Geophysics SIG Meeting – October (Online)

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Speaker: Gary Marsden – Harbour Energy

Topic: 4D Seismic in the Catcher Area – Shining a new light on reservoir management in complex injectite sands

Abstract

The Catcher, Varadero and Burgman fields of the Central North Sea comprise complex Eocene injectite sandstone oil-filled reservoirs with small associated gas attics. First oil was achieved in December 2017 and cumulative production of over 80 MMstb has been realised to date.

15 subsea oil production wells have been drilled across the 3 fields, supported by 4 water injection wells for sweep and pressure support. A pilot gas re-injection scheme commenced in 2020 with the aim of recovering trapped attic oil.

Field development is geophysically driven and benefits from high quality 2011 3D baseline acquisition. Seismic response of thin sub-tuning sands is strongly influenced by reservoir fluids and far stack coloured inversion has proven highly effective in discrimination of hydrocarbon sands and pay prediction.

A VOI study, supported by Sim2Seis modelling, demonstrated significant economic value in 4D seismic acquisition. Benefits included improvements in dynamic understanding of the reservoir, optimisation of the reservoir management strategy and identification of infill well targets.

A monitor 4D seismic survey was acquired in May 2021 and results demonstrate a strong 4D signature. Hardening responses related to water injection and aquifer influx are clearly evident as are softening responses associated with gas injection.

Gary Marsden – Harbour Energy

Geophysicist with over 35 years of international E&P experience spanning exploration, development, research and operations gained in a variety of subsurface roles across diverse geographical locations.

Graduated with a degree in geophysics from Cardiff in 1985 and started working life in site survey acquisition to experience the bright lights of Grimsby & Hull!!

After a Ph.D. in geodynamics from Liverpool in 1990 a varied subsurface career followed including work as a basin modeller in Shell, a QI geophysicist in PDO, and a development geophysicist in Amerada Hess, Talisman & Maersk.

Has been an independent consultant since 2011 and currently on a contract with Harbour Energy working on the development of the Greater Catcher area.