Offshore Oil & Gas Future Development

Here is the list of activities during pipelay installation. Assume laying pipe from an existing platform to another existing platform. Conventional 8 point mooring derrick lay barge (DLB) is utilized to execute the job.

1. Temporarily drop anchor outside field. Wait for clearance form platform to start operations. Some client might require contractor to brief the platform management on their activities prior start up.
2. Meanwhile waiting for clearance, ensure all preparation to start lay pipe is ready.
   1. Install stinger
   2. Prepare tunnel to lay pipe.
   3. Rig up welding machine.
   4. Tensioner shoes are set up to accommodate pipe size.
   5. Bring along side transportation barge and start transfer as much line pipe to barge deck to fill up tunnel for start up.
   6. Ensure end preparation machine & swabbing rabbit for cleaning is ready in place.
   7. Prepare pipeline internal equipment, i.e. buckle detector, X-ray crawler.
   8. Ensure firing stations and other stations are ready to lay pipe.
   9. Fill up tunnel with appropriate line pipe (Check wall & concrete thickness)
   10. Well start-up head. Start-up head should filled with PIG (Pipeline Internal Gauging)
3. Upon receiving confirmation to start work, perform anchor running operations. Set up barge as per approved anchor pattern.
4. Start-up pipelay. 2 common methods to start laying pipe. i.e. Deadman anchor or Bow string attached to jacket leg.
5. Lay pipe slowly until pipestring touch down to seabed.
6. Slowly pick up speed on pipelay and lay away until the final destination.
7. Common activities during layaway.
   1. Interval check of stinger condition by ROV & air diver.
   2. Profile check by ROV.
   3. Barge will dynamically crawl in an approved anchor pattern.
   4. Survey to ensure barge is always in the right direction and properly record the pipeline asbuilt route.
   5. QA/QC to ensure welding & NDT activities are as per approved procedure.
   6. Safety officer to ensure all procedure & precautions are taken for safe operations.
   7. Maintain communication, good record & reporting to onshore head office.
8. Sometimes contractor might encounter Cable or pipeline crossings.

The above notes is open for discussion, I might miss some important activities. Readers are invited to share experience and knowledge. Next time, I’ll write about laydown activities.