Hydro Test of Pipelines Required

Pipelines filled with diesel oil 300 meters under the ocean and not a scrap of documentation to be found. Operational logs including why it hasn't been used for 2 years? Maintenance and procedure manuals? Test procedure and schedule?

I don't mean to be negative but I hope your pipeline is not near any American beaches.

What a nightmare! I dont know what the rules and regulations stipulate where you are located geographically, but they are obviously very relaxed. In Australia you are required to comply with with all regulatory requirements as per AS2885.3, and have detailed documentation to prove the fact. You really need to contact someone that knows what they are doing! Pipeline maintenance etc should all be documented in something like a 'Pipeline Maintenace and Inspection Plan' (PIMP), if you dont have one of those, then you need to refer to the relevant standards and documentation (by the sounds of it.....you have none). If you find the relevant standard it will tell you when you need to perform a Hydrostatic test, and it will tell you what the necesary steps are for the the reinstatement of a 'moth-balled' pipeline.

Seek competent help immediately is my advise. Oils spills can be VERY costly, both moniterrally and ecologically.

Imagine the problems of getting fuel to service WWII vehicles in Europe. Well they solved that issue with under sea pipe lines from the UK to Northern France. I hope you can enjoy this short historical video.

Undersea pipelines are not new and are still being constructed. The Langeled pipeline is the longest submarine line of significant size. You may want to contact the people involved and find out what standards they used for construction and use. If you are trying to transport oil in North America, you may find the issue very political and subjected to eco-warriors looking for a cause. It may not even be the pipeline itself that is the target but rather people who just do not want anyone to burn fossil fuel. The pipeline is just the soft target that the oil fields need.