EOR CCS webinar slides - Ernie Perkins - August 2011

GLOBAL CCS INSTITUTE

THE CO2 EOR – CCS PLAN HOPE• CO2 EOR can produced significant amounts of

incremental oil.

• After production is halted, significant amount of CO2

remains and can be considered stored.

• Potentially, the field can become a CCS site.

0

5

10

15

20

25

30

35

40

45

50

Jan-55 Jan-61 Jan-67 Jan-73 Jan-79 Jan-85 Jan-91 Jan-97 Jan-03 Jan-09 Jan-15

Primary & Waterflood

Pre-CO2

Horiz Infills

Vertical Infills

Actual

Current production at 35-year high

Waterf lo o d

Impro vement

Source: EnCana Corporation Data after Jan-08 are projections.


CONTENTS

1. CO2 and Oil Properties

2. Reservoir Screening and Development

3. Joffre – an example

4. Transition to CO2 storage - Issues

1


KEY CO2 – OIL PROPERTIES FOR EOR

• CO2 Density (liquid or dense phase) is

close to, but lighter than oil and water.� Efficient sweep of new portion of

reservoir.

X Must be in liquid or dense phase region.

• CO2 is miscible with oil at high

pressures and immiscible at lower P. X MMP is higher with heavier oil.

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X MMP is higher with heavier oil.

X Reservoir heterogeneity means that P

must be significantly above MMP

� Miscibility and lower CO2 density results

in oil swelling.

? Lower MMP through new technologies.

? New technologies to recover at partially

miscible conditions.

? Asphaltenes, waxes, mineral scales,

etc, can precipitate due to CO2

presence. Lab work is needed to

evaluate.


KEY OIL - CO2 – WATER PROPERTIES

• CO2 Viscosity (liquid or dense phase)

is typically in the range of 0.5 to 0.09

cp (higher than gas, but much lower

than water and oil).X Can result in fingering, thus need water

injection for control.

• Mobility ratio (Oil / Water viscosity

ratio) controls recovery – can be

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LL Lower (heavier) LiquidUL Higher (lighter) LiquidV CO2 rich vapour

ratio) controls recovery – can be

improved through increasing water

viscosity (polymer addition, etc). New

Technologies.

• Oil is a complex mixture of

hydrocarbons. The composition varies

significantly even in the same reservoir.

This results in complex phase

behaviour when CO2 is present.


RESERVOIR PROPERTIES

• Pressure and temperature control miscibility.

• Relative permeability effects can impact effect of CO2

injection. Hysteresis effects are critical.

• The formation will exhibit either water-wet, oil-wet or

mixed wettability, which controls recovery and fluid

injectivity.

• Laboratory evaluations are very important.

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IMPLICATIONS OF OIL - CO2 PROPERTIES

Injected

CO2

CO2 with Oil

Components

Oil with

condensed CO2

OilMiscibility

Zone

``Single Phase``

Displacement Direction

Miscibility Zone size changes with time.

Several CO2 – oil phases can exist simultaneously.

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Several CO2 – oil phases can exist simultaneously.

This leads to a rather

simplified snapshot of the

reservoir recovery

process at a given time.

Once breakthrough has

occurred, some form of

WAG (water alternating

gas) will be implemented.


Figure 4.2.2

A SLIGHTLY MORE REALISTIC SNAPSHOT OF THE RESERVOIR

Vertical Water

Injector

Midale

Anhydrite

CO2CO2 & OilOil

Hz CO2 Injector

Midale

Marly

Vertical

Producer

CO2

Hz Producer

• Increasing reservoir heterogeneities result in more complex well geometries

and production methods.

Frobisher

Vert Crosswell

Oil & CO2CO2

Oil

&

Water

Marly

Midale

Vuggy

Water


TECHNICAL & ECONOMIC SCREENING

• Average reservoir pressure and MMP.

• Well patterns and stage of depletion.

• Residual oil saturation.

• Reservoir wettability.• Reservoir wettability.

• Reservoir heterogeneities and inter-well

continuity.

• Ability to inject and produce fluids at economical

rates.

• Cost and amount of CO2.

7


RESERVOIR DEVELOPMENT FOR CO2 EOR

• Gravity dominated floods vs. pattern floods.

• Wellhead & bottom hole injection pressure.

• Effects of impure gas streams.

• Pattern modifications

− Infill drilling− Infill drilling

− Horizontal wells

− Pattern balancing

• Production wells – conversion to flowing.

