Acquisition of zero to negative offset seismic data – proof of concept.

Olje- og gassindustrien har i flere tiår etterlyst 0 til negativ offset marin seismikkdata for forbedret avbildning. Flere forsøk har vært gjort tidligere uten kommersiell suksess. North GeoServices har utviklet et unikt innsamlingssystem som vil muliggjøre 0 til negative offsets. Prosjektet er ment å demonstrere at 0 til negativ offset data kan innhentes, og at det er mulig å håndtere utsetting og innhenting av utstyret i vann trygt og effektivt. Dette demonstrasjonsprosjektet er en av flere byggeklosser for "All-In-One" systemet vårt som vil bli utviklet når 0 til negativ offset og håndtering av utstyr er bevist. Testen vil derfor bli utført med et desimert system som bruker fire streamere og tre luftkanoner. For å bevise funksjonalitet og fleksibilitet, vil offset på +50 m, 0 m og -50 m bli testet. Videre vil ulike interleave-posisjoner bli testet for å demonstrere fleksibilitet og fortreffelighet av systemet.

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Primary objective will be to acquire high/ ultra-high resolution, azimuth rich data set with zero to negative offset using a single vessel only. Zero to negative offset has never been achieved in commercial operations to date. This innovation relates to marine towed seismic systems, specifically the deployment of in-water equipment in such a way that the inline distance from the first sensor on each streamer is in line with each source center point. The system as defined has main seismic streamers suspended from the vessel using streamer lead-in cables. Lead-in cables are positioned such that the heads of all seismic streamers have a common inline offset from the vessel. For this demonstration project it is planned to operate four streamers with equidistance separation. For demonstrating azimuth rich data, and prove the advantage of 0 to negative offsets, three source arrays will be deployed interleaved with the streamers. For proof, the sources will be towed in repetitive test at 50 m ahead of the streamer heads, in line with streamer heads, and 50 m behind streamer head to demonstrate the importance of 0 and very near offsets never acquired previously. Once the streamer systems have been deployed the Seismic Source Array can be positioned between the seismic streamers and with a zero inline offset to them as they have a shallower profile and are unobstructed by the Seismic Streamer Head Floats as the High-Resolution Streamer is suspended without Streamer Head Floats. The secondary objective will confirm that the in-water components provided by SeaMap Pte Ltd, can be deployed and recovered safely and efficiently. The operation of such needs to be verified to ensure the deployment techniques can achieve the zero/negative offset goal. The resulting data set once processed should provide a clearly improved subsurface image in comparison with legacy data sets.