*Performance and Application

In the process of oil and gas extraction, it is often necessary to improve the recovery rate through acid fracturing. The concentration of hydrochloric acid used in the acid fracturing process is as high as 10%~20%. High concentration acid solution not only has a strong dissolution effect on the formation, but also causes serious corrosion to fracturing equipment and downhole tubing that come into direct contact with the acid. Especially in deep and ultra deep well environments, where the bottom hole temperature can reach up to 130-160 ℃, acid solution has a stronger corrosive effect on downhole tubing, and corrosion inhibitors need to be used to control the corrosion. Continuous tubing fracturing technology is a newly emerging process technology for fine fracturing of deep or long horizontal reservoirs in recent years. During the operation of this technology, the acid liquid stays in the tubing for a long time. However, the corrosion inhibitor products currently on the market generally have unsatisfactory corrosion inhibition effects in high temperature environments of 130-160 ℃, and cannot provide protection for oil pipes.

The HTCI series high-temperature acidification corrosion inhibitor is an efficient inhibitor used for high-temperature acidification fracturing. The main agent is Mannich base, and the auxiliary agents are emulsifiers, surfactants, and solvents. It has low toxicity and environmental protection characteristics, and has an efficient corrosion inhibition effect on the corrosion caused by acidification under high temperature conditions, without causing pitting corrosion.

*Product characteristics

◆ Under high temperature (200 ℃) acidification conditions, it still has efficient corrosion inhibition effect

◆ Good compatibility: It has good compatibility with thickeners used in acid fracturing

◆ Degradable, no pollution to the environment

*Corrosion inhibition mechanism

The HTCI series high-temperature acidification corrosion inhibitor is a compound organic corrosion inhibitor, with the main component being Mannich base corrosion inhibitor. Mannich base corrosion inhibitor molecules contain multiple oxygen and nitrogen atoms with lone pair electrons, and there are 2 or 3 non coordinating atoms between oxygen, nitrogen, or nitrogen and oxygen. So the Mannich base molecule is a chelating ligand, and the lone pair electrons of its coordinating atoms enter the DSP empty orbitals hybridized by iron atoms (ions), forming coordination bonds, undergoing chelation, and forming a relatively complete hydrophobic protective film, thereby preventing the anodic process of corrosion reaction in which the corrosion product iron ions diffuse into the solution; The cathodic process of corrosion reaction is suppressed by the coverage effect, which slows down the corrosion reaction rate and achieves the purpose of corrosion inhibition. The synergistic effect of auxiliary agents and corrosion inhibitors enhances the corrosion inhibition effect. By changing the physical state or chemical bonds on the surface of the steel sheet, and forming complexes with some corrosion inhibitors through hydrolysis under high temperature and acidic conditions, the adsorption of corrosion inhibitors on the iron surface is further enhanced, thereby improving the corrosion inhibition effect.

*Technical Indicators

Note: The evaluation of corrosion inhibition performance is based on the standard "SY/T 5405-1996 Test Method and Evaluation Indicators for Corrosion Inhibitors Used in Acidification".

*Usage

The HTCI-06 high-temperature acidification corrosion inhibitor is mainly composed of two agents, A and B. After injection, the mass ratio of A agent to B agent is 3:1. The recommended total addition concentration of Agent A and Agent B in a 20% hydrochloric acid environment at 200 ℃ is 6wt%. However, due to the complexity of on-site conditions and materials, the actual injection concentration still needs to be optimized and adjusted according to the fracturing operation situation.

Specific filling method (6wt% filling concentration): First, add 4.5wt% A agent with acid solution, stir thoroughly, and then add 1.5wt% B agent with acid solution. For example, in 1kg of acid solution, first add 45g of agent A, stir thoroughly, and then add 15g of agent B.

*Packaging And Storage

Corrosion inhibitor HTCI-06 is generally packaged in polyethylene plastic drums, with packaging sizes of 25kg, 200kg, and 1t. During storage and transportation, it should be protected from direct sunlight and vigorous handling. Please store it in a cool, dry, and well ventilated place.

*Safety and Protection

Corrosion inhibitor HTCI-06 is a non-toxic and environmentally friendly chemical agent with minimal harm to human health and the environment. It is non flammable, non explosive, and non corrosive. But if it comes into contact with the skin, it needs to be rinsed with plenty of water, and in severe cases, medical attention should be sought. Operators need to take basic protective measures and wear protective equipment, including rubber gloves, protective goggles, and rubber shoes.