Development of predictive models for the distribution of hydrocarbon reservoir rocks in rift basins
Submitting Institution
University of ManchesterUnit of Assessment
Earth Systems and Environmental SciencesSummary Impact Type
EnvironmentalResearch Subject Area(s)
Earth Sciences: Geology, Geophysics, Physical Geography and Environmental Geoscience
Summary of the impact
Our research has had a global impact on understanding the tectonic
development and fill of rift basins, providing a predictable spatial and
temporal template for the distribution of hydrocarbon reservoir rocks. The
models are embedded in exploration workflows of global oil companies and
have influenced recent exploration success (North and East Africa,
Atlantic conjugate margins). Translational research on 3-D rift basin
outcrop data capture and resulting software licencing has improved
reservoir modelling, optimising positioning of $100m wells. Field-based
training for several hundred oil industry staff since 2005 has ensured
in-depth knowledge transfer.
Underpinning research
The integrated research was undertaken in Manchester from 1993 and is
on-going within the expanded group.
The key researchers have been:
Prof Robert Gawthorpe (1993-2010)
Dr David Hodgetts (Senior Lecturer, 2005 to present)
Prof Jonathan Redfern (2003 to present)
Dr Cathy Hollis (Senior Lecturer, 2007 to present)
Prof Stephen Flint (2012 to present)
Rift basin research at Manchester led the way in developing
process-response models for the effect of extensional fault systems on 3-D
accommodation, by applying concepts from structural geology to
stratigraphic analysis for the first time [1, 2]. This work was
fundamental in turning sequence stratigraphy from a 2-D treatment of
simple passive margins into a rigorous 3-D analysis of the structural
template across which accommodation varies in 3-D over time, as function
of the basic mechanics of crustal stretching [1, 2]. The work has shown
the importance of relay zones in delivery of sediment into rifts, at
points of low accommodation (fault tips) and was pivotal in the
appreciation that depositional dip at the end of a relay can be
multidirectional. The Group went on to convolve 3-D subsidence uplift
patterns with eustatic sea level changes and ideas on sediment supply to
produce the first holistic tectono—sequence stratigraphic models for rift
basins [3, 4, 5]. This work provided a deeper understanding of how stratal
geometries and reservoir rocks are distributed with a rift basin and
therefore a better prediction of lithologies directly from seismic
reflection data.
The work programme was extended to carbonates following appointment of
Hollis, which has included the linking of fault-related fluid movement to
dolomitisation, which has predictive power in porosity/permeability
generation during diagenesis. Extensive studies of basins across North
Africa by Redfern (North Africa Research Group) have applied and
critically tested the concepts [5] and have influenced exploration
activities across the region. The importance of inherited rift fabric on
post-rift intrabasinal shelf morphology is being documented by Flint.
The development of new 'digital outcrop' research techniques to collect
quantitative sedimentological and structural data for reservoir modelling
has served as a translational way of harnessing the more fundamental
results into databases on sand body geometries and architecture for
reservoir modelling [3, 6]. The development of software (Virtual
Reality Geological Studio, VRGS) by Hodgetts allows integration and
interpretation of terrestrial laser scanning, satellite data, digital
imagery and geological datasets in a series of outcrop analogue studies
funded by the oil industry, to refine subsurface reservoir models. The
software has been licenced to oil companies and Universities.
References to the research
All of these papers are in international journals and show the evolution
and translation of the research. References 1 and 2 are highly cited and
regarded globally as foundation papers in rift basin geology. All have
been the subject of invited international presentations.
