It has long been known that the Niobrara Play in the Denver Julesburg (DJ) basin is a stacked play. By definition a stacked play is a play with multiple pay horizons (petroleum producing geologic formations or units) which may be accessed by drilling. While the Niobrara formation with at least 3 productive units, the A, B, and C horizons, has been the main focus of the play to date, the DJ basin has other “zones” with potential equal to that of the Niobrara.
Early on in the development of the DJ basin the Codell formation was recognized as a good producer of oil from the traditional vertical wells in the basin whose main target was the Dakota formation’s D and J sands. Codell production was typically commingled with Dakota and Niobrara production in these vertical wells. At the GHS 100 Energy Conference on June 25th, 2014, PDC Energy presented information that indicates the company views the Codell formation to have an equal or greater potential for oil production than the Niobrara.
The Codell sandstone is the uppermost member of the Carlile formation, which is Upper Cretaceous (Turonian) in age. The Codell is immediately overlain by the Fort Hays limestone member of the Niobrara formation. Both the upper and lower contacts of the Codell are unconformable. (Hively, 1986. Society of Petroleum Engineers)
The Codell is a widespread, blanket-type marine shelf sandstone of relatively uniform thickness and lithology across the area of current activity. The sand-stone is dark gray, very fine grained, and contains abundant clay, both authigenic and detrital. (Hively, 1986. Society of Petroleum Engineers)
PDC to date, has determined that the Codell Fm. is equal to the Niobrara in production in BOE per well, with the Codell producing 12% more oil vs. a Niobrara well.
PDC has had strong Codell results across its entire DJ basin acreage and is aggressively testing downspacing in multiple areas of Core Wattenberg area.