The Permian Coconino sandstone and the Supai group are the primary targets as they are very porous and permeable in the Holbrook Basin. The residual oil shows in the Coconino on the Concho Dome lend evidence to oil entrapment within the Coconino on the Manuel Seep that is structurally 500 feet higher. The Boundary Butte Field on the Utah-Arizona border has produced in excess of four million barrels of oil from 458 surface acres from a depth of 1,500 feet. Since the surface of the Manuel Seep covers 12,766 acres, the recoverable reserve potential is much greater. In addition to oil and gas reserves, the Supai group is host to vast helium reserves.
The Permian Coconino that produced helium at the Pinta Dome, Navajo Springs and East Navajo Springs on the north side of the Holbrook Basin and oil on the Arizona-Utah border and wells on either side of the Manuel Seep. The Permian Fort Apache contained oil, gas and helium in the PetroSun 17-1, gas and helium on the PetroSun 15-1 and the Holbrook Energy 26-1 displaced several barrels of oil on the pit at its Meteor Crater prospect. The Granite Wash contained shows of C1 and C2 in Ridgeway Petroleum’s 1994 CO2 and helium discovery on the St. Johns anticline to the southeast of the Manuel Seep Prospect.
The Devonian formations are considered to be later targets for the following reasons:
(1) The prospective pay zones are present in the Pan American Petroleum NMALCO B-1 well on the East Taylor Anticline, the adjacent surface structure to the southwest, and the absence of the zones in the Pan American NMALCO A-1 well on the top of the Concho Dome, the adjacent surface structure to the northeast;
(2) PetroSun’s NMAL 15-1 well on the flank of the Concho Dome encountered 48 feet of basal Devonian shale, indicating the whole Devonian section should be present on the Manuel Seep;
(3) Gravity and aeromagnetic data indicate rapid thinning of the sedimentary section northeast of the Manuel Seep, which is very likely the pinch-out of the Devonian; and
(4) the McCracken sandstone and the Martin dolomite have excellent reservoir qualities. Dolomite samples from the Devonian oil seep on the East Verde River were analyzed for porosity (17%) and permeability (34md). A cross section using the Amstrat logs from the PanAm wells is attached as Figure 2. A map showing the locations of these wells and the three structures is included as Figure 3. A map of the Bouguer gravity data showing the gradient that indicates the pinch-out of the Devonian is included as Figure 4. Pictures of the Devonian oil seep are included as Figure 5. Source rock analysis of the field. Devonian Martin has indicated that it was buried to sufficient depth to generate oil and natural gas, that it has total organic content (TOC) of 2.8% and that it is at the peak of the oil generation window, capable of generating 246 barrels of oil per acre foot. Oil and natural gas are likely to be encountered on the above because it is likely trapped along the up-dip pinch-out of the Devonian source rocks and reservoir beds.