Shawn Maxwell is Chief Geophysicist and Advisor for Schlumberger’s Hydraulic Fracture Monitoring corporate business unit, and is based in Calgary, Alberta. Shawn is responsible for development, implementation and culturing of Schlumberger’s StimMAP service. Prior to Schlumberger, he served as Chief Geophysicist with Pinnacle Technologies in Calgary; Manager of Petroleum Services with ESG in Kingston, Ontario; and Lecturer at Keele University in England. Shawn was awarded a Ph.D. in earthquake seismology, a M.Sc. in Engineering Physics and a B.Sc. in Geophysics from Queen’s University.
He has over 20 years experience in a broad range of microseismic monitoring applications, including mapping hydraulic fractures, fracture networks, steam floods, gas floods, water floods, casing failures, reservoir compaction, gas storage and sequestration, excavation damage around underground tunnels, and mining induced seismicity and rockbursts. Dr. Maxwell has been active in projects throughout North America, Europe, Africa and the Middle East, and his expertise includes velocity tomography of active and passive seismicity, seismic raytracing, synthetic seismograms, in addition to microseismic source characterization, data acquisition, processing and interpretation. Shawn has authored numerous publications in journals and professional abstracts.
Shawn is a pioneer in microseismic monitoring, and an internationally recognized expert on this innovative technology. Recently he was on the organizing committee and a keynote speaker for the very successful 2009 CSEG Microseismic Workshop (www.ucalgary.ca/CSEG_workshop) and will give a GeoCanada 2010 short course. The RECORDER invited Shawn to share his experience in pioneering these developments and his vision of the future of microseismic technology. Following are excerpts from that interview.
(Photos courtesy: Penny Colton)
Shawn, tell us about your educational background and your work experience – what paths led to where you are today?
I did a Ph.D. at Queen’s specializing in mining induced seismicity to understand rockbursts: earthquakes that damage mine tunnels and cause a safety hazard to miners. I was lucky to be able to visit some interesting mines in Canada and South Africa, as well as some big international research projects investigating induced fracturing around tunnels for nuclear waste storage. But I was always more interested in petroleum microseismic applications, which lead me to working in the service industry creating a business around microseismic monitoring.
So you have your B.Sc. in Geophysical Engineering, M.Sc. in Engineering Physics and a Ph.D. in Geophysics. Why the switch between Physics and Geophysics?
During my education I was working towards a job in petroleum, but every time I graduated oil and gas prices would once again tank and job prospects would dry up. I decided to do a Masters and then a Ph.D. to expand my education and pursue some interesting research projects. After completing my undergrad I had the opportunity to do a Masters in Engineering Physics looking at Nuclear Magnetic Resonance, a topical subject now but mid 80’s it was a little before its time. During my Masters, I met Paul Young who was a new Professor at Queen’s looking at induced seismicity and I thought how cool is that: going down into a mine that is literally blowing itself up. My Ph.D. project with Paul ended up taking me back to Geophysics.
Shawn, if I were to ask you to list three qualities that would reflect your personality, what would they be?
I am a reserved, quiet person. Beyond that I think I am even keeled, and relatively calm. I would also say that I am focused, both in my personal and professional life, I like to have a target and focus in on achieving that.
You started your career as a lecturer at Keele University in the UK. You stayed there for 3 – 4 years and then joined the service sector at ESG Canada and then on to Pinnacle and Schlumberger. Tell us how you decided to make these moves.
I moved my family to Keele University, where I was a Lecturer which is an Assistant Professor type of position. It was an interesting opportunity to get international experience and live in a different country. Pretty soon I came to the realization that my research interests were very applied and sat somewhere between consulting and applied research, so it became more and more obvious that I was probably better suited to being in the service industry. I joined ESG and returned home to Canada to try and kick off microseismic as a commercial offering for oil and gas applications. I have always been convinced of the benefits of microseismic as a monitoring technique in the petroleum industry and my various positions have allowed me to take on different professional challenges as the technology has evolved from a niche market into wide spread acceptance in our industry. Microseismic has always been my passion and I have always had strong convictions and a vision of how the technology needs to evolve with the changing market place. My various career moves have allowed me to both follow my passion and realize my vision for the technology.
