A drill pipe is one of the critical components of the drill string along with the heavy weight drill pipe and drill collars. However, it must be connected by secure and compatible threaded connections at both ends to maintain the safety and integrity of the drill string and allow for a safe and efficient drilling process.
A drill pipe connectivity chart can be a viable tool in choosing threaded connections that match securely to suit different drilling applications. Creating matching connections to join different drill pipe sections ensures the drilling process continues without the risk of equipment failure.
Drill Pipe Connectivity Chart
| Connection Type | Drill Pipe Size (inches) | Compatibility With Other Connections |
| NC 26 | 2 3/8 | 2 3/8 REG, 2 3/8 IF |
| NC 31 | 2 7/8 | 2 7/8 REG, 2 7/8 IF |
| NC 38 | 3 1/2 | 3 1/2 REG, 3 1/2 IF |
| NC 40 | 4 | 4 REG, 4 IF |
| NC 46 | 4 1/2 | 4 1/2 REG, 4 1/2 IF |
| NC 50 | 5 | 5 REG, 5 IF |
| NC 56 | 5 1/2 | 5 1/2 REG, 5 1/2 FH |
| NC 70 | 6 5/8 | 6 5/8 REG, 6 5/8 FH |
| NC 77 | 7 | 7 REG, 7 FH |
Importance of Drill Pipe Connectivity
Drill pipe tool joints and threaded connections are a major aspect of drill pipe specifications and form the basis for safe and efficient drilling operations. The drill pipe joints are thickened sections at the ends of the drill pipe body consisting of an external male thread (pin) and female thread (box) welded at each end.
Any successful drilling operation depends on a tight and secure connection between the pin and box. The drill pipe joints and compatible threaded connections contribute to the integrity and performance of the drill string while securely connecting the drill pipe and keeping it from disintegrating.
They bear tremendous pressures, rotational torque, and tensile loads as encountered during drilling operations and play a pivotal role in ensuring that the drill string remains intact and functions effectively.
Matching the right connections with each other is vital to preventing drill pipe failure and reducing nonproductive time (NPT). It also minimizes stress concentrations and uneven wear, extending the service life of the drill pipe and tool joints while saving costs in the long term.
Compatible tool joint connections provide a tight, leak-proof seal that enables smoother fluid flow by regulating high-pressure drilling fluids inside the drill string, preventing leaks and potential blowouts in the wellbore.
The tool joints often feature corrosion and wear-resistant coating like hard banding to withstand the abrasive conditions within the wellbore, extending the life of the drill pipe.
Selecting the correct connections can often be guided by tools such as a drill pipe classification chart, which helps ensure that the chosen connections are appropriate for the specific drilling application. This is crucial in preventing mismatches that could lead to equipment failure and costly downtimes.
Drill Pipe Connections
Drill pipe threaded connections are an essential part of drill pipe specifications, ensuring that the drill string functions effectively and safely, maximizing drilling efficiency.
The threaded connections are located on the tool joints of the drill pipe. The pin and box thread together to connect individual sections of the drill pipe, forming a continuous and secure drill string. Drill pipe connections can be classified as premium and standard API (American Petroleum Institute) connections.
Premium or proprietary connections are custom-designed by different manufacturers depending on specific drilling applications, offering higher torque capacity, enhanced sealing capabilities, and exceptional durability in demanding drilling environments.
In contrast, API connections are standardized and do not work with premium connections but are compatible and interchangeable with other API threads from various manufacturers. The API regulates four types of tool joint connections for a drill pipe. These include:
Regular (REG)
The reg (REG) tool joint thread connects the inner upset drill pipe and features a smaller inner diameter than the thickened end of the drill pipe. Regular connections feature a V-shaped thread profile and provide the appropriate mechanical strength to withstand the high torque and tensile loads while preventing drilling fluids from leaking by ensuring strong sealing.
Internal Flush (IF)
An internal flush (IF) tool joint connection is used to connect external upset tool joints of the drill pipe. It is designed to maintain a consistent internal diameter as the internal diameter of the tool joint is equal to the internal diameter of the drill pipe. That results in smooth drilling fluid flow in the drill string with minimal resistance and more effective cuttings removal from the wellbore while reducing pressure losses.
Full Hole (FH)
The full hole (FH) drill pipe connection is suitable for inside upset drill pipe. The internal diameter of the drill pipe tool joint matches the thickened end diameter for better fluid flow but is smaller than that of the drill pipe body.
Numbered Connection (NC)
Numbered connections (NC) are identified by specific size numbers, ranging from 10-77. They are designed to join pin and box with equal thread designations while offering interchangeability.
Each connection features a different thread profile to make a secure connection between the drill pipe and the tool joint. The numbers help select the appropriate tool joint size for different drilling operations, ensuring compatibility and optimal performance.
About Sophia Oilfield Supply Services
Sophia Oilfield Supply Services is a recognized and trusted distributor of the highest quality new and used drill pipe for sale, manufactured to provide excellent performance and reliability, boosting your productivity on the oilfield.
While we take immense pride in dealing with all types of oilfield products and equipment for over 30 years, we also know how drill pipe connectivity compatibility is at the core of smooth and safe drilling operations.
Our team of oilfield experts is available to help you choose compatible drill pipe tool joint connections so you can mitigate the potential hazards that come with mismatched threads.
Contact us today to discuss further and receive a customized estimate for our drill pipe threaded connection!