Polyflow

Velocity String Tubing

Description
PolyFlow has developed production tubing to enhance liquid lifting in gas wells thereby maximizing production. By utilizing polymers inert to hydrocarbons, CO2, H2S, and brine and taking advantage of their inherent low coefficient of friction, the tubing has both superior corrosion resistance and half the pressure drop of steel tubing. This allows for smaller diameter tubing to maintain gas flows above the critical velocity required for liquid lifting while not putting additional backpressure on the well formation. The result is consistent maximized gas production. The tubing is approximately one tenth the weight of steel and comes in continuous coils for rapid low cost installation compared with larger steel equipment.
Case studies are available for velocity string tubing.

Benefits
The benefits of properly sized Thermoflex® Velocity Strings include:

• Continuous Liquid Lifting and Maximized Steady Gas Production
• Corrosion Resistance
• Minimal Intervention
• No Paraffin or Salt Adhesion
• No Ongoing Chemical Treatment
• No Mechanical or Moving Parts
• Stable Line Pressures

Applications
Thermoflex® Velocity Strings are not for every application. They are designed for low to moderate liquid inflow into the well and are beneficial with low formation pressures. A general rule of thumb allows for one barrel of fluid for every 10MCF of gas. Fluid can be a mix of brine, oil, condensate or other fluid.

Specifications
Thermoflex® Velocity Strings come in diameters from 1" OD (.63" ID) to 2 3/8" OD (1.88" ID) and in maximum operating pressure from 500PSI to 2,500PSI (Velocity String/Submersible Tubing Size Chart) Other pressure ratings and sizes available upon request. The tubing is constructed from either nylon or Fortron (Polyphenylene Sulfide) depending if the well is sweet or sour and if the well is below 180°F or between 180°F and 250°F. Twaron fibers are braided between and inner and outer layer for both burst strength and to minimize elongation. The product is continuous and requires a metal termination coupling on each end to lock the braid in place. The customer has a choice of zinc chromate plated carbon steel couplings or duplex stainless depending upon the well environment.

Evaluating a Well Candidate
The first step in determining if Thermoflex® Velocity Strings are right for a well candidate, a questionnaire must be filled out and sent to PolyFlow for Nodal Analysis. PolyFlow will run its nodal analysis modeling for thermoplastic tubing to determine the proper tubing and size and construction for the well candidate. A copy of the well analysis will be sent back to the customer and a PolyFlow representative will review the results.

PolyFlow will also put the customer in contact with a certified installer or can coordinate with a customer's existing installer for proper installation training. PolyFlow representatives will provide operator training on the proper operation of the well with Thermoflex® Velocity Strings. Please consult the PolyFlow Installation and Operating Guides for an overview.

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