An interview with Bob Tatham

Coordinated by: Satinder Chopra
Bob Tatham

Robert Tatham (Bob) is a professor of exploration geophysics in the Department of Geological Sciences at the University of Texas at Austin where he holds the Shell Oil Company’s Centennial Chair in Geophysics. Bob has been a visible participant in SEG and GSH (Geophysical Society of Houston) activities and is a well published author. He delivered the Spring 2001 SEG Distinguished Lecture on ‘Breaking Down Barriers to Effective use of Multicomponent Seismic data’ at Calgary on March 19, 2001.

The RECORDER was privileged to grab some of Bob’s precious time and get his views on different issues ranging from his present assignment to current trends in the industry. The following are the excerpts from the talk.

[Satinder]: You received your undergraduate degree in Physics at Cal State Northridge in 1967, and then switched over to Geophysics and got your Master’s in 1970. What made you switch from Physics to Geophysics, and why did you choose to become a Geophysicist?

Well, actually, I became a Geophysicist with my first job. When I graduated with my degree in Physics in ‘67 there were several kinds of job opportunities available to me. The space industry was very active, and they were hiring a lot of people as programmers. At the same time the petroleum industry was hiring - I was looking at both Schlumberger and Texaco on campus that year. I chose to go with Texaco, and that meant Houston. Aerospace would’ve taken me to Houston too - it was kind of the center of the universe as far as job opportunities for young people went! I’d never been that far east before - it was a big move for me! So I went to work as a Geophysicist, and from that I took some Geology courses in the evening at the University of Houston, because of course I didn’t know anything about Geology.

[Satinder]: When you look back at your long innings in the Geophysical industry...

[Oliver]: Hold on Satinder - are you slipping into cricket terminology on us?!

Well we have innings in baseball too!

[Satinder]: Well yes, I did borrow “long innings” from cricket, no doubt! But Bob, you were in industry for a long time, mainly at Texaco, and now you’re in academia. Could you tell us about some of the things that stand out in your career: the difficulties, the milestones, the research motivations?

Well it’s really kind of interesting, because I started out with my Bachelor’s just doing data processing. From there I grew with the industry. I wouldn’t say there were any real difficulties - just the need to change with the industry. And I have seen a lot of changes over the years! I had to learn some Geology, then I took a Master’s, and that’s when I started to get into the research. I finished my Ph.D., and then I came back into more of a research area at work. Now I’ve gone back to academia at the University of Texas, which is quite a change as well, but that was clearly the direction I was going anyway. And the challenge there is heading up a new exploration geophysics program.

[Satinder]: In your opinion what are the merits of working in industry versus those of academia?

One of the merits of working in industry is you just have so much more momentum. If you decide to do something, well, you just go out and do it! You follow through, and you generally get an answer. If you come up with a prospect, people are going to drill it, whether you’re right or not; if you come up with a new technique, they are going to apply it, that’s the whole point of it. In academia, the big advantage there is you can pretty well do whatever you want. At least that was the way it was sold to me! The idea is you’re the one to decide what needs to be done, and how to do it. On the other hand, you have to go out and find your own resources to do it often times. And it’s a different culture, but I won’t say one’s better than the other, they’re just different in a lot of ways. The measure of success is different. In industry you find out if you’re right or not, in academia quite often you don’t. And that’s both good and bad!

[Satinder]: You’ve worked in different areas of Geophysics. I’ve seen papers on physical modeling, migration, anisotropy, then multicomponent seismology. You’ve covered a lot of ground. Which area fascinates you the most and why?

I think one thing that all my work has in common is that we’re always trying to get back to looking at the rocks, to say something about the rocks themselves. That’s what fascinates me the most - to take the Geophysics and say something about the most fundamental properties. I still find the Vp/Vs ratio and shear wave integration fascinating, and now getting some students to do new work in those areas is very interesting and rewarding.

I’ve done a little bit of non-seismic work. One area always intrigued me, but I never got into it as much as I’d liked, and that was some of the active electrical methods. It seemed like there was a lot that could be done very inexpensively on the surface, but for some reason I was never able to generate much interest in it among others.

[Satinder]: In the last decade there’s been a lot of talk on multi-component seismic: 3C, 4C, then 9C. But somehow it hasn’t caught on yet as perhaps it might have. In the early days I remember S-wave surveys weren’t useful because of the poor data quality. And there were recording and processing limitations which held the technology back. But now those limitations don’t exist, and yet still, this multi-component technology is not being adopted on a regular basis. Why is that?

