13 Oct 09 9:06
I guess a little background would be warranted based on the answer by Mr. Jones. We are building a polymer injection facility to inject polymer and water into existing oil wells. So, the piping we built was for a water and polymer mixture. Neither the water or polymer should be corrosive. So to answer the questions above:
a) The fabrication quality control is very good. Full visual inspection during fabrication, radiography and hydrotest after construction in accordance with B31.3 requirements.
b) There really should be nothing going on inside the pipe except transferring polymer and water from the injection facility into the well heads. Keep in mind, this polymer basically makes the water a bit more viscous.
c) Consequence of corrosion would be a leak in a moderatley high pressure line (approximately 50 bar). Since there are no toxic chemicals, hydrocarbons, lethal implications or anything similar, the risk of a release is very minimal. Remember, this is in essence water lines.
d) We are working off customer specifications which required external cleaning of the welds, but nothing mentioning internal passivation.
This whole situation is because of corrosion we are seeing in the pipes due to water which was left in the pipe for several months. After testing some pumps and equipment, we did not drain the water. The water had some chlorides and H2S, along with other chemicals typical with well water. The pipes sat with water in the hot Middle Eastern sun (Oman) for upwards of 7 months while another portion of the plant was being constructed. Over time, the pipes developed pits which worked their way into holes. Metallurgical review has stated this is typical of fresh water contamination in stainless steel and even if the pipes had been internally passivated, the leaks would still have occurred.
The basis for my question is because there is specualtion that the construction company should have passivated the pipes internally. They claim that it is not standard practice unless it is required by specification. For example the food industry or in the service of a specialty chemical. What I'm trying to do is take blame from the construction company and assign it to where it should exist, with the company not following preservation procedures after commissioning and testing of equipment. I was hoping to gauge a sampling of construction procedures to see how often internal passivation is done. For the record, in my 21 years as a quality manager in large construction projects, I have never passivated internal pipes, nor have seen it specified.
Regards gentlemen. Any input would be appreciated.