192

Indeed many of the Triassic sandstones and limestones appear to be very
tight and impermeable; possibly some of the Paleozoic and Triassic shell
limestones have porosity suitable for a reservoir. Hage notes the induration
of many of the sandstones of the Bullhead group, but suggests that this may
decrease eastward. It may be further noted that the Bullhead group
entirely disappears north of Prophet River, where it need not be considered
when drilling is planned.

Hage (1944) states that structures with closure have been mapped.
‘Several have been outlined sufficiently to show their extent and type”
(See Chapter IV). :

A well drilled for water for a construction camp near Indian Creek was
carried to a depth of 410 feet. It passed through 50 feet of glacial drift and
360 feet of dark grey shale. A small flow of gas occurred at 190 feet. ‘The
gas burned with a flare about 4 feet long as it escaped from a 1-inch pipe.
It was under very little pressure” (Hage, 1944).

FORT NELSON TO VALLEY OF TETSA RIVER

No special investigation of porosity or permeability of the rocks
exposed along the Alaska Highway west of Fort Nelson has been made.
Williams (1944), however, notes “that the Mississippian formations include
argillaceous and arenaceous limestones of a type commonly petroliferous.
Overlying chert beds . . . are suitable as cover rocks. The thick Triassic
arenaceous limestones also suggest porosity’’.

So far as known, and subject to confirmation as future investigation
proceeds, the structure of the eastern Triassic block (See Chapter IV) does
not include faults and is one of folds only. Williams considers that the
wide, gentle structures near Steamboat Mountain deserve attention. He
concludes that the “main hope for petroleum production lies in the thick
assemblage of marine, calcareous and arenaceous beds of upper Paleozoic
and Triassic ages. .... A variety of structures is available, but a test
location should be made only after careful field investigation”.

Hage (1944) has described three wells drilled for water at the Fort
Nelson airport. No. 1 well “reached a depth of 521 feet and was wholly in
glacial drift. It encountered a pocket of gas and was abandoned”. No. 2
well reached a depth of 1,451 feet, passed from drift into bedrock between
720 and 730 feet and encountered a flow of gas at 1,010 feet in fine-grained
sandstone. A supply of water was found in coarse gravel at the base of the
drift, and rose to within 250 feet of the surface. An analysis of the gas
is as follows:

Per cent by
volume
Methane'yiaiaccun wasrstecs errs ter een recta te eee ee 98-41
OLDEST ae Geer e NEO aGUE atte BARN CSUR SD CREAR oie 0-18
Propane sires aie te ee ees Ae a nee aE RIE ene a Nil
Butaness Siiriocy tacts reed mapa tae a pe ee en INE Nil
BERtanesircr pis eine catce Sore eae ee lt eae aE 0-10
Carbontdioxide ss een r ti etn treatin nme ROaEC 0-28
RY SOM yorsreloholeroketnrl Cecickerheheleesiete ister ee eee ee 0-91
INI ERO REN es sere rs tet vara teen sien ee pee ie a ee ae 0-12
SIT Bar annum Aaa eons nAL Horns GUMS ECib ise ie Boonie coulis Trace
Potala e cura heen ere er en reee her tered Cenreee 100-00

Specific gravity (Air=1-000) 0-575
Heating value at 760 mm. and 60°F.
B.t.u. per cu. ft. =999