Oilfield Chemicals – Role of Demulsifiers and Corrosion Inhibitors in an Oilfield

Oilfield Chemicals – Role of Demulsifiers and Corrosion Inhibitors in an Oilfield

Demulsifiers are chemicals that are used to separate emulsions. They are mostly used when the substance mixture is stable and thus the substances cannot separate easily. Stable emulsions do not break easily. The choice of the type of demulsifier depends on the emulsions present.

An emulsion contains of the dominating substance known as the matrix. The substance present in smaller proportions is contained in the matrix and is known to exist in droplets. A demulsifier will initiate a chemical reaction similar to clumping, such that droplets will break away from the other substance in the emulsion. Bigger structures of the droplets are formed, making it easier for separation from the matrix.

Role of Demulsifiers in an Oilfield

In industrial settings, the most common emulsions are oil in water or water in oil. The latter is common in oilfields. Crude oil usually contains water during the initial stages of production. Separation of water from the crude oil is essential because water can alter oil properties. In fact, crude oil contains salt and water that are responsible for corrosion properties in the oil.

Application of pure demulsifiers as oilfield chemicals involves their injection down the hole or in batches on the manifold. Demulsifiers, once they come into contact with the water-in-oil emulsion, weaken or cancel out the electrostatic forces of repulsion between water droplets with an effect of causing them to come together. They also help by changing wet ability of solid micro-particles found at the interface between the substances. This helps in separation of water and other substances from the oil at the oilfields.

Water Soluble and Oil Soluble Demulsifiers

Water soluble demulsifiers are soluble in the emulsion and carries out the demulsification process in the soluble state. They dissolve in water once applied and can dissolve in water at room temperature. Water soluble demulsifiers are applied as oilfield chemicals in separating of oil from water in the oil-in-water emulsions and start demulsification process immediately. Water soluble demulsifiers must be degradable for application in crude oil processing and must contain no phenolic substances. They are non-toxic and non-hazardous.

Oil soluble demulsifiers dissolve in crude oil at room temperatures and can carry out demulsification in water-in-oil and oil-in-water emulsions to separate the two. Oil soluble demulsifiers can also dissolve in toluene and xylene and acts best when temperature is increased above certain degree.

What are Corrosion Inhibitors?

Corrosion Inhibitors are chemicals that change the corrosion rate of metals or their alloys. They are helpful in that they can prevent metals from corrosion caused by oxygen, carbon dioxide and carbon dioxide. They have also been applied to prevent bacterial, yeast and fungi growth. In water-based drilling systems, they can be applied to remove oxygen that is dissolved in water or search for sulphide.

Role of Corrosion Inhibitors in an Oilfield

Corrosion inhibitors are applied as oilfield chemicals to prevent metal equipment from corrosion damage, as might result when the metal surface is exposed to corrosive gases. These gases include hydrogen sulphide, oxygen and carbon dioxide. The corrosion inhibitors absorb on metal surfaces as protective films and thus prevent occurrence of corrosive reactions on the surface of the metal equipment.

Water Soluble and Oil Soluble Inhibitors

Water soluble corrosive inhibitors are compounds that are soluble in water and are put in water to reach the steel surfaces in order to prevent corrosion, especially in water cut producing wells. They can also be used to protect corrosion of metals in transmission lines and separators. They protect steel equipment in oil production, especially when there are mixed liquid components (water and oil) that could also contain corrosive gases.

Oil soluble corrosive inhibitors are mainly carboxylic acid salts of organic amines that can dissolve in oil and are used to prevent metal equipment from corrosion, especially in oil and gas mines. They also form a film on metal surfaces to prevent corrosive reactions between metals and gases.

This article has been written by Govindbhai Mathurdas Patel.