What is a Vertical Well?
A vertical well is a traditional technique used to access underground reserves of oil or natural gas by drilling straight down into the ground. This method has been a standard practice in the oil and gas industry for decades, standing in contrast to the more modern directional drilling techniques being increasingly adopted.
Key Features of Vertical Wells
- Direct Extraction: Vertical wells are specifically designed to extract oil and natural gas reserves directly located beneath the well site.
- Traditional Approach: Historically, vertical wells were the primary method for reaching subterranean resources due to a lack of advanced drilling technologies.
- Continued Relevance: Despite the growing popularity of directional drilling techniques, vertical wells are still used in the oil extraction industry, particularly in offshore drilling operations.
How Vertical Wells Function
The process of creating a vertical well starts with drilling a borehole straight down to access a resource located beneath the surface. The relative simplicity of vertical wells often leads to cost savings in both equipment and labor. This method can also reduce the time taken to exploit available resources. However, inefficiency can arise if the underground reserve stretches horizontally across a wide area, necessitating the drilling of multiple vertical wells for adequate access.
Comparison with Directional Drilling
Directional drilling offers a solution for reaching reserves that are not situated directly beneath a drilling site. It involves drilling down vertically first and then adjusting the angle to drill horizontally or at an inclination, allowing for access to adjacent sections of the reservoir. This technique can result in the extraction of oil from multiple reserves using just a single vertical well, enhancing efficiency.
Vertical Well vs. Horizontal Well
The primary distinction between vertical and horizontal wells lies in their drilling angles. A vertical well is drilled straight downward, while a horizontal well emerges from a vertical borehole, shifting to a drilling angle of at least 80 degrees.
According to industry statistics, horizontal wells surpassed vertical wells in number for the first time in 2017. By the end of 2018, active vertical wells accounted for over 88,000, but they produced significantly less oil compared to horizontal wells, which were responsible for 96% of crude oil production and 97% of natural gas production in U.S. shale plays.
The Role of Vertical Wells in Oil Extraction
As conventional oil sources become scarcer, the reliance on purely vertical wells is diminishing, yet they maintain an essential role in the industry. All directional drilling projects commence with the drilling of a vertical well, which serves as a critical starting point.
Geological Assessments
Engineers frequently employ vertical wells to collect rock samples at varying depths. Through geological analysis of these samples, they can identify potential oil reserves, thereby guiding the subsequent direction of drilling efforts.
Furthermore, the data gathered from these vertical wells can enhance the efficiency of extraction operations. It allows companies to extract resources from multiple distinct underground reservoirs using directional drilling, leading to substantial cost savings while minimizing environmental disruptions from heavy machinery.
Offshore Oil Extraction
Vertical wells are particularly relevant in offshore drilling operations. Given the complexity involved in drilling from offshore platforms, vertical wells are typically favored over directional drilling, which can be more expensive and technically challenging in such environments. The simplicity and effectiveness of vertical wells make them the go-to option in many offshore scenarios.
Conclusion
In summary, vertical wells continue to play a vital role in oil and gas extraction despite the rising prominence of directional drilling. Their straightforward design allows for cost-effective extraction of resources and minimizes surface disruption. As the industry progresses toward tapping into more complex reserves, vertical wells will remain a fundamental component of the oil drilling landscape, particularly in offshore applications and initial exploratory drilling. Understanding the function and significance of vertical wells is crucial for anyone looking to grasp the essential components of energy resource extraction.