INTERVIEW COORDINATED BY SATINDER CHOPRA

 

“I would encourage those who have an interest in

geoscience to embrace an interdisciplinary approach.”

Henry Posamentier is renowned for his pioneering work in developing the contemporary approach to sequence stratigraphy, integrating sedimentology, stratigraphy, and depositional systems analysis, primarily in the context of oil and gas exploration. With a career spanning over 50 years at prominent companies such as Exxon, ARCO, Veritas, Anadarko, and Chevron, Henry now serves as a global geological and geophysical consultant to companies engaged in petroleum exploration and development. His expertise covers nearly all significant onshore and offshore basins worldwide, and he has edited 10 books and authored over 200 publications in leading international journals. He has conducted numerous in-house and public courses on topics like sequence stratigraphy, seismic stratigraphy, 3D seismic visualization, and seismic geomorphology. As a recognized expert, he has delivered lectures at more than 100 companies and universities across North America and globally. His exceptional technical skills have earned him various professional accolades and awards.

Henry and his family commute between their coastal home in California and their second residence in Canmore to take advantage of the optimal weather each location offers: the mild winters and the summer coastal fog in California, followed by the pleasant summer months in Canmore.

When invited for an interview, Henry graciously accepted, to our great pleasure. What follows are excerpts from that interview.

1. HENRY, COULD YOU BEGIN BY SHARING DETAILS ABOUT YOUR EDUCATIONAL BACKGROUND AND WORK EXPERIENCE?

My undergraduate degree was in Geology from The City College of New York (CCNY). I went on to graduate school at Syracuse University where I received a MA and PhD degree in Geology. My area of specialization was in glacial geology. My thesis involved the study of neo-glaciation in the Austrian Alps. After graduation I got a job as Assistant Professor of Geosciences at Rider University, where I taught stratigraphy and sedimentology, geomorphology, and introductory geology. After five years, I had an offer from Exxon Production Research Co. (EPRCo) to join their research lab. I was assigned to the seismic stratigraphy team and on day one was the first time I had ever seen a seismic section! It was a case of being in the right place at the right time. I was able to contribute to the development of sequence stratigraphic concepts as a follow-up to the seismic stratigraphic concepts that had just been published a few years earlier. While at Exxon, I took an “overseas” assignment in Calgary, where I was a member of the Technical Excellence Team. With Esso Resources (as Imperial Oil was called then) I had the opportunity to ramp up my skills with core and well log-based stratigraphy and facies analysis, thanks to the mentorship, in particular, of my friend David James. I subsequently left Exxon and joined ARCO in Dallas as Senior Research Advisor. The latter part of my time with ARCO involved a posting to Jakarta, Indonesia. It was during my time with ARCO during the 1990’s that I first had the opportunity to work with 3D seismic data. I had the good fortune of working with a research group that focused on the development of seismic interpretation software. Anytime I would conjure up another workflow, they would write the code and incorporate it into the proprietary system. After my posting in Indonesia, I left ARCO when it was acquired by BP and joined Anadarko as Chief Geologist based in Calgary. In 2007 I left Anadarko and joined Chevron as a research advisor. I retired in 2014 and have been a consultant to numerous oil and gas exploration companies since then. For the past two decades I have been involved in the development of seismic stratigraphic/geomorphic concepts.

Henry after completing a recent Canmore Rocky Mountain Half-Marathon

Three Sisters peaks above Canmore from across the valley.

2. ALTHOUGH TRAINED AS A GEOLOGIST, YOU HAVE EXTENSIVELY UTILIZED 3D SEISMIC DATA AND VISUALIZATION TO COMPREHEND SEISMIC GEOMORPHOLOGY AND STRATIGRAPHY. COULD YOU TELL US HOW YOU DEVELOPED THIS FACET OF YOUR CAREER, AND HOW IT HAS BENEFITED YOU?

It was a natural progression to go from 2D to 3D seismic data once 3D seismic data became more ubiquitous. It was a natural expansion of my horizons (no pun intended). And with my academic background in geomorphology, I was drawn to the potential that 3D seismic had to offer. I came to appreciate that the integration of stratigraphy and geomorphology was greater than the sum of its parts and had the potential for significantly enhancing our predictive abilities when it came to understanding subsurface lithologic distribution and reservoir compartmentalization.