How did you decide to focus on the borehole side of things rather than surface seismic?
Microseismic is a technology well suited to borehole geophysics. It comes from roots in earthquake seismology (the other surface seismic!) and to record the small amplitude microearthquakes in reservoirs requires borehole monitoring to get sensors close to the target. The borehole side also comes in terms of the main monitoring applications. When I began pushing microseismic there were really two potential applications, short term monitoring of hydraulic fracturing of production wells and longer term reservoir monitoring of production, fault activations, and water, gas and steam floods. It has been very interesting to get involved not only in the borehole geophysics side of our industry but also in the reservoir engineering and completion aspects of boreholes.
Shawn what do you have to say about how your career has shaped up so far?
I’ve been extremely lucky to be involved early on in a technology that has finally taken off. I have been pushing the benefits of microseismic since the mid 90’s and for a long time it was like talking to a brick wall. It is really satisfying to see the technology being accepted and used so widely. For example in 2003 I remember submitting three abstracts to the Annual Meeting of the SEG and all three were rejected. One of the papers in particular was positively reviewed but ended up being rejected because microseismic was outside of the interest of the SEG. At that time microseismic was already starting to explode with applications in the Barnett Shale but it just wasn’t on the SEG radar screen. Since that time specific microseismic sessions have started at the SEG and last fall in Houston there were three oral and two poster sessions, it’s on the radar screen now! So I feel very fortunate to have been there from the early days and to see that brick wall come down.
Looking back at your geophysical career will you share with us one or two of your most exciting successes?
I have been very fortunate throughout my career to have been involved with some amazing projects. One would have to be a project at the infamous Ekofisk field, where I did a microseismic monitoring project in 1997. It was an exciting project to be involved with and one that is often considered to be a turning point for the technology.
Another one has to be the first frac that was monitored in the Barnett Shale. Now the Barnett is like the poster child of shale gas plays, and where microseismic is very high profile. I remember as the processing started to show this strange fracturing network we were left trying to convince the client that we were really seeing a complex fracture network. Looking back it is funny to recall the debate between the engineers and geologists and geophysicists about natural fractures in the Barnett, which is now so widely accepted. These days shale gas plays are all about that same hydraulic fracture complexity which is the key to making these unconventional plays economic and I was lucky to process the first one.
So what would be your most important contribution to geophysics?
I am hoping the best is yet to come. But there have been a number of projects where the information has been so fundamental that it has changed the way clients conceptualize their reservoir. Along with that there have been some impressive financial benefits, but often the projects with the biggest impact are not the ones we get to share with the industry. I have been very impressed with the openness of clients, and especially here in Calgary, giving permission to share results with the industry. Fortunately for some very interesting projects, I was able to present the results and increase the industry visibility of the technology. But I don’t know if it’s truly a contribution.
The fact that you have played a significant role in the evolution of the technology in the last seven to ten years, that in itself is a big contribution I think.
What professional and personal visions or goals that you are working towards now?
I think we are at an important turning point where we need to focus on maturing the technology in the industry. While microseismic is widely used, it is still early days and has been compared by several people to the early days of 3D and 4D seismic. Microseismic is certainly very visible and many people want to use it, but I think we need to standardize products and deliverables. At the same time we need to continue focusing on the benefits and value that we get from the microseismicity and refine how we use the reservoir knowledge.
Okay, let’s get to these technical questions then – has there been a shift in how Microseismic data is used by operators in recent years?
Yes, I think there certainly has been a shift. Microseismic is somewhat unique in that it’s a geophysical technology that initially was pushed by the engineering community. Engineers had a clear need of a technology to image hydraulic fractures. At the same time that the SEG was rejecting papers on the topic the SPE was all over it talking about the benefits. Recently we have seen geophysicists take it more on board and start to take stewardship of the technology. Issues like velocity model construction that is critical for accurate answers, qualifying and benchmarking the processing and raising awareness about confidence and uncertainty in the measurements and incorporate it in the interpretation. In the early days there was an image with just a set of dots representing the discrete microseismic locations, but fortunately now there is much more awareness of the confidence and accuracy of the image.
