Basically its like a time-lapse. Think of it as an equivalent of...

Basically its like a time-lapse. Think of it as an equivalent of taking a selfie each year on your b'day. Each year there's something different as part of the ageing process. Out in the Deepwater, u take a high res image pre-production, compare that with earlier ones where the wells were flowtested. A few years later revisit with another 3Dseis & so on. It is money well spent by a JV.

For instance at SNE, he JV should have record of 3Dseis from 3 surveys shot from 2007, 2015 & currently in 2019, alongwith any VSP survey done during drilling the appraisals. This will help them in identifying Oil-swept zones, any attics or isolated compartments where oil that can b flushed out at a later date by optimum location for a future Oil producer or water/gas injector.

I think their phase-1 gross reserves, i.e 2P - 230 mmbbls should last apprx 8yrs ballpark estimate. Compare that with Jubilee in Ghana, its produced 265 mmbbls from 28th Nov 2010 to 30th June 2019 & the JV r now chasing another 2P-300 with their next phase). Hope this helps.