November 2016: Michael Domenick

Michael Domenick | Slick Oil


The Northern DJ Codell: Distribution of Rock Properties


Since the early 1980s, the Codell Sandstone member of the Carlile Shale has received much attention from the petroleum industry for its productive potential in the Northern DJ Basin. Academic focus has been on the depositional environment of the Codell, and its place in the Turonian Stage Greenhorn Marine Cycle. There have been differences of opinion regarding the sediment source and depositional environment of the Codell, with an eastern source and shelf area favored mostly by recent petroleum industry workers. Also complicating the provenance interpretation is the relatively contemporaneous deposition of Frontier Formation clastic wedge sediments sourced from the west. Vertical juxtaposition of Codell and Frontier units is seen across several unconformable sequence boundaries dividing both units (Figure 1).

The purpose of this study is to add to the understanding of regional Codell Sandstone distribution, particularly with respect to discriminating Codell facies from those of the Frontier. A brief review of the existing literature is provided, and used to inform the construction of fence diagrams using open-hole well logs. Log correlations benefitted from the presence of laterally extensive bentonite markers, as well as relatively unambiguous log properties seen for shale and carbonate units in the lower part of the Carlile Shale, underlying the Codell Sandstone.

Log correlations were augmented by data from public domain cores, from over 50 wells. The integrated data were used to categorize the Codell and associated facies into 5 general rock types, as follows:

1) Bioturbated sandstone – This rock type is dominant at Wattenberg, and southern Wyoming. The original depositional bedding has been disturbed by burrowing organisms, but the sandstone retains 12+ % porosity, and thicknesses >15-20 feet for much of the Wattenberg area. Poor log response due to high clay content and high bound water volume has contributed to the belated development of the play outside of Wattenberg field, but vertical production of bioturbated Codell has been ongoing since the 1980s.

2) Bedded sandstone - This rock type is similar to the bioturbated facies in mineralogical composition, but retains depositional bedding. In southern Wyoming, the bedding is generally horizontal to hummocky cross-stratified, usually associated with storm beds. These "laminated" facies are seen to exhibit higher permeability than the adjacent bioturbated facies. In Goshen County and north, the sandstone bedding is more commonly cross-stratified or crypto-bioturbated, and beds are more "massive" and lighter in appearance, which points to their deposition in an upper to middle shoreface environment, or

gradational delta front to delta plain environment.

3) Mud Drape - The dominantly mud-draped sandstone rock type typically occurs beneath, or within, the shoreface Bedded sandstone. As such, the Mud Drape rock type is seen as related to and deposited with other shoreface facies, supported by the fact that they are not seen in association with the Bedded or Bioturbated rock types to the south and east. The Mud Drape facies has not been identified to any significant extent east into Nebraska.

4) Layered sandstone - The Layered sandstone rock type consists of alternating thin (~1" thick) layers of sandstone and shale, and is generally devoid of bioturbation. The Layered sandstone rock type is seen primarily in Wyoming and has tentatively been identified in the lower portions of southwestern Nebraska cores. The preserved bedding in these rocks and lack of bioturbation is taken to indicate relatively rapid deposition in a pro-delta environment.

5) Shale - The Shale rock type has been identified in the most general of ways, principally to discriminate the facies from other rock types with easily identifiable sandstone components, as identified above.

The Codell of the Wattenberg Field area in Colorado is dominated by the Bioturbated rock type. Thickening and reservoir quality improvement to the west is believed to be an expression of increased shelf energy, and not necessarily an indication that these rocks were sourced from the west. Very little Layered rock type has appeared to have reached as far south as the Colorado State line, into the Wattenberg area. In southern Colorado however, outcrop studies verify the presence of Layered rock type in association with Bedded/Mud Drape rock type. These rock types in southern Colorado are believed to be associated with an eastern sediment source. Relevant features of the paleo-shelf are surmised to be related to some of the same processes which created the Wattenberg High and Morrill County High. General southeastward thickening of the Carlile, off the flanks of the aforementioned features, also supports this hypothesis.

In contrast, Bedded/Mud Drape and Layered rock types are dominant in the northernmost DJ Basin, in Goshen and Platte Counties, Wyoming. Together with isopach mapping of key units, rock type distribution suggests that the rocks in Wyoming show a greater influence from a western source area. This study supports the hypothesis that these northernmost DJ facies, generally identified as Codell in earlier work, are actually equivalent to the (Frontier) Wall Creek of the Powder River Basin.


