Publications

Pertamina Hulu Energi (PHE) Offshore Northwest Java Lima Field is experiencing continuous sea bed subsidence at a rate of 0.15 meter/year resulting in serious operational risk at Lima Flowstation. The subsidence has reduced the air gap between platform decks to sea level up to 3 meters from the original design. The subsidence also has affected a number of wellhead platforms in Lima Area. The immediate solution to mitigate the risk at the wellhead platforms was to relocate equipment from cellar decks to main decks. The focus of this paper is the complex task of synchronized raising of three platforms, interconnecting bridges and flare bridge of Lima Flowstation Complex. Various studies were undertaken to return Lima Complex back to safe operations. It was concluded that a two stage solution would require the shortest period of Lima production shut down with acceptable levels of project costs. Two stages were required as the consequence of the limited air gap. First stage was to raise the objective structures 1 meter to give enough head room to install the second stage 4-meter raising jacks. Project Management strategy was the key to successful execution of platform deck raising. It began with contracting strategy, engineering design including interface between Versabar as the designer and provider of the synchronized deck raising system and PT Timas Supplindo as the EPCI Contractor for installation of the system, procurement and fabrication strategy, HSSE plan, quality plan and offshore execution strategy including commissioning and start up. All specifications were determined in the Project Execution Plan and Project Master Schedule. The project summary was to raise three platforms, interconnecting bridges and flare bridge of Lima Complex at synchronized and controlled speed. It was achieved by controlling the pressure and hydraulic oil flow to each hydraulic jack. Elevation variance of each leg was monitored from the control room by means of string pot and certain levels were selected to stop raising operations for calibration. Fifty-five days following shutdown the Lima Platform was back online, five days ahead of schedule. The first raising of approximately 1 meter was completed on September 4, 2013 and second raising of additional 3 meters on September 19, returning Lima Flowstation to safe operations and ensuring PHE ONWJ an additional 12-15 years of use.