Alberta Geological Survey

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)

Initial Established

No.	Field	Formation	No. of Pools	Marketable Reserves	In-place Volume	Cumulative Production	Discovery Year
1	Gilby	Jurassic/Rndl	16	21,396	29,140	15,636	1953
2	Paddle River	Nrdg/Lmnvl/Rndl	7	8,385	13,615	6,835	1957
3	Niton	Rock Creek	10	7,862	12,155	3,155	1965
4	Whitecourt	Jurassic	13	5,061	8,427	2,361	1954
5	Sylvan Lake	Jurassic	29	3,636	5,293	1,093	1953
6	Pine Creek	Nordegg	3	3,206	5,091	656	1965
7	Wapiti	Nikassin	22	2,926	4,710	6	1977
8	Brazeau River	Rock Creek/Nrdg	11	2,820	3,926	199	1972
9	Greencourt	Jurassic	4	2,683	3,700	2,001	1961
10	Blueridge	Jurassic	6	2,626	4,020	1,665	1957

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
over 10000	4	41,4457	30,509
Total	438	127,488 x 106m3	58,669 x 106m3