Well, that relates back to the theme of my talk today: people really don’t know what to do with the data. I think with multicomponent interpretation you’re looking at two different datasets simultaneously, and that’s very different. So I think it’s a matter of educating the end user - how to handle the data and what to do with it. That’s why right now in my teaching I’m focusing on the interpretation of the multi-component data. I think that’s where there’s the big hole. In acquisition there’s a lot of things to be improved, but people know how to do that. Same in processing, there’s a lot of challenges, but people see a path there, they know what to try next.

[Satinder]: What about the cost part of it?

I think the cost part of it will take care of itself. Cost isn’t the real issue, it’s cost-effectiveness. We’ve seen that story in 3D. There were contractors who probably blew the future of the company by not getting into the business of 3D because they thought nobody would ever buy it because it was too expensive. Before multi-component gets really low cost, at least on land, there’s going to have to be enough market demand; and before there’s going to be enough market demand, the price is going to have to go down. So it’s still kind of a chicken and egg situation that needs to work itself out.

[Satinder]: This Vp/Vs ratio that you talked about way back, it’s not unique, because different lithologies can have the same Vp/Vs ratio. Instead of multi-component seismology, people have been successfully using AVO, and in Canada anyway, its extension, LMR. Do you really need to go to multi-component seismic? What is your impression of this?

My impression with a lot of the AVO that’s being done, where you extract similar quantities to the Vp/Vs, is that you’re basically looking at an interface property. When you’re looking at the Vp/Vs ratio itself, depending how you determine it, you’re looking at a bulk property over an interval. So you’re looking at somewhat of a different property. I think AVO does answer a lot of the questions - many times you’re just looking at a single reflection, and that is valid. On the other hand, there’s more stability, although less resolution, in the Vp/Vs measurement. I think that has its place, and as far as that being unique with lithology, it really depends on what you mean by unique - if you’re going to go out there and try to estimate lithology by just saying, “Oh, I’m going to give you this Vp/Vs value, can you give me the lithology?”, well the answer is no, you really can’t. But if you’re willing to put a little geologic sense into it, you can use it as a discrimination tool. In a sand-shale section it becomes a sand-shale ratio; in a carbonate-shale section, it can tell you how much shale you have versus carbonate. Those are the kind of things you can do with it. I’ve seen it discriminate between dolomites and limestones. If you can assume you only have two members and you need to discriminate between them, then it holds up pretty well. In some ways the bulk property you’re looking at with Vp/Vs can give you better than the AVO. The AVO measurements are unstable.

[Oliver]: Do you think industry might move towards a combination of the two techniques?

Ultimately, yes. I think especially with the PSv we’re looking at now - we may be able to actually see density effects, which would get us around this fizz water problem. Again, I think it’s going to be a discrimination kind of thing, we’re going to have to do the early work to really nail down everything except the density, and then bring in the additional data to look at density variations. I wouldn’t go so far as to suggest we could use AVO to get density variations, but I think incorporating all of it together, doing one interpretation and then moving it more towards a discrimination problem, I think there’s hope for that.

[Oliver]: What do you think were the main milestones in the evolution of multi-component seismology?

I guess about 15 years ago anisotropy came along, and that was really a very major breakthrough - a lot of additional ways we could use multi-component data became possible, in particular shear wave polarization. More recently, a big development was the contractors getting into bottom cable recording. As little as five years ago we were wondering whether we could record reasonable shear wave data with a 3-component geophone underwater. Now we’ve got these 4-component phones, and pretty routinely gather good data. I’m not saying all the problems are solved, but certainly I would consider that a major breakthrough.

[Satinder]: What do you think of the volume of data which the 9C work generates, and the value it represents? Is it commensurate?

Commensurate with the expense you put into it? Depends on the problem you’re trying to address. Overall with the 9C you’re looking for the fracture orientation, the anisotropy. Yeah, there’s certainly cases where that’s going to pay off. It’s going to be in areas of tertiary recovery, where you’re looking at a field and trying to get more detail out of it to get that additional oil. The economics are different there, because it’s not exploration - you know the stuff’s there, you’re just have to figure out how to get it out. So you have an idea of the prize before you start.

Fig. 01
Editors in conversation with Bob.

[Oliver]: What developments to you foresee in the next decade for the multi-component technology?

Well again, I think interpretation is going to be the area where all this ties together. I see advances in understanding how the S1/S2 ratio relates to the fluid pressure. Does fluid pressure actually change the S1/S2 ratio? That’s been hypothesized. I think a lot of the imaging issues with anisotropy will come into play. I see us taking all this data, and developing models to tie it all together. And I think the big issues are really going to be the unconsolidated sediments. The well-consolidated sediments, the true elastic solids, we seem to have pretty good models for, and we don’t for the unconsolidated sediments. The fluid effects can have a tremendous effect on the rigidity curves. We have a lot to learn there.

