Technologies and Practices for Plugging and Remediating Orphaned and Abandoned Oil and Gas Wells

All right, welcome everybody. Um, thank you for joining us today. Um, I'll say a few um, introductory words and then we will um, move into our um, expert presentation and discussion. Um, so to give a little context about the task at hand, um, this is a um, consensus study committee work of the nationalmies of sciences, engineering and medicine. Um and our charge is to assess potential causes, consequences, and remediation of plug failures. Um you can find the full um statement of task for this committee and the report in the link that I'll provide in the chat shortly. Um and to give um a little more detail about the format of today's meeting, um we will be hearing from Dr. Bernard Mayor um who is the um professor and head of the department of geoscience at the University of um Calgary um and he'll be talking to us largely about um this topic area in the context of um monitoring hydrocarbon um wells and well sites and um different leakages and potential um movement of subsurface fluids and gases. Um, in addition, um, just logistically, I want to note that this is an open on the record session. Um, and we may address, um, any questions provided in the chat by, um, any public attendees that we have with us today. Um, but the priority of the meeting is for committee members to ask questions to our invited expert. Um, to that point, I also just want to briefly remind everyone that this is an information gathering session. Um and what that means is the committee is in process of assembling materials to examine and discuss um in order to uh formulate its findings, conclusions and recommendations that will ultimately be published in our final report. Um therefore, you know, just to be mindful that the committee has made no particular conclusions at this point. Um, and lastly, we just um ask that all attendees be respectful of each other throughout this meeting. Um, and with that said, I will turn it over to you, Dr. Mayor, um, for your brief presentation. Oh, and let me make sure that you can have screen sharing capabilities. >> Okay. >> Yeah, turns out I do have not. >> Okay. Um, can you give it a try one more time? >> Now it looks better. >> All right, great. >> See how this works out. Can you see your PowerPoint slide? >> Um, no. You may have shared um the wrong screen. Right now, we're seeing your Zoom. Okay, try it in a second time. >> All right, there we go. >> Is it any better? >> Yes. Oh. >> Oops. >> Take your time. All right, there's your >> lock now. >> Yeah. >> And you have a full screen now. >> Yes. >> Okay. Um, yeah, as mentioned, my name is Bernard Mer. I'm with the University of Calgary since 1997. And um so for more than 25 years I'm now involved in geochemical techniques to monitor for movement of subsurface gases and fluids in the near surface environment. One correction from the introduction I want to make is that I'm no longer the head of the department thankfully in terms of um key ingredients for monitoring of migrating gases and fluids. There's a diagram of a fracked val here on the right hand side. Uh the three areas of interest we are involved in studying is widespread sampling and analysis of dissolved and free gases from aquifers and from soils to establish baseline conditions in the near surface environment. We are very interested in collecting information on chemical and isotopic composition of gases from the intermediate zone. So that would be below the shallow groundwater but above the resource play. And finally we also as a third ingredient need to know the chemical and isotopic composition of gases and fluids from the production zone in the various areas. And all my expertise is from resource plays in western Canada. I have no expertise in the United States on similar issues. The types of samples and the sampling approaches we like to pursue from the left to the right on this diagram is to sample produced gases and fluids. That is typically done in produced gases in stainless steel containers. We interested in collecting mud gas samples during the drilling of wells. So the natural gases which come with the ma mud to the surface. We have quite a bit of experience in analyzing groundwater samples including free and dissolved gases. We have some experience with soil gases either with chambers at the soil atmosphere interface or with drive point probes where we can collect soil gases in various steps and then relatively limited experience with surface casing vents. The analytical tools we use in our laboratory is the chemical characterization of water samples and gas samples. Uh that includes major and minor ions in water samples, the hydrocarbons and dissolved and free gases, CO2, argon, other gases um to characterize the gas composition. And in addition to that we specialized in doing stabilizotope analysis on various compounds that includes water dissolved inorganic carbon sulfate various others but most importantly for this context the isotopic composition of methane and they're abundant also ethane propane and CO2. On the right hand