The offshore HC Jacket is located in the Heera Field of ONGC Mumbai High at a water depth of 60.10 meter. During inspection the framing level, which is located at EL(-) 06.00 meters of the HC platform, was found to be detached. Dolphin Offshore Enterprises (India) Limited requested Nautec to replace the entire frame with a new frame through the application of grouted clamps methodology.


  • Pre-Engineering; Inspection; In-place; Fatigue; Pushover and FEA analysis
  • Supply/provision of grouting material NaX® Q140
  • Supervision of installation of clamps
  • Grouting facility; tools and equipment; engineer and grouting crew
  • Cubes casting and testing


  • Due to the installation of numerous clamps that were all interconnected to form a single structure, grouting of single clamp was not possible, hence all the clamps were grouted in one go.
  • Holding all the clamps together from start till finish of the grouting process was a huge task in itself and was made possible by installing the leg clamps one at a time, carefully following the sequence of installation.
  • The job required intense rigging arrangements in order to hold all the clamps together.


  • Nautec provided engineering and grouting services for underwater member replacement of Level-C on HC platform using high performance cement NaX® Q140.

Client Benefits

  • The entire level-C, located at (-) 06.00meters, was replaced with grouted clamps without any underwater welding or shut down of the platform.
  • This structural repair was one of its kind in restoring the jacket strength to allowable margin of operation.
  • All the deliverables were achieved with high quality performance, client acceptance and satisfaction.

Click here to download the project case history.