Maximize the value of 4D seismic from non-repeatable surveys: A case study of ORN-on-streamer 4D processing to enable the seafloor transition at Liza, offshore Guyana

High-resolution streamer surveys have been exclusively used in the past to develop and monitor the sanctioned oil fields in the Guyana Stabroek Block. In 2022, the block coventurers decided to transition to seafloor 4D acquisition. This decision was driven by anticipation of increased field facilities and simultaneous operations (SIMOPs), a modified reservoir depletion plan to include water-alternating-gas (WAG) injection, and OBN’s superior ability in monitoring complex and subtle 4D signals. This paper highlights considerations in business timeline, acquisition planning, and 4D interpretation that mitigated the risk of this transition, and how modern workflows and processing technologies (e.g., OBN-on-streamer 4D and least-squares migration) were leveraged to enable this transition and maximize the value of 4D seismic from non-repeatable seismic surveys.