Directional drilling is a technique used to drill non-vertical wells that can be used in a variety of industries such as oil and gas, mining, and civil engineering.
Techniques of Directional Drilling:
Here are the two techniques of directional drilling:
Horizontal directional drilling:
HDD is a specialized drilling technique that allows for the construction of underground infrastructure without significant surface disruption. Horizontal directional drilling is commonly used to install pipelines, electrical cables, and other types of infrastructure that need to cross waterways, roads, and other sensitive areas.
HDD involves the use of a drilling rig that can steer the drill bit horizontally through the ground while monitoring its location and orientation. The process begins with the drilling of a pilot hole, which is typically smaller in diameter than the final product pipe. The pilot hole is drilled along the path that the pipeline or cable will follow.
Once the pilot hole has been drilled, a reamer is used to enlarge the hole to the desired diameter. The reamer is attached to the drill string and pulled back through the pilot hole, enlarging it as it goes. The final step is to pull the pipeline or cable through the hole using a pullback process.
HDD has a number of advantages over traditional open-cut methods of infrastructure installation. These include:
- Reduced surface disruption: HDD requires a smaller work area and is less disruptive to the surface environment, making it a good option for sensitive areas.
- Minimal environmental impact: HDD is a low-impact method of infrastructure installation that reduces soil and groundwater disturbance, as well as limiting noise and air pollution.
- Reduced construction time: HDD is faster than traditional open-cut methods of infrastructure installation, allowing for quicker project completion times.
- Improved safety: HDD is safer for workers as it eliminates the need for deep excavations and trenching.
Vertical Directional Drilling:
Vertical directional drilling (VDD), also known as extended reach drilling, is a technique used to drill wells that are at an angle or that curve in a particular direction. This method is often used in the oil and gas industry to access reserves that are not accessible through conventional vertical drilling.
The process of VDD is similar to that of horizontal directional drilling, but with a focus on creating a wellbore that deviates from the vertical axis. The process begins by drilling a vertical section of the well, followed by a curved section that gradually deviates from the vertical axis, and then a horizontal section that extends through the targeted hydrocarbon reservoir.
VDD involves the use of specialized equipment and advanced technologies, including measurement while drilling (MWD) and logging while drilling (LWD) tools, that allow for real-time monitoring and control of the drilling process. MWD and LWD tools help the driller to determine the location, orientation, and geological properties of the rock formations being drilled, allowing for precise steering of the wellbore.
The benefits of VDD include:
- Improved access to reserves: VDD allows for access to reserves that are not easily accessible through traditional vertical drilling, thereby increasing the amount of recoverable oil and gas.
- Reduced environmental impact: VDD reduces the environmental impact of drilling by requiring fewer wells and less surface disturbance.
- Reduced surface footprint: VDD reduces the surface footprint of drilling operations, making it easier to conduct drilling activities in sensitive areas.
- Increased safety: VDD is safer for workers as it reduces the need for multiple drilling sites and allows for greater control over the drilling process.
The following are some situations where directional drilling might be necessary:
Accessing hard-to-reach locations:
Directional drilling can be used to access locations that are difficult to reach with traditional vertical drilling techniques. This could include drilling under rivers, highways, or other sensitive areas where the environmental impact needs to be minimized.
Reducing surface disturbance:
In some cases, surface disturbance needs to be minimized, such as in urban or residential areas where construction activities can be disruptive to the local community. Directional drilling can be used to drill wells without causing extensive surface damage.
Directional drilling can be used to improve productivity by drilling multiple wells from a single location. This technique is often used in oil and gas production to extract oil and gas from reservoirs that are difficult to access using traditional vertical drilling techniques.
In resource exploration, directional drilling can be used to access resources that are located beneath the surface of the earth. This could include minerals or geothermal energy sources.
Directional drilling can also be used for well abandonment by drilling a second well from the surface to intersect the original wellbore at a predetermined depth. This allows for the placement of a plug to isolate the abandoned well from the surrounding environment.