MODENGY coatings have successfully passed trials, and have been implemented to mass production of the hydraulic fracturing equipment

One of the most common technologies to increase the production rate of oil wells is hydraulic fracturing (HF).

Downhole equipment for hydraulic fracturing operates in constant contact with chemically aggressive media in the form of alkaline solutions, groundwater and hydrogen sulfide, as well as passing cement mortar. The consequences of this are corrosion, erosive wear of equipment, deposits (of cement stone) forming, moving units seizing, loss of their operability after downtime.

Looking for an integrated solution for these issues, one of the leading manufacturers of the downhole equipment has addressed the Modengy company.

In order to provide long operability of the hydraulic fracturing equipment, it is required to use special coatings having high chemical resistance, anti-adhesive and anti-corrosive properties, low friction coefficient, high load-carrying capacity, and long service life.

Taking into account the pointed operational conditions and tasks, MODENGY 1014coating was selected and suggested. To verify operability of this product, the equipment manufacturer held benchmark tests for resistance to erosion, and anti-adhesive properties.

Fig.1. General appearance of the coupling for the benchmark tests

MODENGY 1014 testing in the hydraulic fracturing equipment: stages and results

To hold the tests, MODENGY 1014 was applied onto the hydraulic fracturing equipment (see Fig.1, 2).
The essence of testing was in circulation of the test solution, containing among the other things sand and aggressive substances, for 24 hours.

Fig. 2. MODENGY 1014 coating on the parts of the coupling for hydraulic fracturing

When this stage of studying was completed, cement mortar was applied onto the parts before it got cured to verify the anti-adhesive properties of the coating.

After pumping through about 700 tons of ceramic sand and 650 m3 of the hydraulic fracturing liquid combined with the chemical additives of various purposes, no traces of abrasive wear were detected on the parts (see Fig.3).

Fig.3. The parts of the coupling treated with MODENGY 1014 coating without traces of abrasive wear

After pumping through about 700 m³ of the mortar of 1,500 kg/m³ density containing 3-4% of sand, and testing for forming cement stone, the result was considered to be positive (see Fig.4).

Fig.4. The surface of the equipment flow part after testing with MODENGY 1014 coating on it. Cement stone sticking-on is virtually absent

The trials have shown that MODENGY 1014 anti-friction solid-film coating has high resistance to abrasive wear, retains its anti-corrosive and anti-adhesive properties for a long while. MODENGY 1014 has already been implemented into mass application at producing hydraulic fracturing equipment.

MODENGY 1014 is applied onto the parts surface by spraying method, and requires baking in a kiln. After getting polymerized, it forms a thin layer that provides resistance to erosion and corrosion, prevents cement stone from sticking on the flow part of the equipment.

This coating loses no its properties after long downtime, and is able to provide lubrication of the rubbing and moving parts under extreme operational conditions. It is compatible with polymer seals and threaded greases.

So, MODENGY 1014 coating is successfully used on the downhole equipment, and solves the following tasks:

• Protecting the flow part against abrasive wear and corrosive failure
• Reducing and stabilizing the force of opening/closing hydraulic fracturing ports
• Preventing cement stone from sticking-on
• Protecting the surfaces against exposure to HCl (hydrochloric acid), CaCl₂ (calcium chloride), and H₂S (hydrogen sulfide)
• Excluding seizing/ jamming of the moving and rubbing parts after long downtime
• Providing operability of the units with various friction pairs including metal-to-metal, metal-to-polymer, polymer-to-polymer
• Preventing galling of the threaded connections.