OBN for a passive margin? The streamer to seafloor transition in Guyana

Between 2022 and 2023, ExxonMobil and its Stabroek coventurers acquired two 4D monitoring campaigns over the Liza field. One used streamer technology, while the other used ocean bottom nodes. The transition from streamer to seafloor seismic was driven by technical and operational considerations. With Liza in the early stages of the production stage, decisions were considered within a full life of field perspective to pursue maximum value from 4D. A primary technical driver for transition to seafloor was the expectation that the ability to observe 4D signals from water alternating gas (WAG) injection is improved by the lower noise recorded by seafloor data. An additional operations driver was expected with the location of field infrastructure having less impact on 4D imaging and increased SIMOPS flexibility with seafloor operations. A 15-month, blockwide OBN campaign acquired baselines over all five of the development areas as well as the first node monitor over Liza. OBN-on-Streamer processing was used to bridge the gap between the streamer and node datasets at Liza, and early 4D analysis has revealed insights and actions that support the value we have placed on 4D seismic in the Stabroek development.