Reservoirs Under Stress: Improved productivity through geomechanics and microseismicity in petroleum systems
Submitting InstitutionUniversity of Bristol
Unit of AssessmentEarth Systems and Environmental Sciences
Summary Impact TypeEconomic
Research Subject Area(s)
Earth Sciences: Geophysics
Engineering: Resources Engineering and Extractive Metallurgy, Interdisciplinary Engineering
Summary of the impact
Bristol researchers have been working with the oil and gas industry to
develop new methods for monitoring and modelling deformation in oil and
gas reservoirs. Industry and NERC funded research has led to the
development of (i) novel techniques that better utilise microseismicity
monitoring of petroleum reservoirs, and (ii) new software which couples
geomechanical deformation and fluid flow with geophysical observations.
The research has led directly to development and improvement of commercial
software to enhance exploration efforts and minimise costs. Bristol
software is now used by several multinational companies worldwide and its
development has led to a successful start-up company.
Since 2005, the Bristol Seismology Group has received £2.4 million for
largely industry-funded research to investigate the microseismicity,
fluid-flow and geomechanics of oil and gas reservoirs [1-12]. This
research has been conducted under the umbrella of two large Joint Industry
Projects (JIPs): (i) the Integrated Petroleum Engineering, Geophysics and
Geomechanics (IPEGG) project, which aims to better integrate the
disciplines of petroleum engineering, geology, geophysics, and
geomechanics in order to achieve maximum value from reservoirs [13-15,10],
and (ii) the Bristol University Microseismicity Projects (BUMPS), which
investigates natural and induced microearthquakes in petroleum reservoirs
in a variety of settings [3,16-18].
Geomechanics has, in recent years, emerged as an important area for the
oil and gas industry because of the need to extract petroleum from
challenging environments such as deep water, high temperature-high
pressure, or structurally complex fields. Many reservoirs experience
significant compaction during petroleum extraction, which can lead to
problems such as sea floor subsidence and seismicity, which can
dramatically alter reservoir permeability and redistribute reservoir
stresses. These geomechanical-related problems are not easily addressed by
conventional software tools used by petroleum engineers. IPEGG (2005-2009)
has brought together expertise in reservoir deformation and fluid flow at
the University of Leeds, the University of Bristol, and Rockfield Software
Ltd - a Swansea-based company that specialises in advanced numerical
analysis for geomechanical applications. "The project was led by
Quentin Fisher at Leeds, with Bristol coordinating the geophysics
component. The University of Bristol played a significant role in the
project, helping in part to build production simulation and
geomechanical models, developing methods to populate the geomechanical
models with mechanical properties based on down-hole tool and field
seismic data... Bristol led the component that built seismic models to
investigate the use of 4D and passive seismic for detective fault
compartmentalized reservoirs" [a]. IPEGG has made key
developments in linking deformation and fluid flow within reservoirs to
geophysical observations, such as microseismicity [13-18]. IPEGG
developed numerical techniques and workflows to couple Rockfield's finite
element model (ELFENTM) to industry standard production
simulation models (e.g. TempestTM, EclipseTM, VIPTM),
which predict reservoir behaviour.
Reservoir stimulation is one of the fastest growing sectors in the
petroleum industry and is used extensively in unconventional reservoirs
such as shale gas, shale oil and tight gas sandstones. Monitoring the
geomechanical response through induced seismicity is the primary means of
assessing the efficacy of stimulation, but is also important for
regulating the industry. Kendall has established one of the world's
leading consortia in microseismicity (BUMPS; 2009-present), the first to
develop downhole and surface seismic monitoring techniques for fracture
characterisation and stress field evaluation, extending the utility of
microseismic data far beyond simply locating microearthquakes [b,16-18].
