Transcript PPT

Petrological insights into thermal maturity,
source rocks, migration, diagenesis
L.D. Stasiuk and N.S.F Wilson
Natural Resources Canada
Geological Survey of Canada
Thermal maturity – 2002-03
progress
•
Reassess Vitrinite %Ro from
Evenchick et al, 2002 (~ 160
samples).
• New Vitrinite % Ro and Tmax
from Rock Eval for about ~ 200
samples.
Reassess Vitrinite %Ro from Evenchick et al, 2002
580
5.00
560
R2 = 0.7838
4.00
540
3.50
520
Tmax (oC)
Old vitrinite %Ro mesurements
4.50
3.00
2.50
New data
500
480
2.00
460
1.50
440
1.00
420
0.50
0.50
Bowser
Basin - old
data
Type III
400
1.00
1.50
2.00
2.50 3.00
3.50
4.00
New Vitrinite %Ro measurements
4.50
5.00
0.20 0.40 0.60 0.80 1.00 1.20 1.40 1.60 1.80 2.00
%RoR vitrinite
Petrology of Organic Matter and Rock Eval
Evaluation of Potential Source Rocks
Osadetz et al. have defined ‘Effective Petroleum Systems’ in
Bowser Basin related to petroleum stains / shows proposed to
come from:
1. a Paleozoic carbonate marine source rock deposited in a
mesohaline to hypersaline setting (for stains in Muskaboo
Creek Assemblage at Tsatia Mountain);
2. Mesozoic lacustrine – non-marine source rocks (for stains
in Triangle zone)
3. Mesozoic normal marine source rock in Richie Well
stains (e.g. 6745’) and in stains near Bucking Horse &
Spatsizi River intersect.
Aptian to Albian to Campanian
Tango Creek Formation; Nonmarine potential hydrocarbon
source rocks
Aptian to Albian to Campanian Tango Creek
Formation: non-marine potential hydrocarbon source
rocks in triangle zone
Black shales (44/89, 872-875/92 series) :
Bowser Basin: 1.34 - 2.54, 8.4 % TOC just North of Kitchener
Lake.
Sustut Basin 4.7 % TOC, near Stikine River-Cullivan Creek
crossing for source rocks in the mid-late oil window (0.90 to 1.2
%Ro vitrinite).
Coaly partings: 60-70 % TOC
Rock Eval pyrolysis for Tango Creek, Triangle Zone and
Sustut Basin (for Rocks with vitrinite %Ro > 1.0 – 1.5 and
Tmax > 450 C – i.e. late oil window to condensate - dry gas
Rock Eval pyrolysis for Tango Creek ?? for coals and black
shales with vitrinite %Ro > 1.2-2.5 and Tmax > 480-560 C –
i.e. condensate - dry gas
20.0
%Total Organic Carbon
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0
C-439420 C439421 C-439422
C-439423 C439424 C-439425
C-439426 C439427 C-439428
Terrestrial – cuticular organic matter in coals and shales
Upper Jurassic to Upper Cretaceous deltaic deposits,
Bowser and Sustut basins
Tango Creek
shales – 8 % Total
Organic Carbon
Terrestrial – cuticular organic matter in coals and shales
Upper Jurassic to Upper Cretaceous deltaic deposits,
Bowser and Sustut basins
Aptian to Albian to Campanian Tango Creek Formation;
Non-marine potential hydrocarbon source rocks – coals ?
Vitrinite %Ro = 0.87
Aptian to Albian to Campanian Tango Creek Formation;
Non-marine potential hydrocarbon source rocks – coals ?
875/92
Rock Eval pyrolysis for Skelhorne assemblage for coals and
black shales with vitrinite %Ro of 2.6- 5.0 and Tmax > 600 oC
– i.e. dry dry gas to sub-green schist
% Total Organic carbon
EP-95-001b EP-95-004a EP-95-017a EP-95-023 b EP-95-025a EP-95-034a
EP-95-044b EP-95-051c EP-95-055c EP-95-056a EP-95-061c EP-95-065a
EP-95-067c EP-95-071c EP-95-074a EP-95-085a EP-95-107c EP-95-135b
EP-95-146b EP-95-187
15.0
14.0
13.0
12.0
11.0
10.0
9.0
8.0
7.0
6.0
5.0
4.0
3.0
2.0
1.0
0.0
Recycled lacustrine Type I kerogen
source rock clasts in Eagles Nest
Assemblage (reworked from
Muskaboo Creek ??)
Recycled lacustrine Type I kerogen source rock clasts in
Eagles Nest Assemblage (reworked from Muskaboo Creek
??) Vitrinite %Ro 0.80-0.90.
Fluorescent light
White light
Recycled lacustrine Type I kerogen source rock clasts in
Eagles Nest Assemblage showing Pediastrum like
morphology (freshwater, e.g. lacustrine algae)
Fluorescent light
Modern
•Some Pediastrum species also is characteristic of the littoral zone
of oligotrophic waters
Crude oil generation from recycled lacustrine Type I
kerogen source rock clasts in Eagles Nest Assemblage and
migration of higher API oils in microfractures
High maturity recycled possible lacustrine Type I kerogen
source rock clasts in Tango Creek, Eagles Nest and Todagin
assemblage; Gas Zone, 1.0 to 1.4 %Ro
Recycled lacustrine Type I kerogen source rock clasts in
Eagles Nest Assemblage (reworked from Muskaboo Creek
??)
Evenchick et al.,
2002
•Some Pediastrum species also characteristic of the littoral
zone of oligotrophic waters
Sedimentary petrology
Calcite filled
porosity with
HC inclusions
EP-91-91
Pyrobitumen
lining pores
- dissolution
- HC inclusions
EP-91-91
Leached Pore
space
EP-91-91
Calcite cements
Pyrobitumen +
HC Inclusions
Pore space –
Fewer HC incs
EP-91-91
EP-89-101