What aspects of corrosion prevention for oil casing need attention

First, what are the corrosion prevention measures for oil casing?
1. We ensure water quality meets standards; we strictly monitor and manage water quality. 1. Implement separate injection for clean and contaminated water, strengthen the cleaning of the main water pipeline, ensure that the water quality in the station and at the bottom of the well meets the standards, and reduce the introduction of corrosion sources into the annular space.
2. For newly commissioned injection wells, adopt annular protective fluid mainly for sterilization, and establish a system for regular addition.
3. Given that mechanical abrasion accelerates corrosion of oil casing, it is recommended to add a rubber ring to the tubing coupling or a centralizer in areas of severe well deviation to prevent the tubing from scratching the oil casing or contacting it on one side during operation and water injection.
4. To address severe under-scale bacterial corrosion and the slow growth and killing of SRB at high temperatures, high-temperature water or steam at 100 degrees Celsius can be injected into the annulus periodically to kill under-scale SRB.
5. Before corrosion inside the oil casing of injection wells is effectively controlled, it is not recommended to promote the use of cathodic protection and coated oil casing.

Second, what are the points to note when preventing corrosion of oil casing? 
(1) When using oil well casing to transport water, it is essential to ensure that the water quality is up to standard before use. Furthermore, a separate cleaning and discharging process must be implemented. During use, the main water pipeline must be thoroughly cleaned to ensure that no corrosive substances remain inside the oil well casing after use. The oil well casing must be brought to zero before use.
(2) For water injection wells already in production, annular protective fluid should be added during use. Regularly adding this protective fluid should be a standard practice to ensure the oil well casing can be used sustainably. 
(3) When using oil casing, there will be mechanical scratches, which will affect the corrosion protection of the oil casing and accelerate the corrosion of the oil casing. It is recommended to add a rubber ring to the oil pipe coupling when using it, so as to reduce the corrosion of the oil casing.