PVDF Encapsulated Control Line Flatpack for Subsurface Application in Oil and Gas Wells

Meilong Tube manufactures either welded or seamless hydraulic control lines for subsurface applications. Hydraulic control line is available in mainly five materials, varying wall thicknesses, and a wide range of working pressure ratings. The line is supplied on spools to exact length requirements. Upon request, it is pressure tested hydraulically, purged with nitrogen gas, or clean oil liquid, and sealed on both ends prior to shipping.

Welded hydraulic control line is floating plug drawn to ASTM specifications and is available in any length. Material types for hydraulic control lines include stainless steel TP316L which is suitable for sweet to moderately corrosive environments, Duplex stainless steel 2205, Super Duplex stainless steel 2507, nickel alloy Incoloy 825 and Inconel 625 are suitable for severely corrosive environments and high working pressures and temperatures. Control system fluids must be compatible with the environments and operating temperatures of the control line.

Control line encapsulation also is available, where requested, to provide additional crush and abrasion resistance during installation. The encapsulation material should be matched for compatibility with well fluids and temperature requirements.

Encapsulated Control Line Flatpack

Encapsulation is a plastic that is extruded over metal tube. Encapsulation prevents damage to the metal tubes during the manufacturing process. The encapsulation also provides additional abrasion resistance and is required if cable protectors are installed to enhance the holding force over each production tubing connection.

Encapsulations are available in a wide range of configurations with options of single pass encapsulation and dual pass encapsulation for added protection.

Application of Flatpack

Flatpacks are commonly used when several different lines are terminated at approximately the same depth in the well.

Common applications include intelligent well systems, deep-set chemical injection lines with downhole gauge cable and safety valve lines with shallow set chemical injection lines. For some applications bumper bars are also encapsulated into the flatpack to provide additional crush resistance.

Standard & Approvals

Control Lines are manufactured according to applicable ASTM standards for each specific material.

Tubes can be supplied flushed, filled, and filtered per client requirements and to the appropriate NAS/SAE standards.

Quality & Testing

- Manufactured in accordance with Standard Inspection and Quality Plans

Design & Construction

- Encapsulation for single line

- Encapsulation profiles to suit customer application

- Custom Line Marking

- Full range of application materials

Encapsulation Materials

- PP (Polypropylene) /TPR (Santoprene) / PA

(Nylon) / PVDF / ETFE (Tefzel) / ECTFE (Halar)

FEP / PFA / ECA 3000

Features of Encapsulated Control Line Flatpack

Maximize protection of downhole line

Increase crush resistance during installation

Protect control line against abrasion and pinching

Eliminate long term stress corrosion failure of control line

Improve clamping profile

Single or multiple encapsulation for ease of running and added protection

Available Alloy Grades for Control Line Tubing Inside Encapsulation

Chemical Composition of TP316L

Norm Equivalence

TP316L is an austenitic chromium-nickel stainless steel with molybdenum and a low carbon content.

Corrosion Resistance

Organic acids at high concentrations and moderate temperatures

Inorganic acids, e.g. phosphoric and sulphuric acids, at moderate concentrations and temperatures. The steel can also be used in sulphuric acid of concentrations above 90% at low temperature.

Salt solutions, e.g. sulphates, sulphides and sulphites

Caustic environments

Austenitic steels are susceptible to stress corrosion cracking. This may occur at temperatures above about 60°C (140°F) if the steel is subjected to tensile stresses and at the same time comes into contact with certain solutions, particularly those containing chlorides. Such service conditions should therefore be avoided. Conditions when plants are shut down must also be considered, as the condensates which are then formed can develop conditions that lead to both stress corrosion cracking and pitting.

TP316L has a low carbon content and therefore better resistance to intergranular corrosion than steels of type TP316.

Standard Flatpack Encapsulation Profiles

Round, Single Line	Item	Standard Dimensions
	1/8’’ OD Line	0.250’’ (6.35 mm) Dia.
	1/4’’ OD Line	0.433’’ (11.0 mm) Dia.
	3/8’’ OD Line	0.535’’ (13.6 mm) Dia.
	1/2’’ OD Line	0.660’’ (16.8 mm) Dia.

Square, Single Line	Item	Standard Dimensions
	1/8’’ OD Line	0.250’’ x 0.250’’ (6.35 mm x 6.35 mm)
	1/4’’ OD Line	0.433’’ x 0.433’’ (11.0 mm x 11.0 mm)
	3/8’’ OD Line	0.535’’ x 0.535’’ (13.6 mm x 13.6 mm)
	1/2’’ OD Line	0.660’’ x 0.660’’ (16.8 mm x 16.8 mm)

Rectangular, 2 Lines	Item	Standard Dimensions
	1/4’’ OD Line	Width: 0.710’’ (18.0 mm) Height: 0.410’’ (10.4 mm)

Rectangular, 3 Lines	Item	Standard Dimensions
	1/4’’ OD Line	Width: 0.990’’ (25.1 mm) Height: 0.410’’ (10.4 mm)