What are the Anti-Corrosion Processes of Oil Casings?

Let's take a brief look at:

1. Cement sealing and anti-corrosion technology

In the early stage, the main reason for the damage of the casing was
that the cement was not able to return high, and the external water
layer was not completely sealed, and corrosive gas in the water layer
was formed to corrode the surface of the casing to form corrosion.
Therefore, in the 1980s, the strategy of increasing the cement height
was proposed to increase the corrosion resistance of the casing. After
this technique, the corrosion level of the casing is reduced, but the
casing corrosion is not completely prevented, so the corrosion
resistance of the casing is not raised from the spring source.

2. Use corrosion-resistant alloy pipe

Since 2000, the anti-corrosion plan for offshore oil casings has begun
to seek treatment plans from materials to improve the corrosion
protection of the oil casings, thus completely dealing with the
corrosion problems of the oil casings. In the frequency test, through
the indoor test, under the conditions of affirmative temperature and
pressure conditions and corrosive gas, the Cr-containing pipes such as
1Cr, 3Cr, 9Cr and 13Cr were evaluated, and an anti-corrosion plate
suitable for the oil casing of the offshore oil and gas field was
developed.

3. Inject corrosion inhibitor

From the completion of the completion process, if the formation
contains oily corrosive gases, chemical antiseptic agents will be
added to the well fluid for anti-scaling, anti-wax and anti-corrosion.
Therefore, the use of chemical methods for the corrosion protection of
oil casings is also a common means outside China. Depending on the
difference in the oil and gas field, it may be possible to use a batch
or continuous injection of corrosion inhibitor for corrosion
protection. The amount of injection varies depending on the corrosive
environment of the oil and gas field. Since the demand for the
addition of corrosion inhibitors has continued, on the one hand, the
cost is higher, and it will also have a positive impact on the on-site
production.

4. Apply anti-corrosion coating tube

Regarding oil casings, it is also a useful anti-corrosion method to
use anti-corrosion coatings in China to block their infiltration in
corrosive gases. Some oilfields use nitriding technology for internal
and external corrosion protection of oil pipes, and their wear
resistance is good. However, the anti-corrosion method of the inner
and outer walls will accelerate the corrosion of the inner wall of the
casing at a certain level, and the nitriding pipe will be rough, which
will make the oil pipe The knot is tighter than the other types of
tubes. In addition, some oil and gas fields use epoxy powder coating,
titanium nano coating, epoxy ester phenolic coating to prevent
corrosion.