Moya Little, President
Suite 105, 214 - 11 Avenue SE,
Calgary, Alberta, Canada
Phone: (403) 543-4080
Geological & Reservoir Discussion
This Cessford area oil pool was on production in 1990 and is developed with 7 producing wells. There are currently 4 active oil wells producing at a combined rate of 4.0 m3/day oil, 3.1 103m3/day gas and 0.04 m3/day water. From structure and net pay mapping, a volumetric initial oil in place of 907,000 m3 was established. Material balance reserves calculated at the current reservoir pressure indicate initial oil in place of 839,000 m3. The material balance reserves conservatively support the volumetric estimate for the pool.
The pool drive is solution gas, ultimate primary production of the 876 kg/m3 density oil is estimated from decline analysis at 96,935 m3 or 12% of the original oil in place. This would be an average primary recovery for a solution gas drive pool.
Production from this pool began in June 1990 with the drilling and completion of the well 100/08-34-024-13 W4, over the following two year period six additional wells 100/16-34, 102/06-34, 100/04-35, 100/12-35, 100/10-34 and 103/06-35-024-13 W4 were drilled, completed and placed on production. Peak production from this pool reached 45.0 m3/day oil, 32.0 103m3/day gas and 0.3 m3/day water in early 1992.
There is a central oil proration battery located on lsd 08-34 and the producing wells are flowlined to this facility. Each well is tested weekly, clean crude oil is trucked to pipeline, gas is gathered and processed at the Conoco Cessford 02-08-024-12 W4 facility and all produced water is trucked for disposal.
Sandstone 100%, fine to medium grain, moderately well sorted, well rounded to sub-angular, loose silica cemented quartz grains, clear to opaque. Porosity to 24%. Medium brown oil stain, bright yellow fluorescence, instant yellow streaming cut. Lamina of bitumen near bottom of sandstone (1m). Trace of Glauconite.
Net Pay: 9 feet
Average Permeability (horiz.): 147 md
Average Permeability (vert.): 32 md
Average Porosity: 23 percent
Average Oil Saturation: 15 percent
Average Water Saturation: 17 percent
With reference to the enclosed structural and net oil pay map the oil trap is a stratigraphic type with evidence of non-deposition of the sand to all quadrants. The reservoir is overall structurally flat with a slight dip to the south-southeast.
From open-hole log evaluation net oil pay was determined using cut-off values of 15% density log porosity and a 50% log derived water saturation and ranges from 1.2 meter to 3.6 meters. From these cut-offs the net oil pay map was constructed.
The net oil pay map was planimetered and a reservoir volume of 659.6 Ha-m. was determined. Using an average porosity of 23%, water saturation of 30% and an oil shrinkage of 0.92 the volumetric initial oil in place calculated; Volumetric Initial Oil in Place: 907,000 m3