• Phased-in or delayed field development.

• WAG optimization and CO2 slug size

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RELATIVE NEED FOR FACILITIES

Primary Waterflood CO2 EOR

Production Wells (infill)

Injection Wells (infill)

Water-Oil Separation

Gas separationGas separation

Water Injection

Water Recycle

Makeup Water

CO2 Source

Gas Compression

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Indicates that these facilities are needed.

Number indicates relative amount.


JOFFRE CO2 EOR• Currently a light oil CO2 miscible flood.

• As of 2009,

– 57.6 bcf CO2 injected, 40.4 bcf CO2

produced, resulting in a 30% storage factor.

– Current Oil production ~450 bbls/day

– 4.86 MMbbls recovered.

– 11.5% OOIP recovered.

– Goal is 16.5% OOIP recovery

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TRANSITION TO CCS

• Long term planning is critical. CO2 EOR tries to

maximize oil production and minimize CO2

usage.

• EOR fields are generally governed under a

petroleum act. Transition to CCS issues will

include, but are not limited to …

– Long term liability.

– Different rules / regulations for well

abandonment and reclamation.

– Stewardship fund.

– Pore ownership issues.

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TRANSITION TO CCS

Why Transition?

– Why not blow the field down and sell the CO2

to the field down the road at a discount.

Until there is a value for stored CO2, this is always

a possibility.

Ultimately, there is no issue as long as the CO2

can be tracked and accounted for.

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TRANSITION TO CCS

• When will EOR finish?

– Many CO2 EOR floods have been running for

30 to 40 years. They will finish when it is no

longer economic to produce oil.

– In the later years, they will not import and

used additional CO2, rather they will recycle

the produced CO2.

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TRANSITION TO CCS

Can CO2 injection (CCS) continue after EOR?

• Probably only in for limited volumes for some

fields.

– The field may be pressurized from the CO2– The field may be pressurized from the CO2

EOR activities.

– There are potential well issues.

– Monitoring may be an issue.

• Other fields may have none of these issues.

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THE WELL ISSUE

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1 mile


DURING 1950-1955, 1 WELLS DRILLEDTOTAL NUMBER OF WELLS IS 1

1 mile

Initial Exploration Period


DURING 1955-1964, 511 WELLS DRILLED,TOTAL NUMBER OF WELLS IS 512

1 mile

Primary Production Period



Water Flooding Period

1 mile



Water Flooding Period (Infill vertical Drilling)

1 mile


DURING1991-2000, 553 WELLS DRILLEDTOTAL NUMBER OF WELLS IS 1427

1 mile

Water Flooding Period (Drilling Horizontal Wells)

1 mile



CO2-EOR Operation Period

1 mile


THE KEY WELL ISSUES

• How to check, maintain and enforce well

integrity at a reasonable cost.

• Potential interference with neighboring

resources with different owners.resources with different owners.

• How to ensure neighboring wells / fields within

the sphere of influence are maintained and

abandoned at the same technical level as in the

CO2 EOR field.

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MONITORING ISSUES

Monitoring is necessary for CCS

• CO2 injected for EOR complicates monitoring

– what is old CO2 and what is new CO2

• The field has existing industrial and residual

chemical signatures. This would complicate

the monitoring signal / process.

• Baseline measurements are probably not

possible (too late).23


CAN THESE ISSUES BE DEALT WITH?

YES! (1)

• Why store rather than re-use?

– A CO2 credit / tax will increase the incentive to

store CO2.

– Accounting regulations need to be established.– Accounting regulations need to be established.

• When will CO2 EOR finish and CCS start?

– Not important as CO2 EOR currently stores CO2.

CCS can start as necessary.

• Are well integrity issues too onerous?

– No. Industry is dealing with them under current

regulations.

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CAN THESE ISSUES BE DEALT WITH?

YES! (2)

• Can we monitor effectively without a baseline?

– More research into monitoring technologies and techniques may have to be undertaken.

– Many “modern fields” are monitoring to maximize production.

• Is interference with neighboring resources (sphere of

influence issues) a deal breaker?

– No. Currently these issues are resolved through regulation.

– Specific regulations will have to be developed for CCS.

• Can CCS be implemented after CO2 EOR?

– This will be dependent on the specific field / reservoir properties.

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DISCUSSION …

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EOR CCS webinar slides - Ernie Perkins - August 2011

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