CCS Technical Workshop– Approaches to Address Concerns over CO2 Seepage from Reservoirs –Summary
RITE, in association with the Ministry of Economy, Trade and Industry (METI), hosted a CCS
Technical Workshop with a theme, Approaches to Address Concerns over CO2 Seepage fromReservoirs, in Tokyo on 24 January 2013. There were 137 participants from businesses,universities, research institutes and governments. The attendees discussed how to addressconcerns of this kind and how to secure the safety of CCS through presentations from four
experts, two from overseas and the other two from RITE, moderated by Prof Toru Sato, theUniversity of Tokyo. At the end of the workshop, it was concluded that large projects such as
CCS should be discussed from two viewpoints – economic growth and environmental impacts –and that taking environmental impacts into consideration should be recognized as an addedvalue.
1. Background and Objectives
Establishing the safety of CCS has been increasingly recognized as an important part ofpromoting CCS technologies in the world. Japan launched a large‐scale CCS demonstration
project in 2012, which is set to start work on safety issues. In the case of offshore CO2 storagein Japan, measures to secure safety are required by a permitting scheme under the Marine
Pollution Protection Act. These activities are also essential for responding to the generalpublic’s concerns about safety.
With this background, the workshop was designed to focus on CO2 seepage from reservoirs.
The workshop provided an opportunity to discuss how to address concerns of this kind andhow to secure the safety of CCS through presentations on frameworks for environmental
impacts assessment, including regulations; an approach to avoid CO2 seepage; a methodology
for assessing potential environmental impacts in the unlikely event of CO2 leakage based oncomputational simulations; and a field survey conducted in response to an alleged leakage.
2. Participants
There were 137 participants. Those from universities/ research institutes, engineeringbusinesses and consultant firms/ think tanks accounted for 40%, 41% and 13%, respectively,
and there were some from governmental ministries/ agencies.
3. Overview of the Workshop and Conclusions
Aims
The workshop was kicked off with greetings from the host and the co‐host. Firstly, Prof Kenji
Yamaji, Director General, RITE, began by touching upon the initiation of preparation for Japan’s
full‐chain demonstration in 2012 and then pointed out that CO2 should not leak but can leak.
He asserted that it was therefore necessary to take approaches on the assumption of a CO2

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leak, including the clarification of leak mechanisms, site characterization, the establishment ofmethodologies for leak detection and environmental impacts assessment. Then he introduced
that, under the assumption that CO2 leakage is possible, monitoring is required under Japan’sMarine Pollution Prevention Act.

Following Prof Yamaji’s remarks, Mr Koji Hachiyama, Director of the Global Environment
Partnership and Technologies Office, METI, said that we are required to secure economic
growth by increasing fossil fuel‐derived power as an alternative to nuclear and also to reduce
CO2 emissions. He expressed METI’s intention to do their best to reduce costs toward CCS
commercialization by promoting technology development in the full‐chain demonstration; toprepare regulations; and to improve local public perception. In order to present scientificevidence to look into risks, the Director introduced that METI had commissioned various
studies to RITE such as developing techniques for geological characterization; CO2 behavior
analyses in reservoirs; and analyses of CO2 migration from reservoirs. He concluded hisremarks by saying that outcomes from RITE studies were well‐valued globally and that METI
wants to present data to the society to discuss risks openly with a wide range of stakeholders
Before moving on to the presentations, Prof Toru Sato of the University of Tokyo as themoderator briefed the purposes of the workshop. Stating that the purposes had been alreadymentioned in the previous greetings, Prof Sato proposed that Japan present its CCS technology
as a package combined with safety and environmental impacts assessment in promoting it
domestically and internationally after the Japan’s full‐chain CCS demonstration. He concluded
his remarks by reemphasizing that it was essential to assess impacts of potential CO2 leakage
and then the first presentation was started.
Frameworks of Environmental Impacts Assessment
As a first presentation, Dr. Jun Kita, a senior researcher from RITE, talked about CCS
regulations in Japan and overseas, the outline of environmental impacts assessment, theAustralian Gorgon and US FutureGen projects as case studies for such assessment and a UK‐
Japan joint experiment to improve understanding on potential impacts of CO2 leakage on themarine environment.
All safety issues to be considered in CCS projects are covered in a guideline released by METI in2009, “For safe operation of a CCS demonstration project”. In Japan, CCS operators arerequired for damping CO2 under the seabed to obtain a permit; to assess environmental
impacts; and to monitor the marine environment by the Act for the Prevention of Marine
Pollution and Maritime Disasters amended to ratify the London Convention in 2007. Therequirements should be imposed to Japan’s full‐chain demonstration planned in Tomakomai,Hokkaido. A discussion raised from the floor was regarding allowable periods and amounts of
CO2 leakage under the Act. Such allowable values are not specified in the law and the Ministryof the Environment (MOE) as a regulator is to judge the results of assessment presented by a2