Michael A. Domenick (Mick) has over 30 years professional experience in the petroleum industry, based exclusively in Denver, and is currently consulting for several clients working in the Rockies. Mick's expertise extends from exploration to development and operations, with primary emphasis on Rocky Mountain basins but including experience in the Hugoton and Anadarko basins and the Texas and Louisiana Gulf Coast. Mick has focused on the Denver and Powder River Basins for the past ten years. Mick formed Slick Oil Limited in July 2015, in order to better position himself for the inevitable up-turn in petroleum commodity prices. Slick Oil's strategy includes the acquisition of mineral leases and equity interest, in collaborative efforts with other like-minded individuals and entities. Slick Oil anticipates increasing industry activity in 2017(!). Mick’s technical areas of focus are 1) tight "halo" sandstone plays, including the DJ Basin Codell, as well as "migrated semi-conventional" plays throughout the Rockies; 2) hybrid reservoir full realization to define thicker total petroleum systems, as was done with the Bakken into the Three Forks; and 3) low-profile conventional plays situated in space and time as bridges to increased unconventional resource opportunities .

Mick strives to fully utilize the foundational wealth of work and knowledge which has come before, as viewed through the lens of modern technology and work-flows. As an improvisational jazz saxophonist, Mick plays his music and geology by the rules, respecting the conventions, but on the boundaries of the "chord structure" and with the ear of the audience in mind. As a small- to mid-cap employee throughout his career, Mick owes a debt of gratitude to mentors and colleagues too numerous to mention, who set high standards and provided constructive feedback on a diverse career arc.

Mick earned a Master of Science degree in Geology in 1981 and a Bachelor of Science degree in Geology/Biology in 1979 from the University of Rochester in New York. In addition, Mick completed post-graduate studies in Hydrogeology at the Colorado School of Mines, and Petroleum Geology at the University of Colorado.

Relevant speaking engagements include the keynote address at the Emerging North American Shale Conference in January 2012 (analyzing geologic anomalies in the Niobrara); the Tight Oil Niobrara Congress in May 2012 (regional geologic variability in the Niobrara); the Global Technology Conference in June 2012 (Niobrara sub-plays and fractured reservoir types); the Emerging Shale Plays USA in April 2013 (Des Moines hybrid reservoir properties); the RMAG Hot Play Symposium in September 2016 (Codell petrophysics and horizontal well production); and will speak at the upcoming SEPM luncheon in November 2016 (distribution of Codell reservoir properties).

October 2016: John McLeod

John McLeod | SM Energy


When Clastics and Carbonates Collide: Preservation and Exposure of a Unique Upper Pennsylvanian (Missourian) Fossil Assemblage from the Fort Worth Basin of North Texas


The Lake Bridgeport Shale (Upper Pennsylvanian, Missourian) is a local lithofacies of the Graford Formation that outcrops extensively around Lake Bridgeport in the Fort Worth Basin of Wise County, north central Texas. From 2011 until mid-2015, the dam-impounded lake dropped to record-low water levels due to a combination of drought and consumption demand by the city of Fort Worth. During this four-year window, extensive outcrops of formerly submergent formations afforded detailed study of the stratigraphy, sedimentology and fossil content of formerly inaccessible localities. Owing to its unique paleogeographic setting and favorable conditions for preservation, the fossil assemblage is unusual in containing a diverse mixture of terrestrial and marine plants, large invertebrates, vertebrates, trace fossils and sedimentary structures.

The Pennsylvanian Bridgeport seas in the Fort Worth Basin were intermittently silled to the north by the emergent Wichita Mountains and were subject to additional siliciclastic sediment from the Perrin Delta emanating from the rising Ouachita Mountains to the east. Although much of the shallow muddy substrate was well-oxygenated, at least two thin intervals of less-oxic sediments preserve phosphatic nodules containing a unique vertebrate-dominated fauna. A major flooding event eventually drowned the muddy substrate with algal carbonate but some of the predecessor benthic and pelagic species survived and even prospered in the new environment. A massive collection of fossils and associated sedimentary structures from Lake Bridgeport collected over a 30-year period has yielded a number of new or unique specimens.

Missouri Stage petroleum systems are of economic importance in Texas due to development of coal in non-marine facies of the Graford and the Canyon Lime oil and gas play farther west in the Panhandle Palo Duro Basin. This assemblage provides a unique perspective of the biodiversity, rock-forming processes, diagenesis and biogenic constituents that were present during this time in north Texas.


