Petroleum Occurrences in Drillholes from Pictou Coalfield
By K. S. Gillis
For nearly 150 years the Pictou Coalfield has been the target of exploration for coal and coalbed methane. Exploration drilling programs by government and industry resulted in approximately 500 drillholes over the course of mining activity in the coalfield.
Coal was the main commodity sought in the majority of drillholes; however, a number of holes were drilled for coalbed methane and oil shale. In the search for coal, a number of drillholes reported petroleum occurrences in the form of natural gas, bitumen, liquid petroleum, hydrocarbon odour or staining, and ozocerite which is a native paraffin.
In this report, the term petroleum occurrence refers to hydrocarbons or mixtures of hydrocarbons that occur naturally, such as those listed above. It does not include the solid natural hydrocarbons found in oil shale, torbanite, and boghead or cannel coal, which yield oil only by destructive distillation. The coalbed methane holes, although not a petroleum occurrence
per se,
are included because methane gas was quantified.
The purpose of this report is to catalogue the drillholes that encountered signs of petroleum and attempts to relate the occurrences to the stratigraphic and structural fabric of the coalfield. Information for the report was taken from the logs of approximately 500 drillholes found in Nova Scotia Department of Mines annual reports and assessment reports submitted by private companies that are on file with the Nova Scotia Department of Natural Resources.
In Nova Scotia, onshore exploration for petroleum has been confined to Carboniferous strata consisting of clastic sediments, limestone and evaporites. Most petroleum occurrences recorded are the result of drilling; actual seepages of petroleum or gas are rare. The first active exploration for petroleum was at Lake Ainslie where, in the middle of the last Century, the only significant oil seep in the Province was reported (Bell, 1958; Short, 1986).
In the Pictou Coalfield, the first occurrence of petroleum was recorded by Poole (1895, p. 339) who reported bitumen associated with calcite in an outcrop on the East River south of the Town of Stellarton, and with limestone in a quarry to the north of the Town. Petroleum was also found associated with calcite and fireclay beds underlying the Foord and Cage coal seams (Bell, 1958). Gas was encountered where the coal seams outcropped on the riverbanks and from the mine workings. The remainder of petroleum shows in the coalfield are recorded from drillholes.
The Stellarton Graben (Fig. 1) is a Late Carboniferous fault-bounded sedimentary basin that formed in response to dextral movement on the Cobequid and Hollow faults system (Yeo and Gao, 1987).
The oldest sedimentary fill of the graben is represented by Windsor Group strata, followed by the Namurian Canso Group. Cumberland Group assemblages of Westphalian B age are represented by conglomerate of the New Glasgow Formation. The above mentioned rock units are generally restricted to the periphery of the graben. These strata are in fault contact with rocks of the Stellarton Formation. The Stellarton Formation, historically assigned to the Pictou Group, is now part of the Cumberland Group based on the revisions of Ryan
et al.
(1991). The Pictou Group represents predominantly redbed strata of Westphalian D to Early Permian age. Pictou Coalfield is the name applied to coal-bearing members of the Stellarton Formation (Fig. 2).
The Stellarton Formation is a thick sequence of grey and red mudstone, lithic sandstone, minor conglomerate, coal seams and oil shales. The sandstones and redbeds are considered floodplain and fluvial deposits, whereas the grey and black mudstones with associated coal seams and oil shales are considered lacustrine and deltaic in nature (Yeo and Gao, 1987). The strata span a time interval from Westphalian A to late Westphalian D. The coal seams, based on spore assemblages, range from Westphalian C to late Westphalian D (Dolby, 1986; Hacquebard and Donaldson, 1969). The Stellarton Formation (Fig. 3) is subdivided into seven members. In ascending order they are the Middle River, Skinner Brook, Westville, Plymouth, Albion, Coal Brook and Thorburn members.
The Middle River Member is considered to be the basal unit of the Stellarton Graben (J. Waldron, personal communication, 1997). The member consists of red sandstone, mudstone and arenaceous mudstone interbedded with greenish-grey sandstone and thin beds of red and grey conglomerate. The conglomerate contains well rounded pebbles of quartzite and sandstone. Some beds and lenses of intraformational limestone conglomerate are also present. The Middle River Member shows very little mottling of the red and grey beds in contrast to the overlying Skinner Brook Member. The age of the Middle River Member, based on palynological evidence, is Westphalian A, corresponding in age to the overlying Skinner Brook Member.
The Skinner Brook Member consists of mottled red and grey mudstone, sandstone and conglomerate. The Westville Member is a sequence of fine grained, grey sandstone and mudstone with interbedded coal seams. Above the coal seams, which lie near the base of the member, are several oil shale units. The Plymouth Member is best developed on the southern margin of the graben and gradually interfingers with the overlying Albion Member in the central part of the graben. The Plymouth Member consists of interbedded red and mottled red/green mudstone and sandstone and is lithologically similar to the Skinner Brook Member.
