Zenith field is located on the moderately-dipping, eastern flank of the Denver-Julesburg basin, approximately 43.4 km east of Denver. The field was discovered in March 1979, with the completion of Empire Drilling Company 1 Hilton for 1,285 bbl of oil per day and 750 Mcf of gas per day from the Lower Cretaceous (Muddy) "D" sandstone from 2,222 to 2,234 m. Development drilling by Empire, Champlin Petroleum Inc., and Amoco Production Co. has increased the number of producing wells in the field to five "D" sandstone wells and one Muddy "J" sandstone well. The initial potentials of the additional wells range from 50 to 500 bbl of oil per day with 1,000 Mcf of gas per day. Cumulative production for the field to November 1, 1979, was estimated at 96 thousand bbl of oil and 64 MM f of gas. Several other wells are in the process of being drilled and completed. Six wells in the field have been plugged and abandoned.

The "D" sandstone throughout the D-J basin is developed as marine-bar and distributary channel sandstones, and hydrocarbon accumulations are found primarily in stratigraphic traps. Zenith field is part of an east-west trending distributary channel which is also productive at Strasburg field, 3.2 km to the east, and Bennett field, 5.6 km to the west. The channel averages less than 1.6 km in width. The productive limits of all three fields are controlled by the pinch-out of porosity and permeability associated with facies changes within the channel. At least three distinct facies can be identified from well logs in Zenith field.

The "D" sandstone of Zenith field is predominantly fine grained, poorly sorted, and very shaly. The sandstone ranges in thickness from less than 6 m to greater than 15 m. The "D" sandstone thickness is producing wells is usually greater than 12 m. The average porosity and permeability in the "D" sandstone are low.

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