PLEASE NOTE THAT THE VENUE FOR ABERDEEN EVENING LECTURES HAS CHANGED FOR THE REST OF 2017, EFFECTIVE FROM THIS MONTH.

These events will now take place at the Jurys Inn Aberdeen. The closest car parks are Union Square Car Park and College Street Car Park. Timings remain the same. Food and beverages will still be served. These member-only events are FREE to attend.

‘Challenges of future exploration within the UK Rockall Basin’

With Nick Schofield, University of Aberdeen

Tuesday 16 May 2017, 6.30pm
Jurys Inn Aberdeen, Union Square, Guild Street, Aberdeen AB11 5RG

The UK Rockall Basin is one of the most underexplored areas of the UK Continental Shelf (UKCS), with only 12 exploration wells drilled since 1980. With only one discovery made in 2000 (Benbecula (154/1-1) gas discovery), the general view of the basin from an exploration viewpoint is not positive. However, over the last 15 years, our knowledge of the petroleum systems of the Atlantic Margin has substantially increased. With the recent acquisition of new seismic data by the UK Government as part of the OGA’s Frontiers Basin Research Programme, it is a pertinent time to re-examine the prospectivity of the UK Rockall Basin.

In this talk, we look at the history of exploration in the UK Rockall, and examine some of the key geoscience challenges and unknowns concerning future long-term exploration within the basin, applying some of the updated knowledge developed through recent research on the petroleum systems from other areas of the Atlantic margin, including intra-basaltic plays in the Faroe-Shetland Basin (Schofield & Jolley 2013) and present evidence that points to the potential of a viable intra-basaltic (Rosebank) type play along the eastern flank of the Rockall Basin. In particular, we argue that some of the existing preconceptions of the basin (e.g. lack of viable source rocks), reasons for dry holes and understanding of the future exploration potential may be incorrect.

Importantly, exploration in Rockall is potentially at odds with normal dip-closure-driven exploration and workflows within other UKCS and global basins: as in the UK Rockall, these closures have potentially not been subject to efficient hydrocarbon migration and charge. It is therefore an interesting proposition that the lack of discovery of hydrocarbons within the UK Rockall may be the result of protracted hydrocarbon migration routes, rather than a lack of viable source rocks, which is often cited as the main inhibitor to exploration within the basin.

We also emphasize that, although it is important not to become overly focused on the volcanic sequences within Rockall, the key to fully understanding the prospectivity is the correct integration and understanding of the potential effects that the volcanic rocks within the basin have had on the evolution of the petroleum system.

This work forms part of the Oil and Gas Authority (OGA) Frontier Basins Research Programme and funding award for the 2 year project to The University of Aberdeen ‘Evaluating the Prospectivity of the Rockall Trough –Towards a Complete View of the Petroleum System West of Britain’.

 

 

Coming up in Aberdeen…

AAPG/PESGB Technical Mastery Series
Sand Injectites: Characteristics & Implications for Exploration and Production

With Professor Andrew Hurst, University of Aberdeen & Professor Mads Huuse, University of Manchester

Thursday 29 June 2017
University of Aberdeen, Seminar Room 224, King’s College, Aberdeen, Aberdeenshire, AB24 3FX (http://www.abdn.ac.uk/about/campus/maps/view/112/)

Book your £20 ticket

Sand injectites are the product of subsurface sand remobilization and injection. Large-scale sand injectites were first reported about a Century ago from outcrops in California where they were linked with oil migration through shales. Over the past three decades sand injectites have increasingly become important in the Paleocene to Eocene deepwater sandstone play of the North Sea Basin and injectites are important reservoir units in some of the largest ongoing developments in the UKCS including Mariner, Kraken and Catcher. Sand injection leads to enhanced connectivity across large distances of otherwise low permeabilty mudstones, and targeting of oil accumulations within large-scale sand injectite ‘wings’ has led to rejuvenation of fields such as Gryphon and Harding, although detailed geometries can be complex and difficult to model. Detailed outcrop work has provided vital analogue data that together with increasingly high-definition 3D seismic data are used to inform more optimal development and production scenarios of oil fields hosted in sand injectites.

This workshop aims to present an overview of the characteristics of large-scale sand injection complexes around the world and in California and the North Sea in particular and, to outline their importance to development and production. It should be of interest to anyone involved with exploration, development and production in deepwater clastic sequences including the North Sea Paleogene, but also more frontier areas such as the North and South Atlantic, East Africa, etc.

In most subsurface examples sand injectites co-exist with polygonal fault systems, affecting pelagic and hemipelagic deepwater mudstone sequences, although the presence of polygonal faults is difficult to confirm in most outcrop examples. The best exposures of sand injectites are located in the San Joaquin Basin where detailed examination of individual sandstone intrusions as well as entire injection complexes is possible over hundreds of square kilometres. Outcrop characterization provides useful analogues for subsurface modelling and highlights the significance of dykes which are notoriously difficult to image using subsurface techniques.

Widespread and repeated occurrence of sand injection within the North Sea and San Joaquin basins suggests that triggering and driving mechanisms affected large tracts of the basins more or less simultaneously, although the specific combination of processes has proven difficult to establish and may vary for each basin and injection episode. Impacts of large-scale sand remobilization includes major re-organization of basin plumbing systems, shifting of km3 of sand (reservoir), and insertion of field-size sandstone-prone intervals with geometrically complex geometry that imaging fails to resolve and modelling techniques struggle to represent. The focus of the workshop will be on identification and characterization of sand injectites and on the assessment of their impact on exploration and development.