Fractured basement play development on the UK and Norwegian rifted margins

Abstract

Fractured crystalline basement reservoirs (basement) on the UK Continental Shelf (UKCS) and the Norwegian Continental Shelf (NCS) have been underexplored. Over the last 12 years, Hurricane Energy has deliberately set out to explore basement potential by exploring and appraising the Rona Ridge, West of Shetland; and the Rona Ridge Lancaster Field is now being progressed towards being the first UK basement field development. The Norwegian basement play is also recognized as a potentially material resource through serendipitous oil discoveries, with the 16/1-15 well, drilled in 2011, being the first successful full-scale basement test on the NCS. Building on this success, the 2018 Rolvsnes appraisal well (16/1-28 S) has demonstrated the significant basement potential of the extensive Utsira High and confirmed the materiality of a Norwegian basement play. The Rona Ridge and Utsira basement discoveries are used as a comparison with two other, yet to be evaluated, prospective basement plays on the NCS, with the objective of establishing technical subject areas where future UKCS and NCS collaboration would aid in accelerating understanding of the UKCS-NCS basement play.

Volcanic reservoirs: historic and current context

“…All of them are available in supplementary material, sorted by country. In the fractured basement alone, there are 126 production fields spread across 24 countries (Trice et al, 2019). In this type of igneous reservoir, the biggest highlight was in the Bach Ho field in Vietnam, discovered in 1975 in the offshore Cuu Long Basin.…”

“…The field produced oil from Cretaceous and Triassic granodioritic and granitic rocks overlaid by Oligocene lake shales, and production was estimated in 2,000,000 Mbbl with flow rates of 14,000 barrels of oil per day (BOPD) (Tan et al, 2016). More recent discoveries from the Shetlands platform, the Lancaster and Whirlwind fields, in the United Kingdom, have a potential of 3,000,000 Mbbl (Trice et al, 2019) and the La Paz field, in Venezuela, with an average production of 3,600 BOPD in granites (Koning, 2014) also represent a good example of volcanic reservoirs.…”

“…In the case of older ages, in particular, the presence of fault and fracture zones is important for the exploration of fractured basement reservoirs (Trice et al, 2019). These fractures develop an interconnected system that contributes to increasing the permeability of reservoir and also allowing the hydrocarbon migration, as shown in figure 7.…”

Basement highs: Definitions, characterisation and origins

“…(a) Geoseismic section used to show how a fractured basement high reservoir and trap can: (1) be charged by petroleum from onlapping source rock kitchens, (2) be sealed above and laterally and (3) have been a provenance for adjacent clastic reservoirs. Modified from Trice, Hiorth, and Holdsworth (2019). (b) Schematic illustration of the Rona Ridge petroleum source kitchens (Nuzzo et al, 2018) and schematic charge pathways into the Rona Ridge basement high.…”

Characteristics and formation mechanism of the fractures in Archaean buried hill: A case study in the BZ19‐6 Block, Bohai Bay Basin, China

“…One of the most important fractures in these reservoirs is those created by tectonic events (Hasan, Shang, & Jin, 2018; Salah & Alsharhan, 1998; Ye, Chen, Niu, & Wang, 2020; Yu et al, 2019); fractures are ubiquitous and control both strength and transport of the fluid (McCaffrey, Sleight, Pugliese, & Holdsworth, 2003). Previous works have demonstrated the first order control that fracture networks exert over the porosity and permeability of the reservoirs in the Sousa Basin (Carvalho, Mendes, & Costa, 2013), the PengLai oil field in the Bohai Bay Basin (Ye, Niu, & Wei, 2020), and the Lancaster Field and the Lewisian Gneiss Complex of NW Scotland (Holdsworth et al, 2019; Holdsworth et al, 2020; McCaffrey, Holdsworth, Pless, Franklin, & Hardman, 2020; Trice, Hiorth, & Holdsworth, 2019).…”