Case study



T & T Salvage and Sealand Projects are currently undertaking a Decommissioning Options Assessment Study for the Block 31 North East Development.

The primary objective of the study is to identify and evaluate feasible options for decommissioning of the facilities, enabling BP to decide on the best possible option to take forward to the next stage of the project.

The north-eastern sector of Block 31 Field is roughly 400km from Luanda and represents the PSVM development. It comprises four separate oil fields named Plutao, Saturno, Venus and Marte (PSVM) spread over an area 34 kilometers wide and in water depths of up to 2,040 meters, Reservoir fluids are to be produced with Single Leg Hybrid Riser (SLHR) systems, and Lazy Wave service umbilicals.

The PSVM area has been developed and is operated by BP who have a 26.67% equity interest in the project. The remaining 73.33% is shared between Sonangol, SSI and Equinor. Production commenced in December 2012.

Oil is exported via a dedicated FPSO (Floating Production Storage & Offtake) vessel, loading to shuttle tankers. Storage on the FPSO is 1.6 mmbbls. There is a total of 36 wells divided between Plutao (12), Saturno (7), Venus (8) and Marte (9).

BP are investigating the costs associated with the decommissioning of the Block 31 Field with a Workshop and study to be performed to allow BP to prepare recommendations for permitting partners and concessionaire approval of Block 31 PSVM decommissioning scope, timescale and cost for submission to Angola Region.

Work included:

  • Concept Screening
  • Cost, Schedule & Risk Modelling
  • GAP Assessment
  • Enabling Assets & Equipment Screening
  • P.L.A.N.C.
  • Tow Master
  • Data Review
  • FPSO Cleaning
  • Basis of Decommissioning
  • Option Selection
  • Onshore Disposal
  • Assurance & Risk Management