Geophysical quantification of seafloor greenhouse gas: the effect of gas bubble and hydrate morphology on sediment geophysical properties.

Lead Research Organisation: University of Southampton
Department Name: Faculty of Engineering & the Environment

Abstract

Global climate prediction models need accurate information on the amount of greenhouse gases (methane CH4 and carbon dioxide CO2) hosted by seafloor sediments as free gas and gas hydrates. Extensive distributions of seafloor methane gas and methane gas hydrate have been detected by geophysical surveys on continental margins around the world, while monitoring of carbon dioxide seepage from sub-seafloor CO2 reservoirs will become increasingly important as full scale carbon capture and storage facilities come online in future. However, quantification of the amount of in situ gas using geophysical remote sensing methods remains a challenge. In this technology-led proposal, we intend to provide the required step change in knowledge that will allow us to relate seafloor geophysical measurements to gas content and thus provide the marine community with the necessary survey know-how.
The main barrier to progress is our poor state of knowledge of the effect of gas and gas hydrate morphology (i.e., size and shape) on the measured geophysical sediment properties acoustic velocity and attenuation, and electrical resistivity. Gas bubbles in sediments are known to show complex shapes and size distributions that are strongly influenced by sediment type. Muddy sediments show crack-like gas bubbles while sandy sediments show spheroidal gas bubbles. If these sediments occur in deep enough water on the continental slope, then methane gas hydrate may form producing equivalent crack-like or disseminated hydrate morphologies. Only dedicated, well controlled laboratory experiments can hope to unravel the complex interaction between gas and hydrate morphology, sediment type and the observed geophysical properties. Unfortunately, no such experimental capability exists at present, so we will have to develop our own laboratory measurement system.
Our solution is to build the world's first acoustic pulse tube for gas- and gas hydrate-bearing sediment studies. It will enable the bulk acoustic and electrical properties of large sediment core samples, up to 1 m long, containing natural methane (or carbon dioxide) gas bubbles or hydrate, to be measured under simulated seafloor pressures and temperatures. Experiments on synthetic muds with known amounts of methane and hydrate will also assist our understanding of these physical property inter-relationships. We will also study relevant theoretical models that will be tested against the laboratory experimental results. These validated models are what we need to interpret seafloor geophysical measurements in terms of in situ gas and hydrate content. We will interact with other scientists seeking to quantify seafloor greenhouse gas associated with methane hydrates in the Arctic and sub-seafloor carbon dioxide storage sites, and with potential industry and government end-users of seafloor geophysical technologies.

Planned Impact

Improved seafloor geophysical surveys are increasingly in demand to help answer pressing societal questions such as: 1) how will the oceans affect global climate change in future? and 2) how can we sustainably exploit global ocean resources? While the academic sector and inter-governmental agencies are mainly focussed on answering question 1), question 2) is largely in the hands of the private sector. UK companies are major players in the highly competitive global seafloor survey market driven currently by the oil and gas (energy) sector. The leading edge geophysical survey know-how developed here would enable them to sustain and increase their market share, creating jobs and wealth for the UK as a whole. Most importantly, it will enable them to deliver the seafloor data needed, at the scale needed, to manage the ocean economy in an environmentally responsible way. In particular, the proposed research will be of great value to the offshore community working in the following areas:
1) Geophysical and geotechnical survey. Improved geophysical methods are needed to gain faster (ie more economic) and more accurate information on sediment load-bearing capacity and slope stability for the safe siting of seafloor structures, such as wind farms, tidal power generators, oil platforms, pipelines and cable routes. Better knowledge of gas content would also benefit the avoidance of shallow gas pockets as a drilling hazard (e.g . could allow drilling in gassy seafloor areas with only minor gas content that previously would be avoided altogether because present methods can only say if gas is present or not). The project results would also be of interest to geotechnical companies offering specialised autoclave sediment sampling and physical properties measurements.
2) Hydrates exploitation. Better geophysical methods are needed for the commercial assessment of hydrate deposits for natural gas fuel in future (reservoir exploration, characterisation and monitoring during production). Improved high resolution geophysical methods would be particularly useful for locating and assessing relatively small hydrate reservoirs (compared to conventional deep natural gas reservoirs). Hydrate deposits may be exploited in future in combination with CO2 storage (eg German SUGAR project) by replacing methane with CO2 hydrate. Such complex industrial scale seabed operations would require tight control of seabed gas and hydrate contents through geophysical survey.
3) Carbon capture and storage (CCS). There will be an increasing demand for monitoring of seafloor CO2 leakage (and CO2 distribution within storage reservoirs themselves) as large marine CO2 storage projects come online around the world (e.g. Sleipner, Snoehvit, China, India, etc). CCS is currently the only pragmatic engineering solution to arrest the rise in anthropogenic CO2 emissions from burning of fossil fuels. The oil and gas sector will need the new geophysical survey know-how provided by this project to adapt to this emerging new market, estimated to be worth billions of pounds in future.
4) Naval defence. Improved knowledge of the acoustic and electrical properties of seafloor sediments, particularly gas-bearing shelf and continental slope sediments, will be of direct benefit to the protection from mines of military, civilian and relief sea transport and landing operations, as well as submarine warfare. Also, knowledge of possible energy sources on the seabed (eg from methane gas) would be useful for long-term seafloor monitoring stations, including autonomous underwater vehicle (AUV) docking stations (the same technology is relevant to future autonomous oceanographic surveys). Geophysical survey methods are needed for rapid environmental assessment of large areas of seabed prior to military operations. The UK military and strategic allies would benefit from this know-how, thus contributing to national security.

