Completing the Kizomba A and Kizomba B projects in concert with one another and with world-class schedule performance was a rare opportunity which yielded outstanding results. These two projects, located within 7 miles of each other in Block 15 offshore Angola, were brought online 11 months apart and combine for recoverable reserves estimates of approximately 2,000 MBO with a daily production greater than 500,000 barrels per day. Kizomba B built upon experience gained from Kizomba A to improve execution performance from contract award to the start of production (31 vs. 36 onths).
This paper highlights the installation phase of the KizombaA and B Tiebacks sub-project, outlining key challenges relative to safety, technology, vessel spreads, simultaneous operations (SimOps) management, timeline, and performance indicators. Due to considerable differences between Kizomba A and B tiebacks, the Tiebacks sub-project did not claim as much direct synergy from the 'Design One, Build Multiple' strategy as did the other Engineering, Procurement, and Construction (EPC) Kizomba work packages. However, continuous implementation of lessons learned and the deliberate repeat use of Kizomba A prime contractors and ExxonMobil personnel led to accelerations and additional flexibility of installation activities that ultimately contributed to an improved first oil date for Kizomba B compared to that of the already impressive Kizomba A schedule.
Kizomba A and B shared the same field development concept. This concept includes subsea drill centers and a close-moored surface wellhead platform (SWHP) tied back to a spreadmoored floating production, storage, and offloading vessel (FPSO). The FPSO and SWHP are connected via flexible fluidtransfer lines (FTLs). Oil is offloaded from the FPSO via a buoy based oil offloading system (OOS) composed of one oil offloading buoy (OOB), its mooring system, and two 20-inch, rigid steel pipe oil offloading lines (OOLs). Figures 1 and 2 illustrate the similar Kizomba A and B field development concepts.
Figure 1. Kizomba A Field Development Concept (available in fullpaper)
Figure 2. Kizomba B Field Development Concept(available in fullpaper)
The execution strategy, which was consistent between the two projects, specified four EPC sub-projects, awarded to four prime contractors, and separate contracts for a mobile offshore drilling unit (MODU) and a main instrumentation and controls contractor (MICC). Following is a brief description of the four major sub-projects:
EPC1 (SWHP): the supply, transport, installation, hook-up, and commissioning of the SWHP, awarded to ABB Lummus Global (ABB-LG) for Kizomba A and Daewoo Shipbuilding and Marine Engineering (DSME) for Kizomba B.
EPC2 (FPSO): the supply, transport, and commissioning of the FPSO, awarded to Hyundai Heavy Industries (HHI) for both Kizomba A and B.