The Albion Member is a grey to black mudstone sequence containing minor oil shale and fine grained sandstone units as well as numerous coal seams. Most of the coal production in the Pictou Coalfield has been from this member. The upper limit of the member, as defined by Bell (1940), is the top of the Foord seam. Conformably overlying the Albion is the Coal Brook Member, consisting of a thick sequence of grey and black, rhythmically layered mudstone and oil shale with minor, fine grained sandstone occupying the basin margins. A single coal seam, the McLeod seam, occurs approximately 150 m above the base of the unit. The uppermost unit of the Stellarton Formation is the Thorburn Member, located at the eastern end of the graben. The member consists of interstratified grey sandstone, mudstone and minor conglomerate, along with coal seams. The base of the member, established by Bell (1940), is the McBean seam.
Coal from the Stellarton Graben is ranked as a high volatile 'A' bituminous coal, although the Westville coal, at depth and in the central part of the graben, reaches a low volatile rank (Hacquebard, 1984). The highest heat flow values reported in the Maritimes (30°-33°C/km) are found in the Stellarton Graben (Yeo, 1985) and this fact may explain the high rank attained by the Westville coal. Depth of burial could also be a contributing factor to the coal rank (Hacquebard and Donaldson, 1969).
Coal samples from the Coal Brook and Albion members were examined for permeability, porosity and maturity (Mukhopadhyay, 1994). The coal samples had a permeability and porosity that varied between 0.02 and 1.01 mD and 0.5 and 6.6%, respectively. The maturity of the coal ranged between 0.8 and 0.9% R
max
at surface to 1.8 and 2.0% R
max
at a depth of 1250 m. There is a paucity of information regarding permeability and porosity in the strata of the coalfield. In a single drillhole, P-54, five samples of sandstone/siltstone in the interval from 622-652 m indicated poor to fair porosity and very poor permeability (
Table 1
).
The Stellarton Formation holds the largest oil shale resource in Nova Scotia. Attempts at mining the resource took place in the mid 1800s and in the early years of this Century. Sixty oil shale beds have been delineated in the Stellarton Graben (Smith and Naylor, 1990). The beds range from 0.3 m-35 m thick with an average thickness of 5 m. Oil shale beds are found in the Westville, Albion, Coal Brook and Thorburn members, but the best development is found in the Coal Brook Member. Average hydrocarbon yields of 1-88 l/t have been obtained with 50% of 60 oil shale beds yielding in excess of 25 l/t.
There have been approximately 500 holes drilled in the search for coal in the Pictou Coalfield (Gillis, 1997; Suncor Inc., 1986; Shillabeer, 1988). Drill logs of the individual holes were examined for any references to petroleum occurrences. Approximately one hole in ten, for a total of 47 holes, indicated the presence of petroleum (
Table 2
). Some holes recorded only one showing and others yielded numerous petroleum-bearing horizons. There are 108 separate oil shows in stratigraphic intervals ranging from several centimetres to 6 m in thickness (
Table 3
). The types of occurrences include natural gas, petroliferous odour, bitumen, bitumen staining, oil seepages and native wax. A compilation of the data indicates the following percentages of petroleum occurrences for each of the three main rock types: sandstone/siltstone (76%), mudstone (21%) and oil shale (3%).
The coalbed methane potential of several coal seams was tested in nine holes (E-5 to E-8, E-10, E-15, E-24 to E-26;
Table 2
, Fig. 3) (Algas Resources Ltd., 1981). Gas content estimates ranged from 0.1-6.54 ml/g. An additional four holes were drilled as initial methane production test wells (AP-4 to AP-7;
Table 2
, Fig. 3) (Thompson, 1990, 1992). Several wells were stimulated and monitored from 1981-1987 and some production rates tabulated (unpublished well production records, Algas Resources Ltd.). The combined methane flow rate from the wells peaked at 25,000 ft
3
. per day and gradually decreased over time (Isenor, 1982). Suncor Inc., as part of their coal exploration program, randomly sampled coal seams for methane content. The results were comparable to those obtained by Algas Resources (Suncor Inc., 1986). REI Nova Scotia Inc. recently drilled three wells (SB-P1, -P2, -P3;
Table 2
, Fig. 3) in search of coalbed methane. The wells havebeen stimulated and are presently being monitored for methane flow.
The locations of drillholes with petroleum shows are plotted on a geology map of the Pictou Coalfield (Fig. 3; coloured version in back). In addition, two cross-sections (Figs. 4 and 5) reveal the structure in the area of greatest drillhole concentration and identify the location of petroleum occurrences in individual holes.
A general observation is that the greatest density of drillholes containing oil seepages are found on the eastern side of the East River and the holes on the western side show solid bitumen. Drillholes on the western side that indicate oil seepage are located in the faulted zone on the north-northwest boundary of the coalfield. The eastern side of the river is where the only appreciable gas flow recorded in a drillhole was encountered (ACC-56, just north of the Trans-Canada Highway 104). A gas seep also was reported on the bank of McLellans Brook near its debouchment on the East River (Fig. 3).