[Oliver]: So in a nutshell you’re saying the acquisition and processing technology is already there, but the interpretation world has to catch up.

I think that’s a big part of it. We have to take everything we know, and tie it all together. We’ve made a lot of progress, but nobody’s really brought it all together yet.

[Oliver]: I gather that you see your role, and the universities’ in general, as educating the students in all these new technologies, so that when that generation moves into industry, and is faced with problems, they won’t ask, “Should we use multi-component data?” They’ll just say, “ This seems to be a problem where we could use multi-component data.”

I’m finding that right now, especially with petroleum engineers. They’re taking some of my courses and they seem to be picking up on that very rapidly.

[Oliver]: Perhaps it’s similar to the situation not that long ago when there was this big debate whether 3D seismic, period, was good. As a processor you almost had to talk people into it. Now there’s no question that it’s a good thing for many situations.

The banks even ask for it!

[Oliver]: We’ve heard a lot of talk about how the majors are reducing their investment in R&D. The Leading Edge ran a very pessimistic article by Ken Larner in the January 2001 issue. How do you feel about that?

I think by not doing additional R&D you’re certainly passing up opportunities. I think the companies are doing less of it, and they think someone else is going to do it and pay for it. Until that all shakes out, and they go for a while without new developments, that’s going to continue. There will come a time when it is recognized that there is value in R&D - a lack of new things coming down the pipe will trigger that. I don’t see it as a positive trend at all, but on the other hand, the companies are under so much pressure from the investment community for results, and research generally doesn’t produce instant results - not quarter to quarter anyway. I think the petroleum industry is unusual in that it basically produces a commodity, yet it takes high technology to drive it. How do you fit R&D and high-tech into a commodity driven mindset - how do you put all that into one big business model?

[Oliver]: Well, it is obvious the business model is changing. In the 60’s, 70’s, 80’s the majors had large internal R&D efforts, and gradually they’ve shed that, until now some of them have basically shut it down. As you say, perhaps they expect the expertise from the service companies but haven’t thought through how the costs are to be shared.

Basically the complaint you hear from the service companies is that they don’t have the money to develop new technology, in a big way. Their margins are so small. The same companies which are telling them to develop new technology are also trying to turn everything they’re doing into a commodity, so it becomes very price sensitive. You see that in terms of the perceived costs of some of these techniques we’re talking about. Management never compares it with the cost of 3D seismic, it’s compared to the invoice they get for spec 3D, which of course represents only a fraction of the real cost of the 3D survey. In a way we’re pushing in two directions at the same time, and wondering why we aren’t getting results. The majors are trying to commoditize everything they’re buying from the contractors, to reduce the price, and the margins, yet at the same time they’re saying the contractors need to do more research. Where are the margins going to come from to fund that kind of thing?

[Oliver]: What sort of role do you see the universities playing in this?

A major role. In the universities one thing we don’t have is large amounts of capital, but certainly universities have participated in large-capital projects in the past, government-funded projects in particular. Right now, I hear petroleum companies saying we should be working on certain kinds of research. I’ve even had them say, “Why are you working on this, or that?” I think if the industry wants very specific research which will benefit them, it’s going to have to be funded by the people who would be using that technology. The government funds certain fundamental research, but applied research is ultimately going to have to be funded through consortia or other kinds of models. Companies are very reluctant to fund the consortia we have in universities now, but I do see a willingness to get together shorter term, very focused types of projects in universities, especially the research arms of the universities. They can do relatively large projects - I mean they’re not Los Alamos, but they can certainly do it!

[Satinder]: Bob, I used to notice that you had at least 2-3 papers at the SEG meeting every year, but lately not many.

Yeah, that’s going to be changing very shortly!

[Satinder]: I was wondering whether it’s because of your present assignments - do they involve a lot of administrative responsibilities?

During my last few years in industry I became increasingly focused on administration, and had less time to publish papers. That certainly affected my decision to move on to the academic environment. I’ve been at the university a little over a year now, and we didn’t put in any papers this year, because it’s a new program and the first crop of students just started last fall. But they’re working on projects, so just wait ‘til next year! We’ll certainly be there!

[Oliver]: Would I be correct in saying you’re now settled in at the university, and ready to get back into research more, back into publishing more papers?

Well, I’ll have to be! Not only that though - part of my purpose in going to the university was to bring in more students to work in exploration geophysics. And from industry every time the recruiters come to campus they ask, “Where are the Geophysicists?” There seems to be a real need for Geophysicists right now - even more so than Geologists. The expectation is that there will be more students coming out.

[Oliver]: It’s always a half cycle out of sync!

