The geoscience community at large now has access to a major trove of data gathered by ExxonMobil in the 1980s and ‘90s. ExxonMobil will share the results of its behind-the-outcrop coring program through a website created by the Society for Sedimentary Geology.
The dataset contains 2,334 feet of high-resolution photos from nine cores collected by the sequence stratigraphy group at Exxon Production Research, prior to the merger between Exxon and Mobil.
“These cores are from Utah, Texas and California, covering fluvial, deltaic, shoreface and deepwater fan settings,” said Howard R. Feldman, who recently retired as a senior geoscience adviser for ExxonMobil Upstream Integrated Solutions.
Michael Blum, SEPM president and director of graduate studies at the Earth, Energy and Environment Centerof the University of Kansas in Lawrence, called the contribution “historic” because of its scientific and academic value.
“My perspective on this historic contribution comes from two points-of-view.I am a career academic who knew about these data and cores, had seen publications that utilize these data, and had commonly wished I had access for my own teaching purposes.I also spent six years within ExxonMobil Upstream Research directly using these resources for teaching purposes in the industry context. Using these well logs, cores and other related data for exercises was a pleasure, and I would commonly stay after the classes and just go over the cores myself to learn more,” he explained. “There is hardly a better way to convey to young industry scientists the basic concepts of environments of deposition than using real examples, where they can examine composition, vertical trends in facies and rock properties that are important to exploration and production.”
“This contribution will likely generate interest among many stratigraphers who are currently using those outcrops for training and research,” Feldman said.
Sources of the Core
This coring program was primarily in the Book Cliffs (Utah and Colorado) behind several key outcrops that are still regularly visited today, and in a few other areas. The program was designed to illustrate key facies and stratigraphic stacking patterns, and test the new (at the time) concept of parasequences. Parasequences are shallowing-upward successions of facies, and some of these cores were located to test this critical concept in a range of Cretaceous coastal settings, Feldman explained. Several of these cores were collected by John Van Wagoner, who was the driving force of high-frequency sequence stratigraphy, building on the work of Peter Vail.
“Also included in the dataset are three cores from deepwater fan facies of the Permian Brushy Formation in west Texas. These cores illustrate channel and lobe facies behind key outcrops that are no longer accessible,” Feldman said.
Peter Vail’s work integrating stratigraphy and seismic revolutionized seismic interpretation in the 1970s and ‘80s. This work was further advanced with outcrop studies, which were supplemented with these cores. The behind-the-outcrop data cores collected by Exxon, and the principles they illustrated, led to more efficient drilling programs and had a huge impact in academia, Feldman said.
The Ground Truth
These data have been used for decades as a teaching and training tool, both within ExxonMobil and in public AAPG and SEPM workshops. However, the entire set of core photos have never before been available.
The SEPM website went live on March 1.
“The scale and quality of primary data and core photographs that are being shared through SEPM is also historically significant in that it was, in many cases the basis, the ground truth if you will, for models of environments of deposition in ancient fluvial, shore face, deltaic, and deepwater settings, which became widely used in industry, government and academic research. This will be a huge benefit to the broader sedimentary geology community for decades to come,” Blum said.
“I would also say this data set reminds us of a time when there was much research investment from the oil industry. There were many stratigraphy related studies sponsored by Exxon Production Research, now ExxonMobil Upstream Research, and other IOCs. This type of investment in what was essentially basic science research was essential in the early days of facies models and sequence stratigraphy, but is uncommon today.Hence, this is important data from that perspective, and represents investments that would have never been possible outside of industry. After all of these years, it is exciting to realize it will now be available to the broader community of academic, government and private industry scientists outside of the oil industry.” Blum added.
Feldman said the project is exciting for him personally, because he collected one of the cores himself from the Morrison Formation in the mid-1990s.
“Collecting this core was one of my first assignments after I joined the stratigraphy team at EPR, and it remains a key core because it was collected from an exhumed fluvial channel at an outcrop that is easily accessible today, so the fluvial bar morphology can be compared to the stacking patterns in the core. And this core has never been made public,” he said.
Outcrops suffer from inaccessibility of tall cliffs, covered intervals and weathering of mudstones in particular. The cores provided a complete, easy-to-read succession of facies and stratigraphic patterns similar to those observed in cores from petroleum wells.
“The data was previously only available in limited portions through publications, and as a result of this release through SEPM, it will be available to all, and this is a milestone in itself,” Feldman said. The EPR program not only allowed Exxon researchers to test key concepts, but use them to train and teach others. “It’s an amazing teaching tool,” he added.
The website is SEPM.org/Exxon