The project has developed novel migration methods for automatically
locating events in near real time using surface arrays of sensors. It was
the first to use shear-wave splitting measurements to quantify fracture
induced anisotropy, most recently extending this work to estimate fracture
size and compliance, invaluable information for assessing the efficacy of
hydraulic stimulation. The considerable synergies between IPEGG and BUMPS
have been used, for example, to compare the geomechanical and microseismic
response in the world's largest CO2 sequestration projects [15,17].
References to the research
 Kendall (2012-2015). FRACGAS: Improved hydraulic fracture
stimulation of tight gas reservoirs using FE modelling and microseismic
monitoring. Industry Technology Facilitator (EBN, Shell, Chevron,
Marathon, Nexen, Total, ExxonMobil, Noble). £160,000 to Bristol (a further
£780,000 to PI Rance, Rockfield; Fisher, Leeds).
 Kendall (2011-2014). Still or sparkling: Microseismic
monitoring of CO2 injection at In Salah.
NERC Partnership Grant with BP. £281,000.
 Kendall (2010-2016). Bristol University Microseismity
ProjectS (BUMPS). Joint Industry Project (funding from 8 companies;
ExxonMobil, Pinnacle, Microseismic Inc., Maersk, Chevron, Schlumberger,
Rio Tinto, BP). £940,000.
 Kendall (2009-2012). Enhanced integrated
geomechanics-seismic model of improvement of lifecycle performance of
tight gas sand reservoirs (GESER). Industry Technology Facilitator
(Shell, Chevron, ConocoPhilipps, DECC). £195,000 to Bristol (a further
£465,000 awarded to co-PI Dutko, Rockfield; Fisher, Leeds).
 Kendall (2008-2010). Passive seismic emission tomography:
the dynamics of a reservoir. NERC Partnership Grant with BP.
 Kendall (2008-2012). Passive seismic monitoring of CO2
injection: Weyburn Phase I and II. Petroleum Research Technology
Council (Canada). £75,000 and £110,000.
 Kendall (2006-2009). Microseismic monitoring and
geomechanical modelling of CO2 storage in
subsurface reservoirs. U.K. Energy Research Centre. £60,000.
 Kendall (2006-2010). Microseismicity in the Ekofisk Field:
Faulting and fracturing in a compacting chalk reservoir. NERC CASE
studentship with Schlumberger Cambridge Research. £60,000.
 Awarded to Imperial College University of London and 15 other
institutions (including Kendall at Bristol) (2005-2008). UK Carbon
Capture and Storage Consortium. NERC Consortium Grant. £2,000,000
(£50,000 to Bristol).
 Kendall (2005-2008). Integrated Petroleum Engineering,
Geomechanics and Geophysics (IPEGG). Industry Technology Facilitator
(Statoil, BP, BG, ENI). £580,000 (£192,000 to Bristol) (co-PI Fisher,
Leeds; Crook, Rockfield).
 Kendall (2005-2006). Analysis of passive seismicity using
life of field survey data. BP Norge. £40,000.
 Kendall (2005-2008). Development of robust tools for
focal mechanism and shear-wave splitting analysis of microseismic data.
Shell (UK). £51,000.
 Angus, D.A., Kendall, J.M., Fisher, Q., Segura, J.M.,
Skachkov, S., Crook, A. and Dutko, M. (2010), Modelling microseismicity of
a producing reservoir from coupled fb02uid-fb02ow and geomechanical
simulation. Geophysical Prospecting 58: 901-914. DOI:
 Angus, D.A., Verdon, J.P., Fisher, Q.J., Kendall,
J.M., Segura, J.M., Kristiansen, T.G., Crook, A.J.L., Skachkov, S.,
Yu, J. and Dutko, M. (2011), Integrated fluid-flow, geomechanics and
seismic modeling for reservoir characterization. Canadian Society
Exploration Geophysics - Recorder, 26-35, May. Can be supplied upon
 Verdon, J.P., Kendall, J.M., Stork, A.L.,
Chadwick, R.A., White, D.J. and Bissell, R.C. (2013), Comparison of
geomechanical deformation induced by megatonne-scale CO2
storage at Sleipner, Weyburn, and In Salah. Proceedings of the
National Academy of Sciences USA 110 (30): E2762-71. DOI:
 Chambers, K., Kendall, J.M., Brabdsberg-Dahl,
S. and Rueda, J. (2010), Testing the ability of surface arrays to monitor
microseismic activity. Geophysical Prospecting 58: 821-830. DOI:
 Verdon, J.P., Kendall, J.M., White, D.J. And Angus,
D.A. (2011), Linking microseismic event observations with
geomechanical models to minimise the risks of storing CO2 in
geological formations. Earth and Planetary Science Letters 305:
143-152. DOI: 10.1016/j.epsl.2011.02.048.*
 Baird, W.A.F., Kendall, J.M., Verdon,
J.P., Wuestefeld, A., Noble, T.E., Yongyi, Li., Dutko, M.
