Milliken: Finding the Upside of a Downturn

Robert R. Berg/Wallace E. Pratt Awards

While not wanting to be dismissive of the current downturn in the oil and gas industry, Kitty L. Milliken - winner of AAPG's Robert R. Berg Outstanding Research Award and co-recipient of the Wallace E. Pratt Memorial Award for best AAPG Bulletin article - points out that had she not been laid off during the 1980s' oil glut, she might be applauding others for groundbreaking research benefitting the nation's shale energy boom.

Today, Milliken works as a senior research scientist at the Bureau of Economic Geology (BEG) in Austin, Texas, and is a global authority on sedimentary petrography, the microscopic description and classification of sedimentary rocks.

However, in 1986 - less than a year after she earned her doctorate degree in geology - she became a target of the Exxon Production Research Company's budget cuts, which prompted her to contact her former thesis adviser, Lynton S. Land, at the University of Texas at Austin for help.

"He said, 'Come back and we'll figure something out,'" she recalled. "I was given a table in the corner of a lab, and that was my desk for the next 20 years."

As a sedimentary petrologist, Milliken's initial interests focused on the microscopic makeup of carbonates and sandstones. Yet when the trying times of the 1980s took her back to her alma mater's research laboratory - where she initially was paid a salary equivalent to that of an undergraduate research assistant - she turned her attention toward mudrocks, known in the industry as shales.

As a result of her creative thinking, integrative research, and willingness to spend hours in a darkened room watching the raster of a scanning electron microscope screen, Milliken today is performing invaluable research and posing testable hypotheses about crystals smaller than 0.0625 millimeters that dominate in mudrocks.

"My research has applicability in helping people in the industry make more informed decisions about which rocks are going to be favorable for hydraulic fracturing," said Milliken, who also serves as president of the Society for Sedimentary Geology. "My work is aimed at improving our ability to make predictions about porosity and mechanical rock properties - things that matter in production."

When discussing the rarity of a geologist winning two AAPG awards in one year, Milliken said the only word that comes to mind is "flabbergasted."

And to think it all began with a childhood affinity for small things.

Let's Get Small

As a child in Franklin, Ky., Milliken played in the streambeds and fields near her home, examining chert nodules and other bits of silicified limestone with fossils and quartz crystals that she remembers as "treasures."

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While not wanting to be dismissive of the current downturn in the oil and gas industry, Kitty L. Milliken - winner of AAPG's Robert R. Berg Outstanding Research Award and co-recipient of the Wallace E. Pratt Memorial Award for best AAPG Bulletin article - points out that had she not been laid off during the 1980s' oil glut, she might be applauding others for groundbreaking research benefitting the nation's shale energy boom.

Today, Milliken works as a senior research scientist at the Bureau of Economic Geology (BEG) in Austin, Texas, and is a global authority on sedimentary petrography, the microscopic description and classification of sedimentary rocks.

However, in 1986 - less than a year after she earned her doctorate degree in geology - she became a target of the Exxon Production Research Company's budget cuts, which prompted her to contact her former thesis adviser, Lynton S. Land, at the University of Texas at Austin for help.

"He said, 'Come back and we'll figure something out,'" she recalled. "I was given a table in the corner of a lab, and that was my desk for the next 20 years."

As a sedimentary petrologist, Milliken's initial interests focused on the microscopic makeup of carbonates and sandstones. Yet when the trying times of the 1980s took her back to her alma mater's research laboratory - where she initially was paid a salary equivalent to that of an undergraduate research assistant - she turned her attention toward mudrocks, known in the industry as shales.

As a result of her creative thinking, integrative research, and willingness to spend hours in a darkened room watching the raster of a scanning electron microscope screen, Milliken today is performing invaluable research and posing testable hypotheses about crystals smaller than 0.0625 millimeters that dominate in mudrocks.

"My research has applicability in helping people in the industry make more informed decisions about which rocks are going to be favorable for hydraulic fracturing," said Milliken, who also serves as president of the Society for Sedimentary Geology. "My work is aimed at improving our ability to make predictions about porosity and mechanical rock properties - things that matter in production."

When discussing the rarity of a geologist winning two AAPG awards in one year, Milliken said the only word that comes to mind is "flabbergasted."

And to think it all began with a childhood affinity for small things.

Let's Get Small

As a child in Franklin, Ky., Milliken played in the streambeds and fields near her home, examining chert nodules and other bits of silicified limestone with fossils and quartz crystals that she remembers as "treasures."

"I loved looking at their detailed features and soon had boxes and boxes filled with rocks," she recalled.

Even today, she has a marble and stone sphere collection that continues to grow.

"There are all kinds of variations and they are beautiful. It's the same thing with sand grains," she said. "You can't come to an understanding about mudrocks and not focus on the tiny details."

