Brian Gilroy on Slawson Whitetail Waterflood Project
Slawson Whitetail Waterflood Prospect
There are several stages of oil development and production. Most outside the industry are only familiar with the initial production phase. For those affiliated with the oil and gas business, it is commonly accepted that in some areas the primary stage will only allow 5-25% of the oil in place to come to the surface. This is why water flooding and various other injection methods have become common place in many formations. Secondary and tertiary development can in some cases produce 2-5x the original oil in place. “This is why we feel the Whitetail prospect is such a great opportunity” reports Brain Gilroy, oil and gas expert and co-founder of OilBoomUSA.
The Whitetail is a simple secondary waterflood prospect in the southern Minnelusa fairway of the Powder River Basin, Wyoming. The prospect centers on a field discovery by Home Petroleum in 1981 which yielded 396,089 barrels of oil (BO) before being temporarily at a production rate of 30 barrels of oil per day (BOPD) in 1987. It was abandoned because of a drop in oil prices but then started again in 1989 and finally plugged in 1991.
The Home discovery produced 40° light crude from an upper Minnelusa (Permian-Penn age) sand in a single well bore. It is known that the upper (younger) Minnelusa sands, deposited as Aeolian dunes on a broad flat sabkha, are totally encapsulated in anhydrite upon burial and thus sealed from pressure-enhancing natural water drives in the lower sands. The sands in the Minnelusa contain porosities from 6%-25% and permeability’s from 1mD to 1Darcy and therefore make excellent candidates for secondary pressure maintenance. Once the primary reserves in the reservoir are pressure depleted the “tank” simply needs to be “recharged” with water to recover an equal or greater amount of “secondary” reserves. Studies have shown that the primary production is a fraction of ultimate recoverable reserves in the upper sands of the Minnelusa. Often the primary reserves is just 5-15% of OOIP (Original Oil In Place) with secondary maintenance often 2-5 x that of primary or 35% and higher of OOIP. There have been more than 130 water flood programs in the Powder River Basin in Wyoming.
Using Enhanced Oil Recovery (EOR), Slawson Energy’s goal is to re-enter the plugged producer, reportedly with casing at the surface, drill a twin to the down dip pressure test of 1983 and begin injecting water to recover the “stranded oil.” This is a type of “water flooding.” (Please refer to the video on this website for more information). Slawson estimates an average injection pressure of 1500 psi and proposed maximum pressure of 2500 psi surface based on a fracture gradient of 0.7 psi/ft of 9800’ depth.
According to the Department of Energy, there are nearly 400 billion barrels of “Unrecoverable Oil” in the U.S. and that 60%, or 240 billion barrels of oil, are recoverable through EOR.
Reserve estimates by Slawson Energy for the Whitetail prospect are “679,000 BO with a potential upside of over 1,000,000 BO.”