Hydrocarbon Potential of the Bakken

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Hydrocarbon Potential of the Bakken and Torquay
Formations, Southeastern Saskatchewan
L.K. Kreis(1), A. L. Costa(1), K. Osadetz(2)
1-Saskatchewan Industry and Resources
2- Geological Survey of Canada
2
Williston Basin
SE SASK
SK
AB
MB
MT
ND
SD
WY
3
TALK OUTLINE

• Bakken Petroleum System
• Bakken and Torquay Production in SE Saskatchewan
• By-passed pay in Bakken and Torquay formations in
  SE Saskatchewan

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BAKKEN ISOPACH
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BAKKEN PETROLEUM SYSTEM

• SOURCE ROCK
• MIGRATION
• TRAP

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NAL ET AL TORQUAY 15-31-3-11
U. BAKKEN SHALE
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BAKKEN PETROLEUM SYSTEM

• SOURCE ROCK
• Bakken shales are rich source rocks
• Type II oil-prone kerogen averaging 12.1 and
  11.5 TOC by weight for U and L shale
• At least 100 billion barrels of oil generated in
  the Williston Basin
• Oil generated is commonly 40o API or greater

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LOWER BAKKEN SHALE
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LOWER BAKKEN SHALE RESISTIVITY
9 OHM-M
2,000 OHM-M
AREA OF MATURE BAKKEN SHALE?
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UPPER BAKKEN SHALE
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UPPER BAKKEN SHALE RESISTIVITY
9 OHM-M
25,000 OHM-M
AREA OF MATURE BAKKEN SHALE?
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MIDDLE BAKKEN ISOPACH
NON-RESERVOIR
RESERVOIR
RESERVOIR
NON-RESERVOIR
A
A
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NAL ET AL TORQUAY 15-31-3-11
TRANSWEST ROCANVILLE
8-5-16-31W1
NORTHROCK ET AL HUMMINGBIRD 14-1-2-19W2
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BISON VIEWFIELD 8-6-8-8W2

• Daily Average Production 30 bls/d

UNIT B ???
UNIT C
M. BAK.
lt 4 ohms
UNIT A1
UNIT A
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MIDDLE BAKKEN PRODUCTION
ROCANVILLE 5.1M BLS CUM 1-104 BLS/DAY 34
BLS/DAY AVER
A
RONCOTT 0.8M BLS CUM 5-67 BLS/DAY 28 BLS/DAY
AVER
HUMMINGBIRD 1.2M BLS CUM 78 BLS/DAY AVER
VIEWFIELD 0.8M BLS CUM 1-104 BLS/DAY 47 BLS/DAY
AVER
A
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BAKKEN PETROLEUM SYSTEM

• MIGRATION AND TRAP (MIDDLE BAKKEN
  SANDSTONE)
• Middle Bakken sandstones provide both migration
  paths and reservoir
• Middle Bakken sandstones usually have low
  permeabities (i.e. 1 to 20 md)
• Porosity is commonly between 5 to 15 but locally
  can have 100s md permeability and over 20 (e.g.
  Rocanville Pool).

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BAKKEN PETROLEUM SYSTEM

• MIGRATION AND TRAP
• Porosity is oil-wet in mature and over-pressured
  areas
• Bakken oil is believed to have migrated into
  overlying Mississippian and underlying Devonian
  units (e.g. Souris Valley and Torquay)
• Oil is often trapped in subtle structural traps
  with poor quality reservoirs (e.g. Viewfield)
• Others exhibit obvious structure (e.g.
  Hummingbird Pool)

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BAKKEN PETROLEUM SYSTEM

• TRAP
• Porosity and permeability pinchouts appear to
  play a significant role in trapping within Middle
  Bakken sandstones

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TORQUAY ISOPACH
BAKKEN OIL IN TORQUAY?
DOMINANT RESERVOIR
MINOR RESERVOIR
SINCLAIR POOL TORQUAY PRODUCTION 1.2M BLS
CUM
SASK. TORQUAY PRODUCTION 93,500 BLS CUM 27
BLS/DAY AVER
SINCLAIR
ANTLER
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(No Transcript)
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BY-PASSED PAY IN BAKKEN AND TORQUAY FORMATIONS
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BY-PASSED PAY IN BAKKEN AND TORQUAY FORMATIONS

• REASONS FOR BY-PASSED PAY
• Poor drill-stem tests
• Tests often only show oil-cut water and/or mud
  even from producing intervals
• Significant recovery of free oil in drill-stem
  tests is not common

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BY-PASSED PAY IN BAKKEN AND TORQUAY FORMATIONS
BISON VIEWFIELD 8-6-8-8W2
UNIT B ???
M. BAK.
lt 4 ohms
UNIT A1

• REASONS FOR BY-PASSED PAY
• Oil stains of 40o API oil tend to be very faint
  and are often invisible to the naked-eye
• Milk-white oil cuts were obtained from most cores
  examined in this study when reservoir-quality
  rock was present
• Low resistivity values (i.e. lt4 ohms) over
  producing sandstone interval in many wells (e.g.
  Viewfield Pool).

UNIT A
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Conclusions

• Upper and Lower Bakken shales are world-class
  source-rocks and might have generated oil in SE
  Sask. in an area proximal to the U.S. border
• Widespread Bakken oil shows and production
  indicates significant exploration potential
• Low resistivity, light oil stain and poor DST
  recoveries suggest large potential for by-passed
  pay
• Torquay is prospective in a region along
  Saskatchewan/Manitoba border

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THRUST FAULT NORMAL FAULT
ENGINEERS FAULT
D