The concentration of holes exhibiting petroleum shows are found in close proximity to the axis of the Priestville Anticline, a broad and illdefined structure that plunges northeastward. The anticlinal nature is seen by the position of the Foord seam in the two cross-sections (Figs. 4, 5).
The petroleum occurrences are distributed in the members of the Stellarton Formation as follows: Coal Brook (55%), Albion (15%), Thorburn (13%), Westville (13%) and Plymouth (4%).
The occurrence of native wax was reported in holes AP-0355 and NS-2466, which are separated by 3.5 km. In hole NS-2466 the wax, along with asphaltic material and calcite, was found at a depth of 111 m in a vein in siltstone. The wax was identified by the Fuels Division, Mines Branch, Department of Mines and Technical Surveys, Ottawa, as asphaltic ozocerite (ozokerite of Bell, 1958) and lies in the Plymouth Member (Bell, 1958). In hole AP-0355 the wax was found at a depth of 625.15 m in mudstone. The wax appeared as a 3 mm thick wafer on a joint surface and was estimated to lie at the boundary of the Westville Member and the overlying Plymouth Member. The wax in this hole has not been classified.
The plot of holes encountering petroleum occurrences indicates that the eastern end of the Pictou Coalfield holds potential for oil and gas exploration. The majority of holes are concentrated in the axial region of an anticlinal fold; therefore, structure, along with heat flow and depth of burial is probably a controlling factor. The extreme eastern end of the coalfield did not record any petroleum shows. This is probably because drillholes in this area were shallow and confined to the upper part of the Thorburn Member. To assess the potential of the area, holes intersecting the Coal Brook and Albion members are required.
The results of permeability and porosity tests on hole P-54 were not encouraging. However, the testing of the sandstones over a broad area is needed before any conclusion can be drawn.
-
Algas Resources Ltd. 1981:
-
Nova Scotia demethanation project: a coalbed methane content evaluation of the Pictou Coalfield, Pictou County, Nova Scotia; Nova Scotia Department of Mines and Energy, Assessment Report 81-035.
-
Bell, W. A. 1940:
-
The Pictou Coalfield, Nova Scotia; Geological Survey of Canada, Memoir 225.
-
Bell, W. A. 1958:
-
Possibilities for occurrence of petroleum reservoirs in Nova Scotia; Province of Nova Scotia, Department of Mines, Miscellaneous Publication 58-02.
-
Chandler, F. W., Waldron, J. W. F., Giles, P. S. and Gall, Q. 1998:
-
Map geology, Stellarton Gap, Nova Scotia (11E/10, parts of 11E/07, 08, 09, 15, 16); Geological Survey of Canada 3535, scale 1:50 000.
-
Dolby, G. 1986:
-
A palynological study of sixty samples from the late Westphalian coal measures in the Stellarton Gap area, northern Nova Scotia; unpublished report by Robertson Research Canada Ltd. for Geological Survey of Canada, 48 p.
-
Gillis, K. S. 1997:
-
Compilation of drillhole logs relating to coal exploration in the Pictou Coalfield from 1866 to 1954; Nova Scotia Department of Natural Resources, Mineral Resources Branch, Open File Report 97-002.
-
Hacquebard, P. A. 1984:
-
Coal rank changes in the Sydney and Pictou coalfields of Nova Scotia: cause and economic significance; Canadian Institute of Mining and Metallurgy, Bulletin, v. 77, p. 33-40.
-
Hacquebard, P. A. and Donaldson, J. R. 1969:
-
Carboniferous coal deposits associated with flood-plain and limnic environments in Nova Scotia; Geological Society of America, Special Paper 114, p. 143-191.
-
Isenor, G. P. 1982:
-
The Nova Scotia demethanation project, summary report on gas production from wells AST81-P4, AST81-P5 and AST81-P6; Algas Resources Limited; Nova Scotia Department of Mines and Energy, Assessment Report 82-044, 1981.
-
Keppie, J. D. 1982:
-
Tectonic map of the Province of Nova Scotia; Nova Scotia Department of Mines and Energy, scale 1:500 000.
-
Mukhopadhyay, P. K. 1994:
-
Coalbed methane potential of selected coal seams from the Stellarton Basin, Nova Scotia, based on maturation and important physical and chemical properties for Department of Natural Resources; Nova Scotia Department of Natural Resources, Mineral Resources Branch, Open File Report 94-029.
-
Poole, H. S. 1895:
-
The Pictou Coalfield: a geological revision; Nova Scotia Institute of Science, Proceedings and Transactions, ser. 2, v. 1, p. 228-343.
