The end is nigh. I have submitted my Ph.D. dissertation, “Stable Isotope and Geochemical Investigations into the Hydrogeology and Biogeochemistry of Oil Sands Reservoir Systems in Northeastern Alberta, Canada,” to my examination committee and will defend my thesis on September 11 at 9AM. If you happen to be in Calgary and would like to attend, everything should be open and some of my work I’m presenting publicly for the first time ever! This is unusual in the modern science-industrial complex, where Ph.D. theses are sometimes completely published in journals before ever being compiled into a thesis. Because of this, few people actually ever read your thesis, or use it as a reference: all the good stuff has been published elsewhere in a more accessible format! Part of the reason why my work is being presented for the first time at my defense is that parts of the work resulted from industry collaborations, that required certain data to remain confidential. We have finally extracted the good stuff, the research that can be presented openly, and put it together in a thesis that should be beneficial to industry, government, and water resources groups doing work in the Athabasca oil sands region. I’ve put together a short summary of my thesis work below:
- I compiled public data and mapped the salinity of McMurray formation waters across the entire Athabasca region, and came up with a new geological explanation for why there is so much variability in the groundwater chemistry of one formation. The McMurray formation contains most of the oil sands deposits, so there are fairly widespread implications for our regional-scale observations. This work was partially presented at the CSPG/CSEG Geoconvention in May of this year, but we have refined the message and identified some key features to look for when evaluating water systems on a smaller scale, such as an oil sands lease area.
- Evaluating the geochemical composition of water in the McMurray formation used to be difficult. The bitumen in the oil sands are very hydrophobic, so drilling groundwater wells into the bitumen-saturated reservoir to find out the chemical makeup of water isn’t easy, and most of the time it just doesn’t work at all. However, Gushor has been producing small volumes of water from drill core in addition to the oil that they extract for routine geochemical analysis of bitumen. As you might suspect, the water is wildly contaminated by drilling fluids (water-based muds are used to lubricate the drill bit), so analyzing its chemistry seemed like an expensive and somewhat absurd undertaking at first. However, using stable isotope geochemistry we were able to make a few calculations and can now determine the stable isotope composition and the Total Dissolved Solids (TDS) concentration of the original formation waters, completely eliminating the contribution of drilling fluid! This is an important development because of the very substantial variability in water chemistry in the McMurray formation that can change by thousands of mg/L over short lateral distances (kms or less). We can now map these changes in water composition using drill core samples that are being routinely analyzed for petroleum geochemistry, giving hydrogeologists a brand new tool to investigate water systems in oil sands lease areas. What’s even more awesome is that we can do this water mapping in three dimensions, identifying changes in water composition both vertically within a single reservoir, and laterally when multiple wells are sampled across a lease area (Mark Rabin and Jason Wilkins cleverly dubbed this technique 3DH2O over breakfast one day, feasibly we could make this 4DH2O if we sampled the area at different times, perhaps to find out where injected steam has moved around). We did a proof of concept study using this technique to map the heterogeneity within an active SAGD lease area, and found some really interesting results, but unfortunately you’ll have to wait for the paper to see them (sorry!). I’m also doing this work as a consultant for a couple companies if you’re reading this and are interested in exploring the water systems of your own oil sands lease area.
- While we were thinking about differences in water chemistry in the McMurray groundwater across the Athabasca region, it also occurred to me that there is a very active biological community in the oil sands reservoirs. Microbes exploit the oil-water interface to consume petroleum hydrocarbons, usually by methanogenesis. However, microbes are influenced by the aqueous geochemistry of the reservoir system, and methanogens are particularly sensitive to increases in salinity. To see how bugs can be influenced by the variations in salinity that we see in the Athabasca region, I created some oil sands microcosms with salinity values that span what we observe in the Athabasca oil sands region in cooperation with the wonderful people of the Gieg Lab in Bioscience. Special thanks is owed to Dr. Sandra Wilson, who tolerated and encouraged my sometimes clumsy transition to becoming a part-time molecular biologist. We monitored the progress of the microcosms over a year-long period, and saw some very real differences in the isotopic composition of methane, and the inferred metabolic pathways of the microbes under the different salinity conditions. Unfortunately, biology in the lab doesn’t always look like biology in environmental systems, and while the bugs behaved very differently under different salinity conditions in the lab, the methane they produced didn’t look anything like what we see in the field. More work required on this one, but I think this study identified some further questions and research directions that we could take to work on the idea of salinity controlling biodegradation in parts of the oil sands regions.
- Finally we tried to put some timing on methanogenesis in a coalbed methane system, which is analogous to oil sands systems in many ways. While not completely similar, both CBM and oil sands are shallow organic carbon-rich reservoirs with active hydrogeological systems and rapid carbon cycling due to microbial activity. Using compound-specific natural abundance radiocarbon analysis we found no detectable radiocarbon in dissolved inorganic carbon or methane, even at the shallowest reservoir depths (<100m), suggesting that microbial carbon cycling of coal is occurring much faster than inputs of dissolved inorganic carbon from shallow groundwater. This work was conducted in Montana, collaborating with the fantastic Drs. David Vinson and Jen McIntosh without whom this project would not have been possible.
These papers represent the main bulk of my thesis work that has been conducted over the past few years, and I’m pretty happy with how it all turned out. Like all Ph.D. projects, there are serious bumps in the road that happen, and you can either let them derail you completely or let the bad things slide and find other opportunities. I tend to choose the second option, having realized from many years of playing baseball that hitters that fail 7 out of 10 times at bat are called “hall of famers.” Sometimes you strike out, and when that happens you just have to get back up to bat and take another swing. There were periods during my degree when the data we were getting was junk, when corporate confidentiality took an entire project away from me (this will never be published, sadly), when we couldn’t get funding for any of our best ideas, and that time when I spent an entire summer in Europe developing a project that never came to fruition (ok, this one wasn’t so bad…). Looking back at the entire Ph.D. process as a whole, things tended to work out pretty well. I’m very grateful for the funding that supported this work, from NSERC and our sponsors at Suncor and ConocoPhillips who all continue to support excellent university research, plus the awards to collaborators in the Gieg Lab and McIntosh group that keep their research machines humming smoothly.
If you’re interested in the work we’ve done, please don’t hesitate to get in touch with me, I’m happy to share more details and data as it becomes available for us to publish. As for me, my next steps in my career and life are finally being ironed out, and I’ll be sure to write about them soon.
ps – the last few months I have spent my time writing in the amazing city of Toronto, Ontario. I decided that a change of scenery would accelerate my writing, and I think I was right about that. I highly recommend this tactic for other Ph.D.’s – sometimes it’s easy to get caught up in the day to day lab buzz, and you spend your time doing anything but writing. As for TO, Toronto is an incredible, vibrant city with so much going on at any time it’s easy to get wrapped up in all the amazing things that are happening here. The Jays have been terrible, but entertaining, the music scene has been fun, and lakeshore is beautiful as always whenever I needed a bike ride to clear my head and get some exercise. Thanks for being a great writing buddy, TO; you’ve been elevated to header-image status on this blog.