Hydrotest water quality

[mishaal]

Good day,
Is there a standard on the water quality used for hydrotesting oil flow lines? i mean in terms of salinty level, ph, bacteria, etc.........
thanks in advanced.
regards,
mishaal

 

[zdas04]

Mishaal,
If there is a standard, many years of looking for it have failed to turn one up. There's bits and pieces in several places. Most states in the US have regulations about the quality of water that must be met before discharging test water onto the surface or into agriculture or rivers. Pretty generic stuff for the most part.

I like to use water that is pretty nasty (e.g., produced water with moderately high TDS, pH above 7.0, and minimal hydrocarbons) already because it can't get much nastier. I can usually return this water to where I got it.

If I start with city water, then it gets rusty, has disolved gases that mess up the test etc. Disposing of the red-looking water is often a big problem.

Water from lakes, rivers, ponds, bar ditches and other untreated sources always have bacteria which can yield corrosion problems, H2S generation and other really bad problems - and you can never put the water back into the river because it looks bad from the iron oxide you've washed off the pipe.

David

 

[mishaal]

thanks for the quick reply,
my question is can we use salty water for hydrotesting? will it affect the oil flowlines?
the salt level is like 10 times as salt as sea water.

regards,
mishaal

 

[Hench]

I think the most important thing to look at is. How will impurities in the water effect the piping material I'm testing? If you are preparing a Hyrotest package for a client. Your client will most likely have a standard procedure which will provide you with all the information you need.

Good Luck!

Hench

 

[zdas04]

Mishaal,
If you use very salty brine, you are asking for a world of problems. No matter how carefully you de-water the line, some of this stuff will get left behind and you have a very good chance that introducing oil will start corrosion cells (not to mention possibly pushing your oil out of spec for the refinery). Maybe not, but I wouldn't risk it.

I stop at a maximum TDS of 10,000 mg/l which is considerably less than sea water. I also make sure the water pH is more than 7.5. Occasionally I put in biocide, but then the water must be disposed of as a waste stream that can't go into an E&P disposal stream.

David

 

[jr98]

My suggestion is use De-mineralised water of PH say 9.5 for the hydrotest of lines.Salt water is not appreciable because after hydrotest u have to do Chemical cleaning on the line to give magnetite coating on the internal surfaces of the pipeline against corrosion.

jacob