Chapter 18 Table Gas Production from the Jurassic
Gas production from the Jurassic primarily occurs along the Jurassic wedge edge in central Alberta, although scattered small Sawtooth gas pools are also present in southeast Alberta and southwest Saskatchewan. There is no Jurassic gas production in B.C. or in northern Alberta.
There are 18 Jurassic gas fields with Initial Established Marketable Gas Reserves of over 1000 x l06m3 (35 BCF) The ten largest Jurassic gas fields, listed in order of Initial Established Marketable gas reserves, are shown inTable 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 Gas Fields (in units of 106m3).
|No.||Field||Formation||No. of Pools||Marketable Reserves||In-place Volume||Cumulative Production||Discovery Year|
|8||Brazeau River||Rock Creek/Nrdg||11||2,820||3,926||199||1972|
All of these ten largest Jurassic gas fields occur in stratigraphic traps, i.e. in porous zones along erosional Jurassic wedge edges in central and western Alberta where they are overlain by tight Lower Cretaceous clastics.
Total recoverable gas reserves in the Jurassic are estimated at 127.5 x 109m3, of which 58.7 x 109m3 have already been produced. Initial Established In-Place Volume of Jurassic gas reserves totals 178 x 109m3 There are a total of 438 Jurassic gas pools, with an average 291 x 106m3 recoverable gas reserves/pool.
Table 2 lists the distribution of Jurassic gas reserves according to In-Place Pool Size.
Table 2. Size Distribution of Jurassic Gas Pools (in units of 106m3).
|In-Place Pool Size Class||No. of Pools||Recoverable Reserves||Cumulative Production|
|1.0 to 10||19||73||19|
|10 to 100||199||6,623||979|
|100 to 1000||189||35,788||8,870|
|1000 to 10000||27||43,547||18,291|
|Total||438||127,488 x 106m3||58,669 x 106m3|