The oil and gas industry has for decades requested 0 to negative offset marine seismic data for improved imaging. Several attempts have been made in the past without commercial success. North GeoServices has developed a unique acquisition system that will enable 0 to negative offsets. The project is intended to demonstrate that 0 to negative offset data are acquired, and that it is possible to deploy and recover the in-water equipment safely and efficiently.
This demonstration project is one of several building blocks for our All-In-One system that will be developed when the 0 to negative offset and deployment and recovery is proven. Thus, the test will be performed with a decimated system employing four streamers and three air-gun source arrays. In order to prove operability and flexibility, offsets of +50 m, 0 m, and -50 m will be tested. Further, various interleave positions will be tested to demonstrate flexibility and excellence of the system.
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.