Propane-Natural Gas Stimulation of Newly Converted
J. W. GREGG ; JA CK WAHL ; NORMAN ORR
The Pembina Cardium pool is a low permeability, stratified, solution-gas drive reservoir. Water-flooding hu proven to be an effective means of pressure maintenance for all areas of the pool in which an economic rate of water injection can be maintained. The majority of water injection wells in the pool are converted oil well~ with capacities greater than 100 millidarey- feet. If the average injection rate per unit of capacity can be increased the lower capacity areas of the pool can be economically flooded. Theory, laboratory work, and two . early miscible-flooding projects within the pool suggested that average water injection rates for converted wells could be increased two to threefold by the initial injection of natural gas liquids and natural gas. However, these two early projects received volumes of natural gas liquid!:' and high-pressure natural gas which would be economically prohibitive for . routine stimulation. Area D, one of the Five-Way Properties in the southeast corner of the pool, has an average permeability thickness product of only 82.5 millidarcey- feet, which is usually considered to be too low for successful water-flooding in Pembina. However, beginning in May, 1960, three wells along the north boundary of the area were converted to water injectors on a pilot basis. These wells have wellbore capacities of 79, 148 and 35 millidarcey- feet. Prior to water injection, each well received a relatively inexpensive treatment of 200 barrels of propane liquid, followed by 2 M M of natural gas. After injecting continuously some 60,000 barrels per well over a 10-month period, these wells still take water at rates of 190 to •240 barrels per day with wellhead pressures between 1,450 and 1,500 psig. Pressure parting is not evident. It now appears that the stimulation treatment is of lasting benefit and has improved injection rates two to seven-fold; fortunately, the improvement is inversely proportional to wellbore capacity. Where high pressure natural gas is economically available, it is reasonable to expect that stimulation treatments of this type will make areas in the pool with capacities of less than 100 millidarey-feet susceptible to successful water-flooding.
Average Gas Injection Pressure, natural gas, Pembina Cardium sand., propane, water injection, Capacity, Natural gas, Oil, Oils, Permeability, Pressure, Sand, Water, Waters, Wells