Classification of Tubing Pup Joints

In the oil and gas transportation and production system, various types of pipes and accessories play an important role, such as seamless steel pipe for fluid transportation, and tubing pup joints, as common pipe string accessories in oil and gas well operations, are used to flexibly adjust the length of the pipe string to meet the needs of different well conditions and drilling processes. Tubing pup joints can also be divided into three categories according to their functions: double male pup joints, conversion pup joints and adjustment pup joints.

Double male pup joints

Both ends are external threads, external thickening to non-thickening pup joints, external thickening to external thickening pup joints, same diameter pup joints and non-thickening reducing pup joints.

1. Advantages

Simple structure and high strength: double male pup joints are all external thread ends, with strong pressure bearing capacity and suitable for high-load environments.

Quick installation: direct thread engagement with the same specification coupling, no additional conversion parts are required.

2. Application

Drilling measurement: quickly increase or decrease the length of the tubing to adapt to different measurement depths.

Completion operation: When the wellhead equipment is connected in a standardized manner, it is used to quickly adjust the length of the pipe string section and cooperate with the casing pipe to achieve a stable wellhead structure.

Conversion pup joint

One end is external threaded and the other end is internal threaded. The coupling is screwed on the external thickening to non-thickening pup joint, external thickening to external thickening pup joint, same diameter pup joint and non-thickening reducing pup joint.

1. Advantages

Flexible conversion: The external threaded tubing or pipe fittings can be directly connected to the internal threaded tools or couplings without the need for additional conversion sleeves.

Reduce inventory: One pup joint can achieve multiple connection methods and reduce the number of conversion parts of different specifications.

2. Application

Downhole tool switching: such as the interface conversion of measuring instruments, corers and other tools with standard tubing, which is convenient for connection with equipment such as drill pipe.

Operation process integration: Reduce joints, compactly arrange the pipe string, and improve compatibility with OCTG pipe systems.

Adjustment of pup joint

The length is not fixed. It is designed according to the needs of the project. One end is external thread and the other end is internal thread. The coupling is screwed on the pup joint from external thickening to non-thickening, the pup joint from external thickening to external thickening, the pup joint from external thickening to external thickening, the pup joint with the same diameter and the pup joint without thickening.

1. Advantages

Adjustable length: The pitch of the pipe string can be accurately adjusted at the well site according to the actual needs such as depth and wellhead equipment space.

Reduced accessories: There is no need to prepare pup joints of different specifications for each length, and the on-site integrated adjustment can be done.

2. Application

Drilling and completion depth fine-tuning: Used in working conditions such as testing and logging that require high depth accuracy.

Limited wellhead space: Quickly fine-tune the arrangement of the pipe string to avoid the accumulation of excess pipe sections.

Selection suggestion

Summary

In actual engineering, the three are often used in combination to balance strength, flexibility and cost. Reasonable selection and matching of pup joints can significantly improve the efficiency and safety of drilling, completion and logging operations.

Read more: What Is The Minimum Length of Welded Pipe Pup Joints?