Maximizing the value of the first time-lapse OBN data at Liza field with co-processing

In this case study, we present results from the first ocean bottom node (OBN) based 4D imaging at the Liza field, offshore Guyana. With two nominally repeated OBN surveys acquired within less than a year, we initially employed a parallel 3D processing flow to generate fast-track 4D images within 12 weeks of receiving all the monitor data, facilitating an early interpretation of the 4D response. Subsequently, the full-track flow utilized all necessary 4D co-processing technologies to address non-repeatability issues from their physical origins. The final products offered high-resolution 4D signals with minimal noise, which was crucial for understanding reservoir changes during this brief period of production and gas/water injection. The improvements achieved by transitioning from a fast-track parallel flow to a full-track co-processing flow demonstrate that, even with highly repeatable time-lapse OBN surveys, appropriate 4D co-processing solutions are still essential for maximizing the value of OBN data for reservoir monitoring.