Mind the quality gap

An interview with Pavlo Cholach

Coordinated by: Satinder Chopra
Pavlo Cholach

Pavlo Cholach is a geophysicist with Abu Dhabi National Energy Company (TAQA) working on conventional oil assets in Alberta and Saskatchewan. Pavlo’s previous seven-year experience with BP included geophysical support of a variety of conventional (structured carbonated and clastic gas reservoirs) and unconventional (tight gas, coal-bed methane, and oil sands) Canadian assets. Pavlo holds a PhD in geophysics from the University of Alberta, Canada, and a diploma with distinction in geophysics from Taras Shevchenko National University of Kyiv, Ukraine.

A present-day geophysicist faces a world of increasing pace, information overload, and a shrinking and aging workforce. Timely delivery of high-quality geophysical interpretation products (e.g. forward models, well-ties, time horizons, depth converted maps and volumes, well prognosis, pore pressure prediction, inversions for reservoir properties, geobodies) in these settings is paramount. A commonly circulated view is that a combination of improved geophysical tools, standardization, and increased efficiency provides the way to meet this challenge. Geophysical tools are delivered by a variety of software companies annually providing ever more sophisticated upgrades. Standardization is addressed through ‘best practice’ and ‘approved’ workflows – concepts that are engraved in the psyche of multinational exploration and production company employees. Achieving higher efficiencies appears to be the most elusive challenge. Efficiency requires a balance between the quality of interpretational products and the time it takes to deliver them.

Established paradigm stipulates that with more time available, the quality of interpretations would improve. Even though extra time provides an opportunity to deliver better products, the relationship between time and quality could be non-linear and complex, as shown here:

Fig. 01

By not fully recognizing how quality could be achieved in a timely manner, a geophysicist faces so-called efficiency stretch almost permanently. We may use phrases like 70 percent solution in an attempt to describe products delivered on artificially compressed (i.e. arbitrary) timelines and to justify potential quality issues. Furthermore, due to extremely tight timelines in our business, efficiency stretch is often a way to drive performance and achieve the 70 percent solution in the shortest time possible.

In other words, a simplified linear assumption about the timing of subsurface products prevails.

It’s inevitable that with an aging geophysical workforce and a shortage of skilled geophysicists this trend will only accelerate. The simplified assumption line leading to the 70 percent solution will simply steepen. It is critical for us to recognize what this means for the quality of interpretations. With shortened delivery time, there must be a deterioration in quality, but this quality gap is poorly understood and difficult to quantify. As shown in the chart, productivity stretch could lead to a significant drop in product quality – a 70 percent stretch solution might only yield 50 percent quality. This prospect should be alarming because poorer quality geophysical products eventually lead to dry holes, one of the biggest expenses in many conventional and some unconventional plays. Poorly performing wells are another outcome. After all, the geophysical contribution to exploration and production projects is to propose the best possible locations to drill, and geophysical products of high quality and reliability are essential in achieving excellent results.

Highly efficient tools and best practices, in combination with sufficient quality and quantity of data and knowledge of the play, will aid a geophysicist in the delivery of great products, and provide an exploration and production organization with a competitive advantage in today’s ever more complex search for hydrocarbons. Chasing better efficiency in a productivity stretch is not a good strategy and just might open a quality gap.


In your article you mention ‘…an aging workforce and a shortage of skilled geophysicists…’ Are we there?

Not quite, but we are on that path (arguably trend was slowed down by 2008 economic events among other factors). No doubt industry is vibrant, healthy and presently still fairly well equipped with talent. Do we have enough geophysical “horse power” to address present industry challenges? The answer is “maybe” in general and “definitely not” in case of unconventional production demands. I will elaborate on this point of view somewhat below.

Perhaps you have heard that talent, genius and greatness are ageless. Then what is there to worry about?

It’s certainly difficult to argue with statement above. However, I think of geophysics as a discipline actively practiced by community that stands on shoulders of giants. That statement assumes efficient model of generational transfer of knowledge. Topics are complex (in terms of mathematical descriptions among other aspects), multidisciplinary and resolutions are time constrained. Any talent that would thrive in that environment needs a time to develop and mature or enjoy sustainable and readily available technical support. If experienced people (25 plus years) keep spending their time delivering geophysical products they obviously not spending that time on mentoring (despite all the conversations about balance). Younger generation of geophysicists (which might include me btw, ha-ha) could no doubts get to the pretty sophisticated level of expertise with time. The oil and gas industry however is not patient. Very few firms have a luxury of not requesting drilling locations from geophysicists for months (till problems are figured out) let alone stepping back to identify and address new challenges. Geophysical discipline faces a need to revolve (not evolve) to address challenges posed by oil and gas industry.