CCS operator. In the UK‐Japan joint test, the QICS project, a CO2 release experiment wasconducted in the sea and acquired data have been under analysis and evaluation.
Through the presentation, it was emphasized that environmental impacts assessment before
the implementation of CCS projects was essential not only to comply with legal requirements
but also to improve public credibility and acceptance for the projects.
Approaches to Avoid CO2 Leakage
The next presentation was delivered by Prof Robert J. Finley from the University of Illinois, USA.
He talked about an approach to avoid leaks of stored CO2 through introducing sitecharacterization and a plan and results of monitoring in the Illinois Basin Decatur Project (IBDP).
IBDP is a CCS project where one million tons of CO2 is captured in a plant to produce chemicals
such as ethanol and stored in a saline aquifer two km deep. Injection was initiated in
November 2011 and amounted to 370,000 tons as of 18 January.
Site characterization was conducted with 2D seismic and core sampling and acquired porosityand permeability was used to determine storage capacity, injectivity and containment. Afterno faults were identified in the vicinity of the site, a geological formation with the porosity ofaround 20% was selected as a reservoir. Near‐surface monitoring in the storage site includes
ground water, soil flux, surface elevation and air sampling. In addition, the deep subsurface
has been monitored from the viewpoint of CO2 distribution and saturation, groundwater
sampling and induced seismicity. It was pointed out that a monitoring plan should include pre‐injection monitoring to define baseline data variation, for example, seasonal variation. It wasalso introduced that brine in groundwater can be an indicator for a CO2 leak in this specific site.
Data such as pressure variation, CO2 distribution and surface elevation acquired to dateconfirm that injected CO2 has been storage safely and stably.
The presentation was followed by discussions, including the necessity of the diversified
monitoring and potential leakage routes. Prof Finley explained several aspects as thebackground of the comprehensive monitoring implemented: requirements regarding
monitoring had not been determined at the beginning as IBDP is one of the first CCS projects inthe USA; the nature of the project was scientific research; monitoring was conducted more
rigorously than is legally required to contribute to public acceptance. Based on outcomes fromthe project, optimal monitoring techniques are selected afterwards. One of the few possible
leakage routes may be vertical fractures below the limit of seismic resolution, but no evidence
for such fractures has yet emerged. Another topic of discussion was the period of post‐monitoring. In the project, post‐monitoring is planned to last for three years due to restrictionof funding. But wells are designed to be durable for 30 years and three to 10 years extension
will be required once an application is accepted to change a class of the injection well fromClass I to Class VI.

