David Fischer, Fischer Oil

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David Fischer, Fischer Oil Gas Inc.

• Grand Forks, ND

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Williston Basin

• Located on North American Craton
• Covers several hundred thousand square miles
• Considered good sequestration candidate
• stratigraphy well studied
• thought to be structurally simple
• thought to be tectonically stable

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PCOR Partnership

• Characterize Williston Basin reservoirs for
  potential CO2 sequestration
• Identify best candidates for sequestration
• Enhanced oil recovery application (EOR)
• Sequestration units (saline aquifers)

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Williston BasinA potential sink for CO2
sequestration

• Sequestration Units
• regional in size
• possibly crossing political boundaries
• complex stratigraphy, possibly involving multiple
  stratigraphic units
• detailed hydrodynamic work
• trapping has to be proven

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Initial Regional Sequestration Criteria

• Stratigraphy
• The reservoir
• The trap
• Hydrodynamics
• Tectonics
• Integrity of sequestration unit

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Stratigraphy

• Relatively thick sedimentary cover
• In excess of 16,000 in Basin Center
• Deposition during all Periods of Phanerozoic
• Lower third dominated by clastics
• Middle dominated by carbonates
• Upper third dominated by clastics
• Oil and Gas productive
• Gas productive red
• Oil productive blue
• Regional porosity mapping needed

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Hydrodynamics

• Major hydrostratigraphic units recognized
• In general, hydrodynamic characteristics
  understood
• Detailed hydrodynamic work needed

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Basin Development

• and tectonics

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Basement Terrain

• Complex
• Continuation of the Canadian Shield
• In general, colliding proto-plates

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Basement Magnetic Profile

• Distinct terrains can be recognized
• Major Paleozoic structures can be identified

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Linears

• Zones of structural weakness
• Superimposed on basement terrain
• Form in response to external pressures
• Control basin development, structure and
  deposition

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Linears Basin Development
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Tectonic Model for Basin
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Linears and Structural Development

• Basement dissected into discrete blocks along
  major and minor linear trends
• Blocks respond to stress with slight movement
• Reactivation through time
• Dissolution of Paleozoic salts, including the
  Devonian Prairie salt may be controlled by some
  extent by linears

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Linears and Structural Development

• Control individual structures

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Linears Control Deposition
from 1994 NorthRock Resources Promotional Map
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Regional Sequestration UnitsWhat is the
Potential for Leakage?

• Along fractures/tectonics
• What is the tectonic integrity of the
  sequestration unit ?
• May need develop testing/monitoring techniques

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Evidence for Sealed Linears

• Few earthquakes in Williston Basin
• some reports may be due to collapse of overburden
  related to salt dissolution

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Evidence for Sealed Linears

• Numerous hydrocarbon traps

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Evidence for Open Linears

• Surface expression along the linear
• Brocton-Froid linear

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Surface expression of linears

• Difficult to see from the ground
• Geomorphology of linears may be similar to
  regional geomorphology

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Evidence for Open Linears

• Proprietary geochemical survey in the eastern
  producing portion of the Williston Basin
• Identified a linear associated with the
  depositional edge of an anhydrite

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Comments

• Additional and detailed work is necessary to
  determine the competency of potential regional
  reservoirs/sinks for sequestration in the
  Williston Basin.
• Since the Williston Basin is considered by many
  as a tectonically stable Basin, in many ways an
  ideal candidate for sequestration, any protocol
  developed to identify and test for zones of
  potential leakage to sequestered gas will be
  significant and applicable in other Basins.