February 2019: Marshall Deacon

Marshall Deacon | Edge Energy Inc.

New Insights and Discoveries of the Permian Lyons sandstone, DJ Basin, Colorado
Edge Energy Inc.



The Permian Lyons sandstone of NE Colorado has received quite the interest over the last 150 years for its use as a building and patio stone, its iconic hogback outcrops and park lands, and high permeability oil reservoirs. From the first oil discovery in the mid 50’s to the present, Rocky Mountain operators have had their sights on the Lyons in the DJ. Noble Energy started a drilling program in 2010 and had the first significant new discovery in the Lyons in over 30 years.  That was followed by two additional new field discoveries. Very little has been published on the Lyons since those early discoveries, but with hundreds of newer well penetrations and large 3D seismic shoots, new opportunities have come to light.

A rich dataset of outcrop, well logs, cuttings, cores, production and 3D seismic reveal a complex depositional, diagenetic, and oil -filling history.  Deposition was primarily by wind transported sediment in a coastal plain setting that extended from near-shore sabkha environments to the east to large dune and fluvial environments adjacent to the Ancestral Rockies to the west.  Inter-bedding of sabkha, sand sheet, dune and fluvial deposits result in a complex reservoir architecture.  The depositional environment also had a strong impact on the diagenetic phases from early anhydrite dominated cement in the east to calcite and silica cements in the west.  The early diagenetic phase is interpreted to have had the largest effect on the preservation and creation of original and secondary porosity.  

The oil-filling history of the Lyons and its relationship to the structural, depositional and diagenetic history is complicated. The source of the oil is undocumented with both a western Phosphoria and eastern Pennsylvanian source hypothesized. Oil staining in the cores consists of a black residual oil, a brown oil and a light tan oil stain often separated at facies boundaries. Staining can be up to 100’ thick implying oil columns significantly greater than exists presently. At least two hydrocarbon filling events are postulated and trapping is by structure, stratigraphy and diagenesis.

Biography: Marshall Deacon

Originally from western Oregon, Marshall followed in his fathers’ footsteps and studied geology at Oregon State University. Having enough of volcanic rocks, he moved on to graduate school at Northern Arizona University to study fluvial and eolian strata on the Colorado plateau. First job took him to the North Slope of Alaska and Prudhoe Bay and then to Norway and the North Sea. Arriving in Denver during the downturn of ‘98 led to some challenging times but has kept busy working exploration and development for Encana, Bonanza Creek, and Noble Energy and now with a small outfit out of Golden – Edge Energy. He spends most of his geology time on the Cretaceous source rocks and reservoirs of the DJ Basin but any sedimentary rock with a good outcrop is hard to pass up.