Application of Outcrop Analogues to Characterize Mudstone Reservoirs: Examples from The Duvernay Formation in Alberta-Canada and the Woodford Shale in Oklahoma-USA 

Speaker: Henry Galvis-Portilla | University of Calgary  

April 15, 2020
Hyatt Hotel, Imperial Ballroom 5/7/9 | 700 Centre Street SE, Calgary AB T2G 5P6

11:30am: Doors Open
12:00pm: Talk Starts


CSPG member ticket price: $46.50+gst 
Non-member ticket price: $55+gst
Please note: The cut-off for ticket sales is 1:00pm, five business days before the event.

Organic-rich mudstone reservoirs are intrinsically heterogeneous at a variety of scales (mm-to-km). In the subsurface, the expression of this heterogeneity can cause variations in drilling and stimulation efficiencies, consequently affecting the well productivity. To analyze the range of spatial variability and to assist in constraining subsurface stratigraphic models, outcrops provide an inexpensive alternative to capturing reservoir architectural information while bridging the scale gap between seismic and well data.

In this presentation we examine two prolific Devonian mudstone reservoirs of north America, where outcrop studies provide insights into the influence of facies characteristics on reservoir quality variability. Exposed strata equivalent to the Duvernay Formation and the Woodford Shale are featured. These two examples illustrate the utility of combining traditional field geology with modern techniques to extract quantitative spatial information relevant for subsurface applications. From outcrops we extract information from facies descriptions, UAV -drone- photogrammetry, hand-held spectral gamma ray, thin section petrography, fracture scanlines, and geochemical analysis (XRD, XRF, TOC). The extracted quantitative data is georeferenced and statistically analyzed to compare with subsurface well cores and logs.

In the Duvernay case study we document the transition from a carbonate reef buildup to off-reef organic-rich mudstones; a depositional model of reciprocal sedimentation is applied to explain the spatial variability in thicknesses and geometry of limestone debris beds alternated with the high-TOC mudstone beds. In the Woodford Shale study, we document in several outcrops the erosional relationship with its underlying unit, establishing that paleo-topography had a significant impact on sedimentation of the overlying transgressive Woodford Shale. Finally, for both examples, the Duvernay and the Woodford, outcrop mechanical stratigraphy is used to visualize how fractures might evolve during artificial fracturing.
After this talk you will see outcrops differently as they offer hands-on access, ‘windows’ to visualize our subsurface reservoirs, and a motivation to get away from office.


Henry Galvis-Portilla graduated with a BSc (Hons) in Geology from the Universidad Industrial de Santander in Colombia in 2011. He began his career working on the stratigraphy and petroleum potential of Cretaceous mudstones in Colombia. Henry worked on R&D having the opportunity to study the La Luna Formation as an unconventional reservoir. In 2016 Henry went to the University of Oklahoma to pursue a MSc in Geology. There he studied the Late Devonian Woodford Shale in outcrops and cores. Then, Henry moved to Canada in the fall 2017 to start his PhD in Geosciences at the University of Calgary. Currently, he is working on the multi-scale characterization of the Duvernay Shale combining sedimentology, geochemistry and petrophysics. He is an active member of CSPG, AAPG, SPE and SEPM, and regularly presents papers at technical conferences.