and Fisher, Q.J. (2013), Monitoring increases in fracture connectivity
during hydraulic stimulations from temporal variations in shear wave
splitting polarization. Geophysical Journal International:
1030-1038. DOI: 10.1093/gji/ggt274.*
Details of the impact
Research from the Bristol seismology group has led to a broad range of
software that has been incorporated into commercial code used for
geomechanical modelling, measuring shear-wave splitting, characterising
fractures, and assessing induced seismicity. Consequently, the end users
(and thus beneficiaries) of this research are oil and gas companies
looking to decrease their risk, improve oil and gas exploratory efforts
and minimise exploration costs. For example, commercial impact is broad in
that many (> 50 worldwide) multinational companies are now using
Rockfield's coupled software to study the geomechanical behaviour and
seismic properties of producing reservoirs and understanding fracturing
and permeability effects; "the output from the IPEGG project has been
used regularly to address major challenges facing the petroleum
industry" [a]. Consequently, the IPEGG project has been
viewed as highly successful by both Rockfield Software and the project
sponsors (BG, BP, ENI, Statoil), with the resulting software being applied
to various projects, such as "predicting stress changes and subsidence
due to the production from major chalk fields in the North Sea;
assessing optimum position to place an oil platform in the North Sea;
assessing the optimal mud-weights to use when drilling deviated wells in
the North Sea and Gulf of Mexico. In addition, we are currently using
the software to conduct a major (£950,000) project to optimize hydraulic
fracturing within shale gas reservoirs"[a].
Rockfield has witnessed impressive software sales leading directly to an
expansion in their oil and gas business. This increase in Rockfield's
capabilities has driven international business to a medium-sized UK based
company; "Since the completion of IPEGG we have witnessed significant
impact both in terms of sales of the software resulting from the project
and consultancy projects that we have undertaken using the
software/workflows. In particular, ELFENTMand
the module to couple to production simulation models was purchased by BP
and ENI of the IPEGG sponsors at a cost of £40,000 per license per year
over the past three years. Additional licenses, which total £80,000/year
have been sold to other companies. In addition, Rockfield Software have
conducted around £400,000 of consultancy work for the petroleum industry
using the software developed" [a]. There is then benefit for
the operators who are hiring Rockfield, in that the improved reservoir
models will enable them to maximise production while minimising the
environmental and operational cost of geomechanical issues like subsidence
(damage to be paid for), well-bore failure (cost of workovers and/or
drilling replacement wells) and caprock fracturing (loss of hydrocarbon
into overburden formations).