Key Publications
[1] Gawthorpe, R.L., Fraser, A. and Collier, R. 1994. Sequence
stratigraphy in active extensional basins: implications for the
interpretation of ancient basin-fills. Marine and Petroleum Geology, 11,
642-658 (89 WoS citations). DoI 10.1016/0264-8172(94)90021-3
[2] Gawthorpe, R.L. and Leeder, M.R. 2000. Tectono-sedimentary
evolution of active extensional basins. Basin Research, 12, 195-218 (123
WoS citations). DOI: 10.1111/j.1365-2117.2000.00121.x
[3] Wilson, P., Hodgetts, D., Rarity, F., Gawthorpe, R. L.
and Sharp, I. R. 2009. Structural geology and 4D evolution of a
half-graben: New digital outcrop modelling techniques applied to the
Nukhul half-graben, Suez rift, Egypt. Journal of Structural Geology 31,
328-345 (8 WoS citations). DOI 10.1016/j.jsg.2008.11.013
Other Relevant Publications
[4] Finch, E., Hardy, S and Gawthorpe, R. 2004. Discrete-element
modelling of extensional fault propogation folding above rigid basement
fault blocks. Basin Research, 16, 489-506 (40 WoS citations). DOI: 10.1111/j.1365-2117.2004.00241.x
[5] Fabuel-Perez, I., Redfern, J. and Hodgetts, D. 2009.
Sedimentology of an intra-montane rift-controlled fluvial dominated
succession: The Upper Triassic Oukaimeden Sandstone Formation, Central
High Atlas, Morocco, Sedimentary Geology, 218, 103-140 (6 WoS citations).
DOI 10.1016/j.sedgeo.2009.04.006
[6] Fabuel-Perez, I., Hodgetts, D. and Redfern, J. 2009. A new
approach for outcrop characterization and geostatistical analysis of a
low-sinuosity fluvial-dominated succession using digital outcrop models;
Upper Triassic Oukaimeden Sandstone Formation, central High Atlas,
Morocco. AAPG Bulletin, 93, 795-827 (13 WoS citations). DOI 10.1306/02230908102
Details of the impact
Prior to the work referred to in this case study, no linked
process-response model for sedimentation in rift basins existed and hence
no consistent way of predicting the distribution of hydrocarbon reservoir
rocks in time and space. Specifically the models provide better prediction
of lithologies directly from seismic reflection data, which are the only
data commonly available in hydrocarbon exploration. Global use of the
models have steered exploration in rift basins worldwide.
The combination of concept-driven prediction of reservoir rock
positioning and timing of deposition with quantitative measurements of
geometries and architecture has had the threefold impact of (a) success in
exploration in rift settings, including the South Atlantic conjugate
margins, North and East Africa, (b) harnessing of additional reserves in
`near field exploration' that required the linked structural-stratigraphic
understandings and (c) optimal siting of wells based on the quantitative
reservoir models made possible through the geometrical databases developed
from VRGS, thus reducing the number of $50M-$100M wells needed per
development.
Pathways to Impact
I. Research on normal fault growth and syn-rift sedimentation was
undertaken as part of the Rifts Analogues Project (TRAP) headed by
Gawthorpe and Hodgetts and funded by Statoil, BP and ConocoPhillips.
Outcrop observations and measurements from modern and ancient rift
settings were distilled into tectono-stratigraphic models. This new
knowledge was embedded into sponsor company workflows through professional
training workshops in classroom and field and supported by the development
of numerical modelling procedures. The pathway has been consolidated by
several generations of project PhDs joining the oil industry.
II. The Virtual Reality Geological Studio (VRGS) software has being
commercialised by UMIP (who manage Manchester University's IP portfolio).
VRGS provides a new innovative tool for reservoir analogue studies to
generate new sedimentological and structural data and interpretations,
centered around LiDAR scanning of outcrops. This allows the quick and
accurate capture of data on reservoir body geometries and spatial
architecture, which has been used to feed reservoir modelling software
used by the industry. This has resulted in more realistic reservoir
models. VRGS has been licenced to Chevron, ConocoPhillips and Fugro
Robertson for in-house reservoir characterisation and modelling projects
[A], [B],[C}.
