Minimal Facility Wellhead Platform, Concept Selection Study, Offshore Indonesia
A South East Asian operator and its prime contractor required a number of unmanned, ~400Te minimal wellhead platform (WHP) concepts to be designed. The development was in 90m water depth, and the well fluids were to be exported by flowline to a nearby host FPSO.
ICON developed WHP Designs (and associated Installation Methodology and Cost) for a number of concepts. Subsequently, an agreed WHP final concept was selected.
Design and Installation
The finalised concept for the WHP was a tripod platform comprising a two-piece jacket and a pile base (template) with driven pile. This concept utilises the proven method of installation using the jack-up rig. The added benefit of this method is that it removes the need for expensive additional offshore construction assets i.e. Heavy Lift Vessels - HLVs.
The entire platform was designed to be installed from one rig position with the upper and lower jacket sections transported horizontally and then upended to the vertical using crane assets on the rig. This negates the need for a Heavy Lift Vessel and hence results in significant cost savings. The platform was designed to also be installed using a HLV, if an HLV could be secured on commercially attractive terms.
Proposed Topsides Concept
This concept option can also be modified to adapt a suction pile base foundation, depending on soil conditions, field life etc.
Well conductors would be protected within the jacket legs and critical connectors would not be directly exposed to the marine environment or risks associated with boat impacts.
The proposed Minimum Jacket configuration was not overly sensitive to the weight of the topsides facilities and provided a flexibility with design concepts and equipment layouts.
‘Future-Proofing’ ESG and Decommissioning
The design concept is consistent with managing current and foreseeable ESG requirements. The design and installation methodology for the proposed WHP means it can eventually be decommissioned and removed and/or abandoned without requiring the use of a heavy lift crane barge.
The decommissioning would be conducted in conjunction with other drilling activities an operator has planned for the area thereby reducing rig mobilisation costs.
Isometric of the Minimal Wellhead Platform Concept