A novel aspect of the IPEGG project has been the development linking
geomechanical modelling with fluid flow . For instance, Roxar
has led to the development of a very efficient memory- passing interface
(MPI) by coupling their software TempestTM with ELFENTM,
which "At a time when operators are looking to optimise production
from increasingly marginal assets and make effective decisions over the
allocation of capital and resources, the models and analytical processes
that define modern reservoir simulation have never been more important"
[c]. More recently, this software has been utilised to assess
potential leakage from CO2 storage sites and to assess the use
of seismic tools for monitoring CO2 movement in the subsurface
[15,17]. This research conducted at Bristol has "influenced BP
operations and future directions in a number of ways, specifically with
application to the Valhall oil field...The success of the project was
influential in BP's decision to use ELFEN for geomechanical modelling in
our North Sea reservoirs. Notably, we are applying the software
extensively to better manage the giant Valhall oilfield which is the 5th
largest field in Norwegian waters" [d]. This has led to two
further JIPs, the GESER and FRACGAS project [a,1,4]. Consequently,
IPEGG and its underpinning research is viewed as a major success by the
Industry Technology Facilitator (ITF); "One of the things that ITF has
tried to encourage is the formation of consortia with world class
expertise to tackle fundamental industry issues. This project is a good
example of how well this approach can work — it has brought together
people that not only have an excellent track record of rapidly applying
research findings to meet the needs of industry but also have experience
bringing software packages to the market place" [e].
At the inception of the BUMPS project "there was significant
scepticism in large parts of industry regarding the viability of the use
of surface seismic arrays for the monitoring of hydraulic fracturing"
[f]. However, the BUMPS project has demonstrated that surface
seismic monitoring was feasible and has helped to provide confidence to
the industry that surface monitoring was viable [f]. Indeed,
Bristol's research into ocean bottom sensors to monitor passive seismic
events in oil fields has influenced the establishment of the Life of Field
Seismic array at Valhall in 2003 at a cost of over $46 million [d].
This research has led to the formation of a small spin-out company, which
in 2012, was bought by Halliburton Energy Services and can be viewed as a
measure of the success of the project [d]; "The BUMPS research
on surface-microseismic imaging spawned a new company that was ripe for
acquisition given the dramatic rise in shale play activity worldwide.
Kit Chambers left Bristol and formed Reservoir RockTalk [sic in 2010], a
microseismic imaging start-up, which was subsequently bought out by
Halliburton Energy Services" [sic in 2012] [b].
The BUMPS consortium has grown from having 4 sponsors to 10 in a short
amount of time and is widely recognised as an industry-leading project
with Kendall providing advice on research quality and directions for
international companies such as Schlumberger. As such, "Schlumberger
views the work of Professor Kendall's consortium as being of both a high
scientific quality and highly relevant to real world problems, setting
it apart from many other academic consortia" [f]. Research
conducted at Bristol has also been "key to defining the standard
magnitude measures used in the mitigation of risks due to induced
seismicity during hydraulic fracturing" and to "reduce location
uncertainties of microseismic events" [f]. It can be
concluded that "BUMPS is an important industry consortium providing
independent fundamental research into new capabilities and applications
of microseismic and other passive seismic monitoring under the advice of
industry service providers and operators. Such research fills a critical
need in the industry due to limited research investments in the private
sector...and allows for quicker advancement and adoption of new
technology across industry improving commercial results and addressing
public interests" [b].
To summarise, "the work done at Bristol over the past decade in
microseismic research has made a significant contribution to the
development of microseismic technology through innovative research,
publication of ideas and case studies, and the training of young
geophysicists who currently work in this business. The research carried
out at Bristol has had significant commercial impact in helping drive
the growth of this business" [g]. In addition, both the
IPEGG and BUMPS projects have trained numerous PhD students, many of whom
have gone on to successful careers in the oil industry as a direct result
of the training, reputation of research excellence, and academic-industry
collaborations of the UoA.
Sources to corroborate the impact
[a] Rockfield Software Limited. Factual Statement.
[b] Microseismic. Factual Statement.
[c] Atomation.com Products Review. Available from: http://www.automation.com/product-showcase/emerson-enhances-roxar-tempest-reservoir-simulation-software
[d] BP Norge. Factual Statement.
[e] ITF Report. Available from: www.oil-itf.com/index/cms-filesystem.../ipegg-technical-article.pdf
[f] Schlumberger Gould Research. Factual Statement.
[g] Pinnacle Halliburton Energy Services. Factual Statement.