3. YOU HAVE COLLABORATED WITH DR. PETER VAIL DURING THE EARLY PART OF YOUR CAREER. COULD YOU PROVIDE A BRIEF OVERVIEW OF HIM AND HIS VISION ABOUT STRATIGRAPHY, AS THERE SEEMS TO BE LIMITED INFORMATION AVAILABLE?

Working with Dr. Peter Vail turned out to be an indispensable stepping stone in my career. He was amazing to work with; always open and receptive to new ideas no matter how far fetched. I always felt incredibly lucky to have had that opportunity. He created an atmosphere of openness and continuous learning; he was quite the role model and mentor for me! Our passions were very much aligned. Pete tended to focus more on global sea-level curves and associated stratigraphic patterns, initially based on 2D seismic data, whereas I tended to focus on the mechanics of the link between sea-level change and stratigraphic architecture. It was this latter effort that ultimately led the way to the development of the sequence stratigraphic concepts.

4. WITH EXTENSIVE EXPERIENCE AND NUMEROUS COURSES TAUGHT IN SEQUENCE STRATIGRAPHY, SEISMIC STRATIGRAPHY, SEISMIC GEOMORPHOLOGY, AND 3D VISUALIZATION, YOUR EXPERTISE IN THESE AREAS IS WELL-ESTABLISHED. COULD YOU SHARE HOW YOUR INTEREST IN EACH OF THESE AREAS DEVELOPED AND HOW THEY HAVE CONTRIBUTED TO YOUR PROFESSIONAL GROWTH?

As I had mentioned before, my first day with Exxon was the first time I had ever seen a seismic section. It was Exxon’s approach at that time to assign geologists rather than geophysicists to the seismic stratigraphy team. They maintained that training a geologist to be comfortable with seismic data was more effective than training a geophysicist to understand and apply the nuances associated with geologic principles. Thus, I was assigned to the seismic stratigraphy team. It turned out to be a natural fit for me. I eventually learned the ins and outs of geophysical data and became comfortable with both geology and geophysics. My first exposure to 3D seismic data came in the early 1980’s, long before interpretation workstations were widely available. At that time each seismic inline was printed on semi-transparent vellum and placed in a three-ring binder. In this way, one could see through to the next seismic section and make appropriate interpretations. But seismic geomorphology was still a long way off. It was in the mid-1990’s when the first rudimentary workstations became available and I saw, for the first time, a seismic horizon slice where I was seeing channels and other geomorphic elements in all their glory; I was hooked! I didn’t abandon seismic stratigraphic analyses but came to appreciate the value of iterating from stratigraphy to geomorphology repeatedly. This iterative approach, where one discipline informed the other, had tremendous potential for yielding significant geologic insight.

Amongst the Redwoods in Northern California

5. ARE YOU HAPPY WITH THE WAY YOUR CAREER SHAPED UP FOR YOU IN YOUR LIFE?

Looking back upon my career, I realize that nothing was ever planned. When great opportunities arose, I went with the flow. I have had the good fortune of being able to follow my passion, which has led me along a path that I would never have anticipated. Luck, with respect to being in the right place at the right time, certainly contributed to my career evolution. It’s been a great experience and continues to this day! If there were one thing I would modify if I could, it would be to have travel less in my job. It was not easy on my wife and family during those early days. My wife sacrificed a potential career in favor of devoting herself to raising our children and creating a home through all our moves over the years, for which I will be forever grateful.

6. REFLECTING ON YOUR GEOSCIENTIFIC CAREER, WHAT HAVE BEEN SOME OF THE NOTABLE MILESTONES?

There have been several milestones that I have passed along the way. The first was my decision to leave academia in favor of industry. Although at the time I wasn’t sure about this decision and therefore initially left academia on a one-year leave of absence, I eventually never looked back. Being assigned to the seismic stratigraphy team and subsequently having had the opportunity to work with Pete Vail was a major milestone and led to my involvement in the development of sequence stratigraphy and the publication of SEPM Special Publication 42. Starting in the mid-1990’s I had the opportunity to work with 3D seismic data for the first time. Eventually, in 2000 I introduced the concepts of seismic geomorphology at the annual AAPG conference, another milestone event.