side, you see a diagram of the carbonizotope ratios of methane versus the hydrogen isotope ratios of methane. And as you probably heard before, this isotopic characterization enables to uh determine whether the methane which occurs is of microbial origin, a thermogenic gas or whether it is uh from some other sources. I also decided to uh give you three or four key findings from our research over the last 20 years which might be relevant to your panel. And all of that again is focused on Western Canada. On the right hand side you see a diagram of carbonizotope ratios of methane versus the gas dryness concentration of methane over concentration of higher alkanes. And it turns out that in western Canada gases in shallow aquifers at baseline gases in cobat methane place and gases in shale gas reservoirs have very different isotopic compositions. The figure on the right shows you not sure if you can see my cursor that would be the average composition of methane and shallow groundwater. The green dots down here are the CBM plays in several hundred meter depths and the black dots over here, these are shell gas reservoirs in two to three and a half kilometer depths in western Canada. So the different chemical compositions indicate that measuring the carbon isotopes of methane and the dryness of a gas is a promising tool for tracing migration from hydrocarbon res gases from hydrocarbon reservoirs towards the near surface environment. I also mentioned that we are interested in characterizing carbonizotope profiles of methane and if abundant ethane and propane in the intermediate zone as well are drilled it's possible to release gases from the mud shaker and these measurements can in fact be done in the field for methane at least and when doing so that gives us a profile of carbonizotope ratios of methane which you see on the left hand side from a literature source, ethane and propane which in western Canada do increase with increasing depths relatively consistently. So that gives us a library of isotopic composition versus various steps which comes in handy if later on we collect gases at the near surface and try to decide from which steps they are released. Second last slide here shows you that in western Canada methane in shallow groundwater at baseline conditions I should say is almost always of microbial origin. Our research group has somewhat limited experience with analyzing gases from surface casing vents, a little bit of experience with measuring soil gases. And whenever we do that in our research areas, we often identified that these gases are most often from the intermediate zone, especially from coal zones which are in the intermediate zone releasing gases which then come back to the surface. My last introductory slide here summarize a couple issues about shallow groundwater. Shallow groundwater influx of dissolved gases and formation water in my view is relatively easy to monitor for because we have a number of different analytical techniques to do so. And it's easy to do so if there are sufficient monitoring access points in groundwater flow direction. However, the movement of free gases in the shallow groundwater and in and in the water unsaturated zone in our experience is much more difficult to predict and monitor. That knowledge comes from a series of gas injection experiments. On the diagram you see one of those where um hydrocarbon gases were injected at depths into this aquifer. The groundwater flow direction here is to the right hand side. So if methane were dissolved in groundwater, it would travel to the right of this diagram. However, if you have a free gas phase, buoyancy comes into play and the sediment characteristics come into play. And you see the orange is the gas distribution, the free gas distribution that through buoyancy and tilted sediment faces that gas goes all over the place, often in directions which are hard to predict. And in this case they are against the groundwater flow direction. So much more difficult to assess where to find the gas outside of the bell bore. That's all I have to present up front. So happy to answer any questions on that or any other related matter. Right. Thank you so much Dr. Mayor. Um I want to take a moment just to see if there are any immediate questions from our committee members. Um we have a few more people who've joined in. Okay. If not, um Mary Kang, can I turn it over to you to provide a little more context about um chapter 5 and kind of what we're looking for um in in a um from a geocchemistry lens in that chapter. >> Yeah. Uh happy to do that. Thank you. Uh and thank you for that presentation. and that was really help uh helpful and uh we're really excited to have you here uh in this session. Um so uh it's chapter five is um called u monitor it's the monitoring chapter of this report and it's broken down into three sections. The first one is environmental monitoring and then we have well integrity monitoring and then the third section is geocchemistry. We actually took out geocchemistry because there's a lot of overlaps um within uh environmental monitoring and well integrity monitoring. Of