-
Ryan, R. J., Boehner, R. C. , Calder, J. H. 1991:
-
Lithostratigraphic revisions of the Upper Carboniferous to Lower Permian strata in the Cumberland Basin, Nova Scotia, and the regional implications for the Maritimes Basin in Canada; Bulletin of Canadian Petroleum Geology, v. 39, p. 289-314.
-
Shillabeer, J. H. 1988:
-
1987 Report of Activities in the Pictou Coalfield; Suncor Inc.; Nova Scotia Department of Mines and Energy, Assessment Report 88-189.
-
Short, G. 1986:
-
Surface petroleum shows, onshore Nova Scotia; Nova Scotia Department of Mines and Energy, Information Series No. 11, 29 p.
-
Smith, W. D. and Naylor, R. D. 1990:
-
Oil shale resources of Nova Scotia; Nova Scotia Department of Mines and Energy, Economic Geology Series 90-3, 73 p.
-
Suncor Inc. 1986:
-
Pictou County coal project feasibility study, volume 1- geology; Nova Scotia Department of Mines and Energy, Assessment Report 87-079.
-
Thompson, A. J. 1990:
-
Exploration expenditures; Special Licence 2/86, New Glasgow, Nova Scotia; Nova Scotia Department of Mines and Energy, Assessment Report 90-175.
-
Thompson, A. J. 1992:
-
Assessment work report; Special Licence 2/86; Nova Scotia Department of Natural Resources, Mines and Energy Branches, Assessment Report 92-028.
-
Yeo, G. 1985:
-
Upper Carboniferous sedimentation in northern Nova Scotia and the origin of the Stellarton Basin;
in
Current Research, Part B; Geological Survey of Canada, Paper 85-1B, p. 511-518.
-
Yeo, G. and Gao, R. 1987:
-
Stellarton Graben: an upper Carboniferous pull-apart basin in northern Nova Scotia;
in
Sedimentary Basins and Basin-forming Mechanisms, eds. C. Beaumont and A. J. Tankard; Canadian Society of Petroleum Geologists, Memoir 12, p. 299-309.
Table 1. Core analyses from drillhole P-54, Pictou Coalfield. See north central part of Figure 3 for location.
|
Sample No.
|
Rock Type
|
Depth (m)
|
Permeability to Air (millidarcys)
|
Porosity
|
|
1 |
Sandstone |
622.20-622.43 |
<0.01 |
0.102 |
|
3 |
Siltstone |
627. 0 |
<0.01 |
0.029 |
|
4 |
Siltstone |
630.38-630.45 |
0.79 |
0.144 |
|
5 |
Siltstone |
639.83-639.91 |
<0.01 |
0.076 |
|
6 |
Siltstone |
651.80-651.90 |
<0.01 |
0.069 |
Table 2. Drillhole data for petroleum occurrences for the Pictou Coalfield. Includes the 47 drillholes showing petroleum occurrences detailed in Table 3
and holes drilled for coalbed methane potential. See Figure 3 for map locations.
|
Hole No.
|
Elevation (m)
|
Depth (m)
|
Northing*
|
Easting*
|
| P-26 |
8.5 |
450 |
5047993.0 |
4411790.0 |
| P-49 |
57.5 |
73 |
5049862.0 |
4409325.9 |
| P-54 |
33.8 |
1017 |
5049527.6 |
4409257.6 |
| P-55 |
38.3 |
491 |
5049138.1 |
4405735.9 |
| P-59A |
38.9 |
1043 |
5048173.9 |
4414623.8 |
| P-63 |
46.0 |
133 |
5046595.0 |
4407388.0 |
| P-64 |
46.0 |
124 |
5046560.0 |
4407387.0 |
| P-65 |
47.0 |
140 |
5046586.0 |
4407420.0 |
| ACC-56 |
