Success with fractured basement rocksThe 35/9-1 well. Photo: NPD Factpages.

Success with fractured basement rocks

Fractured basement is slowly emerging as an interesting offshore play. Hurricane put the Lancaster field on the UKCS in production last year.

Following the Lancaster discovery of 500 MMboe put into production in May 2019, Hurricane yesterday announced in an Operational update (pdf) that operations are going well from the Aoka Mizu FPSO. Hurricane is pursuing a phased development of Lancaster, starting with an Early Production System consisting of two wells tied-back to the Aoka Mizu FPSO.

The Lancaster field (100% owned by Hurricane) is the UK’s first producing basement field.

Hurricane also announced yesterday that the delineation well of last summer on the Lincoln fractured basement discovery, 205/26b-14 (Lincoln Crestal Well), in the Greater Warwick Area (“GWA”), initially planned to be tied-back to Aoka Mizu in 2020, will be further delayed.

In September 2018, Spirit Energy farmed-in to 50% of the Lincoln and Warwick assets, committing to a phased work program targeting sanction of an initial stage of full-field development.

In Norway, the Lundin-operated Edvard Grieg field has a still-to-be-developed segment in fractured basement rocks proved with the 16/1-15 (Tellus) discovery well, on the Utsira High. This well saw the first successful full-scale production test of a reservoir consisting of cracked and porous bedrock on the Norwegian Continental Shelf (NCS), according to the well description.

Basement wells with cores in orange, no cores in grey. Map and data from the NPD Factpages web site.

More than 70 wells have reached basement rocks on the NCS where all pre-Devonian rocks are regarded as economic basement by the authorities. Therefore the basement lithology varies from igneous to sedimentary, and metasedimentary rocks in addition to different kinds of alteration.

Several wells proved fractured or deep weathered basement on the NCS. Most of these are drilled in the Norwegian sea, an example given is the 2/6-5 on the Mandal High east of Ekofisk with shows. At the Utsira High alone at least eleven wells have proved hydrocarbons, mostly shows, in basement rocks of different descriptions. Basement rocks found elsewhere on the NCS have not proven hydrocarbons yet.

Text: TERJE SOLBAKK

Hurricane Oil will present the Lancaster field and their view on fractured basement under the conference NCS Exploration – Recent Discoveries in Oslo on the 12th – 13th of May.

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