Anti-corrosion and anti-wear tubing Manufacturers and Suppliers

Everything You Should Know About Anti-Corrosion And Anti-Wear Tubing

It is estimated that corrosion costs industries in the United States alone a whopping $170 billion every year.

The oil industry is also said to take an above-average share of this cost.

This can be attributed to the complex and demanding production methods, component failure, and environmental threats. Nearly every metal used across all industries are prone to corrosion and wear in certain situations.

However, many ways can be used to prevent corrosion and wear in oil and gas applications, especially offshore.

Accordingly, these techniques require a fundamental understanding of various types of tubing and casing corrosion and their causes.

Knowing the exact place to look for corrosion can help lower the risks of oil rigs and refineries, which, in turn, saves a lot of money.

What Is Tubing and Casing Corrosion?

In general, corrosion is described as the destructive alteration of metal.

This destruction can be caused by a chemical or electrochemical reaction between the metal and the environment, causing a change and weakening of the metal’s properties.

Therefore, corrosion is said to be a process and not necessarily property. Almost every metal is often unstable under atmospheric conditions, and this can allow the metal to be oxidized.

Tubing and casing corrosion occurs when the metal layer is turned or converted into its oxide form. Generally, there are two broad types of corrosion in tubing and casing; electrochemical corrosion and chemical corrosion.

• Electrochemical Corrosion

Electrochemical corrosion occurs when a ferrous (iron-based) material such as metal or any of its alloys comes into contact with an electrolyte, which, in most cases, is usually water or moisture.

The result of the process is what most people call rust.

Slowing tubing and casing corrosion of iron alloys include the addition of rust inhibitors in the formulation.

Rust inhibitors work by sticking to the metal surface to prevent direct contact of the metal surface with water or moisture and acids from atmospheric air.

• Chemical Corrosion

Chemical corrosion occurs when the metal surface is attacked by aggressive chemical components such as acids, bases, and Sulphur.

Chemical corrosion is often due to the oxidation of hydrocarbons and additives with Sulphur or its byproducts on a metal surface.

Additionally, it can be caused by the formation of an oxide layer on the metal surface, leading to the creation of an ionic or oxidized metal compound.

Chemical corrosion does not require water or moisture like electrochemical corrosion since it can happen in organic and aqueous conditions.

The best way of preventing this kind of corrosion, especially in non-noble metal, is the addition of corrosion inhibitors to a lubricant.

The corrosion inhibitors work by forming an inactive layer on the surface of the metal. Some corrosion inhibitors work well by neutralizing the chemical compounds that cause corrosion.

• How Corrosion Occurs

Tubing and casing corrosion occurs when the metal atom is oxidized, resulting in a loss of material on the casing and tubing surface. The loss of material reduces the thickness of the tubing and casing, making them susceptible to mechanical failure.

Metal tubing and casing are mostly used for analytical and process instrumentation, control and utility applications, and hydraulic lines.

When it comes to oil and gas applications, the metals used are often made of stainless steel with more than 10% chromium content.

Chromium forms an oxide layer on the surface of the stainless steel, thus protecting the metal from corrosion and wear. However, some environmental conditions may break the oxide layer, leading to corrosion of the stainless steel tubing and casing.

Almost every metal is prone to corrosion, and the most common type of corrosion is rust, which is the oxidation of iron or its alloys. However, there are many types of tubing and casing corrosion.

Each type poses significant threats that must be assessed and addressed in real-time to prevent losses in the oil and gas industry.

Identifying Common Types tubing and casing of Corrosion

There are many types of tubing, and casing corrosion and all of them can spell doom in oil and gas applications.

Many kinds of corrosion are specific to the metal properties and its environment. As you continue reading on, this article will focus on two primary forms of tubing and casing corrosion; pitting and crevice corrosion.

• Pitting Corrosion

Pitting corrosion happens when the protective chromium oxide layer on the surface of stainless steel tubing and casing is broken down, therefore, allowing the material to become prone to the loss of electrons.

The resulting electrochemical reaction leads to the formation of small cavities “pits” on the surface of the metal.

This kind of tubing and casing corrosion is often easy to detect through visual inspection.

However, the pits can grow deeper and may, at some point, perforate the entire tubing or casing. Additionally, pitting corrosion can cause cracks in tensile stressed pipes. High temperatures and high chloride concentrations offer the perfect environments for pitting corrosion.

The best way to detect pitting corrosion in tubing and casing is by looking for reddish-brown deposits of iron oxide or pits that may have formed on the surface of pipes.

• Crevice Corrosion

Crevice corrosion is also caused by the breakdown of the protective chromium layer on the surface of stainless steel, leading to the formation of shallow pits on pipes. However, crevice corrosion in tubing and casing occurs in crevices and not in plain sights.

In oil and gas applications, crevices are found between tubing and tube supports or clamps, between adjacent tubing and casing, and below dirt accumulated on various surfaces. Avoiding cracks in tubing and casing installation is almost impossible.

Consequently, tight crevices pose one of the greatest dangers of tubing and casing corrosion in oil and gas applications.

Crevice corrosion happens when seawater comes into contact with the cracks, creating an aggressive environment where corrosive ions fail to diffuse out of the crevices. In that way, the entire surface of tubing and casing found within the crack starts to corrode.

