Inhibitors for Seawater to Hydrotest a Pipeline & Long Term Stor

[GregLamberson]

Guys:

We have several pipelines varying in length and diameter, up to 35kms in length and dia of 10" - 24" that are going to be hydrotested and left full of water until commissioning - they may lay in "storage" for a year+.
Nitrogen is not an option, and de-watering, drying and leaving it full of "dry" air has been ruled out.

The pipelines will be laid offshore in shallow water (18m maximum).

As far as an inhibitor mix, what has been proposed (by Nalco) is the following:

1 - EC1304A, a water soluble, oil dipersible corrosion inhibitor effecitvie in fresh & brine water & offers protection from H2s and CO2 corrosion - 100PPM
2 - EC6064A, an ammonium bisulfate oxygen scavenger used to prevent oxygen corrosion - 60PPM
3 - EC6197A, a water soluble aldehyde with quaternary ammonium compound for control of aerobic and anaerobic bacteris - 250PPM

Does anyone see any issues with the proposed inhibitor mix?

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[SJones]

1. Is it all coming as one package with a single dose rate so the poor field crew doesn't have to perform 3 calculations?

2. A bit light on the oxy scav - 100 ppm would be a nice round figure

3. Quat is not a nice biocide for discharging into the sea. If you will be discharging into the sea, look at alternatives like gluteraldehyde or THPS.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdoweb/

 

[SJones]

PS base the concentrations on the 'active constituent' and not the total fluid mixture of the supplied chemmical.

Steve Jones
Materials & Corrosion Engineer

http://www.pdo.co.om/pdoweb/

 

[GregLamberson]

SJones

Thank you for the feedback. Yes, it is all coming in a package, i.e. single dose rate. The water will eventually be processed at the gas plant, so no sea discharge. Will ask them to bump up the O2 scavenger.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com