Henry at Yosemite National Park, California.

7. REVIEWING THE LIST OF BASINS WHERE YOU HAVE HAD THE OPPORTUNITY TO CARRY OUT YOUR ANALYSIS OR STRATIGRAPHIC STUDIES, IT APPEARS THAT NEARLY ALL ONSHORE AND OFFSHORE BASINS WORLDWIDE HAVE BEEN COVERED. IS THIS A CORRECT OBSERVATION? WHAT WERE SOME OF THE MOST INTERESTING ONES?

I’ve certainly been lucky to have seen and worked in so many basins worldwide, onshore and offshore. The benefit of having seen so much geology is that I have come to appreciate the many variations on the general theme that nature is capable of. I hadn’t appreciated early in my career the great value of having seen a lot of geology from so many basins worldwide; I have come to embrace the notion that the more geology one has seen, the better a geologist they become. As for which are the most interesting ones, it’s like asking which of your children is your favorite! They’re all unique and fascinating in different ways. Of course, those data sets that have the highest quality always stand out in my mind, such as the eastern Gulf of Mexico, the Bay of Bengal, offshore northwest Java, the Barents Sea, just to name a few.

Paleo-geomorphic perspective image of mass transport erosional grooves. These grooves, carved into the substrate, were likely formed by large clasts within a mass flow.

8. YOUR EARLY ROLE AS AN ASSISTANT PROFESSOR AT RIDER COLLEGE, NJ LASTED 5 YEARS. DID THIS EXPERIENCE CONTRIBUTE TO YOUR DECISION TO TEACH INDUSTRY COURSES LATER IN YOUR CAREER?

My decision to teach industry courses was not a conscious decision. Rather, it was a natural progression that in part stems from my fascination with what I was encountering in my exploration and development activities, and my natural desire to want to share what I had observed. To use a well-worn phrase, it has enabled me to give back to the next generation of geoscientists. I’ve always felt that we all have benefitted from standing on the shoulders of those who came before us, and now it’s my turn to help the next generation of geoscientists.

9. THROUGHOUT YOUR CAREER, YOU HAVE BEEN HONOURED WITH VARIOUS ACCOLADES, INCLUDING PROFESSIONAL RECOGNITIONS, CITATIONS, AND AWARDS FOR TECHNICAL PRESENTATIONS. NO DOUBT RECEIVING AN AWARD IS DEEPLY GRATIFYING AND SERVES AS A TESTAMENT TO THE DEDICATION AND HARD WORK INVESTED IN YOUR FIELD, BUT PLEASE TELL US ABOUT SOME OF YOUR MOST CHERISHED AWARDS.

It’s always immensely gratifying to receive awards from your peers. One of the highlights was winning the best oral presentation at the 2000 annual AAPG conference and learning that three of the top five presentations were mine. Another highlight was being awarded the SEPM Francis J. Pettijohn Medal for Excellence in Sedimentology. But probably my most cherished award was receiving the William Smith Medal for contributions to applied and economic aspects of geology (Royal Geological Society, London). To follow these giants of geology was, indeed, very humbling.

10. AS AN EXPERIENCED GEOSCIENTIST WITH EXTENSIVE PUBLICATIONS AND TEACHING BACKGROUND, HAVE YOU THOUGHT ABOUT CONSOLIDATING YOUR WORK FROM VARIOUS INTERNATIONAL JOURNALS INTO BOOKS FOCUSED ON YOUR AREAS OF EXPERTISE TO ENSURE THEY ARE PRESERVED FOR FUTURE GENERATIONS?

Although I have been semi-retired and consulting for several years, I continue to be intrigued by the subsurface world. I continue to publish from time to time, and eventually plan to compile overview papers that capture and share the breadth of my experience.

