An area within the North Alma Penn Unit, operated by Samedan Oil Corporation, has been selected to evaluate the effects of injecting a biopolymer at various concentrations into the Sims Sands reservoirs beginning during the early stages of waterflooding. The polymer "slug", sized equivalent to fifteen polymer "slug", sized equivalent to fifteen percent (15%) of the effective pore volume based percent (15%) of the effective pore volume based on a concentration of 250 parts per million (ppm), was started after thirty-one percent (31%) of the reservoir voidage had been filled with straight brine. Approximately thirty-nine percent (30%) of the polymer poundage has percent (30%) of the polymer poundage has been injected at a concentration of 304 ppm and has caused no apparent damage to the reservoirs. Five (5) of nine (9) producing wells have responded to water injection, and three (3) of these have shown a recent reduction in water production. Further injection will be required to fully determine the total effectiveness of the polymer, but there are early indications that the polymer is influencing the water cut in some wells.
The North Alma Penn Unit is located approximately three (3) miles northeast of the townsite of Velma, Oklahoma in Stephens County. The Unit was formed in February, 1970 for the purpose of waterflooding three (3) Deese Sands and three (3) Springer Sands. Water injection was begun in November, 1970, into the lower Deese Sand (Pickens) and the Springer Sands (First, Second and Third Sims); injection into the upper Deese Sands is to be phased in as the in-line Sims producing wells phased in as the in-line Sims producing wells water out. For purposes of this paper, discussion will be limited to the Sims Sands.
The Sims Sands comprise approximately seventy-six percent (76%) of the total acre-feet of the net oil volume. Major faults separate each Sims reservoir into four (4) distinct fault blocks, and the northernmost fault isolates the area herein referred to as the "North Fault Block". It is within the North Fault Block where the injection of biopolymer fluid was begun in August, 1971, and is still in progress.
Selection of the North Fault Block for polymer injection was based on the following: polymer injection was based on the following:
- Uniformity of zones
- Complete closure of reservoirs with aquifers controlling three
- sides and a major fault on the southside.