48.8 |
277 |
5048920.0 |
4413852.0 |
| NS-32 |
41.1 |
295 |
5046800.0 |
4414350.0 |
| NS-2236 |
35.7 |
188 |
5046241.0 |
4413833.0 |
| NS-2239 |
39.8 |
188 |
5046125.0 |
4413992.0 |
| NS-2242 |
45.0 |
158 |
5046485.0 |
4414500.0 |
| NS-2462 |
11.0 |
197 |
5048187.0 |
4412106.0 |
| NS-2466 |
16.4 |
115 |
5046438.0 |
4410525.0 |
| E-5** |
25.9 |
369 |
5047695.1 |
4410698.0 |
| E-6** |
14.9 |
446 |
5047370.1 |
4411278.1 |
| E-7** |
44.8 |
248 |
5048440.0 |
4406888.1 |
| E-8** |
42.0 |
230 |
5049505.0 |
4406273.1 |
| E-10** |
10.0 |
460 |
5047890.1 |
4409738.0 |
| E-15** |
42.0 |
358 |
5049770.1 |
4409522.8 |
| E-24** |
3.0 |
356 |
5047470.1 |
4410053.0 |
| E-25** |
40.0 |
548 |
5047040.1 |
4411883.1 |
| E-26** |
63.0 |
334 |
5049765.1 |
4409033.0 |
| AP-4** |
43.4 |
298 |
5049790.8 |
4409513.7 |
| AP-5** |
46.5 |
305 |
5049787.7 |
4409422.1 |
| AP-6** |
12.0 |
446 |
5047398.8 |
4411347.5 |
| AP-7** |
46.5 |
319 |
5049787.8 |
4409431.1 |
| SB-P1** |
30.0 |
420 |
5049170.0 |
4409233.4 |
| SB-P2** |
26.2 |
1328 |
5048440.0 |
4409130.0 |
| SB-P3** |
38.7 |
723 |
5049520.0 |
4409210.8 |
| AP-0355 |
75.9 |
883 |
5048087.6 |
4407432.9 |
| AP-0370 |
43.8 |
568 |
5046543.6 |
4410956.6 |
| AP-0371 |
10.2 |
720 |
5047847.9 |
4411290.8 |
| AP-0372 |
37.1 |
850 |
5047383.9 |
4412921.6 |
| AP-0373 |
11.8 |
751 |
5048030.3 |
4412263.7 |
| AP-0377 |
44.9 |
799 |
5049169.7 |
4408040.9 |
| AP-0378 |
29.9 |
666 |
5049218.0 |
4409244.0 |
| AP-0386 |
64.6 |
469 |
5049697.2 |
4408293.0 |
| AP-0387 |
52.6 |
622 |
5048815.5 |
4412081.5 |
| AP-0388 |
45.0 |
288 |
5048373.1 |
4406334.5 |
| AP-0389 |
36.2 |
430 |
5048923.7 |
4406279.3 |
| AP-0390 |
40.5 |
445 |
5048620.0 |
4405857.9 |
| AP-0391 |
77.4 |
831 |
5049232.5 |
4412862.0 |
| AP-0392 |
34.5 |
674 |
5048302.5 |
4412801.5 |
| AP-0393 |
41.3 |
708 |
5049393.5 |
4410879.0 |
| AP-0395 |
63.3 |
787 |
5048856.5 |
4413504.0 |
| AP-0397 |
35.7 |
648 |
5047744.5 |
4412924.5 |
| AP-0399 |
15.5 |
593 |
5048238.0 |
4412430.0 |
| AP-0400 |
69.9 |
554 |
5048852.0 |
4412885.5 |
| AP-0401 |
39.7 |
898 |
5048069.0 |
4413620.0 |
| AP-0403 |
38.5 |
562 |
5048428.5 |
4412207.5 |
| AP-0411 |
14.1 |
418 |
5047546.6 |
4411807.9 |
| AP-0412 |
24.4 |
329 |
5047113.0 |
4411234.7 |
| AP-0414 |
26.7 |
105 |
5046763.7 |
4410737.0 |
| AP-0419 |
61.5 |
496 |
5049636.6 |
4412529.4 |
| AP-0420 |
39.5 |
519 |
5048581.9 |
4412198.2 |
| AP-0421 |
34.0 |
616 |
5047911.7 |
4412624.3 |
| AP-0422 |
23.0 |
628 |
5049672.3 |
4411246.9 |
| AP-0426 |
34.5 |
515 |
5047273.5 |
4412058.9 |
| AP-0427 |
37.9 |
504 |
5047432.9 |
4412357.4 |
| AP-0431 |
36.1 |
790 |
5046797.7 |
4413653.3 |
|
*Co-ordinates are in ATS-77, 3° MTM values. **Coalbed methane holes |
Table 3. Petroleum occurrences in drillholes in the Pictou Coalfield. See Table 2 and Figure 3 for locations. (Note: AP-designations not on map).
|
Hole No.