course there's opportunities to kind of put it back uh in into those uh subsections. Um but um hopefully this uh conversation can can help us here. So environmental monitoring um would be more along like groundwater monitoring um everything you mentioned about groundwater monitoring would be relevant there and then well integrity monitoring that could be the surface casing vent flows but also like soil gas sampling all of that would be would be very relevant um so yeah that's kind of the highlevel discussion highle uh overview of the chapter I don't know if anybody wanted to add anything else. >> I don't know, Missy, if you were trying to say something. >> Sorry, I was just saying uh yes. Yeah, that's fine. Yeah, let's keep going. >> Okay, so I I don't know if Noel if we should open it up for to the um discussion component here. >> Yeah, absolutely. Okay. Uh are are Noel, you're moderating the questions, right? >> Correct. Yeah. And I as you were talking, I was thinking um Dr. Mayor, one of the other um sections of our report that I think might help inform um chapter 5 is um emerging technologies and methods. So I'm curious if in your research in your many years of experience um could you tell us any could you highlight some evolution in the methods for um for monitoring like methane leakages or um how methane kind of interacts around in the subsurface around these well sites and how how has the research changed? How have like the tools changed? if you can talk about that. Um I think that might help us find some direction both in our monitoring chapter as well as um the the what will be the final chapter of our report which is kind of more forward looking and um uh yeah just looking toward the future and what needs to be further developed. >> Yeah. Um there has been some analytical development in the last 20 years. So the measurement of gas concentrations and isotope ratios uh is has been done for more than 50 years. Um there are some newer technologies on the market now which are laser based measurements of methane concentrations and methane carbon isotope ratios with ethane slowly coming online. These technologies um enable measurements in the field on a um almost immediate basis for soil gas measurements for samples from uh mud gases for instance. I've shown a picture where we have done this by taking that type of analyzer to a drilling rig and uh sitting there for a week 24 hours 7 days collecting measurements and do the analysis right in the field. So um there are some advances uh the ability to measure methane ethane propane isotopic composition on mud gases has also uh developed to a point where it's now possible to do these measurements on very small amounts of uh gas concentrations. So I think there is incremental improvement. Um but uh for the most part we still use techniques which were available already 30 40 years ago. >> Um there are some scientific developments on clumped isotopes very complicated measurements for which very few analytical facilities exist. And my personal experience is that when it comes to deployment of these techniques in an industrial context, it has to be simple, has to be fast and has to be cheap. >> So anything which takes four months to generate results and is very expensive usually gets not deployed in industrial context. >> Thank you. I'll um turn it to Mary Kang. Thank you so much for that um context, Dr. Mayor. I I I have just to pick up on the industrial context. Um a lot of the methods that you described um of course companies do use them. Um how how um widespread are you know the even just stable isotopes and the uh gas dryness uh used uh in the environmental monitoring contents and then the well integrity monitoring context are they are you know are they used enough are they used sufficiently I guess would be a this is a a kind open-ended question. >> Yeah. Um, a lot of that depends on the regulator in the jurisdiction what they require to have done. In Alberta, Western Canada, we had development of Colate methane plays between 2004 to 2011. And because these cold methane plays were relatively shallow, few hundred meters depths, the regulator required that baseline analysis in groundwater were done on every groundwater well within 600 m of a CBM well. And that included carbon isotope fingerprinting of any methane or higher alkanes, which was rare, the gas composition analysis. And by default you get the dryness or wetness parameter which can be calculated. Uh industry um I I'm less they don't share all what they're doing. Um but I'm very confident that they have similar data for their resource plays and many companies do uh do mudgas profiles I think for their own protection. I don't know how frequent and whether they do that once every township or every well because it does cost some money but um I'm sure most um companies have Matka's profiles just to be legally protected if claims are made against which they need to defend themselves. So in my view, it's probably fairly widespread used both in environmental monitoring if required by the regulator as well as in industry. However, not all of these data