Alberta Geological Survey

Gas Production from the Upper Colorado Group

Gas production from the Upper Colorado Group is widely distributed throughout southern and central Alberta and southwestern Saskatchewan. There is no Upper Colorado Group gas production north of Township 61 or west of the 6th Meridian. Included are fields producing from the Second Specks, Medicine Hat, Chinook, Milk River and Belly River. Note that commingled production from the Belly River and the deeper Second Specks is reported for some fields as producing from the SE Alberta Gas System.

There are 41 Upper Colorado Group gas fields (36 in Alberta and 5 in Saskatchewan) with Initial Established Marketable Gas Reserves of over 1000 x 10⁶m³ (35 BCF). The ten largest Upper Colorado Group gas fields, listed in order of Initial Established Marketable gas reserves, are shown in Table 1. Cumulahve production data for Alberta are updated to the end of 1990 and for Saskatchewan to the end of 1989.

Table 1- Ten Largest Upper Colorado Group Gas Fields (in units of 10⁶m³)

Initial Established

No.	Field	Formation	No. of Pools	Marketable Reserves	In-place Volume	Cumulative Production	Discovery Year
1	Medicine Hat	MilkR/Medhat	42	93,611	147,009	73,453	1904
2	Hatton	MilkR/Medhat	3	48,514	73,705	17,489	1953
3	Suffield	MilkR/Medhat/2WS	9	45,066	67,320	22,712	1904
4	Alderson	MilkR/Medhat/2WS	6	29,564	43,600	16,964	1904
5	Princess	MilkR/Medhat/2WS	10	18,295	27,166	7,629	1904
6	Verger	MilkR/Medhat/2WS	9	14,291	21,254	3,958	1904
7	Countess	MilkR/Medhat	9	14,288	21,247	1,169	1904
8	Bigstick	2WS	1	13,754	17,236	2,700	1980
9	Bantry	MilkR/Medhat/2WS	6	12,169	18,574	8,334	1904
10	Cessford	MilkR/Medhat	33	11,585	17,615	2,038	1904

Eight of these fields occur in southern Alberta, amd the remarnmg two, Hatton and Bigstick, just across the Saskatchewan border.

Total recoverable gas reserves in the Upper Colorado Group are estimated at 419.3 x 10⁹m³, of which 36.8 x 10⁹m³ have already been produced. Initial Established In-Place Volume of Upper Colorado Group gas reserves totals 645 x 10⁹m³. There are a total of 1684 Upper Colorado Group gas pools, with an average 249 x 10⁶m³ recoverable gas reserves/pool. Table 2 lists the distribution of Upper Colorado Group gas reserves accordmg to In-Place Pool Size.

Table 2 - Size Distribution of Upper Colorado Group Gas Pools (in units of 10⁶m³)

In-Place Pool Size Class	No. of Pools	Recoverable Reserves	Cumulative Production
1.0 to 10	244	830	187
10 to 100	1113	22,523	3,434
100 to 1000	258	44,120	12,099
1000 to 10000	56	117,161	5,231
over 10000	13	234,658	15,839
Total	1684	419,292 x 106m3	36,790 x 106m3