11. LET US HEAR FROM THE EXPERT: SEISMIC GEOMORPHOLOGY ENHANCES OUR UNDERSTANDING OF SUBSURFACE GEOLOGY AND ALLOWS ACCURATE STRATIGRAPHIC INTERPRETATION WITH THE OBJECTIVE OF OIL AND GAS EXPLORATION. PLEASE EXPLAIN HOW THIS IS DONE FOR THE UNINITIATED.

The best way to understand what we do with 3D seismic data is to compare it to non-invasive interrogation of the inside of the human body using CT scans. With a CT scan one can “slice and dice” the human body virtually and have a clear three-dimensional picture of what lies within. Similarly, 3D seismic data can be similarly “sliced and diced” to image ancient landscapes and seascapes. By slicing parallel to ancient paleo-landscapes, not only can one image depositional systems in their entirety, but by slicing upwards and downwards one can see the progressive evolution of those landscapes. Images that resemble air photographs in all their detail are not uncommon.

Horizon slice through Pleistocene fluvial deposits offshore Thailand. The last position of the channel appears as a continuous thread across the area. Associated point bars as well as a cutoff meander loop can be observed. Multiple delicate drainage lines off the point bars represent small channels that are associated with tidal rises and falls of sea level.

12. SEISMIC INTERPRETERS SAY THAT STRATIGRAPHIC INTERPRETATION HAS ITS LIMITATIONS. PLEASE ELABORATE ON DIFFERENT ASPECTS THAT PREVENT THE INTERPRETERS FROM ACCURATELY ASSESSING THE COMPLEXITIES OF EARTH’S HISTORY.

There are several key limitations of the seismic stratigraphy/geomorphology approach. Firstly, the deeper one goes in the stratigraphic section (i.e., the deeper the depth of burial of the target horizons), the poorer the data quality and hence one’s ability to clearly image paleo-landscapes. This issue is exacerbated by the presence of shallow high impedance sections (e.g., volcanics or carbonates), which tend to attenuate the seismic signal and lower the frequency content associated with more deeply buried strata, and hence lower the resolution of the seismic data. Similarly, heavily structured sections make it more difficult to effectively slice through the data and clearly image paleo-landscapes. Another issue lies in the assumption that seismic reflections are proxies for timelines. In most instances that is the case and when such reflections are imaged in three dimensions, paleo-landscapes come to life. However, in isolated circumstances reflections do not follow timelines and this assumption breaks down.

Horizon slice through a deep water turbidite submarine fan/terminal splay

13. CAN SEQUENCE STRATIGRAPHIC INTERPRETATION BE USED TO INTERPRET DEEPWATER TURBIDITE DEPOSITS? WHAT WOULD BE A TYPICAL WORKFLOW FOR CARRYING THIS OUT?

The essence of sequence stratigraphy is that stratigraphic sections are inherently cyclic and therefore, to a degree, predictable. This holds true for deep-water turbidites. Deep-water turbidite episodes have a beginning and an end, and through this period of active turbidite deposition gravity flow processes vary predictably. This process tends to repeat cyclically and tends to be related to conditions at the shelf edge up-system of turbidite deposits. These deep-water episodes tend to start with a series of gravity flow events associated with shelf edge slope failure, where each successive flow tends to be larger than the one that preceded it. This “ramping up” of gravity flow events produces successively larger and more erosive events. Inevitably, towards the end of a deep-water episode there is a “ramping down” of gravity flow events characterized by progressively smaller and muddier flows. These processes manifest themselves with deposition of a succession of depositional elements such as channels, channel complexes, terminal/frontal splays/fans, levees, sediment waves, and mass transport deposits. And this is where the seismic workflows associated with seismic stratigraphy and seismic geomorphology come in. Commonly, just prior to the start of a deep-water depositional episode associated with turbidite deposition, sedimentation in the form of widespread hemipelagic and pelagic mud-rich deposits is common. Such deposits often are associated with continuous seismic reflections. The workflow would subsequently involve picking such horizons and then slicing upwards, parallel to these horizons, producing a succession of stratal or horizon slices. Careful evaluation of the patterns observed on these stratal/horizon slices can then potentially yield a robust understanding of how the paleo-landscape evolved and ultimately the lithologic distribution and stratigraphic architecture (i.e., yielding insights regarding reservoir compartmentalization) of the associated deposits. This workflow and the subsequent analyses depend heavily on a good understanding of depositional process as well as an understanding of geophysical data.

