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Specialist Alloy Tubing Tackle Corrosion in Topside and Subsea Applications

Friday, April 05, 2013 by Fine Tubes

With oil and gas extraction moving into harsher and deeper environments the demand for high pressure and highly corrosion-resistant tubing is rising. Fine Tubes' expertise in manufacturing specialist corrosion resistant alloys with those properties needed for control and instrumentation tubing provides cost effective and long term solutions.

Topside Instrumentation

Fine Tubes has been supplying a wide range of high-performance tubes to leading oil and gas companies for the protection of their hydraulic control and instrumentation systems. During the oil and gas extraction process, mainly seamless precision tubing as straight lengths are used for instrumentation equipment that controls measuring devices and supplies hydraulic pumps and tools. The tubing is also used in onshore control panels, topside processing facilities, offshore subsea manifolds and templates up to 2,000m under the sea.

Fine Tubes' control and instrumentation tubing is available from 1.6mm (0.063in) outside diameter for precision instrumentation and monitoring applications on drilling tools up to 63mm (2.475in) OD. High strength stainless-steel, duplex and super duplex stainless-steel, titanium and nickel alloys are used in manufacture. Operating conditions can require our products to be rated up to 60,000Psi operating pressure and with tensile strengths greater than 220ksi (1,515MPa).

The tube mill's extensive range of super austenitic and nickel alloy grade tubes such as alloy 625, 825 and alloy 400 tubes offer longer term solutions over stainless-steels for in harsh offshore environments. Moreover, Fine Tubes' expertise in special grade stainless steels such as 904L and 6 Moly make the tube manufacturers the ideal partner for the supply of instrumentation packages used in the topside construction of Offshore FPSO, FPSSs, Spars and TLPs.

In 904L the corrosion resistant properties are superior to the conventional chrome nickel stainless steels, in particular to sulphuric, phosphoric and acetic acids. It also has a high resistance to pitting in chloride solutions, a high resistance to both crevice and stress corrosion cracking. Therefore, alloy 904L has excellent formability and weldability as well as excellent toughness, even down to cryogenic temperatures.

This grade is particularly useful in control and instrumentation tubing applications where 316 and 317L are not suitable. 6 Moly benefits from high resistance to pitting and crevice corrosion as well as high strength compared with conventional austenitic stainless steels such as 316L. The alloy can also provide excellent resistance to stress corrosion cracking allowing tube cold forming.


Subsea control lines

Improvements in the technology for the enhanced exploitation of oil and gas fields has increasingly required the use of long continuous lengths of stainless-steel and nickel alloy tubing for:

  • Hydraulic control
  • Instrumentation
  • Chemical injection

The benefits of this tubular technology have resulted in reduced operating costs, improved recovery methods and reduced capital expenditure by connecting downhole valves and chemical injection with remote and satellite wells to a fixed or floating central operating platform.

Fine Tubes offers coiled control line in stainless steel and nickel alloys. Our products are used in the following applications:

  • Downhole hydraulic control lines
  • Downhole chemical injection lines
  • Subsea control lines for hydraulic power and chemical injection
  • Smoothbore control lines used in fibre-optic applications