Visual observation of crevice corrosion is only possible when the tubing support or clamp is removed. Crevice corrosion sometimes occurs at lower temperatures compared to pitting corrosion.

What Causes Corrosion in Tubing and Casing?

The most straightforward cause of corrosion is contact.

This can happen when the metal surface comes into contact with water, moisture, oxygen, grime, acids, bases, or other metals.

These elements can cause corrosion for different reasons.

Corrosion starts when a metal loses electrons and is weakened in the process. When the electrons are lost, the metal becomes vulnerable to other aggressive chemical reactions, resulting in cracks, rust, or holes.

• Internal tubing and casing corrosion due to reservoir fluids in oil and gas wells

Reservoir fluids in oil and gas wells are sometimes very corrosive, and this is one of the reasons why the reservoir fluid is typically contained within the tubing. Generally, only the internal parts of the casing come into contact with reservoir fluids.

In some instances, beam pump operations, tubing leaks, or remedial operations can cause other parts of the casing to come into contact with reservoir fluids from oil and gas wells.

Circulating out an influx is another process that may expose intermediate casings to fluids in the wells.

• Internal and external tubing and casing carrion due to drilling, stimulation fluids, and workover completion processes

The fluid used in the drilling process or during completion phases can be corrosive to tubing and casing. Additionally, these fluids become more corrosive when exposed to high temperatures over time.

Muds and brines with low pH and packer fluids in the annuli are some examples of corrosive liquids. Stimulation fluids are corrosive, with a drop in pH or an increase in temperatures for extended periods.

• External tubing and casing corrosion due to fluids from external sources

Uncemented tubing and casing found adjacent to formations with corrosive fluids are also susceptible to corrosion.

Corrosive fluids can be found in formations with water or moisture content and aquifers or in the reservoir.

Rainwater and atmospheric moisture at the surface also pose corrosion threats to tubing and casing.

A mixture of saltwater and oxygen in offshore wells pose corrosion threats in splash zones.

How to prevent Tubing and Casing corrosion and wear

Corrosion in oil tubing and casing is related to the partial pressure of corrosive gas and fluids, temperature, water, and moisture content, salinity, flow rate, pH, among other factors.

Tubing and casing corrosion can sometimes be self-perpetuating.

This means that tuning and casing corrosion worsens with time. However, many ways can be used to prevent corrosion from creeping into tubing and casing.

In tubing and casing designs, corrosion is often caused by the three factors discussed above.

The prevention of tubing and casing corrosion should start by knowing the cause.

The following methods can be used to prevent tubing and casing corrosion:

• Cement sealing

In some analyses, it has been determined that carrion is caused by the failure to cement casing well, allowing water and moisture content to come into contact with the pipes.
When the formation of the external layer of water is not appropriately sealed, the casing becomes prone to corrosion.

In that case, the best way to prevent such corrosion is by using an increased cement back.

However, this method is only used to reduce corrosion and not to stop it completely. Therefore, casing corrosion can still occur even with correct cementing and tight sealing of the casing.

• Using anti-corrosion and anti-wear alloy pipes

The anti-corrosion plan has always considered improving the anti-corrosion function of materials to prevent the corrosion challenge of oil tubing and casing completely.

Laboratory tests have evaluated various compounds of chromium under specific temperature, pressure, and corrosive gas conditions.

The results show that 1Cr, 3Cr, 9Cr, and 13Cr are the best corrosion-resistant plates used for offshore oil and gas tubing and casing.

• Injecting corrosion inhibitors

The addition of chemical anti-corrosion agents to fluids in reservoirs can prevent scale, wax, and corrosion.

This method is more effective when applied at the beginning of the completion process, and mainly if the formation contains corrosive fluids.

Due to differences in the oil and gas industry and fields, the use of intermittent and continuous injection of corrosion inhibitors is more appropriate.

Additionally, the amount of injection should vary according to the corrosive environment of the wells.

For instance, the oil and gas field with more corrosive fluids require more injection of carrion inhibitors compared to oil and gas fields with less corrosive fluids or conditions.

However, the high demand for corrosion inhibitors has driven up the costs. But the process can also have positive contributions to onsite production.

• Using anti-corrosion coating

Do you know what polycore tubing, HDPE liner tubing, HTPT liner tubing, Tungsten coated tubing and sucker rod , and Tungsten plated tubing have in common?

All these are tubing that is protected from corrosion using the corrosion-protective coating.

Tubing and casing for oil and gas applications can be protected from corrosion through anti-corrosion plating.

The nitriding process can be useful for the internal and external corrosion protection of tubing.

This process improves wear resistance of tubing.

However, it may also speed corrosion in the inner casing. Besides, you can also use epoxy powder coating, titanium nano-coating, and epoxy ester phenolic coating.

Corrosion Prevention Across Every Industry

If you are working on any engineering project requiring the use of metal pipes, you probably dread the possibility of tubing and casing corrosion. And this applies to all industries.

The global cost of corrosion is said to be an estimated $2.5 trillion.

Beyond this astronomical cost, corrosion is a threat to production processes and causes injuries at workplaces.

On top of all this, corrosion can be hard to notice, primarily when it attacks tight spots.

However, corrosion does not have to be scary since there are many ways that you can use to fight back to keep pipes whole and save on costs.

We have rounded up everything you need to know about tubing and casing corrosion and how you can stop it.