14. WHAT ARE SOME OF YOUR THOUGHTS ABOUT WHERE SEISMIC STRATIGRAPHY IS HEADED TO IN THE NEXT THREE DECADES?

I see continued integration of seismic stratigraphy and seismic geomorphology as an essential aspect of these analyses. Doing one without the other limits the potential effectiveness of the workflows. As seismic data quality improves, we will see progressively more analyses of sections that in the past could not have been imaged. 3D seismic data can be manipulated numerically to produce a broad range of seismic attributes, which can further improve our ability to leverage 3D datasets. Some of these attributes are horizon-based while some are volume based. Better quality seismic inversion volumes likely also will add to improved seismic volumes for stratigraphic interrogation. But the key to all these workflows is the stratigraphically significant patterns that they yield and the ability of the geoscientist to recognize that significance and populate these patterns with the correct lithologies. Training geoscientists to be comfortable with both geologic and geophysical principles is critical to the success of this approach.

15. LET ME NOW COME TO A PHILOSOPHICAL QUESTION. THERE IS A QUOTE BY ARISTOTLE, THE ANCIENT GREEK PHILOSOPHER AND SCIENTIST, WHICH SAYS ‘PLEASURE IN THE JOB PUTS PERFECTION IN THE WORK’. WHAT WOULD BE YOUR TAKE ON IT?

Who am I to disagree with Aristotle! There is no doubt that if you love what you do, it is more likely that you will excel in that effort. Pleasure in your job inevitably unleashes creativity that elevates your work to a higher level. When your passions are aligned with your avocation, you’re one lucky person! And as I’ve always counseled my kids, if you love what you do, you never will work a day in your life!

Meteor impact craters in Quebec, as observed from a satellite image, and from the Permo-Triassic boundary in Alberta as observed from 3D seismic.

16. ARE YOU ABLE TO SPARE SOME TIME FOR OTHER INTERESTS THAT YOU MAY HAVE, APART FROM THE SCIENCE THAT YOU PRACTICE?

My interests these days involve maintaining an active lifestyle. My wife and I both enjoy running, cycling, and hiking, as well as the occasional round of golf. To this end we have traveled and will continue to travel widely. Our most recent trip involved a two-week excursion to Antarctica aboard a small ship of 12 passengers. Our travels also allow me to indulge in another of my passions – photography. And of course, maintaining close links with our family, who are now spread out across North America, is also a nearly full-time job!

17. WHAT WOULD YOU TELL A YOUNG PERSON CONSIDERING TAKING UP A CAREER IN GEOSCIENCE? HOW DO YOU ENCOURAGE HIM OR HER TO GO AHEAD?

I would encourage those who have an interest in geoscience to embrace an inter-disciplinary approach. You will have more fun taking a holistic approach, plus you’ll be more marketable! A career in energy is very much a reality, whether it be oil and gas, geothermal, hydrogen, or even lithium. Plus, endeavors such as carbon capture and sequestration also require a heavy dose of geologic knowledge.

18. AND FINALLY, WHAT OTHER QUESTION HAD YOU EXPECTED ME TO ASK THAT I DIDN’T. PLEASE STATE THE QUESTION AND ANSWER IT.

What roadblocks have you encountered through the years? One challenge for me has been my red-green colorblindness. I have difficulty recognizing key stratigraphic/geomorphic patterns when they’re displayed in full color; consequently, I default mostly to black and white imagery. Ironically, oil and gas maps use the colors red and green to refer to gas and oil… and it’s virtually impossible for me to see the difference, rendering such maps useless for me! Another frustration is dealing with geoscientists who are siloed into either geology or geophysics and are reluctant to embrace both disciplines simultaneously. All too often I still hear geologists referring to “my geophysicist” and geophysicists referring to “my geologist”. The most effective geoscientist is a person who is comfortable in both camps.