|
Host Strata
|
Thickness Interval (m)
|
Depth (m)
|
Member/Petroleum Type (depths in metres)
|
| P-26 |
Mudstone |
255.9-257.7 |
256.2 |
Coal Brook / Bitumen |
|
P-49 |
Mudstone dark grey |
36.9-39.9 |
36.9 |
Albion / Bitumen in calcite filled veins |
| Mudstone grey |
63.5-65.3 |
63.5 |
Albion / Bitumen in faulted core |
|
P-54 |
Sandstone, grey, very fine grained |
567.7-569.6 |
568.3 |
Westville / Oil seep from fractures |
| Sandstone, grey, very fine grained |
594. 0-595.0 |
594.0 |
Westville / Oil seep for 30 cm along bedding planes, petroleum odour |
| Sandstone, grey, very fined grained |
596.8-600.5 |
596.0 |
Westville / Oil seep on 140 cm of core, light colour, petroleum odour |
| Sandstone, grey, fine grained |
606.4-608.0 |
606.4 |
Westville / Oil seep on total core thickness |
| Sandstone, grey, fine grained |
612.0-687.6 |
612.6 |
Westville / Oil seep throughout core, especially from 634.2-640.2, petroleum odour |
|
P-55 |
Siltstone |
373.5-377.2 |
376.5 |
Plymouth / Bitumen in calcite veins |
| Sandstone, grey |
384.0-387.6 |
386. 0 |
Plymouth / Oil in vugs in calcite-filled fractures |
|
P-59A |
Oil shale |
135.6-158.2 |
138.4 |
Thorburn / Bitumen at 138.4 and 139.3, petroleum odour at 149.4 |
| Sandstone, grey, very fine grained |
325.6-334.7 |
331.4 |
Thorburn / Oil seep for 40 cm |
| Oil shale |
412.6-413.5 |
412.6 |
Thorburn / Oil shale emits petroleum odour |
| Sandstone, grey, very fine grained |
466.7-469.2 |
468.2 |
Thorburn / Oil seep for 100 cm |
| Sandstone, grey very fine grained |
540.3-564.1 |
554.7 |
Coal Brook / Oil seep for 350 cm. At 560 for 40 cm |
| Sandstone/Siltstone, grey |
576.1-584.2 |
581.9 |
Coal Brook / Oil seep at 581.9 and 582.2, 10 cm each, petroleum odour |
| Sandstone/Siltstone, grey |
596.4-603.9 |
596.4 |
Coal Brook / Petroleum odour |
| Oil shale |
635.3-640.8 |
636.6 |
Coal Brook / Petroleum odour for 30 cm |
| Sandstone, grey, very fine grained |
644.6-658.2 |
656.8 |
Coal Brook / Oil seep at 656.8 for 90 cm. Oil seep at 645.6 and 652.3. From 651-656.8 petroleum odour |
| Sandstone, grey/brown, very fine grained |
674.9-685.9 |
674.9 |
Coal Brook / Bitumen on bedding planes. Petroleum odour |
| Sandstone, grey/brown, very fine grained |
715.3-727.0 |
715.3 |
Coal Brook / Petroleum odour |
| Sandstone, grey, very fine grained |
728.2-739.1 |
735.9 |
Coal Brook / Oil seep at 735.9, 736.6 and 736.9 for 15, 6 and 8 cm |
| Sandstone, grey, fine grained |
768.4-773.4 |
768.4 |
Coal Brook / Petroleum odour |
| Sandstone, grey, very fine grained |
776.8-786.4 |
777.7 |
Coal Brook / Oil seep for 5 cm. Sand-stone below oil seep has petroleum odour |
| Sandstone, grey, very fine grained |
791.3-793.6 |
792.8 |
Coal Brook / Petroleum odour for 60 cm |
| Sandstone/Siltstone, grey |
802.3-812.2 |
805.0 |
Coal Brook / Petroleum odour for 30 cm |
| Sandstone/Siltstone, grey |
820.5-828.3 |
822.0 |
Coal Brook / Petroleum odour for 109 cm |
| Sandstone, grey, very fine grained |
829.5-832.8 |
829.5 |
Coal Brook / Petroleum odour |
| Sandstone/Siltstone grey |
856.2-858.9 |
856.8 |
Coal Brook / Petroleum odour for 210 cm |
| Sandstone/Siltstone, grey |
891.9-911.6 |
907.1 |
Coal Brook / Petroleum odour for 450 cm |
| Sandstone/Siltstone, grey |
941.9-952.4 |
944.3 |
Coal Brook / Petroleum odour for 30 cm |
| Sandstone/Siltstone, grey |
977.8-985.2 |
977.6 |
Coal Brook / Petroleum odour for 230 cm |
| Sandstone/Siltstone, grey |
1002.8-1016.7 |
1008.3 |
Coal Brook / Petroleum odour for 290 cm. At 1014.7 for 50 cm |
| P-63 |
Sandstone, grey, very fine grained |
74.4-75.5 |
75.3 |
Westville / Bitumen in calcite-filled fracture |
| P-64 |
Sandstone, grey, very fine grained |
31.7-35.4 |
33.5 |
Westville / Bitumen on fracture surface |
|
P-65 |
Sandstone, grey, very fine grained |
56.8-58.4 |
