What Is a Vertical Well?
Let me tell you directly: a vertical well is a method for tapping into underground oil or natural gas reserves by drilling straight down into the earth. This is the classic approach to oil extraction, unlike the newer directional drilling techniques.
Key Takeaways
- Vertical wells pull oil and natural gas from reserves right under the well site.
- They've become less popular lately because directional drilling is taking over.
- That said, vertical wells are still in use in the industry, especially as the main method for offshore platforms.
How Vertical Wells Work
Here's how it operates: you aim the borehole straight down from the surface into the reserve below. Back in the day, this was the only option since directional drilling wasn't around yet.
The big advantage is its straightforwardness, which saves on equipment, labor, and time to get the reserves out. But it can be inefficient sometimes. For example, if the reserve spreads out horizontally over a large area, you'd need several vertical wells to reach it all effectively.
In those cases, directional drilling makes more sense— you start with a vertical well into the reservoir, then angle it horizontally to cover more ground. That way, one well can drain the whole reserve.
Vertical Well vs. Horizontal Well
As the name suggests, horizontal wells are drilled sideways. They branch off from a vertical borehole and are considered horizontal if they're at least 80 degrees from vertical.
Horizontal wells overtook vertical ones in number for the first time in 2017. By the end of 2018, there were still over 88,000 active vertical wells, but their production lagged far behind horizontal ones. In U.S. shale plays, horizontal drilling accounted for 96% of crude oil and 97% of natural gas production at that time.
Example of Vertical Wells
With conventional oil sources drying up and easy reserves getting scarcer, purely vertical wells are rarer these days. Still, they're vital because every directional drilling project kicks off with a vertical well.
Engineers often use vertical wells to check rock samples at various depths. By studying these, they figure out where the oil is, guiding the drilling direction.
Sometimes, those samples help companies pull oil from several different reserves using directional methods from one vertical well. This setup cuts costs over the project's life and minimizes surface disruption with less equipment and people on site.
Vertical wells also remain key in offshore extraction. Out at sea, drilling from a platform is complicated enough, and while directional drilling is possible, it's usually too costly to bother with.
