Solution of OCTG Casing Pipe in Failed Quality Inspection

If the OCTG casing pipe does not meet the quality inspection standards, the following treatment methods can be adopted:

Evaluation and classification

1. Detailed inspection and analysis

Carry out more in-depth inspection and analysis of OCTG casing pipe that does not meet the quality standards to determine the specific problems. For example, through metallographic analysis, chemical composition testing, mechanical properties testing and other means, find out whether the casing pipe has problems in material, size, strength, sealing and other aspects.

For casing pipe with cracks, severe corrosion or deformation, it is necessary to focus on analyzing the causes of its occurrence and determine whether it is caused by defects in the manufacturing process, improper transportation and storage, or damage during installation.

2. Classification and treatment

Classify the substandard casing pipe according to the test results. If the problem is minor, it may only need to be repaired or rectified: if the problem is serious, it may need to be scrapped or downgraded.

For example, for casing pipe with slight scratches on the surface or loose threaded connection, it can be considered to be repaired and then tested again: for casing pipe with serious cracks or serious lack of strength, it should usually be scrapped directly.

Repair and rectification

1. Repair of surface defects

For minor surface damage, such as scratches and pits, grinding and polishing can be used for repair. Ensure that the repaired surface is smooth and flat, and does not affect the performance and sealing of the casing.

During the repair process, pay attention to controlling the depth and range of the repair to avoid excessive repairs that cause the casing pipe wall thickness to become thinner or the strength to decrease. At the same time, the repaired parts should be re-tested to ensure that the repair quality meets the requirements.

2. Thread repair

If the threads of the casing pipe are damaged or the connection is not tight, thread repair tools can be used for repair. For example, use a thread comber to reprocess the damaged threads to restore them to the standard size and shape.

After the thread repair, the thread connection test should be carried out to ensure that the sealing and strength of the connection meet the requirements. At the same time, the repaired threads should be rust-proofed and treated to prevent damage again.

3. Strength improvement

If the strength of the casing pipe does not meet the standard, heat treatment and other methods can be considered for strengthening. For example, OCTG casing pipe is subjected to heat treatment such as quenching and tempering to improve its strength and hardness.

However, the heat treatment process requires strict control of process parameters to avoid new defects in the casing pipe due to overheating or overcooling. After heat treatment, the mechanical properties of the casing pipe should be tested again to ensure that the strength improvement meets the requirements.

Scrapping and downgrading

1. Scrapping

OCTG casing pipe that is severely damaged, cannot be repaired, or has too high a repair cost should be scrapped. The scrapped casing pipe should be properly disposed of in accordance with relevant regulations to avoid environmental pollution.

For example, the scrapped casing pipe can be cut, crushed, etc., and then recycled as scrap metal. At the same time, the number and reasons of the scrapped casing pipe should be recorded to facilitate subsequent quality analysis and improvement.

2. Downgrading

In some cases, if the quality problem of the casing pipe does not affect its use in a lower-requirement environment, downgrading can be considered. For example, the casing pipe originally used for high-pressure and high-temperature wells can be downgraded to low-pressure and low-temperature wells if the strength is slightly insufficient.

Downgraded use requires strict evaluation and approval to ensure that the casing can meet safety requirements in the new use environment. At the same time, the downgraded casing pipe should be specially marked and managed to facilitate tracking and monitoring of its use.

Summary

In short, for OCTG casing pipe that does not meet the quality inspection standards, reasonable treatment methods should be adopted according to the specific circumstances to ensure the safety and efficiency of oil production. At the same time, it is necessary to strengthen the control and management of casing pipe quality to reduce the occurrence of quality problems from the source.