The Pierce Field, Blocks 23/22a, 23/27, UK North Sea

Abstract

The Pierce Field contains oil and gas in Palaeocene Forties Sand and fractured Chalk, draped around the flanks of a pair of Central Graben salt diapirs. Whilst the two diapirs constitute a single field containing over 387 MMSTB AND 125 BCF, it took almost 25 years, and several advances in seismic, drilling and production technology, for the field to be brought into production. Many appraisal wells were drilled on the field. Data from these wells were interpreted to suggest the field was highly segmented both in terms of petroleum distribution and pressure variance. On the basis of this interpretation an economic development required a floating production system with long reach horizontal wells to penetrate the many reservoir segments.

Salt tectonics in the North Sea Basin: a structural style template for seismic interpreters

“…Some 15 salt diapirs, circular rather than linear in plan view, are fossilized in the Cenozoic section that overlies the Central Graben Birch & Haynes 2003;Rank-Friend & Elders 2004). Seismic sections of salt diapirs are shown in Figure 15.…”

The influence of shortening and sedimentation on rejuvenation of salt diapirs: A new Discrete-Element Modelling approach

“…Rejuvenation of diapirs is a common phenomenon of salt basins around the world and is commonly driven by regional shortening. On continental margins, regional shortening can be caused by gravity-driven salt tectonics, such as in Angola (Hudec and Jackson, 2004), Brazil (Quirk et al, 2012;Fiduk and Rowan, 2012), Nova Scotia M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT (Albertz et al, 2010) and the Gulf of Mexico (Rowan et al, 2000;Hudec et al, 2013) or by its combination with thick-skinned crustal tectonics as in NW Africa (Davison, 2005;Tari and Jabour, 2013;Tari et al, 2017), the North Sea Harding and Huuse, 2015), the Parentis Basin (Ferrer, et al, 2012), and the Gulf of Cadiz (Matias et al, 2011) Some of the most successful salt-related hydrocarbon plays along these margins occur associated with salt structures that were reactivated by shortening, such as the flank-of-diapir play in the Central Graben in the North Sea, examples including Banff, Mashar, Monan, Pierce and many other discoveries in the flanks of squeezed upright diapirs worldwide Birch and Haynes, 2003), and sub-salt plays beneath allochthonous salt tongues and sheets, such as the Ship Shoal and Mahogany oil fields in the Gulf of Mexico, plays that host considerable volumes of hydrocarbons, and are becoming increasingly important as seismic imaging methods improve (Montgomery and Moore, 1997).…”

Halokinetic modulation of sedimentary thickness and architecture: a numerical modelling approach

“…The unique observation from M2 (slow sedimentation) is non-extensive layers that thin towards and eventually onlap and pinchout against the long-lived, salt-related topographic high ( Figure 9A). M2 results are analogous to the Top Cretaceous (lime green) to Mid Eocene (red) stratigraphy around the Pierce diapirs ( Figure 11C), which is not laterally extensive across the diapirs (Davison et al 2000a;Birch and Haynes 2003;Scott et al 2010;Carruthers et al 2013). The Top Cretaceous -Mid Eocene package, equivalent to S1-S3 in the models, thins significantly towards both diapirs, before onlapping the flanks (Figure 9A; 10A; 10C).…”