Materials for produced water systems: A short article

Materials for surface facilities:

  • Piping: GRE, FBE coated CS / HDPE lined CS, DSS / SDSS
  • Well hook-up: FBE coated CS, DSS / SDSS
  • Bulk injection lines: HDPE lined CS, GRE
  • Injection flowlines: Coated CS, HDPE lined CS, GRE
  • Valves: bodies DSS / SDSS or CS with coating or 825 / 625 weld overlay; trim DSS / SDSS
  • Pumps: bodies & impellors DSS / SDSS

Materials for sub-surface facilities:

Tubing: Coated CS, GRE lined CS

Metallic materials for piping & well hook-up:

  • DSS / SDSS
    • DSS PREn > 34
    • SDSS PREn > 40
  • Coated CS
  • FBE coated pipe, spools & fittings
  • HDPE lined CS
  • Loose fit liner and roto-lined spools & fittings

Metallic materials for valves & pumps:

  • Valves: CS, CS with 825 / 625 overlay for Bodies; & DSS / SDSS, 825 for trim
  • Pumps: CS, CS with 825 overlay for Bodies & DSS / SDSS impellors

Non-metallic materials:

GRE:

  • First used in 1982 for low pressure water systems and fire fighting systems
  • >1300 km GRE pipelines, 113 km water service & remainder in multiphase service
  • On-plot piping

Successful use requires:

  • Proper design: standards (ISO/company), qualification testing, stress analysis (supports/anchors), eliminate vibration
  • Manufacture: QC during production
  • Installation: experienced crews, supervision & inspection

Installation of adhesive bonded joint (Fig. 1):

Installation of adhesive bonded joint
Fig. 1: Installation of adhesive bonded joint

GRE Failures:

Most occur during installation due to:

  • Poor workmanship
  • Insufficient anchoring
  • Poor flange alignment

In-service failures are rare & only 2 have occurred: One involved a flowline and second was on flange connected to a pump

In service failures (Fig. 2):

  1. 6” production flowline operating at 5 bar and 60 deg C with > 98% water-cut failed after 4 years due to Insufficient wetting of fibers during manufacture.
  2. Flange on 250 mm diameter piping in oil service directly connected to a pump cracked causing a leak due to pump vibration causing mechanical failure at flange/pipe interface

HDPE:

  • Loose fit liner has been used for water injection lines since 1988
  • >205 km HDPE lined CS pipelines in water service
  • Rotolined spools and some HDPE lined CS pipe used for on-plot piping
  • No limit on pressure; temperature 70 deg C for liner, 60 deg C for rotolined spools

Successful use requires:

  • Proper design & installation: standards (company)
  • Installation: experienced crews / supervision for butt fusion welding of pipe & flanges, & for applying correct tension
Examples showing failures for GRE and HDPE
Fig. 2: Examples showing failures for GRE and HDPE

Failure modes:

  • Radial collapse: HDPE liner collapses inwards radially due to vacuum conditions occurring during shutdown procedure or a pressure build-up in the annulus between the liner and the CS pipe.
  • Axial collapse: HDPE liner buckles inwards due to compressive axial stress resulting from differences in thermal expansion between the steel pipe and the PE liner itself.
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Anup Kumar Dey

I am a Mechanical Engineer turned into a Piping Engineer. Currently, I work in a reputed MNC as a Senior Piping Stress Engineer. I am very much passionate about blogging and always tried to do unique things. This website is my first venture into the world of blogging with the aim of connecting with other piping engineers around the world.

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