Among marine operations, lifting operations are some of the most common. Multiple challenges can be encountered during offshore campaigns. These are approached by Semar’s team through a practical approach, with the choice of lifting methods and through an analysis approach, giving additional information on dynamic effects to be expected. Semar has participated on various operations involving lifting for which, master mariners, hydrodynamic analysts and project engineers all contributed with their experience and competence.
Projects
› IMR Angola – Lifting analysis of various items – 2016-2017
› Gina Krog – Lifting analysis of various items – 2014 -2016
› ENI Goliat – Lifting analysis of various items – 2011 -2016
› Swire Seabed – Deployment analysis – 2014
› KJT – Jacket installation analysis – 2015
› Fred Olsen Seagreen Project – Lifting analysis – 2012
Areas of competence
› Hydrodynamic motion analyses of vessel – RAOs
› Planning, design and analyses of lifting of small and heavy objects in air, through splash zone and during landing on seabed
› Installation analyses:
› Simplified according to requirements
› Advanced time domain simulations using Sima/Orcaflex
› Verification towards limiting criteria such as object installed, cranes, lifting wires and other installation aids
› Structural analyses of transportation vessel and installation aids
ENI Angola with other partners is developing Block 15/06 in the Angolan deep offshore are located approximately 350 km North – North West of Luanda and 130 km West of Soyo. The west hub development field includes: rigid production line, service rigid line, water injection rigid line, PLETs, PLEM, ILTs, cluster manifolds, umbilical’s and flexibles flow lines and risers system connected to an external turret moored FPSO. The job was divided into two scopes:
- Disconnection and reconnection of the Flexible flow line
Contractor was awarded the disconnection and reconnection of the Flexible flow line FJ-3 & FJ-31 connected between Sangos DC and SAN104 XT. This scope includes development of detailed procedure and the installation analysis for removal and reinstallation of FJ 3/31 using the vessel Skandi Seven. The following analyses were performed:
- Static analysis and lay tables for main steps of operation.
- Dynamic analyses for critical stages.
- Additional various scope
In addition to the re-installation of jumper, the following activities has been performed:
- Deployment analysis of pipe walking anchors
- Deployment analysis of XTree’s
- Sea fastening design
In addition to these scopes, Semar followed up the project and maintained continuity by providing on-site assistance during mobilization and operation.
Scope of work summary
› Disconnection and reconnection of the flexible flowline
› As-found survey
› EFL`s disconnection from MNF GN.
› Jumper removal and recovery to shallow water depth. For dissolving of hydrate inside jumper.
› Jumper re-installation
› As-laid survey
› Disconnection of XMT gooseneck on vessel deck (contingency scope)
› Disconnection of MNF gooseneck on vessel deck (contingency scope)
› Wet storage of jumpers without goosenecks (contingency scope)
› Deployment analysis of pipe walking anchors
› Deployment analysis of XTree’s
› Sea fastening design of various equipment
Key figures
| Client | DOF Subsea/ENI Angola |
| Operator | ENI Angola |
| Project duration | 2017 |
| Vessel | Skandi Seven |
| Project characteristics | Mid-term punctual assistance |
| Contribution in different disciplines |