would always be publicly available. >> Thank you for that. Um Noel, can I ask more questions unless other people want to jump in? I don't want to monopolize the time. >> No, of course. Um, yeah, feel free to go ahead and if anyone else has questions, just um use the raise hand function and we'll um work our way around. >> Okay, I I'll jump in and ask a few more questions. Um yeah, thank you for that answer. That's really helpful. I just wanted to ask a bit about um shallow groundwater characterization. uh you know both in terms of uh how do you know if a sample is a good representation of the baseline condition and then the second question is you know how much how much uh monitoring is sufficient you know you mentioned the 600 meter uh limit uh kind of for groundwater monitoring that AER chose to limit for the cob methane um monitoring at groundwater wells uh 600 meters away like is that sufficient? So, how much is sufficient? And also like how do you know what's baseline? >> Yeah. Uh both are loaded questions and there's not a simple answer to all of them. We have done uh groundwater monitoring. Let me start differently. So the the program I mentioned before on CBM groundwater baseline monitoring required one sample to be taken prior to drilling when drilling could commence and um so on so forth. So one sample was viewed sufficient because um well the workload the onus on whoever needs to do that and the cost just multiply if you do it uh frequently more frequently than that. We um had a study where we went to the same well repeatedly and I would have to look up probably 10 to 20 times and it very much depends on what parameter you're most interested in uh how much variability you would find. But intriguingly for that valve we studied the carbonizotope ratio of the methane in the groundwater remained essentially within measurement uncertainty over repeat sampling over several years. So for that parameter I would say if you have one baseline number you're pretty uh have pretty decent information. Your second question remind me was on I can't hear you. >> Sorry. What is uh sufficient radius? >> Yeah. And the radius. >> Yeah. The radius which was chosen at the time um looking at it back I think was relatively arbitrary. If you had um leakage of methane around a oil and gas well into the groundwater and all that methane dissolves, I think ideally you would like to know what the groundwater flow direction is, how fast it goes and then monitor downstream all information which is usually not available at a monitoring site. Um but it's unlikely that you would have transport for several hundred meters at least in our uh environment here in Alberta where we have fine grained uh materials till and so groundwater flow directions are uh groundwater flow velocities are more of the in the meters than in the hundreds of meters. Um my last slide alluded to the fact if your gas leakage were to occur as a free phase. Um I don't want to say all bets are off but it becomes very difficult to predict where it goes in which direction and how far. So in that context picking a number out of a hat what's enough is equally or even more difficult. So, I don't want to be in the regulator shoe to determine what that radius must be. >> That's really helpful. Thank you. Um, well, I could I'll just ask one more question while we're on that. Also, in terms of a timeline, you know, we talked about radius and sufficiency in terms of spatial distance. Um and you said you went to one well over 10 20 times. Um is that over years, months? Uh if you can give us some guidance on that time scale and just your general thoughts on uh how often we should go back and measure. >> Well, the study I mentioned was a baseline study. So we went there over several years um and uh reanalyzed methane contents and carbonizotope well carbonizotope ratios of a methane and that carbonizotope ratio hardly changed because the methane always comes from the same source. concentrations might be a little bit higher, might be a little bit lower. Very much depends how you sample as well, the artifacts you can introduce um by whether you sample free gas, dissolve gas. So that's a little bit more variable, but the carbon isotope fingerprint just wouldn't move because the methane always came from the same from the same source. Um now if you talk about measurements after um well after impact then in that area we do have very little experience because most of our work has been baseline. The jurisdictions in Alberta are such that um in order to do follow-up analysis it needs to be triggered by the land owner. So the land owner needs to um first decide or claim there was impact to the groundwater and then subsequent sampling would be done and very little of that has occurred at least with our involvement. >> Okay, thank you. >> Um any questions from the other um chapter group members? Um, let's go Isish and then David. >> Hi. Yeah, I um I heard that I mean I'm not a microbiologist but I my one of my colleagues is and um she was saying that you know naturally you can have these methane seeps but you know microbes in a subsurface