John McLeod is currently a Geologist – Technical Expert with the Resources team at the corporate headquarters of SM Energy in Denver.

After completing an M.S. in Geology at Northern Illinois University, John embarked on a 35+ year career as a geoscientist, including earlier positions with Mobil Oil, Ladd Petroleum, the Idaho Department of Water Resources (as a hydrogeologist), Oryx Energy, the Illinois State Geological Survey, EOG Resources and Chesapeake Energy. He has lived in 12 different cities, including now his second tenure in Denver.

His current interests involve the analysis of petroleum systems, source rocks, and the determination of thermal maturity in sedimentary basins. He has pursued fossils and geology since 1979 at Lake Bridgeport in north Texas where he owns a residence.

August 2016: Morgan Brown

Morgan Brown | NEOS

Rocky Flats re-revisited: TTI PSDM Case Study in Complex Overthrust Geology



The US Department of Energy acquired a 2D seismic line near the Rocky Flats nuclear facility in Colorado in 1983. The line was designed to image shallow faults that might connect buried contaminants to groundwater. However, it extends west into Coal Creek Canyon, and provides perhaps the best view of sub-thrust geology of any available survey. The data were “lost” by DOE, but “found” by Ned Sterne in 2013 and reprocessed in 2014 by 3D Imaging Technology Inc (in time) and Tenax Geoscience (in depth). Sterne, who teaches a well-known “Geology of the Front Range” field course, updated his interpretation based on the 2014 Prestack Depth Migration (PSDM) image and presented it at the RMAG luncheon. Brown presented the PSDM results in more detail at the 2014 RMS-AAPG meeting. In 2016, NEOS Seismic Imaging Group resurrected the Rocky Flats line, to demonstrate how TTI reflection tomography improve over Brown’s 2014 velocity model. The 2016 processing provides the easiest-yet data to interpret and more clearly confirms Sterne’s earlier interpretations.


Dr. Morgan Brown holds degrees in applied mathematics (BA, 1997) from Rice University and in geophysics (PhD, 2004) from Stanford University. He worked in geophysical R&D at Hess Oil and 3DGeo, before joining a depth imaging startup, Wave Imaging Technology Inc.. He served as CEO from 2008 to the company's sale in 2013 to GeoCenter. After consulting for two years, he recently joined the NEOS Seismic Imaging Group in Denver as a Subject Matter Expert in Depth Imaging.

June 2016: David Budd

David Budd | Colorado University Boulder

Making geologic sense of pore-system characterizations in carbonate-rich mudrocks: an examples from the Niobrara Formation, DJ Basin



Carbonate-rich mudrocks are deposited as biogenic sediments, and their mineralogy means they should have different pore-system characteristics - pore types, sizes, and connectivities - relative to argillaceous and siliceous mudrocks. But not all carbonate mudstones are deposited alike or with the same initial mineralogies. Secular changes in ocean chemistry mean geologic intervals characterized by originally calcitic mudstones and other intervals characterized by originally aragonitic mudstones. Biological evolution has meant time intervals of only benthic-sourced mud (Paleozoic) and intervals of both benthic-and pelagic-sourced muds (post-Jurassic). How these differences translate to pore systems in carbonate mudstones hosting unconventional resources is not well documented. Scanning electron pore imaging of one example, the Niobrara Formation, reveals three key points. An intercrystalline pore network associated with the calcite dominates. Pore associated with clay minerals in the matrix of marls and marly shales, as well as pores within organic matter, are secondary. The intercrystalline pores are bigger, less elongate, have large pore throats, and are better connected than all other pore types. Lithology matters. However, vertical lithologic heterogeneity occurs over three spatial scales (cm to decameter), which means the lithologic control creates tremendous challenges for upscaling.


David Budd received BA, MS, and PhD degrees in geology from the College of Wooster (1976), Duke University (1978), and University of Texas, Austin (1984). After three years in ARCO’s geologic research group, he joined the Department of Geological Sciences at the University of Colorado in 1987. David’s primary research interests are in the diagenesis of carbonate rocks, and the application of carbonate geology to petroleum reservoirs and aquifers. Current research relates to the evolution of nanopore systems in unconventional carbonate reservoirs, reaction-transport modeling of diagenetic patterns, dolomitization, and self-organizing phenomena in carbonates.