57.5 |
Westville / Bitumen in calcite-filled fracture |
| Sandstone, grey, very fine grained |
96.4-98.3 |
96.4 |
Westville / Bitumen in calcite-filled fracture |
| Sandstone, grey, very fine grained |
98.9-100.2 |
98.9 |
Westville / Bitumen on fracture surface |
| Sandstone, grey, very fine grained |
121.4-126.8 |
121.4 |
Westville / Bitumen on fracture surface |
| Sandstone, grey, very fine grained |
128.1-128.4 |
128.1 |
Westville / Bitumen on fracture surface |
| ACC-56 |
Sandstone, argillaceous |
159.3-161.0 |
160.8 |
Thorburn / Gas at 160.8. Gas eased by 203.3 |
| NS-32 |
Sandstone |
161. 0-163.3 |
161 |
Thorburn / Oil seep in places |
| NS-2236 |
Sandstone, brown/grey, fine grained |
126.5-129.1 |
126.5 |
Thorburn / petroliferous laminae |
| NS-2239 |
Sandstone, grey/brown, fine grained |
168.8-171.1 |
168.8 |
Thorburn / petroliferous laminae, 2 cm at 171.9 m |
|
NS-2242 |
Sandstone, light grey, fine grained |
155.2-156. 0 |
155.2 |
Thorburn / petroliferous laminae |
| Sandstone, grey, fine grained |
157.6-158.5 |
157.6 |
Thorburn / petroliferous laminae |
|
NS-2462 |
Sandstone, grey/brown, very fine grained |
114.2-117.3 |
114.3 |
Coal Brook / petroliferous laminae |
| Sandstone, grey/brown, very fine grained |
187.8-190.5 |
187.8 |
Coal Brook / petroliferous laminae |
| NS-2466 |
Siltstone, grey |
112.3-113.4 |
112.3 |
Plymouth / Ozocerite, bitumen in vein, 5 cm |
| E-25 |
Mudstone, grey |
226.2-244.5 |
243.5 |
Coal Brook / Oil stain |
| AP-0355 |
Mudstone, grey |
490.1-711.3 |
625.2 |
Westville / Wax, dark brown, 3 mm thick, on joint surface |
| AP-0370 |
Mudstone, dark grey |
459.4-459.6 |
459.4 |
Plymouth / Bitumen in joints |
|
AP-0371 |
Sandstone, dark grey |
673.7-678.3 |
675.1 |
Albion / Oil seep and Bitumen |
| Mudstone, dark grey |
699.2-710.8 |
699.2 |
Albion / Bitumen on fractures |
|
AP-0372 |
Sandstone, grey, medium grained |
91.9-100.6 |
91.1 |
Thorburn / Oil seep at 91.1 and 95.0 |
| Sandstone, grey |
268.5-277.7 |
271.4 |
Coal Brook / Oil seep |
| Sandstone, grey, fine grained |
392.3-401.5 |
392.3 |
Coal Brook / Oil seep throughout, green colour |
| Sandstone, dark grey |
410.8-415.0 |
412.9 |
Coal Brook / Oil seep over 200 cm, green colour |
|
AP-0373 |
Sandstone, brown |
210.0-212.3 |
210.6 |
Coal Brook / Oil seep at Mudstone bands |
| Mudstone, grey |
212.3-215.0 |
213.7 |
Coal Brook / Oil seep at 213.7 for 5 cm |
|
AP-0377 |
Sandstone, grey |
166.1-173.2 |
171.6 |
Albion / Bitumen on joint surfaces |
| Sandstone, grey |
248.6-281.2 |
263.4 |
Albion / Bitumen in vugs |
| Mudstone, grey |
642.7-798.6 |
744.9 |
Westville / Oil seep for 33 cm, yellow foam |
|
AP-0378 |
Sandstone, grey, very fine grained |
384.7-387.3 |
384.7 |
Albion / Bitumen in calcite fractures |
| Mudstone, dark grey |
387.3-395.2 |
388.6 |
Albion / Bitumen in fractures |
| AP-0386 |
Sandstone, brown/grey |
149.1-151.6 |
149.9 |
Albion / Bitumen in calcite-filled fractures |
| AP-0387 |
Mudstone, dark grey |
330. 0-361.8 |
354.8 |
Coal Brook / Oil seep in calcite bands |
|
AP-0388 |
Mudstone, grey, arenaceous |
202.9-220.5 |
216.4 |
Albion / Oil seep and Bitumen in vugs |
| Mudstone, dark grey |
220.5-227.1 |
222.6 |
Albion / Bitumen in calcite band |
| Mudstone, grey, arenaceous |
269.0-274.2 |
272.6 |
Albion / Oil and Bitumen in calcite stringers |
| AP-0389 |
Mudstone, dark grey |
314.6-330.9 |
315.8 |
Albion / Bitumen filled fracture |
| AP-0390 |
Sandstone, light brown |
426.5-428.7 |
426.8 |
Albion / Oil seep for 160 cm |
| AP-0391 |
Mudstone, grey |
616.0-700.6 |
624.0 |
Coal Brook / Oil seep on bedding plane |
| AP-0392 |
Sandstone, light grey |
427.7-430.4 |
428.6 |
Coal Brook / Oil seep on joints and bedding |
|
AP-0393 |
Mudstone dark grey |
461.0-479.1 |
465.4 |
Coal Brook / Oil seep in calcite fracture |
| Mudstone, grey |
