What is a Drill Pipe?
A significant part of oil and gas drill pipes are designed to withstand high pressure - both internal and external. This type of piping can tolerate high bending and torsional stress despite being hollow.
Drill pipes are typically used to extract oil, gas, water, and other natural resources. For these operations, the pipes are often exposed to subterranean conditions. To withstand challenging environments, drilling companies use seamless, accident-resistant, and durable pipes in their operations.
Drilling operations rely on the rotation of the drill bit to extract raw resources from the earth's crust. To facilitate this movement, a drill pipe circulates valuable fluid in the well while also enabling the rotation. Simply put, once the drill bit carves into the well, it is the responsibility of the hollow drill pipe to begin the pumping/circulation process.
These pieces are connected to the drill string, composing almost 95% of the whole length. Because of these factors, drill pipes have to be checked regularly for defects and wear.
Drill Pipe Details
Drill pipes are hollow, high-resistance tubular primarily used in oil and gas. Aluminum and steel are the preferred materials because they create compact (thin-walled) yet durable products. These pipes are used in drilling rigs to pump drilling fluid from reserves back up the annulus.
Drill pipes are generally used to extract crude oil and natural gas. However, they may also be applied in less complex borewells such as water wells. In rigs, these pipes help circulate drill fluid to wells by facilitating a continuous rotation of the drill bit. However, by having a higher rate of
Drill Pipe Thickness
To avoid wear, a drill pipe will have specific thicknesses on its pin end and box end. The side meeting the drill collar is generally the strongest and most durable section. The area around the drill bit is the thickest, as this section faces the most internal and external resistance. In comparison, the part around the box end tends to be thinner. Additionally, drill pipes may also be used as a conduit when joining or adding downhole tools to the existing setup.
The OD for most drill pipes is also similar, averaging around 114 mm or 4.5 inches. However, different thicknesses are also not uncommon, and the following size drill pipes are readily available
- 2 ⅜ inch thick drill pipe
- 5 inch thick drill pipe
- 6 ⅝ inch drill pipe.
Additionally, drill pipes of varying thicknesses are used in a drill string. For example, the pieces in the upper sections are different from the HWDP pipes connecting the drill collars and the regular drill pipe.
Difference in Length
The tube length tends to vary from 30 to 32 feet, but longer Range 3 models are also available. The length of these pipes can reach up to 45 feet and is commonly used in deep water drilling applications and casing. Because of their increased length, Range 3 pipes have fewer tool joints, resulting in a shorter product life. In addition, the tool joints in these types of pipes are under more stress compared to shorter piping, causing the items to wear down faster.
Types of Drill Pipes Based on Spherometer Check
Based on differences in factors like circumference, wall thickness, and diameter, drill pipes can be categorized into three categories,
Drill pipes are designed to withstand high internal and external pressure. These pipes are often used to bore into the earth's crust. These factors require the production to be notch. Because of this, the cost of these products is very high.
Therefore, companies often reuse their drill pipes until they become unusable. Classes P and C on this list represent these types of goods that have seen prior use but are still capable of functioning efficiently.
C- Class
The lowest quality drill pipes, C-Class pieces are items that have seen extensive wear. Pipes that have been used thoroughly and are nearing the end of their lifespan fall under this category. Depending on their usability and wear, these pieces are further subclassed into C -1, C - 2, and C - 3 pipes. Once C-Class pipes are worn beyond use, they are sold for scrap depending on the material quality.
P-Class
Also referred to as premium pipes, P-Class pipes are a step up from C-Class tubular products. These items generally have a low to moderate amount of wear. Drill pipes resold after one or two uses can be categorized as P-Class. Despite exposure to the elements, these pieces are capable of functioning efficiently.
N-Class
Also called new pipes, N-Class pipes are the highest quality drill pipes. These products are factory-fresh, meaning they have seen no prior use. These are also the strongest type of drill pipes. N-Class pipes have no damage or wear and are usually in pristine condition.
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Drill Pipes: Important Terms
Drill String
The column used to drill into wells, in its entirety, is known as a drill string. The drill pipe, tools like shaft collars, and the drill bit combine to form this.
- The pipe consists of over 90% of the drill string length. It circulates the essential fluids from the wells.
- Meanwhile, the drill bit tops the drill bit - this tool helps operators carve into subterraneous resources and regions.
- On the other hand, the shaft collars hold the components in place and facilitate their movement.
A drill string is typically about 33 feet long on average, but this length can vary depending on the depth of the boring well. Since these are made from high-grade seamless, tempered steel, their prices are also very high. For expenditure cutbacks and ease of transport, projects may choose smaller-sized drill strings.
Tool joints may be used in offshore drilling projects requiring extra long pieces. If a drilling operation exceeds 10,000 to 15,00 feet, the operators may use these tools to link male sections with the female ends of the pipe.
Sources:
https://www.globalspec.com/learnmore/specialized_industrial_products/mining_equipment/drill_pipe
https://en.wikipedia.org/wiki/Drill_pipe
https://www.sciencedirect.com/topics/engineering/drillpipe
https://www.worldironsteel.com/news/what-is-the-classification-and-grades-of-drill-14345056.html