We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.
Machinery

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

What is a Drill String?

By Keith Koons
Updated: May 17, 2024
Views: 12,717
Share

A drill string is a tool that is used for boring deep holes into the ground in order to locate and extract oil or other resources. The construction of such a device allows for rapid drilling while simultaneously extracting large amounts of rock and ore from an excavation site. Mud also is injected down through the drill string to help cool the drill bit while it is in motion and to soften the surface that it is boring through, lessening the chances of an improper cut and increasing the overall lifespan of the bit. An average drill string extends 15,000 feet (4,572 m) into the ground when assembled on land and up to 30,000 feet (9,144 m) or more when constructed offshore, so the quality and precision of this instrument are paramount in order to avoid system failure and potentially becoming stuck a great distance below the Earth's surface.

Within the drill string assembly, there are four major components: the bottom hole assembly (BHA), the transition pipe, the drill pipes and the drill stem subs. The BHA is the stabilization system that is made up of the drill bit itself and the massive drill collars that apply tremendous amounts of downward force to assist in the boring operation. A transition pipe connects the drill collars to the actual drill pipe, and together these two components provide the much-needed stability in order to ensure that the drill bit remains sturdy at such drastic depths. Drill pipes also make up the majority of the length within a drill string, so they must be constructed using specific chemical compositions and forged under extreme temperatures. There also are giant braces called drill stem subs that hold the other components together, so they also have to be created with a focus on superior durability and craftsmanship.

Most of the components within a drill string are constructed in intervals of 31 or 46 feet (9.4 or 14 m), and two to four of them are combined to make what is referred to as a stand. Each stand is then lowered into the ground before drilling commences, in order to ensure that the drill always remains within perfect alignment. Likewise, they are removed from the ground before the drill is extracted.

At times, the stands can become stuck and become difficult to remove, and specialized retrieval tools called drill string jars and resonant vibrators are used to rectify this otherwise difficult situation. These methods normally are implemented by experienced laborers from the oil companies. Technological advancements discovered during the middle of the 20th century have made drill strings much easier to manage.

Share
About Mechanics is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
Share
https://www.aboutmechanics.com/what-is-a-drill-string.htm
Copy this link
About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.

About Mechanics, in your inbox

Our latest articles, guides, and more, delivered daily.