Chapter 18 Table Oil Production from the Jurassic
Oil production from the Jurassic primarily occurs along the north-south Fosterton-Dollard trend in southwest and central Saskatchewan. Other scattered Jurassic oil fields are also present along the porous Jurassic erosional wedge edge in southern and central Alberta and in southeast Saskatchewan.
There are 23 Jurassic oil fields (17 in Saskatchewan and 6 in Alberta) with Initial Established Recoverable Oil Reserves of over 1 x 106m3 (6 MMBbls). The ten largest Jurassic oil fields, listed in order of Initial Established Recoverable Reserves, are shown in Table 1. Cumulative production data for Alberta are updated to the end of 1990 and for Saskatchewan to the end of 1989.
Table 1. Ten Largest Jurassic Oil Fields (in units of 106m3).
|No.||Field||Formation||No. of Pools||Marketable Reserves||In-place Volume||Cumulative Production||Discovery Year|
|7||North Premier||Roseray Sand||2||5.0||15.9||4.5||1953|
|10||South Success||Roseray Sand||1||4.5||10.9||3.8||1953|
Seven of these fields occur along the Fosterton-Dollard trend in southwest Saskatchewan, and the remaining three, Grand Forks, Medicine River and Gilby, along the Jurassic wedge edge in southern and central Alberta. Battrum, Fosterton, North Premier and South Success fields are stratigraphic traps formed at the Roseray Sand unconformity edge. Dollard, Instow and Rapdan fields occur as stratigraphic traps in Upper Shaunavon shallow marine and shoreline sands. The Grand Forks field consists of numerous small pools trapped by stratigraphic facies pinchouts and drape structures. Medicine River and Gilby fields are stratigraphic traps developed in porous valley-fill sands. All of these ten largest fields, except for Grand Forks, contain light to medium gravity oil.
Total recoverable oil reserves in theJurassic are estimated at 136.1 x 106m3, of which 102.1 x 106m3 have already been produced Initial Established In-Place Volume of Jurassic oil reserves totals 513.6 x 106m3. There are 275 Jurassic oil pools, with an average 495 x 103m3 recoverable oil reserves/pool. Table 2 lists the distribution of Jurassic oil reserves according to n-Place Pool Size.
Table 2. Size Distribution of Jurassic Oil Pools (in units of 106m3).
|In-Place Pool Size Class||No. of Pools||Recoverable Reserves||Cumulative Production|
|less than 0.1||48||0.22||0.09|
|0.1 to 1||146||5.86||2.81|
|1.0 to 10||70||55.32||40.58|
|10.0 to 100||11||74.67||58.63|
|Total||275||136.07 x 106m3||102.11 x 106m3|