Extensive subsea pipeline remedial work offshore Qatar

During an As Built Survey upon completion of installation of a Gas Export line from Qatar to UAE, it was discovered that damage had occurred at various locations to subsea fabric formwork at frames protecting expansion loops. 

The Client had a predicament as how to complete repairs. Due to two factors, shallow water depth which prevented the use of a DP II vessel to deploy Divers and a congested area with pipelines which prevented the use of an anchored mooring system.

Zakher Marine came up with an innovative plan to utilise a Jack Up Barge to complete the repairs.

Zakher Marine project Team developed procedures and risk assessments prior to mobilisation of a team consisting of Divers, Surveyors, grouting equipment and personnel.

Upon arrival at location divers deployed marker buoys on the repair locations and adjacent pipelines giving the Barge Master a visual guide to the locations. In addition to the Barge Management Survey Software, a Sector Scan Sonar was deployed on a survey pole mounted on the Bow of the Barge. This gave the Master a clear view of the seabed locations of the target area and location of adjacent pipelines.

This permitted the barge to safely approach the repair locations to within 6 meters distance.

The barge then Jacked Up at the locations, a small Air Gap was maintained and Divers deployed to install new fabric formwork which was then filled with grout pumped from the barge.

Twelve total locations completed within time and budget.

Extensive subsea pipeline remedial work offshore Qatar

Extensive subsea pipeline remedial work offshore Qatar

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