So what are the biggest problems or issues that microseismic technology must deal with in order to gain more acceptance in Industry?
I think one issue is standardization, including data formats and data deliverables. There are a growing number of vendors and each have a different way of processing the data and produce different products. I think from the client prospective it becomes very confusing to decide what’s correct and how to differentiate the various options. For example there is no standardized quality control, so confidence is certainly an area for improvement. I think this can only be achieved with more transparency and education of the relative pros and cons of these differences. Much of this is common to other geophysical techniques, but because microseismic is a purely passive technology we have no control on the strength of the signal so besides vendor specific differences there is also an issue with the data quality and signal-to-noise ratio that changes with each data set. I think the critical factor is educating the users and transparently demonstrating the confidence to enable informed interpretation.
The next one has to do with the two camps that we have in the microseismic technology, downhole and surface. Could you comment on why this appears to be so divisive within our Industry?
I think there is no question that downhole recording of discrete signals and processing with algorithms based on earthquake seismology is the more matured and validated method. In the last few years we have seen new processing methods emerge based on migration or beam forming techniques. The migration type methods can be used to process discrete borehole data, and can also be used to stack large surface spreads. Surface spreads processed with migration methods are more aligned with reflection and so closer to the comfort zone of most geophysicists. Surface spreads also open up opportunities where there are no observation wells. But I fear the method is not as validated as downhole monitoring, and we don’t know enough about the accuracy and how far we can push the stacking to pull small amplitude signals out of the noise. Until we overcome this aspect it is difficult to know when and where the technology can be reliably used. But I also think it is important to remember that surface monitoring of microearthquakes is common place in earthquake seismology, although again it is normally using discrete signals. So we know if the amplitudes are large enough the signals can be detected on surface, but I think the divisive part comes is in how far this can pushed to detect the very small amplitude signals that we struggle with recording downhole close to the reservoir. I haven’t seen a true integration of downhole and surface data and so to me that makes it very difficult to fundamentally understand what we could record from surface.
Geophysicists have only recently started to get involved in microseismic projects. Why do you think it has taken it so long?
Well it has certainly been visible in the geophysical community for long time, but it’s really the wide spread acceptance of the technology that’s taken place now. Many geophysicists are unaware of what a hydraulic fracture is, let alone what the drivers would be to monitor it. It is unfortunate because successful hydraulic fracture stimulations are so critical to economic development of unconventional reservoirs. As I mentioned before, microseismic was initially pushed by engineers and we have an unfortunate situation in our industry that there are big differences in culture between engineers and geophysicists which sometimes can be a barrier to communication. As the technology became widely used by engineers, geophysicists have had to get more involved. From my point of view I also think that our industry is a little conservative in adopting new technologies. But I think there is also a lesson to be learned by the geophysical community as a whole, here is an example where the engineers have been able to really define the technology that matches their needs. Maybe we should learn from this on a broader sense as we start to look for new technologies to really optimize production. I made a comparison with 4D seismic earlier, but one big difference is that the engineer end users are more comfortable with microseismic than even 4D seismic.
Right, that is true for I think for many new technologies, like the 3D technology, it was tested in the late 70s and it became normal in the late 80s and then in the early 90s there came volumne attributes and curvatures. Industry takes time to assimilate and then use new technologies.
Yes, exactly and it is normal for new technologies to follow an ‘S-curve’ with slow early growth with some early adopters and then rapid expansion as the technology becomes proven and others jump on board. But I also think that the industry needs to be more open minded to really understand the subtleties of new technologies and potential benefits to allow faster adaptation of ones that can make a significant improvement.
Shawn, microseismic as you have mentioned before is more earthquake seismology than it is exploration seismic. Now that having been said, there are a range of technologies developed for surface seismic that may be of use to microseismic, multichannel filter and things like that. Do you see technology cross-overs either now or in the future that could benefit both?
