Oil Field and Gas Gathering

PolyPipe^®: The Single Source for Total System Solutions

Moving fluids through pipe in the oil field demands the utmost in flexibility, reliability and performance. That is why PolyPipe^® is the best choice for the energy business. Our high-density polyethylene (HDPE) pipe provides superior flow characteristics, extended life and durability and reduced maintenance than traditional piping materials, anywhere in the oil patch.

We offer a wide selection of HDPE pipe to meet your needs for any oil field application. As a leader in the pressure rated pipe industry, PolyPipe^® features a network of sales offices and distribution centers across the U.S. and around the world. PolyPipe^® has seven U.S. manufacturing facilities that are regionally located to assure timely, accurate delivery to any location you require.

PolyPipe^® has products specifically for the oil and gas industry for gas gathering, crude transmission, water lines and auxiliary lines. Polypipe^® also manufactures products in accordance with the American Petroleum Institute (API) specification 15LE.

TYPICAL APPLICATIONS

• Gas Gathering
• Crude Oil Flow
• Water Flood
• Saltwater Disposal
• Supply Water
• Fuel Transfer
• Main Lines

PE3408/3608 Extra High Molecular Weight (EHMW) Black Pipe - a premium quality, high density, extra high molecular weight, polyethylene pipe specifically designed for the rigors of the oil field. It is produced from PE3408/3608 resin containing not less than two percent (2%) carbon black for superior resistance to UV degradation. This pipe offers outstanding environmental stress crack resistance (ESCR), the best chemical resistance of any polyethylene pipe and high impact resistance. PolyPipe^® oil field products are available in diameters from 1/2" CTS to 6" IPS coiled and straight lengths from 1/2" through 65" IPS.

Fluid and Gas Flow

Fluid Flow

PolyPipe^® has an extremely smooth surface resulting in a very low coefficient of friction and a minimal loss of head pressure due to frictional losses. This, combined with excellent corrosion and abrasion properties, results in excellent flow characteristics throughout the life of the pipe.

For pressurized systems, a Hazen-Williams "C" factor of 150 is used.

Gas Flow

The flow formula for smooth pipe should be used to compute the gas flow rate through PolyPipe^®. It has been found that the Mueller formula for smooth wall pipe describes the flow characteristics of PolyPipe^®.

Refer to the PolyPipe^® Design and Engineering Guide for Polyethylene Piping for additional information.

Chemical Resistance

Polyethylene will not rust, rot, pit or corrode as a result of chemical, electrolytic or galvanic action. Chemicals that pose potentially serious problems for polyethylene are strong oxidizing agents or certain hydrocarbons. These chemicals may reduce the pressure rating for the pipe or be unsuitable for transport. Either can be a function of service temperature or chemical concentration. Continuous exposure to hydrocarbons can lead to permeation through the material or elastomeric gaskets used at joints. The degree of permeation is a function of pressure, temperature, the nature of the hydrocarbons and the polymer structure of the piping material. The chemical environment may also be of concern where the purity of the fluid within the pipe must be maintained. Hydrocarbon permeation may affect pressure ratings and hinder future connections. Refer to the PolyPipe^® Design and Engineering Guide for Polyethylene Piping for additional information.

Thermal Expansion

Polyethylene, like other plastics, has a thermal coefficient of expansion higher than metals. When subjected to a temperature change, unrestrained (not buried) polyethylene pipe will experience expansion and contraction.

The coefficient of thermal expansion/contraction for PolyPipe^® is 1.0 x 10^-4 in/in/°F. As a general allowance, 1" per 100' of pipe per 10°F change in temperature.

Forces due to thermal expansion and contraction can be significant. Proper system design should be used to account for the compressive and tension stresses that can be generated.

Refer to the PolyPipe^® Design and Engineering Guide for Polyethylene Piping for additional information.

Bending Radius

An inherent advantage of PolyPipe^® is its flexibility and resiliency. The minimum bending radius is based upon the Dimension Ratio (DR) of the pipe. This radius is determined by multiplying the outside diameter of the pipe by the radius factor for the corresponding DR.

When pipe is used in pressure applications, the longitudinal stress created by the sum of the bending radius, internal pressure and other stress loads on the pipe should not exceed the material’s design stress rating. Severe but acceptable bends in polyethylene pipelines should be buried or properly restrained.

Design Pressure Rating

The pressure rating of PolyPipe^® is determined in accordance with the Plastics Pipe Institute (PPI) recommended hydrostatic design basis (HDB) for the material, the physical dimensions of the pipe and the appropriate design and service factors. Pressure design calculations are based on the following formula, which relates the stress on the pipe wall to the internal pressure:

Where	P =	Internal pressure, psig
S =		Long term hydrostatic strength, psi (1,600 for PolyPipe® PE3608)
DR =		Dimension Ratio (OD/t)
OD =		Outside Diameter, inches
t =		Minimum wall thickness,inches
DF =		Design factor, 0.5 for PE3608 (GB30 &40), 0.63 for PE4710 (GB50)
F =		Service factor (see table)

Substance	Service Factor, F
Water	1.0
Dry Natural Gas	1.0
Federally Regulated Dry Natural Gas	0.64
Wet Natural Gas	0.5
Crude Oil	0.5

Weatherability

Black PE pipe has a minimum of 2% finely dispersed carbon black; the most effective additive for protecting polyethylene from the effects of weathering.

HDPE PE3408/3608 black PolyPipe^® is suitable for long term above ground storage with a 50 year maximum storage time. Further, these products are suitable for long-term service in above ground applications.

PolyPipe^®: The Advantage in the Field

Cost Effective

Significant cost savings should be expected over traditional pipe materials (steel, fiberglass, PVC) within the same design parameter. Savings accrue both on the initial product cost and by improved installation efficiency.

Ease of Handling and Installation

PolyPipe^® weighs less than one-fourth of comparable steel pipe. Significant savings can be realized in transportation, handling and installation.

Pipe diameters up to 6" IPS can be coiled for ease of handling and storing.

PolyPipe^® is quickly and easily joined and installed by using the heat fusion method or special polyethylene mechanical fittings. Heat fusion produces a solid, leakproof joint as strong as the pipe itself.

Water Hammer and Pressure Surge

The momentum, or inertia, of a moving column of liquid has inherent characteristics that must be dealt with in a piping system. When liquid flow is stopped suddenly, as by a quick closing valve, the inertia is converted into a shock wave or high pressure surge. The faster the liquid velocity and the longer the line, the greater the shock load. Controlled dissipation of this energy is a design feature and a significant advantage of polyethylene pipe.

Refer to the PolyPipe^® Design and Engineering Guide for Polyethylene Piping for additional information.

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