Inland + Coastal

Shallow water pipelay


Atchafalaya Bay, Louisiana

Morrison was contracted to lay & bury dual 12-inch pipelines and a 20-inch pipeline in 2-feet to 6-feet of water.  The pipelines were installed in various pipeline sections with welded tie-ins installed along the pipeline routes.  Burial of the lines were to 3-feet of cover.  The project also involved a 20-inch and 30-inch hot tap.  The subsea valve assembly installed allowed for two subsea tie-ins, (1) 12-inch and (1) 20 inch.  The 12-inch pipelines terminated at the main facility and offshore platform.  The 20-inch pipeline terminated at the main facility and subsea tie-in.

There were multiple unique aspects of this project, one of which was Morrison’s engineered solution to avoid mid-line tie-in flanges.

Additional unique aspects of the project:

  • Pre-planned job with client to determine constructability issues related to the pipeline route
  • Engineered solutions to provide safer, more cost-efficient solutions
  • Worked with the client to perform temporary tie-in of 12-inch pipeline so that client could begin producing prior to project completion
  • Installed approximately 18-miles of pipe and a subsea assembly that was over 100-feet in total length
  • Project consisted of approximately 90 people, including in-house dive teams

Morrison laid inland pipeline with offshore conventional lay barges, which allowed for 24-hour pipelay operations.   The project spanned over 7 months, with crews working 24/7 operations during winter months.



The project was located in wildlife management area and was completed safely, without environmental impact.

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