Drilling is a crucial part of extracting oil and gas from below the surface of the Earth. It allows access to the rocks containing the minerals. In the oil and gas industries, there are different kinds of drilling, including vertical drilling, which is the most common one.
Vertical drilling is sometimes useable interchangeably with the term vertical well. In this post, we’ll cover everything about this particular type of drilling. We’ll talk about its benefits, shortcomings, and how it fares against other techniques in drilling.
What is Vertical Drilling?
Vertical drilling is employable when the minerals are directly below the drilling sites. In simpler words, this type of drilling progresses vertically underground, i.e, at a 90 degrees angle (perpendicular to the surface).
Since the discovery of oil and its extraction in different parts of the world, this type of drilling has been the de facto method of drilling for oil and gas. This technique is used both above and below sea fields.
The well that forms as a result of vertical drilling is a vertical well.
Vertical wells can only extract oil or gas directly below the point where they are dug. They can only access a limited square foot of the area surrounding the borehole.
Vertical drilling also plays an important role in the research phase as engineers often drill vertical wells to analyze rock fragments at different levels. With the help of this analysis, they can determine whether creating an oil well at this particular position will be feasible enough or not. In simpler words, whether the rock underneath can produce ample oil to make the well productive, and ultimately, profitable.
In offshore fields, this drilling is even more common, as its benefits help offset the challenges of drilling under the ocean.
Methods for Vertical Drilling
Vertical drilling mainly describes the direction of the drilling. However, drilling also differentiates based on the technology or method used for drilling.
Therefore, within this type of drilling, these are the four useable methods of drilling:
- Percussion or Cable Drilling
- Rotary Drilling
- Dual-Wall Reverse Circulation Drilling
The percussion drilling method is the oldest, dating back to the time of the first commercial oil wells in the late 1800s. However, rotary drilling was a much better improvement over percussion or cable drilling. It’s still the most commonly used method of drilling for oil and gas wells.
Electro drilling and dual-wall reverse circulation drilling are just extensions of rotary drilling.
Benefits of Vertical Drilling
This type of drilling, by its very nature, is simple. You have to drill in a single direction, and the only challenging consideration is how deep to drill. This allows vertical drilling to be less costly than its counterpart (directional drilling).
It gives direct access to the resources below the drilling point, which means the product can be optimized for that particular point.
For decades, this drilling type was the only technique to drill wells into the Earth for oil and gas production. The technology was relatively simpler than that used for some of the newer techniques of drilling.
Now, automatic vertical drilling technology is also in the works, which can make vertical wells even easier to dig and that too quite deeper.
Shortcomings of Vertical Drilling
Even though the drilling type was the standard for a very long time for oil and gas wells, it does have its drawbacks. The biggest disadvantage of the type of drilling is that it only allows access to a small area (directly beneath the drilling site). It doesn’t reach areas adjacent to that point.
For instance, if the oil reserves are being spread across a larger area, one vertical well will not be enough. Several vertical drillings need to access all that area.
Drilling many vertical wells in the same field can be costly. This essentially makes even this type of drilling a lot expensive when accessing oil or gas sources spread across a field horizontally.
This is why unconventional oil sources like shale oil cannot be reached with just using this drilling technique. This is where directional drilling or horizontal drilling comes in handy.
Since oil resources around the world are depleting fast, vertical drilling just doesn’t cut it anymore, which is why it’s now mainly useable in offshore drilling.
Vertical vs. Horizontal Drilling
In contrast to vertical drilling, horizontal drilling is done parallel to the surface or at an angle nearly parallel to the surface. Horizontal drilling comes under directional drilling where the wellbore is made at an angle that allows access to more area and ultimately yields a bigger pay zone.
It’s important to understand that horizontal drilling also relies on this type of drilling. To drill along the length of the formation, the drilling companies first have to drill vertically. So horizontal drilling isn’t possible without some vertical drilling in the first place.
In comparison, horizontal drilling is more cost-effective. Again, it allows better access to the oil or gas reserves, which are often spread across the rock formation.
In some cases, rock formations cannot be reached with this drilling type. For example, if the depth directly above the formation is hard to drill into or there are other technical difficulties. In such cases, horizontal drilling can be the solution.
Two decades ago, horizontal drilling was just not possible on some sites or just too expensive because of the lack of technology. However, things have changed, and the technology to drill rocks at an angle is very much common. This has resulted in better production in many oil wells that were previously producing below their optimal production levels.
In the US, horizontal wells officially surpassed vertical wells in 2017.
Vertical drilling, although not as common as it used to be, is an important part of the drilling operation. Even for directional drilling or horizontal drilling, the first part is essentially vertical drilling, even if the resultant well is not a vertical well.
Vertical wells have significant shortcomings, which is why the oil and gas industry has moved to horizontal drilling and horizontal wells. In the shale oil industry, vertical wells simply don’t exist as they don’t work with shale rocks.
If you have more question about this type of drilling, reach out to Ranger Land & Minerals here today.