Essay Sample on Cathodic Protection in Oil and Gas: Defending Against Corrosion Risks

Introduction

The oil and gas sector is normally divided into three main sectors established on operations and its functions: the downstream, midstream, and upstream (Makhlouf, 2018). The upstream segment locates, explores, and produces natural gas and crude oil from the offshore and onshore fields. In most cases, the upstream sector is referred to as (E&P) the exploration and production. The midstream segment comprises the transportation, wholesale marketing, and storage of refined petroleum products or crude oil (Harbi, 2017). The transportation of oil and gas can be done by an oil tanker, rail, barge, pipeline, or truck. However, the main component of the midstream segment is pipelines. The pipelines are a suitable form of transportation of oil and gas products over long distances.

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Finally, the third element is the downstream sector which comprises petroleum plants, crude oil refineries, and petroleum distribution products. The stream can be dry or wet, depending on the water content. Since water stimulates corrosion, the dry stream is non-corrosive due to the absence of water. The water stage can be condensed water or have various salt levels. Some salts, for example, chlorides, can aggravate or exacerbate corrosion, which will result in an attack that is localized. The stream can be categorized as sweet when it contains (CO2) carbon dioxide only, and the stream can also be classified as sour if (H2S) hydrogen sulfide is available (Ameh, 2017). The corrosion regulation technique applied to the systems dominated by CO2 varies from the system that is dominated by H2S.

Introduction Corrosion in the Oil and Gas Industry

Corrosion can be defined as the destructive attack of a material when it reacts with its environment (Rodopoulos, 2019). In the oil and gas industry, almost any form of aqueous surroundings can stimulate corrosion. Corrosion usually occurs in various complex processes and conditions in the oil and gas processing, production, and pipeline systems (Unueroh, 2016). The corrosion process involves three components, an electrolyte, an anode, and a cathode. The electrolyte is the corrosive medium, which allows the movement of electrons from the cathode to anode. The cathode is made of an electrical conductor that is not used up in the corrosion process. Finally, the anode is the spot of the metal that corrodes (Makhlouf, 2018). Natural gas and crude oil can have numerous impurities which can stimulate corrosion. The corrosion causes degradation, which results in the loss of mechanical possessions such as durability, strength, impact strength, and many other valuable properties. As a result, corrosion results in loss of material decreased thickness, and sometimes a complete or a total breakdown.

The Problem of Corrosion in the Oil and Gas Industry

Corrosion has had numerous negative effects on the gas and oil industry. Corrosion has resulted in material degradation, which results in damage to the mechanical strength and durability of the transportation pipeline systems (Harbi, 2017). Consequently, corrosion has resulted in a reduction of thickness, which, in the end, leads to the loss of the entire material (Harbi, 2017). In a situation where intensive corrosion has occurred, the component may break down, which may require replacement while the production has ceased. Many oil and gas industries have had to utilize a huge amount of money to repair and compensate for the losses resulting from corrosion.

Background Corrosion in the Oil and Gas Industry

At the start of the oil and gas production process, all the stages existed at one point. The streams are divided into various stages at the surface of the amenities, such as water, gas, and oil. Following these phases, inhabitation is used to the corrosive stage only (XU, et al., 2015). As a result, the former industries were not aware of the dangers of corrosion until its effects became evident due to the risks that corrosion posed.

Purpose of The Cathodic Protection Technique

The cathodic technique was first applied in 1824 by Sir Humphrey Davy years before the theoretical foundation was established (Ameh, 2017). The cathodic technique of protection is a formula applied to reduce corrosion by reducing the difference in reaction probable between the cathode and anode. This method is attained by applying a high current to the structure, such as pipes, for protection (Rodopoulos, 2019). When a considerable amount of current is used, the entire structure will be at a single potential hence eliminating the anode and the cathode.

The cathodic process is normally applied in conjunction with coating. Also, the cathodic technique can be reflected as a secondary corrosion regulation technique. The main purpose of the cathodic method is to control and prevent microbiological and oxygen-regulated corrosion.

Scope of the Cathodic Protection Technique

There are two main techniques for applying the cathodic protection method. The first technique is (SACP) Sacrificial or Galvanic anode-cathode protection (XU, et al., 2015). In this kind of application or protection, the electrochemical potential naturally-occurring of various metals is applied to generate protection. The sacrificial anodes are attached to the structure (pipe system) under the conventional and protection flow of current from the anode to the pipe system. The structure provided the structure is less active than the anode (Ameh, 2017). As the current passes, all the corrosion will take place on the anode to protect the structure from corrosion, hence the term sacrificial.