Yes, absolutely and actually I am fortunate with Schlumberger to be in the WesternGeco office so I can take advantage of the spin-offs. I am convinced there are a number of filters that can help with microseismic, but it often needs to be redeveloped from first principles to be properly applied. Anything we can do to improve Signal to Noise Ratio will have a positive impact. Going the other way, I know there have been some recent papers using microseismic location methods to image diffractions. Integrating microseismic into time-lapse VSP and also reservoir characterization has proven to improve processing and interpretation. At the end of the day it is all seismology and we are trying to image the same reservoir using both methods.
So where do you think the next stepchange in microseismic technology will be?
It strikes me that despite the wide use of microseismic we really don’t understand the rock physics or the geomechanics of how the reservoir responds to fracturing. We are seeing a lot of microearthquake sources that are mostly shear deformation while we are actually injecting fluids to create a tensile crack in the rock. So reconciling the shear deformation with the tensile frac opening I think is critical so we can really fully exploit the information. Once we have a better rock physics understanding we will be better placed to optimize the permeability of the hydraulic fracture network and be able to tie it to a reservoir simulation to optimize the reservoir drainage. At that point we will really see the full benefit of microseismic.
Is there a role for microseismic in conventional plays, could you explain that, elaborate a little more?
Yes there certainly is, although much of the recent adoption is unconventional reservoirs with shale gas, coal bed methane, tight gas stimulations and steam floods. Hydraulic fracturing is also sometimes used in conventional plays and so there are similar drivers there. I also think that once we better understand the rock physics and geomechanics of microseismicity during hydraulic fracturing we will also be better positioned to use the technology more for reservoir monitoring of conventional reservoir production, fault activation, and imaging water floods or gas floods.
Many experienced geophysicists document their work in the form of a book or something like that which other people can use. Has that thought crossed your mind and are you planning anything in that direction?
I am having too much fun learning about the technology and how it can be integrated with other measurements, to take time out to try and write a definitive book on the topic while it is still evolving. I suspect there would be a lot of interest so maybe it is something to consider.
Do you volunteer your time for professional societies or would you like to offer any comments?
This year I have become an Assistant Editor for Geophysics for a new section on passive seismic. I have also been working with Jeff Deere editing a special issue of the Leading Edge on microseismic, and helped with a CSEG microseismic workshop committee. I have also put on a couple courses for the DoodleTrain and the upcoming GeoCanada 2010 meeting.
Shawn, tell us about your experiences so far at Schlumberger? You’ve been there a year now?
Yes it has been almost exactly one year. I have been traveling a lot. Schlumberger is obviously a huge global organization and so I have been getting up to speed with the various groups in the company involved with microseismic. I am impressed with how many people in the company are interested in microseismic, the variety of skills and talents in research and engineering centers, and different geomarkets. It is incredible the visibility and resources within Schlumberger that are being invested in the technology.
Shawn, can you tell us about your interests other than the technical work of your career.
Its great living in Calgary, so close to the mountains. I don’t get out as much as I’d like to, but walking, hiking, skiing, even driving through the mountains is amazing.
I also spend lots of time at my cottage in Ontario. It’s on a beautiful, quiet isolated lake and completely off the grid. I’ve been doing lots of work on it, installing solar systems and trying to convince my daughter Jackie and son Bobby the joys of getting away from it all with no internet, TV or cell phones. Last summer we erected a yurt, a structure based on a Mongolian Nomad dwelling. It was lots of fun putting it up with help from family and friends, but it made me realize how great it is to get back to professional work where I know what I am doing.
Shawn, we are almost close to the end I’d like to you, what would be your message for young geophysicists who are entering our Industry?
My advice would be to be patient especially if they are looking at oil and gas for a career. As I have found during my career, the industry is very cyclic and whenever it’s up you know it’s going to come down again. Besides being patient in terms of the normal business cycles of the industry, I also think it is important to be patient in terms of building experience. I think a lot of us tend to be quite impatient and try to quickly advance our careers, but when I look back at my career the most important aspect has been the variety of experiences that I have enjoyed. Few of us know where our careers will ultimately lead, but the experiences accumulated along the way are always something that can be built upon.
Are there any question that you had intended to be asked and we didn’t cover so far?
No I think we covered it all, but I want to thank you again for invitation. I always enjoy reading your interviews Satinder, and it is an honor to be invited.