Oil casing is an octg pipe used to support the walls of oil and gas wells to ensure the normal operation of the entire oil well after the drilling process and completion. Each well uses several layers of casing according to different drilling depths and geological conditions. Cement cementing is used after the casing is lowered into the well. Unlike oil pipes and drill pipes, it cannot be reused and is a one-time consumable material. Therefore, the consumption of casing accounts for more than 70% of all oil well pipes.
Anti-corrosion countermeasures for oil casing in use
1. First of all, do a good job in meeting water quality standards, and strictly monitor and manage water quality. Carry out cleaning and separate injection, strengthen the cleaning of the main water pipeline, ensure that the water quality in the station and the bottom of the well is up to standard, and reduce the introduction of corrosion sources into the annular space;
2. For the water injection wells that have been newly put into production, the annular protection fluid mainly for sterilization is adopted, and a system is formed to add it regularly;
3. In view of the accelerated effect of mechanical abrasion on the corrosion of oil casing, it is recommended to add a rubber ring on the tubing coupling or add a centralizer to the serious part of the well deviation, so as to avoid the tubing scratching the casing and one side contacting the casing during operation and water injection;
4. In view of the serious corrosion of sub-scale bacteria and the slow growth and killing of SRB at high temperature, high-temperature water or steam at 100 degrees Celsius can be injected into the annular space regularly to kill the sub-scale SRB;
5. It is not recommended to promote the use of cathodic protection and coated casing before the corrosion in the casing of the water injection well is effectively controlled.
Anti-corrosion countermeasures for oil casing in use
1. First of all, do a good job in meeting water quality standards, and strictly monitor and manage water quality. Carry out cleaning and separate injection, strengthen the cleaning of the main water pipeline, ensure that the water quality in the station and the bottom of the well is up to standard, and reduce the introduction of corrosion sources into the annular space;
2. For the water injection wells that have been newly put into production, the annular protection fluid mainly for sterilization is adopted, and a system is formed to add it regularly;
3. In view of the accelerated effect of mechanical abrasion on the corrosion of oil casing, it is recommended to add a rubber ring on the tubing coupling or add a centralizer to the serious part of the well deviation, so as to avoid the tubing scratching the casing and one side contacting the casing during operation and water injection;
4. In view of the serious corrosion of sub-scale bacteria and the slow growth and killing of SRB at high temperature, high-temperature water or steam at 100 degrees Celsius can be injected into the annular space regularly to kill the sub-scale SRB;
5. It is not recommended to promote the use of cathodic protection and coated casing before the corrosion in the casing of the water injection well is effectively controlled.