The small details that catch Milliken's eye are the tiny pores and crystals in mudrocks. Her work is to decipher their implications for a lucrative hydraulic fracturing operation.

In her award-winning 2013 paper titled, "Organic Matter-Hosted Pore System, Marcellus Formation (Devonian), Pennsylvania," which she co-authored with colleagues from ExxonMobil and the BEG, she reports observations that were intended to link porosity with a mudrock's thermal maturity.

Her findings - which were not at all what she had predicted - revealed that a rock's porosity may be more closely linked to its organic content than its thermal maturity (although she admits she would like to conduct further testing in additional localities).

"I like research because I like uncertainties," she said. "You don't know what the answer is, so you go and find out. My hope is that people will take the observations I've made, and the conclusions that come out of my research, into the real world and test them.

"I'm not in the practice of exploring for oil or gas," she said, "but for the people who do, perhaps they can take my results and have better success."

Also noteworthy is Milliken's large repertoire of highly cited journal articles and book chapters, said her colleague Kathleen Marsaglia, an AAPG member and professor in the geosciences department at California State University Northridge. Milliken also has developed several educational products, including the AAPG sandstone and carbonate digital tutorial sets and a recent compendium focused on the identification of the components of marine mud, which is available to the public at: iodp.tamu.edu/publications/TN.

Trying Something New

After completing her master's thesis in 1977 on the stable isotopic geochemistry of silicification features in the Mississippian limestones of southern Kentucky and northern Tennessee, Milliken ventured into what was at the time uncharted waters and applied stable isotopes to sandstones - integrating microscopy and chemistry in an effort to understand chemical history.

"Integration of imaging and analysis has been the theme of my research throughout my whole career," Milliken said.

As she worked to understand diagenesis - the process of chemical and mechanical changes that occur in rocks in the subsurface - in sandstones, she realized that sandstones could not be fully understood without understanding mudrocks, as mudrocks comprise more than two-thirds of sedimentary rocks.

At first, she worked on the thick mudrocks of the Gulf of Mexico but eventually expanded her work into different basins, in Italy, the Appalachians and the Iberian margin. After joining the BEG in 2008, Milliken continued her mudrock focus, but with a much broader community taking an interest.

Mudrock components are so small they require a scanning electron microscope to be examined. So, Milliken's affinity for small things became larger, in a way, expanding into additional groups of rocks and the use of more expensive equipment.

With an electron microscope, Milliken found that the architecture and chemistry of mudrocks have a particulate structure that is completely analogous to sandstones, and that mudrocks are subject to a similar range of processes that contribute to lithification and loss of porosity as they are buried.

Her work and her modesty have caught the attention of many over the years.

"Kitty - I don't think anyone calls her 'Dr. Milliken' - has done groundbreaking work on diagenesis and sedimentology, most recently on the fine-grained sedimentary rocks," said geologist and petrophysicist Terri Olson, an AAPG member and colleague of Milliken. "She is fun to work with and a popular speaker."

Marsaglia describes her peer as "a meticulous and insightful scientist of the highest caliber who literally probes diagenetic processes and sediment provenance from the basin level down to the atomic scale."

The Value of Research

While braving the roller coaster of the '80s - her paycheck varying with the success of grant proposals - Milliken used that desk in the corner of the lab to carve out a niche for herself.

"It was an outstanding research situation because I had unfettered access to equipment and a creative bunch of colleagues," she said. As a result, Milliken has made herself practically irreplaceable.

"Maybe I was stubborn to the point of absurdity, but at the time I knew that microscopy and diagenesis were important and I just couldn't abandon these topics," she said.

Understanding that research is often the first expenditure cut during challenging times, Milliken offers a fresh perspective for those in an oil-saturated market.

"The value of research has gone up a lot. The need to make better predictions has become greater," she said. "Although research does cost money, it is still cheap compared to one bad well. You can lose millions with one bad well, but less than that can keep me and several colleagues going for quite a while."

Milliken makes sure to emphasize the value of research in the many talks she gives to audiences that range from junior high students to esteemed colleagues. As she expresses utter delight of the fine details of a rock, she wants all to know why something so small is so important.

Why should people care that tiny quartz crystals precipitate?

"That's a big issue in the mechanical behavior in some shales," Milliken said. "Some are brittle because they have a mass of tiny micro-crystalline quartz that binds the rocks together and makes them hard. If you understand why these crystals form and when they formed and what controlled how abundant they are, that ties directly back to our ability to make predictions of fracturing behavior."

It is Milliken's hope that her and others' research will help to build more accurate models for exploration and development.

"Because mudrocks are fundamentally like sandstones, we can reasonably expect there is the same potential for predictive models to be developed at a variety of scales," she said. "The models might be different because mudrocks differ from sandstones in detail, but the broad characteristics are the same.

"We are still learning about this," she added. "It will be interesting to see what happens."

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