What Is Directional Drilling?

Directional drilling is a technique used by oil-extraction companies in order to access oil in underground reserves. Directional drilling is also called directional boring. 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. (Directional drilling is used to describe any drilling that doesn't go straight down.)

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 is also called directional boring.
  • 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.
  • The main benefit of directional drilling is that it enables companies to exploit multiple oil reservoirs with a single well.

Understanding Directional Drilling

The practice of directional drilling has been used since the 1920s throughout the oil and gas industry. 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 for directional drilling.

Directional drilling is also used in the installation of utility pipelines and conduits.

Furthermore, directional drilling can be much more cost-effective. Oil rigs and their staff sometimes have day rates that are upwards of hundreds of thousands of dollars. With directional drilling, one rig alone may be able to work up to five or ten square miles (compared to having a dozen or more vertical rigs).

Advantages and Disadvantages of Directional Drilling

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 also be preferable if there have been concerns expressed by residents living near the surface drill sites.

By limiting the number of surface wells used, directional drilling reduces soil disturbance and can make the oil extraction process less disruptive to nearby residents and other stakeholders in the vicinity. By reducing the fractures to existing rock formations, directional drilling also reduces the contamination of groundwater pollution, further protecting the ecosystem and adjacent areas.

Because directional drilling can permit a single location 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. Depending on the location, directional drilling can produce greater amounts of oil and gas.

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. In addition, as with all construction equipment, directional drilling damages the existing ground (although the impact can be minimized). Many directional drilling rigs are very heavy, run on tracks, and tend to damage the areas where they traverse and travel.

Pros of Directional Drilling
  • Reduces soil disturbance

  • Makes the oil extraction process less disruptive to nearby residents and other stakeholders in the vicinity

  • Reduces the fractures to existing rock formations

  • Reduces the contamination of groundwater pollution

  • Protects the ecosystem and adjacent areas

  • Contributes to site safety by reducing the risk of gas ruptures while developing a new well

Cons of Directional Drilling
  • Can make operating wells more complex

  • As with all construction equipment, directional drilling damages the existing ground (although the impact can be minimized)

Directional Drilling FAQs

How Far Can Directional Drilling Go?

The maximum length and diameter of directional drilling are determined by the specific site where the drilling is taking place. However, some horizontal drilling rigs have an outside range of up to 9,843 feet.

How Much Does Directional Drilling Cost?

The cost of directional drilling varies depending on the project. Projects may be priced based on a lump sum, or they may be priced per foot.

There are many different factors that contribute to the cost of directional drilling, including the soil conditions, the length and depth of bore, and the location of the job site.