Publications

10 25 50
 
Description have identified what could be errors in the formulations and techniques used for decades in assessing gas populations using acoustics in the seabed. We are assessing the size of these. We are assessing the impact on civil engineering, environmental considerations, carbon capture and stories and petrochemical (oil and gas) sectors. We have started our major series of publications, the first few of which are now coming out.
Exploitation Route We are in partnership with the NATIONAL OCEANOGRAPHY CENTRE to use our formulations to help them develop diagnostic techniques for examining the seabed.
Sectors Construction,Education,Energy,Environment

URL http://www.southampton.ac.uk/engineering/research/projects/detecting_leaks_from_undersea_gas_pipelines.page?
 
Description We are in partnership with the NATIONAL OCEANOGRAPHY CENTRE to use our formulations to help them develop diagnostic techniques for examining the seabed. They in turn will help civil engineering and environmental and energy companies to make better use of their sonar data from the seabed. We also used the results to give a number of Public Engagement Talks.
First Year Of Impact 2014
Sector Construction,Education,Energy,Environment
Impact Types Societal,Economic

 
Description Public engagement plenary 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact A public engagement plenary given at an open event at the University of Southampton.
Year(s) Of Engagement Activity 2015
URL http://www.southampton.ac.uk/medicine/news/2015/05/3mt-alan-morris.page
 
Description A presentation given at the IEAGHG 10th Monitoring Network Meeting in Berkeley, California, USA in June 2015 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Policymakers/politicians
Results and Impact A presentation given at the IEAGHG 10th Monitoring Network Meeting in Berkeley, California, USA in June 2015.
Year(s) Of Engagement Activity 2015
URL http://www.ieaghg.org/ccs-resources/technical-workshops/64-content
 
Description A presentation given at the UKCCS Research Centre Spring Biannual Meeting 2015 held at Cranfield University, 21-22 April 2015 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact A presentation given at the UKCCS Research Centre Spring Biannual Meeting 2015 held at Cranfield University, 21-22 April 2015
Year(s) Of Engagement Activity 2015
URL https://ukccsrc.ac.uk/news-events/events/ccs-action-cranfield-biannual
 
Description A talent for bursting bubbles - Ingenia magazine article 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Michael Kenward OBE interviews Professor Leighton in this article for the Ingenia Magazine. Ingenia is a quarterly magazine that publishes articles across the whole range of engineering disciplines. Professor Leighton discusses his StarStream invention and the challenge of antimicrobial resistance.
Year(s) Of Engagement Activity 2017
URL http://www.ingenia.org.uk/Ingenia/Articles/1119
 
Description Eton College Engineering Careers Networking Event for students 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Opportunity for students from Eton College and surrounding schools to ask questions to engineers about engineering and how to get involved. Feedback from the Deputy Head of Career Education at Eton College was "The experience was highly valued by our boys and the students from visiting schools. The feedback we have had has been very positive".
Year(s) Of Engagement Activity 2016
 
