The 20th RPI for November-December 2018

Lev Vernik - Scientific Advisor at Ikon Science, Houston, Texas

About Dr. Lev Vernik

After launching my career as a wellsite geologist on the Kola Superdeep Scientific Drilling Project in the Soviet Union, gaining expertise in petrophysics and rock physics, and finally expanding into seismic modelling and inversion, by the early 2000s I had evolved into an all-around geoscientist capable of solving a wide range of complex problems in hydrocarbon exploration and in conventional/unconventional reservoir characterization.

My involvement with the Kola well, still the world’s deepest, was a once-in-a-lifetime opportunity, and I seized it without any hesitation. I hungrily imbibed the knowledge from the best geoscientists engaged in that project focusing on the physical properties of the cores extracted from the well. In 1982 I defended my PhD thesis on “Physical properties of the crystalline basement and their expressions in reflection/refraction seismology.” The 30,000 feet of core and 40,000 feet of log data obtained in that rare field experiment were a luxury, and we were literary swamped in data sets that far exceeded the capabilities of the theoretical models available at that time.

In 1987, when the price of oil hit bottom and the Soviet Union began to collapse, I seized an opportunity to leave, and again I found myself quite lucky – this time by meeting Amos Nur and Mark Zoback (of Stanford University). At Stanford, I focused on the combination of experimental rock physics and in situ stress state and published some pioneering papers on velocity and anisotropy of organic-rich shales, which, as we found, were controlled by their organic richness, thermal maturity, and horizontal microcracks, independent of the stress regime. That contribution ushered in a vast expansion of research on unconventional shale reservoirs worldwide. When by 1995 it was clear that my further professional development was stalled, the time was ripe to begin searching for a “real job.” Soon, I happily joined Arco’s Technology Center in Plano, Texas.

Over the next 20 years I experienced many peaks and valleys in the industry, but in the final analysis I consider myself fortunate to have had the opportunity to work in the technology organizations of five oil and gas operators, sharpening my skills and contributing to many exciting exploration and reservoir characterization projects worldwide. I gradually expanded my skill set to include AVO analysis and seismic inversion, and my solid foundation in rock physics, petrophysics, and geomechanics turned out to be invaluable in the process. After contributing to several major offshore oil and gas discoveries and successful field developments, I gained the status of a subject-matter expert in rock-physics-based AVO analysis, geomechanics, and pore pressure prediction.

My paper list continued to expand and culminated in the publication of the book “Seismic petrophysics in quantitative interpretation” (SEG, 2016) – now the SEG’s top seller for the second year in a row. Over the last 10 years I have benefited notably from involving Mark Kachanov (at Tufts University) in some of my research activities. Mark is a leading mind in the world of micromechanics, a discipline routinely used in materials science but, unfortunately, not yet fully embraced by the rock physics community and the energy industry in general.

In 2017, I signed an exclusive contract with Ikon Science, a prominent software and technology company in the world of rock physics and QI. I am excited to be working on their multifaceted RokDoc software development, to be cooperating in teaching courses on unconventional geoscience, and to be interacting with Ikon’s young and talented staff on technical projects. I am also acting as a Research Professor of Geophysics at the University of Houston, where I cooperate with John Castagna.

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

Quoting my old colleague Leon Thomsen, “The secret of success is to be lucky … but … prepared.” I could not agree more with this view. We cannot manufacture luck, but we should be ready to recognize it and grab any opportunity that is presented. Then, it is entirely up to us to sharpen our skills, maintain our curiosity, and challenge the current status quo.

Indeed, in the early years of my career I was fortunate to have been able to interact with great geoscientists. In addition, it was immediately clear to me that I needed to take courses and read scientific literature, but to be selective in these endeavors. A good education is critical, but it is also important to find your niche early on. By focusing on rock physics in general and on anisotropic elasticity and geomechanics in particular, I delved into the literature in an attempt to explain empirical observations, including those from laboratory and field data.

The secret to success is to be persistent and think outside the box. That may cause some trouble here and there, notably with people who hold different ideas on what is important. In the final analysis, however, the proof is always in the pudding - in the form of major discoveries, successful reservoir development, and even in the form of a predicted, rock physics model (RPM)-based synthetic curves that fit downhole logging measurements and can replace them when necessary.

It is also very important, especially in the second half of your career, to engage in knowledge transmission, mentorship, and teaching. Discovering a great young talent and guiding that person’s own progress is a rewarding and positive experience. The value of an open exchange of ideas, in the workplace and outside it, cannot be overestimated.

Challenges you see in taking rock physics to the next level

The science of seismic petrophysics, including rock physics, has entered the mainstream of exploration geophysics. As a result, some of the theoretical and hybrid RPMs that have advanced during the last 10 years are more sophisticated in building velocity models and accounting for elastic anisotropy and time-lapse changes in situ than many traditional workflows in reflection seismology. For instance, we can routinely model the effects of stress, fluid, and transverse isotropy on offset-dependent reflectivity in the 1D and 2D models necessary in any feasibility study. However, none of the simultaneous inversion engines we use know how to account for anisotropy. This hinders the accuracy of some impedance inversion products and sometimes makes them inferior to a rock physics-based AVO interpretation, especially in exploration settings. Therefore, as a rock physics community, we may now want to relax a bit and consider deepening the existing RPMs instead of continually building new ones.

Additionally, I would like to take the opportunity and mention a few areas that clearly require more attention:

* Focus on theoretical and hybrid RPMs rather than on empirical and heuristic ones,

* Consider proper calibration of any theoretical or hybrid RPM using experimental and field observations (one point in question is a recent paper published in a peer-reviewed journal, predicting quite a high velocity ratio in rich, mature organic mudrocks, whereas the empirical data, including sonic logs, clearly establish the opposite),

* Avoid the temptation to estimate inelastic rock properties from elastic ones by any means other than statistical correlations (I am referring here to brittleness index computation from elastic moduli and Poisson’s ratios, which can be statistically logical in conventional but not in unconventional shale settings),

* Reconsider using questionable experimental data that have been acquired with setups not quite conducive to straightforward wave propagation and velocity measurements in the non-principal directions in highly anisotropic shales (I am referring here to the phase vs. group velocity picking problem),

* Take advantage of the rock physics models in predicting pore pressure changes and 4D time shifts, and

* Incorporate data/models from other disciplines in an attempt to better parameterise our existing RPMs (using petrography and mineral contents in conventional reservoirs, and in unconventional shale reservoirs adding organic geochemistry).

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

It is important to avoid the temptation of oversimplifying the unconventional plays. They may be easier to image seismically than typical targets in conventional offshore environments are, but more challenging in terms of rock physics, pore pressure, and in situ stress state. Notably, try to avoid blind copycatting of conventional workflows in unconventional reservoir characterizations.

If you are a seismologist, take educational courses in rock physics and geomechanics, and vice versa – if you are a geologist or geomechanician, take courses in geophysics. Cross-discipline education will help broaden your horizons, and you will be better positioned to challenge the status quo.

Use every opportunity to keep abreast of what is happening in technology by selective reading books and scientific journals. Kindly ask to be a mentee of experienced people around you.

Finally, do not panic during downturns in the industry – every cloud has its silver lining. At a minimum, you will have more time to read and think and, as a result, to improve your skills by the time of the next boom.

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