Composite downhole scale inhibitor

The deposition of scale in the wellbore of oil wells is the most direct hazard to crude oil production. It can cause a decrease in reservoir permeability, hydrophilicity of the reservoir, blockage of the borehole, difficulty in setting the packer, difficulty in heat dissipation of the electric pump motor, jamming of the electric pump blade guide wheel, pump jamming, pump leakage, and other faults.

The measures currently used in oil fields, such as adding a large dose of anti scaling agent to the oil casing annulus and injecting high concentration anti scaling agent into the near wellbore formation, have achieved good results. However, there are also issues such as high costs and heavy workload. The long-acting solid scale inhibitor made of a combination of high-efficiency scale inhibitor and organic polymer scale inhibitor is used to make a chemical solid scale inhibitor that is lowered into the well. It has the advantages of small dosage, long action cycle, low cost, and convenient use. It is an effective, economical, and feasible anti scaling measure.

Structure and working principle

The composite downhole scale inhibitor consists of solid scale inhibitor blocks, pipe bodies, joints, filter plates, and inner screening tubes. The high-efficiency anti scaling drug block is composed of high-efficiency anti scaling agent, framework support agent, dissolution rate regulator, and a small amount of active agent.

Efficient anti scaling agent AW is mainly composed of a combination of AS-1 and WSP-3 efficient anti scaling agents. AS-1 is a multi-component organic potassium phosphate with good anti scaling effect. WSP-3 is a ternary polymer. The compounded anti scaling agent AW overcomes the inefficiency of a single anti scaling agent, and its anti scaling effect is much higher than using a single anti scaling agent.

Framework support agent, made of polymer, is a good anti wax and anti scaling agent. It has a polymer network structure and has a dispersing effect on scaling crystal nuclei, allowing them to suspend in water without depositing or adhering to metal surfaces to form scale. It is mixed with anti scaling agent and processed to form, supporting the anti scaling agent to slowly dissolve in water.

Dissolution rate regulator is a high molecular weight polymer that can change the dissolution rate of high-efficiency anti scaling agents in anti scaling blocks at different temperatures based on their usage. A small amount of activator has the effect of preventing the adhesion of scaling crystals to the tube wall and damaging the crystal structure.

Mix the above-mentioned drugs in a certain proportion, stir evenly, and solidify them into a solid anti scaling block with a large hole in the middle through specialized equipment. Then, put it into a specially designed working cylinder to make a solid anti scaling device. Under the oil well pump or electric pump, the anti scaling agent slowly dissolves in the downhole fluid and plays an anti scaling role through adsorption, chelation, dispersion, and other effects.

Main technical parameters

Main features

Anti scaling agents can be slowly dissolved in downhole fluids, and their anti scaling effects can be achieved through adsorption, chelation, dispersion, and other processes.