What are the causes and detection methods of oil and gas steel pipeline leakage

There are many reasons for steel pipeline leakage, which can be mainly divided into three categories: corrosion perforation, fatigue cracking, and external force damage.

Although corrosion control measures can substantially slow corrosion, it does not prevent it. When the cathodic protection is insufficient, the steel pipeline corrosion process will be slow but will not stop due to the cathodic protection; when the cathodic protection is shielded, the steel pipeline corrosion cannot be inhibited at all. Insufficient cathodic protection means that the protective current provided by the cathodic protection system cannot meet the requirements of steel pipeline protection; cathodic protection shielding means that the cathodic protection current is blocked in the flow and cannot reach the predetermined position. When there is a large area of damage, continuous leaks, or overall insulation performance degradation on the coating, it is easy to cause insufficient cathodic protection. Since such defects can be found through inspection, corrosion accidents can generally be avoided by repairing them. When the coating and the metal of the pipe are peeled off, it will have a shielding effect on the cathodic protection system, especially the coating made of organic synthetic materials with high insulation performance, but the existing detection technology is difficult to detect the peeling of the coating, so it is easy to produce Corrosion perforation leaks.

Oil and gas steel pipelines operate under high-pressure conditions for a long time, the mechanical properties of the steel pipeline metal will gradually decay, the tiny cracks in the steel pipeline weld itself caused by stress corrosion will expand, and when the cracks develop to a certain extent, it will cause sudden steel pipeline failure Rupture accidents, resulting in leaks. Steel pipeline ruptures can have catastrophic consequences for gas steel pipelines.

External damage mainly includes natural disasters and man-made disasters. Floods, landslides, mudslides, and earthquakes may damage steel pipelines; man-made disasters mainly refer to third-party damage, including unintentional damage caused by various construction projects such as road construction, excavation, etc., as well as oil and gas theft caused by drilling Deliberate sabotage caused by lawless elements has become the main threat to steel pipeline protection, and in some areas, it is even the cause of sabotage.

For large sudden steel pipeline leakage accidents such as pipe bursts and fractures, due to the sudden loss of pressure in the steel pipeline, they can generally be found in time, but on-site inspection is required to determine the specific location. For small leaks, leak detection techniques are required. Leak detection techniques include offline detection and online monitoring.

Offline inspection is an inspection along the steel pipeline regularly or as required. It can be inspected on foot, by car, or by a special plane for flight inspection. Leaks are found by observation of the surface, instrumental detection, or infrared imaging techniques. Because the detection is not carried out from time to time, this method generally cannot detect the leak in time after it occurs.

On-line monitoring is to use the leakage monitoring system specially installed on the steel pipeline to dynamically monitor the steel pipeline, capture the leakage information at the moment of leakage, send an alarm, and quickly calculate the location of the leakage through the computer.

Steel pipeline leakage Oil and gas steel pipeline leakage not only causes oil and gas loss, but also pollutes the environment, and may even cause fires, explosions, and other accidents. Therefore, it is very important to ensure the safe operation of steel pipelines.