can convert them to like CO2. Have you seen any any similar kind of um you know behavior because we're you know in developing even in advanced technologies and in monitoring um just you know maybe you know developing guidance on what we would want to monitor for um and I you know I think that all kind of also plays into the you know how what what's the radius that we look at around >> right >> well And I know it is you know impact or it's impacted by groundwater flow things like that but I was just curious if you had um detected anything like that. >> Yeah. Yeah. So we we do study methane oxidation which is a process which does occur in many different fashions. It can be aerobic methane oxidation or anorobic methane oxidation coupled with iron reduction, nitrate reduction, sulfate reduction, you name it. Um certainly a process you have to be aware of it especially because it changes the isotopic signature of the methane itself uh by enriching the heavy isotopes. So if you had microbial methane with very low carbon isotope values which gets oxidized, it drives its isotopic signature in a direction which appears to be more thermogenic and that can lead to uh false uh assessments if you only look at the gas. Um but as a groundwater geocchemistry research group, we look at all other parameters as well. So not only the methane which gets oxidized but also the CO2 which gets produced. It would have a very specific carbonizotope fingerprint with carbon 12 enriched if that happens. And we look at the other parameter which are affected redux processes always have two half reactions. The methane which gets oxidized but then also either the oxygen, the nitrate or the sulfate which gets reduced. And so if you look in the whole context you uh should be able to identify whether that process occurs and to what extent it has happened. However not with one simple analysis right when in that case it becomes a lot more complex. Now if you had a significant leakage of methane and ethane around a valvelore um for microbes to microbably oxidize all of this in rapid time seems to be challenging I would say. So these redux reactions need to have the right niche in terms of redux environment. So um at a well where significant leakage occurs I think the chances of finding the original um trace or the original movement of that gas which has not been oxidized yet are relatively high but yeah you're correct one has to be aware of meth methane oxidation. >> Thank you. Um any followup to that is >> um do you have any um publications that that we could potentially reference to? Um and some of this, you know, I think we'd like, you know, just like like to have some papers. >> Yeah, I certainly can uh put a list together and make that available. >> That would be excellent. Thank you. >> Right. Thank you so much. Um, let's move to David. >> Hey. Uh, thank you, Dr. Mayor, for the presentation speaking with us today. It's been very, uh, interesting. Um, >> can you check your microphone? I'm not quite sure. I don't hear you very well. >> Hey, can you hear me now? >> Uh, a little bit better. >> Okay. Uh, >> or if you just speak up, it might be better. >> It could be my Cajun accent. So, I'm from South Louisiana. >> Uh, I don't think that's the problem. >> No. >> Okay. Go ahead. >> All right. I'll try to speak loudly. Um, anyway, c can you clarify of all the the monitoring uh studies that you've done, is it prior to the wellbeing plugged in abandoned? Is this during its active life cycle or even during its idle or is this after it's been plugged to regulations or standards or or after the fact? So post plug monitoring to understand if it has what what type of numbers and data do you have in that? >> Yeah. So we have never been involved in a study where well has been plugged and we monitored afterwards. What we mostly involved is baseline analysis of soils and groundwater prior to drilling a well. In very few cases have we taken samples after drilling the well. And in all of those cases, we have not found um gas migration from reservoir level if we had sufficient data to judge that. We have also been involved in a few studies where methane has been artificially injected sometimes methane, ethane and propane uh to see what tools can be deployed to follow the movement of that injected gas either in soils or into shallow aquifers. And that was very insightful. And I think um uh the only other aspect I should add is that uh our research group has also been involved in CO2 injection for CO2 sequestration and where we monitor not only for CO2 but also for leaking methane as an indicator for um well integrity and so uh that's where our expertise comes from. But I restate we never looked at a well after replplugging it. Okay. No, that that's helpful. Um that I mean, like I said, that's kind of the charge of this whole study for us is understanding what's that long-term integrity look like. Knowing what we know about when the well is still standing up. We obviously know that >> surface casing vent flow is a is a problem really universally. So um and uh yeah I guess a second question and and it may be