Description Prof Leighton talk at Thomas Hardye School, Dorset 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Professor Tim Leighton was invited to Thomas Hardye School to present a talk on research underway in Southampton into Antimicrobial Resistance. As part of the talk a collection of £542 was presented to Mary-Jane Butler for her charity Widows and Orphans in Rural Kenya. Mary-Jane is a member of the Global-NAMRIP Steering Group.
Year(s) Of Engagement Activity 2017
 
Description Professional body lecture (Midlands branch of the Institute of Acoustics) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact A presentation given to the AGM of the Midlands Branch of the Institute of Acoustics, held at the University of Derby.
Year(s) Of Engagement Activity 2015
URL https://ioa.org.uk/civicrm/event/info?id=157&reset=1
 
Description Professional body lecture (Institute of Physics, London) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact A presentation given to the London and South East Branch of the Institute of Physics.
Year(s) Of Engagement Activity 2016
URL http://www.iop.org/activity/branches/south_east/lse/calendar/files/file_66665.pdf
 
Description Professional body lecture (Joint Institute of Acoustics and Institute of Physics) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact A presentation given to a joint meeting of the IOA and IOP, held at the University of Hertfordshire.
Year(s) Of Engagement Activity 2015
URL https://ioa.org.uk/civicrm/event/info?id=150&reset=1
 
Description Public Engagement talk to Hampstead Science Society 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact On 16 February 2016 Prof Leighton gave a Public Engagement talk to Hampstead Science Society, which covered a range of scientific projects in which he had been engaged, before covering many of the projects from NAMRIP's work on vaccination, infection prevention, and the mitigation of AMR.
The Society was formed in 1899 under the name of the 'Hampstead Astronomical and General Scientific Society'. The audience were the public, raging from school pupils to pensioners. They numbered around 40. Questions were encouraged and occurred throughout the talk, so many that indeed instead of catching the London Underground to Waterloo, 2 members of the audience fetched their car to drive me to waterloo so that they could continue the conversation.
Year(s) Of Engagement Activity 2016
 
Description Southampton Marine and Maritime Institute (SMMI) university seminar 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact A presentation given to the Southampton Marine and Maritime Institute (SMMI) at a university seminar, held at the University of Southampton.
Year(s) Of Engagement Activity 2015
 
Description The Sea and Me - public engagement talk 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact A public engagement talk, entitled The Sea & Me, given at an open day event attended by local schools and members of the public.
Year(s) Of Engagement Activity 2014
URL http://www.southampton.ac.uk/assets/imported/transforms/content-block/UsefulDownloads_Download/8B221...
 
Description The Sea and Me - public engagement talk 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact A public engagement talk, entitled The Sea & Me, given at an open day event for local schools.
Year(s) Of Engagement Activity 2015
 
Description The acoustic bubble: Carbon budgets; sound in space; dolphins; cold water cleaning and antimicrobial resistance 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Talk by Professor Tim Leighton on 7th March 2017 at The Open University, Milton Keynes.
Year(s) Of Engagement Activity 2017
 
Description The acoustic bubble: Carbon budgets; sound in space; dolphins; cold water cleaning and antimicrobial resistance 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Professor Leighton was invited to present this public lecture at The Open University and Institure of Physics in Milton Keynes on Tuesday 7th March 2017. Excellent feedback was received following the talk including "Prof Leighton's talk yesterday evening was quite inspirational, and I trust you will forward our sincere thanks to him". There were 98 attendees.
Year(s) Of Engagement Activity 2012,2017
 
Description Undertaking lectures to students, and 2 keynotes to senior staff, at Harbin Engineering University, China. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact Invited to give lectures to students, and 2 keynotes to senior staff, at Harbin Engineering University, China 27 May - 2 June 2018
Year(s) Of Engagement Activity 2018
 
Description University Seminar (Dundee) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Professional Practitioners
Results and Impact University researchers from a very wide range of disciplines (academics, postdocs, postgraduate students from engineering, microbiology etc.) attended a presentation, followed by questions and discussion. There were a number of requests for further information following the session.
Year(s) Of Engagement Activity 2016
URL http://www.lifesci.dundee.ac.uk/events/archive