Frequently Asked Questions

1. What ID restrictions are created by the addition of a thermoplastic liner to standard tubing sizes?

Tubing Size

ID with PE Liner

Drift with PE Liner

2 3/8"



2 7/8"



3 1/2"



2. Can Polycore Tubular Linings be used with Hydraulic Fracing?

Polycore liners work with all types of fracing fluids, and will show virtually no sign of wear due to abrasion.

3. Does Polycore thermoplastic liners reduce power requirement for pumping?

Our liners typically reduce power requirements due to the reduced surface roughness compared to steel.

When running your WEM (Well Evaluation Model) for rod pump wells, injection wells, disposal wells, or hydraulic fracing please use the following surface roughness values. These values are tested and verified values from real samples, and tested to the RZ DIN standard.

New Steel 35 microns
Polycore Liners 1.5 microns

4. What is the typical failure mode of Polycore’s thermoplastic liners?

Our in house knowledge base knows which well environments are best suited for our technology, and will help ensure our liners are only used in suitable applications.

Our technology team is continually developing new technologies, which is increasing the number of suitable applications including CO2 and H2S rich environments.

Please refer to our installation instructions for proper handling techniques.

Special care must also be taken not to exceed the temperature rating of our products. Please consider heat created by submersible pumps, and the temperature of well treatments such as hot oil flushes. Excessive heat will cause thermoplastic liners to soften, swell, and weaken. The effects of heat are irreversible.

5. Can Polycore thermoplastic liners be used in CO2 rich environments?

CO2 is a small linear molecule that can permeate all thermoplastics to some degree. In order of permeation to occur, the CO2 must be exposed to the liner in a free gas state. If the CO2 is dissolved or entrained in produced oil or injected water, it will not permeate the thermoplastic liner. The rate and degree of permeation is dependent on the temperature of the line and gas, the pressure of the gas, and the CO2 content in the gas. These three variables are codependent on each other, and in many cases where either the CO2 content of the gas is very low, the temperature is low, or the reservoir pressure is too low, the CO2 gas may not permeate through the thermoplastic liner enough to cause a problem.

Polycore recommends speaking with our technology team prior to the installation of any Polycore product in any particular well Environments. Our team will ensure the technology you have chosen is suitable for the specific application.

Polycore is also developing a CO2 / H2S impermeable liner which will be available very soon.

6. Do routine wireline operations damage thermoplastic liners?

No. Polycore technology has proven to be very durable and resistant to wireline damage.

7. Who produces Polycore’s thermoplastic lines?

We only use approved industry leading thermoplastic tube manufacturers.

8. Can Polycore products be used with a premium connection?

Modified proprietary connections have been developed for aggressive applications and will be available soon.

9. Is paraffin wax build up reduced when using Polycore liners?

Yes. Due to the reduced surface roughness of our thermoplastic lines, paraffin wax build up is generally minimized.

10. How does Polycore protect the coupling from corrosion?

The thermoplastic liner on the end of the tubing is a slightly larger diameter than the pin end. When the coupling is screwed on to the tubing, the coupling threads cut into the thermoplastic liner and create a barrier. Any exposed coupling in the J-Area is protected by an internal thermosetting Fusion Bonded Epoxy Coating. Rings, donuts, or premium connections are never required in most conventional applications.

Polycore’s technology provides 100% holiday free coverage along the entire string of tubing.

11. Can Polycore thermoplastic liners be installed in used tubing?

Yes. The installation of our liner is based on a mechanical bond, therefore allowing our liners to be installed in used tubing. Polycore products can also be installed directly over existing plastic coatings with no cleaning or surface preparation required.

12. Can fiberglass rods be used Polycore liners?

Yes, but Polycore recommends using new fiberglass rods. Used fiberglass rods may have wear spots with exposed glass fibers which can damage the thermoplastic. If used fiberglass rods are going to be used, the need to be resin rich on the surface with no wear spots.

13. How do you inspect thermoplastic liners before “re-running”?

Tubing can be drifted prior to re-running. Because the mechanical bond creates some tension in the thermoplastic liner, cuts during mishandling may case buckling and an ID restriction. A visual inspection can also be conducted to identify liner damage on the pin ends or throughout the tubing.

14. Can you or should you still use rod guides?

No. When using a Polycore thermoplastic liners rod guides are not required or recommended. Operators who use rod guides with thermoplastic lined tubing will dramatically shorten the life of their liner.

15. Will well stimulation fluids damage Polycore’s thermoplastic liners?

No. Polycore’s products are chemically inert, and can be used with most types of well stimulation fluids, including acid.

16. Will Polycore’s thermoplastic liner move inside the tubing?

Our unique installation process provides a mechanical bond down the entire length of the tubing. Our moulded end finish secures the liner in place on both ends of the tube, mitigating any movement and intrusion of corrosive fluids behind the liner.

17. Does heavy sand production cause any concerns with the use of thermoplastic liners?

No, we have never seen a sand related problem.

18. Do Polycore liners come with a pressure rating.

Even though our liners are relatively thin wall with a limited pressure rating of approximately 150 psi, we do not provide a pressure rating. The steel tubing is expected to provide 100% of the structural integrity of a lined tubing string.

Do you have a question for Polycore Tubular Linings?

Please submit your question here.




Do you have a question for Polycore?

Please submit your question here.

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