Purpose

The purpose of this recommendation is to facilitate the cleaning and preservation of the interior of the carbon steel lines on all drilling riser.

Scope

The following procedure is to address the cleaning and preservation of our drilling riser whether it is stored on the rig or on land.  This scope is designed to address risers that have been in storage for a length of time where internal corrosion could build in the main tubes and in the carbon steel auxiliary lines.  This scope will detail the cleaning procedures, application of preservatives, and capping the lines to maintain condition until the riser is ready to run.

Detailed Description

It has become obvious that after the riser has been stored on the deck of the rig, on land or in a service yard for an extended period of time, the carbon steel lines to include the main tube start to corrode.  There have been several incidents where the rigs have suffered extended downtime due to the internal corrosion of these lines.  No one should assume that because the riser is coming from shore base, a service yard, new build facility or has been stored on the rig for an extended period of time, that the riser is ready to run.  When it is known that section of riser has not been used for long periods of time, (no matter what the reason) the information should trigger an inspection of the internal areas of the carbon steel lines to insure they are ready for use.  If they are found to be corroded, this procedure once followed, will have the riser ready for use whether it be run the next day or 6 months.