a loaded question as well is >> I think it's great in that you you get this baseline data and that's what we're learning is it's a little different in the US with these are wells these are wells that the owner has now you know walked away from they may be several decades or even a century old so we don't have the greatest data if if at all um but we know what we see at the surface or what we may you know from a from a format well. Um but still in all you can still take gas sampling to try to finger if the well is leaking me nothing today prior to the going into the plug-in process and you you fingerprint whether it's thermogenic or photogenic. What are your thoughts on risk management as far as at what length do you do to shut that off if it was a biogenic shallow sand which may already be you know uh you know is there you know in a perfect world we want we don't want to have any gas leakage is there you know when you say significant that's a diff you know what is significant how do you you know judge that based on what is ultimate consequence to the environment, consequence to public health and safety and all that. Is there open-mindedness to a risk based approach? Um, but certainly when you go to try to remediate that, there may be a point of diminishing returns how what lengths you take to shut that off. >> Yeah, that's a whole number of questions. Um, and here in Alberta, we have more than 400,000 wells which were drilled since the 1950s. Some of them leaking, many don't. Um, in terms of risk management, I think the approach here is, and there are two areas, um, methane leakage into groundwater and methane leakage into the atmosphere. So from surface casing vents um they're relatively easy to measure what the gas fluxes are and um I think the approach the logical approach would be to try to fix the super leakers the ones which have the highest methane emissions into the atmosphere and if you catch maybe the 3% of those you might be able to reduce 50% of the emissions and not so much worry about the ones which trickle methane into the atmosphere because uh there's a cost involved with all of this. And so if you want to achieve something in terms of greenhouse gas reductions uh start with a big leaks on the groundwater side. It's a little bit more tricky because we often if the leakage occurs outside of the surface casing vent uh the the shoe of a well then it's harder to track where the methane goes in the groundwater and as I mentioned if it migrates as a free gas it becomes more even more of a lottery. So um where it's a I think uh factor of uh doing groundwater analysis to see whether there's clear evidence of methane uh contamination and then see what type of users in the vicinity would be impacted by gassy water which potentially can be explosive. So there's a health risk in that uh area. But yeah, I think I hope I got to most of your question somewhat vaguely. >> No, it it does it helps, right? It's it's a I think it's it's hard to standardize approach. You know, it depends on if the well is in a remote location versus an urban area. There's a different risk profile to it. And I just want to make sure you know our in your personal opinion like I said there should be a logical pragmatic approach to this because the problem is such a widespread. You had 400,000 wells. There's up to 140,000 wells in the US that the government's truly orphaning are having to deal with. How do we I'm I'm in agreement we should go after the heavy hitters first, right? >> Thank you. Thank you for that. Um, let's circle back to Mary Kang. >> Sorry, I have so many questions, but this uh uh so um yeah uh I wanted to ask about uh microbial methane production. We talked a bit about oxidation, but um with the mud gas sampling, you should see would that give you an idea of how deep um microbial uh uh microbially produced methane can be found as because as you drill you're getting the mud, right? >> Yeah. Yeah. Yeah. >> There's there's always this question of like how how deep are the mic microbial methane sources, >> right? Yeah. And to some extent in terms of addressing the charge the panel has um I'm not sure how important that question is. And the the problem why I'm slow with answering is there's not a clear cut off in the carbonizotope fingerprints where we say um a more negative value is always microbial and a more positive value is always thermogenic. There's a pretty gray zone in between I would say uh from -50 per mil to -70 per milll where uh the carbon isotope value of methane alone will not tell you whether that's one or the other. If the carboniz isotope values are more negative than -70 minus 80 per milll yes that is indicative of microbial if they're higher than minus50 but um there's no clear-cut boundary and so I would say that mudgas measurement alone would not be suitable to tell you where that border is. uh there's temperature limits obviously you could imply and um uh help with making that assessment but more importantly that Matt gas profile simply tells you how the isotopic composition changes as you go down and if you have gas leakage um and you measure