
- Mud motor drilling: This method uses a downhole mud motor powered by drilling fluid to rotate the drill bit.
- Horizontal directional drilling (HDD): This is a specific type of directional drilling used to create horizontal or near-horizontal boreholes.