Yes, yes!

[Oliver]: How are you finding the teaching aspect, the atmosphere?

I like the teaching, I like the students, I like the freedom. I find you have to do a lot of things on your own. The culture is different - there’s not always the same sense of urgency as in industry.

[Satinder]: Are the students young, and do they make you feel young?

Yes! The students are very young and very enthusiastic! And yes, that’s one thing about moving to Austin. My wife and I were living in an apartment until our house was done, and we were by far the oldest people in the building, and I think we’re the oldest people in Austin, it’s a very young city.

[Oliver]: I’ve heard it’s a great place. I’m hoping to go the San Antonio convention, and if I do I’d love to visit Austin.

Yeah, it’s a fun place to be. And the students do keep you young, and it’s very dynamic. I think that if I would’ve stayed at Texaco I’d just be waiting to retire. This way it’s not like it’s an entirely new career, because I’m building on what I already had, but it’s certainly a new direction. A rejuvenation.

[Oliver]: You’ve been very involved in the SEG over the years. How do you feel it helps a person professionally to be involved in a society like the SEG or CSEG?

I think it helps a lot, for a number of reasons. For one, just getting to know people. But you also get a much bigger picture, how everything fits together, that’s always very important. You can gauge where your job fits into the overall scheme. It helps a lot in knowing what to take seriously and what not to take seriously! Besides that, I’ve always enjoyed it.

[Satinder]: How about from the companies’ point of view?

That’s a good question, because it kind of waxes and wanes! There was a time there when companies were becoming very focused, and you had to be very productive, and accountability was the big term. In those times, you didn’t brag about the time you were putting into the professional societies. It was seen as a distraction from your job. I mean it might have been helping you professionally, but that was your problem, not the company’s. So you kind of have to use your own judgement about these things, and develop your own career for yourself.

[Oliver]: We’d like to ask you about your experiences as Associate Editor of Geophysics - you did that for many years.

I did that for close to 10 years. I was much more effective early on! As time went on I got busier with other things, and I just spent less time reviewing papers. I was in a fairly narrow area, and they sent me less as time went on. It seemed as I got more experienced though, I got the harder papers!

[Oliver]: What did you feel about the quality of the papers - did it go up and down?

I wouldn’t say the quality varied too much, but the number of papers submitted went down. I blame part of that on the expanded abstracts, which became citable. People have less time to write papers, so they put that time into the abstracts rather than full Geophysics papers. My sense is people are submitting less papers and not reporting things as thoroughly as they once did. And there’s a whole body of gray literature out there now, papers which haven’t been subjected to a rigorous review cycle, like the expanded abstracts. I’d really hate to comment on the quality of the papers though.

[Oliver]: Do you have a message for prospective writers?

My message for prospective writers is to write! There’s nothing like getting into the literature, even within your own company. I find it kind of exciting to look back at some of the papers I wrote in the early ‘80’s. It’s always kind of amazing - “I knew that then?!?” It’s a really good way to capture things, and then you’ve always got them there.

[Oliver]: I think it’s also a great way to crystallize your thoughts, by formally putting them down. A lot of people may have excellent ideas, but they remain in a half-baked state.

Certainly writing forces you to tidy up the loose ends that you really don’t know are there until you start writing. I think this is why companies in their hiring are insisting on students writing a Master’s thesis - because they have to go through that process of bringing it all together. Bringing loose and diverse bits of information into a coherent mass. I keep telling the students, “Start writing early, because you’re going to find holes in your work.” It’s not like you can do the work and then just write it up. It doesn’t work that way.

[Oliver]: At U of C they have two paths for the Masters, one a course-based, one a thesis-based. I gather you would recommend going with the thesis-based one?

Absolutely. At the University of Texas, before we started the exploration geophysics program, we asked most majors to tell us what they most wanted to see in an education program. The answer was overwhelmingly, consistently - “You have to write a thesis, a Master’s thesis.” And the Masters is the level at which most companies are hiring.

[Satinder]: Bob, what words of wisdom do you have for your fellow Geophysicists in the oil industry? I’d like to get an essence of your 30+ years’ experience!

Looking back I’m more sorry for the things I haven’t done than the things I have. Don’t be afraid to take a chance - it’s a high risk business!

In my 30 years, what I’ve always done is keep growing - I was always looking for the next degree, for new ideas. I think looking for new opportunities is important, and doing new things - stay fresh, stay young, and enjoy your work! I think there is a most important thing, not just in the oil industry, anywhere, and that is to enjoy your work. If it isn’t fun, you’re not going to be very creative.

[Satinder]: Thank you so much for giving us this opportunity to chat with you and ask you these questions!


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