Kaombo Start-Up Strategy: Together We Throve!

Abstract

The FPSO Kaombo Norte came on stream on July 27th offshore Angola. When both its FPSOs will be at plateau, Kaombo, the biggest deep offshore project in Angola will account for 15% of the country's oil production. It produces light oil from six fields scattered over an 800-square-kilometer area. Gindungo, Gengibre, and Caril fields are connected to the Norte FPSO while Mostarda, Canela, and Louro fields will be producing on FPSO Sul. The full development stands out for its subsea network size with more than 300 kilometers of lines on the seabed within 1500-2000m water depth, including subsea production wells more than 25km away from the production facility. In order to secure a safe First-Oil and to smoothly start-up the production, a detailed and cross-functional study was carried out. The first step was to start from a clean slate by forgetting all previous startup scenarios: the three loops candidate to start-up hydrocarbon production were re-analyzed in depth to evaluate strengths and weaknesses. A task force composed of all involved disciplines, including contractors, was put in place in order to apply a cross-functional approach. Constraints from reservoir up to topsides were analyzed providing an overall picture and clear ranking to develop the start-up strategy. An ambitious planning of the commissioning activities combined with a relatively short-term reservoir management were crucial to lock production loop priorities with water injection and gas export systems readiness. The work jointly performed contributed to serene environment for a safe start-up and ramp-up. Following the assessment, decision was made to start first the most "powerful" reservoir despite a challenging flowline. The relatively high initial pressure and oil undersaturation, the robust open-hole gravel-pack completions and high productivity wells were beneficial to stabilize the multiphase flow in the subsea network. Improvement of the production was rapidly made with the start-up of the second production loop only fifteen days after. Postponement of the water injection system and the availability of the riser base gas lift were judiciously calculated: the readiness of these systems arrived in due time to respectively slow down the natural depletion of the reservoirs and improve the wells eruptivity and stability of the flowlines. Our capacity to re-invent ourselves and leave behind individual priorities conducted to a collective success captured in the outstanding production levels since early days of field life.