What Is Directional Drilling?

Directional drilling is a technique used by oil-extraction companies in order to access oil in underground reserves. Most oil wells are positioned above the targeted reservoir, so accessing them involves drilling vertically from the surface through to the well below. However, directional drilling is different because it involves drilling at a non-vertical angle, including horizontally.

The main benefit of directional drilling is that it enables companies to exploit multiple oil reservoirs with a single well, thereby reducing the total cost of drilling while also limiting the environmental impact of drilling.

Key Takeaways

  • Directional drilling is the practice of accessing an underground oil or gas reserve by drilling in a non-vertical direction.
  • Directional drilling increases the efficiency of oil and gas extraction, and can also lessen the environmental impact of drilling.
  • Although directional drilling has been used since the 1920s, modern technological improvements to the technique have increased its accuracy and safety.

How Directional Drilling Works

Directional drilling can be especially useful in situations where the underground reservoir has an abnormal shape and vertical entry is considered impractical. Directional drilling may be preferable compared to vertical entry due to concerns expressed by residents living near the surface drill sites. By limiting the number of surface wells used, directional drilling can make the oil extraction process less disruptive to other stakeholders.

Because directional drilling can permit a single well site to be used to access multiple underground reservoirs, it can enable oil companies to explore smaller and less-proven reserves that would otherwise not be economical to access. In addition to allowing companies to access reserves that might otherwise be inaccessible, directional drilling can also contribute to site safety. By creating boreholes far in advance of the mine face in question, directional drilling can allow companies to reduce the risk of gas ruptures while developing a new well.

On the other hand, directional drilling can make operating wells more complex, particularly if the well is dug at an inclination of 40 degrees or greater.

The practice of directional drilling has been used throughout the oil and gas industry since the 1920s. In its early years, directional drilling involved using the same basic equipment as vertical wells, except the drilling itself was done at a non-vertical angle. Modern directional drilling techniques have refined this process by using drill bits that can bend to better accommodate non-vertical angles. Additional technologies, such as the use of hydraulic jets that adjust and guide the drill direction, have further improved the efficiency and reliability of this process.

Today, drill operators can use computers to adjust the angle of the drill bit in real-time, and can even use GPS signals to pinpoint the exact location of an oil and gas field. Using advanced software programs, engineers can create 3-D models of the oil fields to determine the optimal location for the well, as well as the best possible entry point on which to focus directional drilling.