The second method of applying the cathodic protection method is (Impressed Current Cathodic Protection) ICCP. In this kind of method, the current is forced or impressed by a power supply. The source of power should produce a direct current (Unueroh, 2016). The example is solar producing units, transformer rectifier units, and the thermoelectric generators. In this method, the anodes have a low rate of consumption or are inert and can be enclosed by carbonaceous backfill for intensification of efficiency and reduced costs.

Discussion Cathodic Protection Technique

Cathodic protection is a method applied to regulate the corrosion of a metal surface by creating an electrochemical cell. A modest technique of protection joins the metal to be sheltered to a faster-corroded metal that acts as an anode (Ameh, 2017). The outer metal which corrodes faster is known as the sacrificial metal. The cathodic system of protection prevents a wide variety of metallic structures in different environments. The cathodic protection is widely applied in protecting the oil and gas pipeline, and steel storage appliances (Rodopoulos, 2019). In structures, for example, a long pipe system where cathodic protection of galvanic is not enough, direct current from an electric source of power is applied to provide enough current.

Principles and Working of the Cathodic Protection Technique

The basic working principles of cathodic protection methods are founded on altering metals' active surface to passive or inactive (XU, et al., 2015). In other words, it is rendering the active part of the metal an electrochemical cell. By passing a direct current, the metal potential is reduced. This will make the corrosion attack to stop and hence the making the cathodic protection to be achieved.

Significance of Cathodic Protection Technique

Cathodic protection is the most significant technique corrosion protection method. The cathodic protection method, for example, through an external direct electric current source, can be partial; hence the metallic cannot be damaged by the corrosive environment. The cathodic protection practice can be applied to protect numerous metals such as bronze, zinc, copper, and lead not only in every type of soil but also in most aqueous media (Ameh, 2017). Another significance if cathodic protection practice is that the method reduces stress corrosion, intergranular corrosion, fatigue in the pipe system, and the cracking of the pipeline system that transports oil and gas.

Advantages of the Cathodic Protection Technique

The advantage of the cathodic method in reducing and controlling corrosion, which includes anodizing, galvanizing, and painting, is tremendously useful in cases where the transportation pipelines are small and above the ground (Makhlouf, 2018). If the piping system is enormous and buried underwater or underground, applying the above methods will not be economical or practicable. The pipeline that transports gas and oil requires protection against corrosion. In such a situation, the cathodic technique, together with the coating, will be the most advantageous technique. When a cathodic technique is applied, it is possible to monitor if the structures are adequately protected (Unueroh, 2016). Also, it is possible to make necessary adjustments on the voltage and current output in cathodic protection to uphold a high degree of protection. This can happen if the coating depreciates over a given duration.

Applications of the Cathodic Protection Technique

The cathodic protection provides optimum efficiency and safety with the application of the cathodic protection method. Pipeline systems can be conveniently and reliably be operated even in critical aqueous and soil conditions (XU, et al., 2015). The cathodic technique of protection should be applied, especially where the structure is exposed to an environment that is very aggressive or harsh to the system. The method can also be applied to pipelines that are submerged or buried in the soil.

The cathodic protection practice can also be applied to pipelines or structures as a supplement to coating. The cathodic protection methods can be applied on a plain pipeline system as well. Both the impressed current technique and galvanic anode can be used to a buried and submerged pipeline (Ameh, 2017). The application of either of these forms relies on numerous factors such as the resistivity of the soil, the current needed, and the expanse to be protected.

Conclusion

Corrosion is a probabilistic and stochastic occurrence that needs interdisciplinary interventions in concepts such as material science, surface science, electrochemistry, kinetics, and thermodynamics. Corrosion has numerous negative effects on the gas and oil industry, including the reduction of thickness, which leads to the loss of the entire material. This results in oil spills, which are dangerous and harmful to the environment. The cathodic technique of protection is a formula applied to reduce corrosion by reducing the difference in reaction probable between the cathode and anode

Recommendations

Corrosion can result in environmental catastrophe and industrial breakdown if not well controlled, managed, and prevented on time. Hence, the oil and gas industries are highly recommended to manage their units more safely. The oil and gas industries should perform risk assessments related to corrosion, plan a course of action, and set the required standards to control and prevent that risk brought about by corrosion. Corrosion management should be performed from time to time with an enormous spectrum of interaction among various specialists to establish monitoring, operating limits, and inspection plans to ensure corrosion is kept checked.

References

Ameh, E. S., & Ikpeseni, S. C. (2017). Pipelines cathodic protection design methodologies for impressed current and sacrificial anode systems. Nigerian Journal of Technology, 36(4), 1072-1077.