Common sealing methods of OCTG casing pipe

Oil Country Tubular Goods (OCTG) casing pipes require effective sealing methods to ensure their performance and reliability in various applications. Here are some of the most common sealing methods used for OCTG casing pipes.

Rubber Sealing Ring Method

The rubber sealing ring is a widely used method for casing sealing due to its excellent performance, adaptability to various conditions, and ease of installation. This method involves placing a sealing ring around the root of the casing, inserting the casing into the pipe to be sealed, and then pouring aggregate, cement mortar, or foam cement into the pipe to create a high-strength seal at the bottom. Finally, the screws are tightened. It's crucial to match the rubber sealing ring's material and model to the pipe's material and size.

Advantages: Simple process, easy to implement, convenient construction, effective anti-seepage.

Disadvantages: Time-consuming, small flow capacity, potential for unstable quality, environmental pollution.

Applicable Scenarios: Suitable for small-diameter, shallow-depth casings, water supply pipes, drainage pipes, and oil tubing.

Installation: First, install the rubber sealing ring into the casing's flange part, insert the casing into the pipe to be sealed, and finally tighten the screws.

Packing Sealing Method

Packing sealing involves filling sealing materials between the casing and the pipe and compressing the packing to achieve the sealing effect. Common packing materials include mud, polytetrafluoroethylene (PTFE), graphite, and cork. When selecting packing, consider factors such as the chemical properties of the sealing material, temperature extremes, and corrosion resistance.

Advantages: Quick to implement, convenient construction, effective anti-seepage.

Disadvantages: Small flow capacity, potential environmental pollution.

Applicable Scenarios: Suitable for sealing underground structures like residential buildings, factories, and underground parking lots.

Welding Sealing Method

The welding sealing method involves welding the casing and the pipe to achieve a seal. It is essential to consider the material and thickness of the pipe and casing during design and selection to ensure the strength and sealing integrity of the weld.

Advantages: Ideal for environments with high sealing requirements, such as high temperature, high pressure, and corrosion.

Hydraulic Sealing Method

The hydraulic sealing method uses liquid pressure to achieve sealing. The principle is to push the liquid into the sealing cavity to form a high-pressure sealing layer.

Advantages: Excellent sealing, long lifespan, adaptable to high temperature and high pressure environments.

Disadvantages: Sealing effectiveness can be reduced by hydraulic oil leakage, air shortage, and other issues.

Mechanical Sealing Method

The mechanical sealing method relies on friction and pressure between the sealing surfaces. This method uses mechanical seals, such as carbon rings, springs, and packing, to achieve the seal.

Advantages: Good sealing, long lifespan, wide range of applications.

Disadvantages: Requires regular maintenance and replacement of parts to prevent leaks and equipment damage.

Summary

Each casing sealing method has its own advantages, disadvantages, and suitable applications. Construction personnel should choose the appropriate method based on the specific conditions and ensure safety and protective measures to maintain construction quality and worker safety.