Characterisation of effective permeability in heterolithic, distal lower shoreface sandstone reservoirs: Rannoch Formation, Brent Group, UK North Sea
File(s)
Accepted version
Author(s)
Onyenanu, Godspower
Hampson, Gary
Fitch, peter
Jackson, matthew
Type
Journal Article
Abstract
The reservoir properties of distal lower-shoreface and distal wave-dominated delta-front deposits, which consist of sandstone beds with locally scoured bases and mudstone interbeds, are poorly understood. The lower Rannoch Formation (Middle Jurassic Brent Group) forms an interval of such heterolithic sandstones in many North Sea reservoirs, and is used to illustrate a workflow for rapid estimation of reservoir properties and their sensitivity to key parameters. Mudstone-interbed thickness distributions in cored reservoir successions are compared to the thickness distribution of sandstone scour-fills in an outcrop analogue(s) in order to identify mudstones with the potential to form laterally extensive barriers to vertical flow. Effective kv/kh at the scale of several typical reservoir-model grid cells (200 × 100 × 20 m) is estimated in intervals bounded by these mudstone barriers via a simple analytical technique that is calibrated to previously documented reservoir-modelling experiments, using values of sandstone proportion measured in cored reservoir successions. Using data from the G2 parasequence (Grassy Member, Blackhawk Formation, east-central Utah, USA) outcrop analogue, mudstones bounding 3–8 m-thick, upwards-coarsening successions in the lower Rannoch Formation may define separate stratigraphic compartments in which grid-cell-scale effective kv/kh is estimated to be 0.0001–0.001 using a streamline-based analytical method.
Date Issued
2019-11-01
Date Acceptance
2018-11-01
Citation
Petroleum Geoscience, 2019, 25 (4), pp.519-531
ISSN
1354-0793
Publisher
Geological Society
Start Page
519
End Page
531
Journal / Book Title
Petroleum Geoscience
Volume
25
Issue
4
Copyright Statement
© 2018 The Author(s). Published by The Geological Society of London for GSL and EAGE. All rights reserved. For permissions: http://www.geolsoc.org.
uk/permissions. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics
uk/permissions. Publishing disclaimer: www.geolsoc.org.uk/pub_ethics
Subjects
Science & Technology
Physical Sciences
Geosciences, Multidisciplinary
Geology
BOOK-CLIFFS
DISCONTINUITY SURFACES
BLACKHAWK FORMATION
GRASSY MEMBER
DEPOSITS
ARCHITECTURE
UTAH
PARASEQUENCE
STRATIFICATION
SEDIMENTOLOGY
Energy
0403 Geology
0914 Resources Engineering and Extractive Metallurgy
Publication Status
Published