Geophysics SIG Meeting – April (Virtual Event)

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Topic: Efficient regional MC OBN survey to unlock prospectivity within UKCS

Speaker: Per Helge Semb, Chief Geophysicist – Magseis Fairfield 

Speaker: Hari Krishna, Technical Business Development Manager – CGG

Abstract

During the North Sea summer season 2020 Magseis Fairfield and its partner CGG completed the largest OBN survey ever acquired on the UKCS, covering a total of 1680 sq. km. in the Central North Sea. Covering several producing fields in an area with a lot of subsurface installations and pipelines, preplanning and preparation was key to the success of the project. With long offsets and full azimuth data the scene is set for new insight into this petroleum rich but geologically complex province.

This survey was specifically designed to address the challenges associated with deeper, higher-risk Jurassic and Triassic plays, typically under high-pressure, high-temperature conditions, and the presence of complex structural processes associated with Permian salt movement. The combination of full-azimuth imaging, additional fold and near-offset data will result in significant improvement of deep illumination and noise removal, while helping to illuminate and image the steep flanks and complex architecture created by salt diapirism.

The OBN Cornerstone 2020 project represented a total of 813,000 man-hours with zero Lost Time Incidents (LTIs) was acquired amidst the global COVID pandemic, regulatory and supply chain challenges. The processed MC dataset will benefit from CGG’s high-end OBN processing routines, advanced pre-processing and imaging technologies including FWI. The resulting dataset is designed to bring a step-change in seismic imaging quality and reservoir characterization detail while also bringing new insight to aid continued development of plays and existing fields in the Central North Sea region.

This survey is one of the most efficient OBN surveys acquired to date and has given essential insight into how to operate large scale OBN surveys and deliver cost-efficient OBN exploration surveys.

Figure 1: Cornerstone Multi-client OBN Survey UK – CNS Q23 and Q29 (Acquired by Magseis Fairfield and Processed by CGG)

Figure 2. OBN instrument – Magseis-Fairfield-MASS-ZNODAL

Figure 3. Image courtesy of CGG Multi-Client. Initial Images from OBN Data.