an isotopic composition at the surface casing vent as you know better than I do in fact uh you can estimate where the leak might occur and that kind of helps you then with deploying your cement squeeze techniques to uh potentially um address the problem. So whether that gas is then microbial or early material thermogenic is of secondary interest in my view in fixing the problem. >> Oh thank you for that. I I totally agree with you. Um just picking up on that u you showed like the mil milkov and at plots uh kind of characterization I think uh I don't know if you showed it for the dryness versus 13C but you showed another one maybe it's not milk and I'm sorry where you kind of show where the regions are for thermogenic microbial and so forth. Um and my understanding is that all of that is based on you know uh put looking at a lot of samples lot of known origin samples and kind of mapping that together. Um I think I know I just know one publication Milkov and ETO published something compiled like something like 20,000 samples globally and it sounds like a lot but um you know it's also maybe not a lot and how how much uncertainty or how you know are uh is in those kind of using those pre-defined areas and how could or may ho how might they change And it's kind of a similar question. >> Yeah, there's always a risk of uh using these textbook diagrams which try to summarize the whole planet into one diagram and especially on what we call the shell diagram where carbon isotopes versus hydrogen isotopes are shown. There's a significant uncertainty in it because the hydrogen isotope values of the methane and the ethane and propane are dependent on the water in which uh that uh hydrogen containing gas is formed. And that water can be quite different depending whether you're in the Arctic regions in temperate regions or whether you're in inland regions such as Colorado or Alberta or Texas for that matter. So yeah, considerable variability. I just looked at the diagram I showed. Uh it's it uses the Ethiopia and um Milkoff uh publication and they have a fairly clear cut off between microbial gas versus early mature thermogenic. Um in my discussion with colleagues Kalis Mu for instance, that's a lot more uncertain that that there's no clear boundary I would say. So some people claim that early mature thermogenic gas can be generated at very low temperatures and would go much further into the microbial field whereas others are arguing that microbial gas can have quite high carbonizotope values and so yeah a lot of scientific discussion around that. Um, but again for the purpose of detecting in which depths the gas leaks, I'm not too worried what we call it as long as we know whether it's in 300 m depths or in 600 meter depths because that's what the drillers need to know. >> Yeah, thank you for that. Um, are there other questions? I don't want to monopolize the time, but um uh but thank you so much. I I could ask another question if Noel gives me the Okay. Yeah, I think it's okay. Um just a quick time check. We have um 13 more minutes left. Um yeah, so we'll we'll see where we are closer to the um hour. Thanks, Mary. Yeah, I mean I could ask a bunch of different questions, but uh one of the things that I'll just pick up on Irish's question about microbial um processes. Um you mentioned about different geochemical parameters. Um how do you have some experience working with like microbial community analysis and how um and how to kind of put that together with the geochemical data? If you could just kind of speak to that. Yeah, we um since I don't know maybe five years we collaborate with a microbiology team here at the University of Calgary which does uh DNA fingerprinting, proteomics and the whole gamut of new microbiological tools which can be used to identify not only which microbes are in the subsurface but also whether they active and what exactly they do. And uh certainly a steep learning curve for somebody like me. But uh intriguing information coming out of that which essentially uh revealed in context like shallow groundwater where methane occurs is that uh there are all kinds of microbes around using that methane and producing that methane. And it turns out that both of them are active at the same time. is kind of a twist sometimes. But in groundwater which is highly reducing where we geocchemically argue that all parameters indicate that methanogenesis happens in situ in this aquifer microorganisms by one or the other pathways which exist. The microbiologists then confirm that that the microbes are there and they are can do that. But they also find at the same time methane oxidizing microorganisms. And so turns out I think the microbiology points to a much more active cycling environment than our geochemical parameters would indicate. But it doesn't kind of counteract any conclusions we have done made based on the isotopic and chemical parameters about the source of a methane. So it's complimentary and intriguing uh provides new insights but again it has requirements in terms of how the samples are taken, how they're stored and how quickly they're analyzed