Pavlo, the research work you carried out on anisotropy for your Ph.D. was done well. Could you tell our readers what all you did and how you drifted away from it when you started working?

Thanks. You are too kind. I attempted to figure out how to describe intrinsic elastic properties of anisotropic rocks. That effort excluded anisotropic effect imposed by fractures for instance or stresses. It’s absolutely exhilarating to learn and demonstrate that the same mathematical description of natural phenomenon applicable to sediments (shales are notoriously anisotropic), metamorphic rocks (in my case the study of metasediments from Flin Flon area in Manitoba) and upper mantle rocks such as peridotites. Different symmetries, magnitudes, and commercial applicability of anisotropy – sure but the same physical phenomenon. It’s just fascinating to realize how integral anisotropy is in nature.

And to address second part of the question may be I am not as much drifted as just paused. I’d like to think that time will come when I could apply my knowledge to “value creation” process.

How did you decide to work on anisotropy?

It’s just curiosity and presence of a challenge I guess. Seismic anisotropy is directly observable manifestation of nature’s symmetry delivered to observer through wave propagation. And symmetry is essential to existence as some scholars try to demonstrate mathematically with E8 structures etc. Knowingly or not people make decisions daily based on observation of symmetry in nature (and willing to pay substantial sums of money for oh so symmetric diamonds). Unlike diamond’s symmetry that is readily observable subsurface symmetry is more complex, variable and often requires expensive physical experiment (like 3D seismic) to be reviled.

Despite its importance, how much is anisotropy being accounted for in our industry? How is it being done?

It’s still fairly new topic. Implementations of theory is arguably poorly developed. Benefits are huge but we are not there yet to take a full advantage. Just to give you an example: orthorhombic symmetry should actually be called orthotropic (the same way as nobody calls transverse isotropy (TI) a hexagonal symmetry). Still early days I guess.

With unconventional resource plays, accounting for anisotropy becomes really important. Still simplistic characterization procedures are being followed. How do you think this can be changed?

Deriving my conclusions from observations made locally here in Calgary I would postulate that 2013 situation with the industry was a testament to engineering ability to characterize subsurface. Stating obvious evolution is a heavily weighted function of time and in case of unconventional resource the time to evolve is of an essence like nowhere else. Geophysical thought process has to evolve to address new challenges such as determination of relevant rock property that characterize unconventional reservoirs. Anisotropy becomes relevant very rapidly because changes in reservoir properties manifested in seismic are of the same or comparable magnitude to anisotropic effects observed in modern 3Ds. Unless we address and “correct” for anisotropy in many instances reservoir characterizations would be prone to errors. I would like to emphasize the need for ability to invert for actual calibrated to wells physical values (in units like GPa) that could be plugged into frac modelling software directly. I would like to think geophysicists will be doing this routinely in 5-10 years… Achieving such inversion results requires time… and talent. Some geophysicists might already be there. However it’s not the industry practice yet: everybody is fracing, very few characterize, understand results and translate it into decisions based on geophysical analysis.

How do you think geophysics has an effective role to play in shale resource characterization?

It most certainly has a critical role. “How” is a million dollar question. It’s all about relevant and applicable reservoir characterization for shale plays. Geophysicists as community spent decades figuring out where the resource is. All techniques were centered around that question. “No dry holes” approach. Now is the time to figure out where the most effective places to recover hydrocarbon with present completion technologies are. Totally different challenge… and attainable one.

You refer to ‘highly efficient tools and best practices …’ in your article. Could you elaborate on both these items? I am really curious about your comments on best practices.

“Effective tools” is mainly a reference to good quality integrated software that provides step changing improvement in efficiency. Very few of those packages are in existence i.e. only small number of geophysicists takes a full advantage of these products.

“Best practice” is indeed controversial concept. There is a perception out there that it hampers creativity. My position on this is very simple: there is no need to re-invent wheel every day. Well-thought through “protocols” to deliver good quality subsurface products are in place in some organizations for a reason. They facilitate delivery of products that provide very solid first look on subsurface challenge. That step needs to be done and that’s what best practice is all about. There is always an opportunity to build on those results and products. Cutting corners with “creative short-term solutions” in on the other side of the spectrum. That’s where luck becomes critical.

Walt Disney once said ‘It is kind of fun to do the impossible’. What do you think about it? Do you believe in this?

Love it. Definitely a big fan of delivering impossible. Not necessarily by me or me alone. I enjoy observing other very talented individuals doing this fairly often. This is the only acceptable way forward.


Share This Interview