The 19th RPI for September-October 2018

Doug Angus - Director of R&D at ESG Solutions, Ontario, Canada

About Dr. Doug Angus

I am currently Director of R&D at ESG Solutions after having left the University of Leeds in 2016 as an Associate Professor of Seismic Geomechanics. I have been working on developing and applying new technology in the field of seismic geo-mechanics to address reservoir production and injection challenges as well as mine hazard assessment, specifically to improve characterization and monitoring of induced strain and stress changes. Specifically, the focus of my R&D has been towards bridging the gap between seismic observation and prediction as well as calibration of hydro-mechanical models. Basically, this work involves the integration of microseismicity, time-lapse seismology, rock physics, surface deformation, and coupled fluid-flow and geo-mechanical modelling. Although I am a seismologist by training (having been involved in seismic research for over 20 years), I have published on a range of diverse problems, including hydrocarbon, carbon and radioactive waste storage, underground mining, and engineering scale problems. To do this, it was essential to evolve into a highly multi-disciplinary geophysicist to enable applying my expertize in solving wave propagation problems towards integrating time-lapse and microseismic modelling with coupled flow and mechanical simulation.

I received my BSc in Engineering Geophysics at Queen’s University, Kingston, Canada and subsequently started my research career as an MSc Engineering student jointly between the Department of Geological Sciences and Geological Engineering, Queen’s University and industry partner ESG studying earthquake source mechanics with focus on the application of moment tensor inversion to mine-induced seismicity. To expand my expertize in wave propagation, I completed a PhD at Queen’s University under the supervision of Colin Thomson developing and applying algorithms to model seismic wave propagation in complex anisotropic media. After spending a year as a post-doctoral researcher with James Ni at NMSU, Las Cruces, New Mexico in the USA developing and applying a novel approach to image the base of tectonic plates, I moved to the UK to focus on energy related geophysics problems, with specific focus on hydrocarbon reservoirs. I spent over 2 years as a research associate working with Mike Kendall at Bristol University, where I developed novel workflows to integrate coupled fluid-flow and geo-mechanical simulation with seismology. I subsequently moved to the University of Leeds to take on a permanent academic position to broaden my expertize to include CO2 and radioactive waste storage issues. While at the University of Leeds I was successful attracting £2M in grant income, which allowed me to build a research team of 12 members focusing on multi-physical algorithms to maximize usage of reservoir characterization data as well as improve the prediction capabilities of integrated reservoir characterization workflows.

Pathways or recipes for your success in becoming a well-known name in the rock physics community

As a research associated at Bristol University on a joint-industry project to integrate petroleum engineering, geophysics and geomechanics, I started my journey in the field of rock physics. I spent about 3 months reviewing the extensive rock physics models in the scientific literature, with particular focus on saturation and stress dependent models. I was very excited about a few models I came across, which I brought to the attention of one of the lead investigators on the joint-industry project (Prof Quentin Fisher at Leeds University). Once I realized only three of the twenty model input parameters was measured in our lab, I went back to the literature and focused on sufficiently sophisticated models with easily measurable input parameters.

I guess my recipe for success was carving out an aspect of rock physics research that few people were working on. I knew I wasn’t interested in developing new models but also knew that existing models were poorly con

strained for solving real world problems. So I spent a month combing through the literature creating a database of ultrasonic stress versus velocity measurements as well as working with Quentin Fisher at Leeds University to build a statistically significant database to calibrate and constrain the various rock physics models I was interested in. This database has grown over time with input from my students and new R&D efforts from Quentin Fisher on the tight-gas and shale-gas side. Furthermore, only a few people were publishing research where rock physics models were applied to coupled flow-geomechanical models to predict time-lapse seismic attributes. So I took ideas developed by Jorg Herwanger and adapted and developed new workflows to assess stress dependent changes in seismic velocity and anisotropy from hydro-mechanical models using the calibrated rock physics models. At the time, the solution seemed simple and relevant to the specific problem at hand, but in hindsight it clearly had relevance to the greater community. It was during this time that I was fortunate to have met and received very constructive feedback from great scientist of the likes of Colin Sayers, Colin MacBeth, Jorg Herwanger, Boris Guerich and Mark Chapman (to name a few).

Challenges you see in taking rock physics to the next level

I believe there are two fundamental challenges in rock physics. The first is calibrating rock physics models using in situ data. Although core data are extremely useful, they suffer from scale related issues (e.g., may not capture the true heterogeneity of lithological units as well as material weaknesses such as fractures, joints and cracks) as well as potential core damage due to extraction from depth and time-dependent changes in sample properties (e.g., changes in cementation due to changes in atmospheric moisture). The next step in rock physics model calibration and constraining input parameters requires using in situ stress-dependent velocity measurements from borehole tool measurements or other novel remote sensing technology. A second challenge is the development of stress-dependent rock physics models that incorporate anelastic effects, such as strain hardening and weakening. Many of the existing models only consider elastic behaviour and, as such, do not allow modelling the impact of irreversible deformation such as compaction and shear failure.

Advice for early career scientists (rock physicists, geophysicists, etc.)

I would say:

Never turn down an opportunity, whether it is to collaborate with someone or take on a new project. Opportunities may appear plentiful now, but they can soon disappear quickly.
Never be afraid to delve into a new field outside your realm of expertise. It may be daunting but learning something entirely new will make you more multi-disciplinary and enhance your existing toolset.
Never put off doing something that can be done now for tomorrow or make excuses for not completing work. Just do, otherwise the world will pass you by quickly with that mindset.

We thank Doug for his continuous contributions to the rock physics community

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