Thermoflex® pipe is ideal for downhole applications including velocity strings and submersible tubing.

Using Thermoflex® pipe for downhole applications has numerous benefits over steel tubing:

  • Unmatched corrosion resistance

  • Lower coefficient of friction

  • Lower pressure drop, allowing applications for smaller diameter tubing

  • Higher fluid velocities, resulting in more lifting capacity for solids without creating additional pressure

Velocity Strings

Small-diameter Thermoflex® production tubing can be used as velocity strings to enhance liquid lifting in gas wells.

Thermoflex® tubing is manufactured using polymers that are inert to hydrocarbons, CO2, H2S and brine, eliminating corrosion concerns. The tubing also has half the pressure drop of steel pipe of similar size, allowing smaller diameter tubing to be used to maintain gas flow above critical velocity without exerting additional backpressure on the formation.

The tubing weighs approximately one tenth the weight of steel, and comes in continuous coils for rapid, low-cost installation.

Applications 

Thermoflex® tubing is designed for wells that exhibit low to moderate liquid inflow into the well along with low formation pressures. A general rule of thumb allows for one barrel of fluid for every 10 MCF of gas produced. Fluid can be a mix of brine, oil, condensate or other fluid.

Specifications

Thermoflex® tubing for velocity strings available in sizes from 1 in. OD (0.63 in. ID) to 2.375 in. OD (1.88 in. ID) in pressure ranges from 500 to 2,500 psi. Other sizes and pressure ranges are available upon request. Depending on the corrosiveness of the well and the expected downhole temperature, the tubing is constructed from either nylon (wells below 180° F) or polyphenylene sulfide (for wells between 180°F and 250°F). Twaron fibers are braided between and inner and outer layer to improve burst strength and to minimize elongation. Delivered on continuous spools, Thermoflex® tubing requires a metal termination coupling on each end to lock the braid in place. Either zinc chromate-plated carbon steel or duplex stainless steel couplings can be used, again depending on the well environment.

ESP and Tubing

Thermoflex® submersible tubing works well when electric submersible pumps (ESPs) are used to lift significant volumes of fluids from wells.

The tubing weighs approximately one tenth the weight of steel, and comes in continuous coils for rapid, low-cost installation.

Applications

The tubing can be used with centrifugal, diaphragm or hydraulic pumps. Thermoflex® continuous tubing is designed to handle the weight of the pump and electric cable, and can withstand the hydrostatic pressure in wells up to 4,000 feet TVD. For wells over 4,000 ft TVD, contact your Polyflow representative for special design consideration.

Well candidate evaluation

At Polyflow, we can help you determine if a Thermoflex® submersible tubing is right for your well and your ESP application.

Candidate evaluation begins by properly sizing the tubing to create the minimum critical velocity required to lift solids in the flow stream. Once the tubing diameter is selected the total dynamic head curve is generated for the specific well depth. This curve is used to select the best ESP for the well conditions. Thermoflex® production tubing can be matched with commercially available ESP style and models for the best application.

Benefits of Thermoflex® submersible tubing

The benefits of Thermoflex® tubing versus conventional steel are derived from its inherent corrosion resistance and its low coefficient of friction. The tubing has roughly half the pressure drop of similarly sized steel tubing. This allows the use of smaller diameter tubing to create fluid velocities to lift solids along with the flow stream without creating additional pressure against the pump. For example, 1 in. OD (0.63 in. ID) submersible tubing can lift up to 250 bbls/day of fluid, and 1.25 in. OD (0.88 in. ID) can lift up to 600 bbls/day of fluid.

The benefits of Thermoflex® Submersible Tubing include:

  • High velocity flow to lift solids from the well improving pump life

  • Corrosion resistant to CO2, H2S and brine

  • Rapid, low-cost installation

Specifications

Thermoflex® production tubing is available in sizes from 1 in. to 1.75 in. OD, in pressure ranges from 1,000 to 3,000 psi. Other sizes and pressure ranges are available on request. Depending on the corrosiveness of the well environment and expected downhole temperature, the tubing liner and jacket is constructed from either nylon (for wells below 180° F) or polyphenylene sulfide (for wells between 180° and 250° F). It is reinforced with braided Aramid fibers to improve burst strength and provide resistance to elongation. Delivered on continuous spools, Thermoflex® tubing requires a metal termination coupling on each end to lock the braid in place. Either zinc chromate-plated carbon steel or duplex stainless steel couplings can be used, again depending on the well environment.