which are not always easy to implement on an industrial site. >> Great. Thank you for that. >> Any other questions, Mary? I think you might be um taking us home here. >> Oh, I mean I I I do have more questions. I have a long list. uh uh but um I mean while we're on that topic of uh you know the complexity of the microbial activity in the groundwater uh and in in the aquifer in the saturated zone I mean there's also a lot of activity happening in the unsaturated zone. Uh so that's one question. Another question is you know other um so it's not just methane that we're worried about. We're worried about a whole range of environmental risks. Uh for example, hydrogen sulfide production can also happen in groundwater. Um you so and you know other um environmental impacts, other uh air pollutants uh and you know you could leakage of methane maybe creating other um dangerous compounds or in groundwater if people were to use it. I don't know if you can speak a little bit to not just methane but other um concerns and then the unsaturated saturated zone that's a separate question I guess. >> Thank you. >> Yeah, let's start with the unsaturated zone. If methane leaks up there, yes, oxidation by oxygen reduction is the logical fate of that methane. But if the flux is high, these reactions might not be fast enough to consume all the methane. Ideally, we like it to be converted to CO2 because of the greenhouse impact being less. But, uh, large leak versus small leak probably makes a difference. Uh, yes, in the groundwater. So if methane intrudes into an oxic aquifer and it makes the aquifer more reducing uh the consequence is a whole sequence of potential reactions such as iron reduction, manganese reduction, manganese coming up as a groundwater contaminant. Um if you get into bacterial sulfate reduction, yes, H2S becomes a problem. Now free iron exists in the aquifer that will precipitate. So it's extremely sightsp specific. Um arsenic could be mobilized. So all of these where all kinds of potential negative impacts. Um, our studies which looked at those indicates they do occur but often in in fairly small environments around the wellbor and then very sight specific because it depends what's in your sediments. If there's no arsenic, you don't get arsenic reduction. If there's no manganesees, you don't get that problem. If you have free iron in ground water or iron 2 then H2S will not become a free gas phase. So hard to make uh general um statements about that except to say that all of these processes are an option in Alberta. We have uh our shallow groundwater is often quite surprisingly reducing already. So if H if methane leaks into it then there's already biogenic methane. Some of these geo chemicals should I call it side reactions uh do not occur because they already played out in the natural environment. Interestingly enough. >> Great. Thank you. Thank you for that. Um you know what well can I ask just one last question? Sorry. Um so we had this uh the monitoring section is broken down into environmental monitoring and well integrity monitoring. And for geocchemistry we had a lot of discussion of whether trying to put that within a subsection for those two environmental well integrity monitoring or keeping it separately. Um, I I just wanted to get your thoughts on on how you you would structure that cuz because there would be a lot of repeated text to talk that's why we we thought we'd do it separately, but would love to hear your thoughts on how best to communicate this. >> Yeah. And I don't uh want to tell you how to write a report but my notion would be to uh not have it as a separate uh third chapter. In my view geocchemistry is one tool of several you would use. You would probably do pressure measurements and hydraulic head measurements and all of these. And um geocchemistry plays in pretty much all the analysis you do in the soils in the groundwater and the in the mud gas profiles in the reservoir but it's not the only tool and on its own it's also not as useful as in combination with others. So my gut feeling would be envir including all the tools you need into environmental monitoring and all the tools into well monitoring that that cuts down on uh duplication of text and um you also don't give the impression that there's one magic tool out which resolves all questions. You want to use all the tools at your disposal and geocchemistry is just one of them. Great. Thank you for that. That's very helpful. All right. Um, any final questions or thoughts for Dr. Mayor? Hearing none. Um, Dr. Mayor, thank you so much. Um, we definitely threw you into this hour at full speed. So, thank you. I I really appreciate you taking the time and I'm sure the um our committee members here do as well. And it seems like we will likely be in touch with you again over email. Um yeah, and aside from potentially asking addition additional questions, I'll keep you posted on the status of the report and when we um intend to to make our um pre-publication available online to the public. Um and with that, just thank you so much again. Um, and enjoy the rest of your day and have a great