518.9-535.5 |
524.1 |
Coal Brook / Oil seep on fracture planes |
|
AP-0395 |
Sandstone, grey |
175.6-178.1 |
177.1 |
Thorburn / Oil seep |
| Sandstone, light grey |
300.9-310.6 |
306.4 |
Coal Brook / Oil seep in 6 locations for 82 cm |
| Sandstone, grey |
397.4-400.1 |
398.8 |
Coal Brook / Oil seep for 15 cm |
|
AP-0397 |
Sandstone, grey, argillaceous |
76.1-85.0 |
80.4 |
Thorburn / Oil seep for 46 cm |
| Sandstone, light grey |
85.0-116.7 |
98.3 |
Thorburn / Oil seep in bands for 15 m |
| Sandstone, grey, fine grained |
331.9-334.0 |
333.4 |
Coal Brook / Oil seep for 56 cm |
| Sandstone, light grey |
391.1-398.0 |
395.2 |
Coal Brook / Oil seep, also at 395.9 |
| Sandstone, light grey, fine grained |
399.6-410.2 |
402.0 |
Coal Brook / Oil seep in 10 locations for 85 cm |
| Sandstone grey, argillaceous |
492.7-504.7 |
492.7 |
Coal Brook / Oil seep |
| AP-0399 |
Mudstone dark grey |
341.8-364.5 |
350.8 |
Coal Brook / Oil seep in arenaceous band |
| AP-0400 |
Mudstone, dark grey |
196.6-207.8 |
198.1 |
Coal Brook / Oil seep for 52 cm |
|
AP-0401 |
Sandstone, grey/brown |
336.3-339.5 |
336.3 |
Coal Brook / Oil seep for 37 cm |
| Mudstone, dark grey |
450.7-457.5 |
453.8 |
Coal Brook / Oil seep in sandstone band, 12 cm |
| Sandstone grey, medium grained |
469.1-483.7 |
481.8 |
Coal Brook / Oil seep on bedding planes for 54 cm |
| Sandstone, grey, fine grained |
547.5-566.0 |
551.5 |
Coal Brook / Oil seep from 551.5 to 566 |
| AP-0403 |
Sandstone, grey/brown, fine grained |
218.5-223.1 |
219.7 |
Coal Brook / Oil seep in bands for 73 cm |
|
AP-0411 |
Mudstone, black |
86.9-95.0 |
93.7 |
Coal Brook / Oil seep for 56 cm. Halite on core |
| Mudstone, dark grey |
153.0-163.3 |
156 |
Coal Brook / Bitumen in vugs for 19 cm |
| Sandstone, grey |
303.2-315.8 |
307.2 |
Coal Brook / Oil seep |
| Sandstone, grey, fine grained |
363.4-381.0 |
363.4 |
Coal Brook / Oil seep in bands for 5 m |
| AP-0412 |
Sandstone, grey, fine grained |
191.4-207.5 |
200.0 |
Coal Brook / Bitumen |
| AP-0414 |
Sandstone, grey, fine grained |
15.8-17.4 |
16.9 |
Albion / Oil seep |
| AP-0419 |
Sandstone, grey, argillaceous |
458.1-460.2 |
460.0 |
Albion / Oil seep in calcite fractures |
| AP-0420 |
Sandstone grey |
226.3-228.1 |
227.2 |
Coal Brook / Oil seep |
|
AP-0421 |
Sandstone, grey, fine grained |
317.8-322.2 |
319.2 |
Coal Brook / Oil seep at 5 locations for 94 cm |
| Sandstone, grey, argillaceous |
424.7-434.4 |
426.5 |
Coal Brook / Oil seep at 3 locations for 32 cm |
|
AP-0422 |
Sandstone, grey, argillaceous |
316.4-322.5 |
320.8 |
Coal Brook / Bitumen in calcite fracture |
| Mudstone, grey |
504.7-530.0 |
520.7 |
Coal Brook / Bitumen in calcite fracture |
|
AP-0426 |
Siltstone |
166.7-168.9 |
166.7 |
Coal Brook / Oil seep |
| Sandstone, grey, very fine grained |
293.6-305.7 |
296.0 |
Coal Brook / Oil seep at 2 locations for 123 cm |
| AP-0427 |
Sandstone, grey, fine grained |
409.9-412.2 |
410.4 |
Coal Brook / Oil seep for 180 cm |
| AP-0431 |
Sandstone, grey, fine grained |
536.0-541.0 |
539 |
Coal Brook / Oil seep |
Figures: (Not presently available)
Figure 1.
(a) Fault zones in the Canadian Appalachians active during the late Paleozoic. (b) The Stellarton Graben in relation to the Cobequid and Hollow faults.
Figure 2.
Stratigraphy of coal seams in the Pictou Coalfield.
Figure 3.
Preliminary geological map of the Pictou Coalfield showing petroleum occurrences in drillholes (NTS map sheet 11E/10), Pictou County, Nova Scotia.
Figure 4.
Longitudinal section A-B in the Pictou Coalfield indicating location of petroleum occurrences. See Figure 3 for section location.
Figure 5.
Cross-section C-D in the Pictou Coalfield indicating location of petroleum occurrences. See Figure 3 for section location.
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