Reach and Significance of the Impact
1. The results of the research are embedded in the global exploration
models of Statoil, for example."Innovative new exploration concepts
have resulted from the research that has led to exploration successes"
[D] In addition, the results of this research "are very much in use in
defining new exploration plays and concepts, and are recently used for
the new concession round application in the North Sea and were also used
for the 27th Concession Round application on
the UK Continental Shelf" [D]. The concepts have also directly
influenced exploration for the last 15 years in BP, who state "the
technical impact of this research has been substantial, particularly in
relation to understanding of depositional processes in rift systems"
[E]. The models have been used by the industry in frontier exploration
along the South Atlantic conjugate margin, with successful new discoveries
in completely new areas (e.g. French Guyana, Ghana). The new exploration
models have improved business performance across the exploration sector.
2. The new concepts for hydrocarbon reservoir prediction have been
embedded into the professional workforce of many oil companies including
Statoil and BP by a series of bespoke knowledge transfer training courses
in Norway, Egypt and Greece. Statoil "estimate "that at least 200
Statoil geoscientists have attended these workshops" [D]. BP state
that `the incorporation of integrated structural-stratigraphic rift
models in BP's in-house training programs has been achieved through
knowledge transfer from Manchester via field courses for BP over the
last 15 years [2]. We regard the production of a highly trained
doctoral workforce for the industry as an impact as well as a pathway to
impact because it has led to changes in practices and improvements in
processes. This argument is supported by the UK Government Oil and Gas
Industrial Strategy and the plans for a NERC Centre for Doctoral Training
in oil and gas, both of which are responses to an identified skills
shortage in engineering and geoscience.
3. The impact of VRGS has been an improved ability to develop models of
subsurface reservoirs by constraining in outcrop analogues: a) the
geometry of key stratal surfaces defining the boundaries of reservoir
zones, and b) the geostatistics of sedimentary bodies that occur within
the reservoir zones. This has reduced the time taken to capture analogue
data and has allowed statistically more sophisticated conditioning to be
developed. The impact is in enabling better and more constrained
understanding and characterisation of uncertainty in subsurface reservoir
descriptions, allowing the creation of alternate scenarios. A direct
application is in refined well placement, where the saving of a single
well can save $50m - $100m from a development project of commonly 5-50
wells.
As explained by BP [E], it is not possible to fully quantify the global
savings from the increased geological understandings because other factors
also influence well positioning but the saving of one well per field
across the industry in which several hundred wells have been completed in
rift basin prospects over the last 5 years is considerable. When this work
started, over 200 billion barrels of recoverable hydrocarbons was known to
be hosted in rift basins and one of the most significant new plays is the
syn-rift pre-salt succession of the South Atlantic basin, currently
thought to contain 38 Billion barrels of oil equivalent. With an oil price
of $100+ per barrel, this is a multi billion dollar industry.
The research has involved training company personnel in data collection
and interpretation, placing members of the research team within the
sponsors' offices for work periods and the employment of the highly
skilled researchers by the global industry.
Sources to corroborate the impact
These research projects have all been funded directly by industry, and
the research has involved close liaison with the companies, for
dissemination of the results and training of company staff. Rather than
supply letters from every company who has been impacted by the research
(20+ companies) we will supply detailed supporting letters from two
companies with global portfolios who have worked with Manchester for the
last 20 years.
[A] License agreement for VRGS corroborating permission for Chevron to
use our software package.
[B] License agreement for VRGS corroborating permission for
ConocoPhillips to use our software package.
[C] License agreement for VRGS corroborating permission for Fugro
Robertson to use our software package.
[D] Statoil supporting letter corroborating the strong research
collaboration previously developed between the Manchester group with Norsk
Hydro and the ongoing and lasting relationship that has persisted since
the merger between Statoil and Norsk Hydro.
[E] BP supporting letter corroborating the use that BP have made of the
conceptual framework developed in Manchester in their global exploration
activities.