3Computational Simulation‐base Evaluation of Potential Impacts if CO2 is leaked
The next speaker was Dr. Keisuke Uchimoto, a Researcher in RITE, who explained the necessityof environmental impacts assessment under the assumption of an unlikely CO2 leak from areservoir under the seabed and then introduced an assessment methodology that RITE wasdeveloping.
Although stored CO2 has nearly no chance to escape due to a cap rock and various trapping
mechanisms, environmental impacts assessment is still necessary because of a number ofreasons: science and technology is not perfect; the probability of leak is not zero; it ismandatory under the regulation; and it plays an great role in the improvement of public
acceptance. As an evaluation technique, three models are under development along anescape path from a reservoir to seawater column: geological formations, an unconsolidated
sediment and seawater. Each of the models was described in detail mainly from the viewpointof CO2 state and dominant parameters. In the formation model, faults and wells can provide
leak pathways but it is difficult to determine parameters such as the permeability of faults
since there are no faults identified around the site. The sediment model is a layer of only afew 10 cm regardless of the thickness of actual sediment layers. The model scale is muchsmaller than those of the formation and seawater models but evaluation with the model isimportant because in the layer various reactions take place that have significant influences on
the concentration of dissolved CO2. A question was raised on the definition of sediments fromthe floor. Important in the model is a few 10 cm from the sediment surface so that a boundary
between sediments and a formation below is insignificant. It was also discussed whether theaim of the sediment model was to see CO2 behavior or impacts on creatures in sediment. Theevaluation with the model has the both aspects and the factors to be evaluated in the CO2
behavior are changes in the concentration of dissolved CO2. The model for seawater considers
factors such as marine topography and water flow. Accounting for transformation from CO2
bubbles to dissolved CO2, it calculates changes due to leak, for example, changes in CO2
concentration.
Finally, a database under development was introduced, which is on the effects of CO2
concentration elevation on maritime creatures. Checking with the database, the changes ofCO2 concentration estimated with computational simulations can be assessed as the potential
impacts of CO2 leak on the marine environment.
Case Study for a Field Study in Response to an Alleged CO2 leak
The final presentation was delivered by Dr. Katherine Romanak from The University of Texas atAustin. She talked about a field study conducted in response to an alleged CO2 leak at theWeyburn‐Midale project and its outcomes. The Weyburn project is an EOR project, using
captured CO2, initiated in 2000 and the world’s first project where large‐scale long‐termmonitoring was operated. In the project, injected CO2 has topped 17 million tons so far.

4Soon after the project was started, a suspicion of CO2 leakage from the project was raised by
the Kerr family who lived nearby. Although the project operator had analyzed groundwater,water in pits and soil from an early stage of the project and later the Government had also
worked on analyses of water, air and soil gas, the Kerrs’ concerns had not been resolved overnine years. The Kerr family consequently commissioned an investigation to a consultant firmand based on its results they alleged that CO2 was leaked from a reservoir in the Weyburn
project and that the leakage resulted in adverse effects on their land. The results from thestudy were questioned by experts who were involved in monitoring activities in Weyburn andas a result resurveys were carried out by three groups, including a team lead by Dr. Romanak.
Romanak’s group validated various issues such as the plan and records of background dataacquisition and the applicability of CO2 concentration‐based surveys (surveys that rely oncomparison with background data) and then decided to employ a process‐based soil gasanalyses. In the process‐based method, background CO2 measurements are not used but
ratios among major gases such as CO2, CH4, N2 and O2. The analyses led to the following
conclusions: CO2 is from biologic respiration with some dissolution of CO2 into groundwater;no indication of exogenous gas from depth; and CO2 derived from oxidation of methane fromoil fields is negligible. These outcomes clarified that there had been no CO2 leak from thereservoirs, a conclusion that was finally accepted by the Kerrs. In parallel with the field survey,
an incident response protocol was created. It should be learnt from a series of the events thatsetting up a protocol of this kind in advance of a project is essential. In a case where CO2 leakis suspected, tools to be adopted should be inexpensive but adequate it was proved that theprocess‐based approach is effective in this sense. From the floor, a question was raised on theadaptability of C13 and C14 analyses in the allegation case. Both of them were not used there
mainly because it was already known by the initial study that there were no differences interms of C13 between injected CO2 and natural CO2 and C14 investigation was costly. In
response to a question on the applicability of the process‐based method to offshore CO2storage, it was introduced that application to ground water was under study and that greatinterest in collaborative research had been expressed by a number of offshore monitoring
experts.

Wrap‐up
Following the presentations, Moderator Prof Sato summarized the workshop. To begin, hepointed out that although CCS experts can select a site that should not allow CO2 leakage
through deliberate examinations, the public who have learned there are no “absolutes” from
Fukushima could not help but have concerns about leakage. In this context, the moderator
presented his understanding that it was necessary to carry out environmental impacts
assessment; to implement an incident response protocol ahead of a project; to take measures
to detect potential CO2 leakage; and to develop methodologies to predict potential impacts ofCO2 leakage based on computational simulations. Finally, Prof Sato concluded the workshop
by emphasizing that not only in CCS but also in other large developments it was important to5

take both the viewpoint of economic development and that of environmental impacts and thatcountermeasures against environmental impacts should be recognized as an added value.

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