co2 immiscible gas displacement recovery...dec 09, 2012 · co 2 immiscible gas displacement...
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CO2 Immiscible Gas Displacement Recovery
18th Annual CO2 Flooding
Conference, Midland, Texas
Mark H HoltzMark H HoltzDecember 2012December 2012
Immiscible CO2 Flooding Recovery Mechanisms• Oil Swelling• Viscosity Reduction• 3 Phase Relative Permeability (Kr effects)
– Reduce Sor , and Krw
– Accelerated oil recovery, higher core flood recovery (Olsen et. al., 1992, Dale & Skauge, 2005)
• Oil Film Flow– IFT balance between phases in pores
• Improved Volumetric Sweep EfficiencyModified from Fernandez and Pascual. 2007 Spe # 108031
CO2 Effect On Oil Swelling and Viscosity Reduction• The Greater the CO2 Solubility,
The Greater the Oil Swelling and Viscosity Reduction.
• CO2 Solubility– Decreases with increased temperature,– Increases with increased pressure, – Increases with increased Oil API gravity– Gaseous CO2 is more soluble than liquid
• Oil Swelling Increases So
Simon and Graue, JPT 1/1965 SPE # 917
CO2 Effect On Oil Solubility and Viscosity Reduction
From SPE # 129710, Bui, et al., 2010
MMP
At 50% of MMP Viscosity decrease s by 75%
Immiscible CO2 in Under-Saturated Reservoirs, Milne field Example• Oil Viscosity Reduction
is Found to be The Dominant Mechanism
• 6-9 % OOIP Reserve Growth – Simulation of a reservoir
with Pb = 1,875 psi and Pi=3,500 psi
• Milne Point Field Data Supported Lab and Simulation Results.
Ning & McGuire, 2004, SPE # 89353
Experimental Immiscible CO2 Gas Flooding, Viscosity Reduction
• Experimented On 12.4 API Oil
• CO2 Dissolves Readily in Heavy Oil– 4% volume increase– Six-fold reduction in
viscosity• At low pressures flue
gas (CO2 & N2 ) displaced oil almost as well as pure CO2
Zhang, et al., JCPT 2/2006, Paper 2006-014
290 580 870 psi
Effect of Gas Saturation on Residual Oil Saturation, Stone 1, 3 Phase Kr Model
gtorwor aSSS orS orwSWhere:a gtS
= Residual oil saturation = Sor to waterflood
= coefficient = Trapped gas saturation
Author Wetability “a” CoefficientHolmgren and Morse (1951) Water-wet 0.5Kyte Oil-wet 0Skauge (1996) Water-wet 0.5 to 1.0MacAllister et al. (1993) Water-wet 0.75
MacAllister et al. (1993) Mixed-wet 0.25
MacAllister et al. (1993) Oil-wet 0.04
Wetability effects Sor in the presence of trapped gas
SPE # 62997, Kralik et al., 2000
3 Phase Pore Level Interaction• Initially Gas Only Moves into the Oil Bearing Pores because
– Threshold capillary pressure into water saturated pores is much higher.
• Oil Forms a Continuous Layer between Gas and Water.• Water Relative Permeability is Reduced.• Sweep Efficiency is Increased
From Dong et al., 2001, JCPT
2 Menisci
1 Menisci
Oil film
Gas Oil
Kuparuk River IWAG Example• Gas Saturation Reduces
Water Mobility– Reduces water handling– Increases sweep
efficiency• Mechanism Results in
Lower Residual Oil Saturation
From Ma and Youngren,1994 SPE # 28602
Immiscible CO2 Flooding Recovery Mechanisms• Oil Swelling• Viscosity Reduction• 3 Phase Relative Permeability (Kr effects)
– Reduce Sor, and Krw– Accelerated oil recovery, higher core flood recovery
(Olsen et. al., 1992, Dale & Skauge, 2005)
• Oil Film Flow– IFT balance between phases in pores
• Improved Volumetric Sweep EfficiencyModified from Fernandez and Pascual. 2007 Spe # 108031
Oil Spreading and Film Flow
• Positive Spreading Coefficient is a Function of Interfacial Tension Between Fluids
• The Larger the Spreading Coefficient the lower the Sro .
• High Spreading Coefficient Reduced So by Half.
Maeda and Okats, 2008 SPE 116532
Film flow allows more oil to move out of the pore.
Film Flow Core Test Example
Component Mole %
N2 77.94
CH4 18.91
C2H6 2.24
C3H8 0.91
Core Flood Results
Maeda and Okats, 2008 SPE 116532
S= 31.2
S= 6.2
Low S obtained by adding 1 mole % iso- butanol to brine
CO2 –Water IFT
• CO2- H2 O IFT Decreases Significantly with Increased Pressure
• Temp 78 Degrees F
725 1450 2176 PSIEspinoza and Santamerina, 2009
Polytetrafluroethlene (PTFE)
Deonized H2O, 78 F
CO2 less SolubleCO2 More Soluble
Increased Sweep EfficiencyMobility Ratio “M”
wkM
o
o
w
w
k
k
M
ow
ow
kkM
Immiscible CO2
Immiscible CO2 results in a cumulative effect of reducing the mobility ratio
Immiscible CO2 Flooding Examples• Core Studies• Field Examples
IWAG Core Studies• Immiscible CO2-Methane WAG on Core• Sor Reduced To 13 %• Over 20% Reserve Growth
SPE # 89360, Fernandez, et, al., 2004
Core Flood Experiments Comparing Applications
• Six foot Berea core flooded immiscibly
• IWAG 58% of residual oil recovered
• GAGD, 65% of residual oil recovered
From Rao et al., 2004
Gas Displacement Recovery Immiscible Reserve Growth Applications
• Gas Assisted Gravity Drainage• Immiscible DisplacementGas cap gasOil reservoir IWAG
• Huff n Puff• Pressure Maintenance
– Pressure maintenance condensate and retrograde condensate reservoirs
– oil reservoirs• Mixed Gas ApplicationsDriving agent for slug/bufferMixed gases for density control
Gas Assisted Gravity Drainage (GAGD) Field Examples
• Mauddud Field, Bahrain, GAGD Obtained Reserve Growth from 25% to 41 % of OOIP “16%” increase (Kantzas et al., 1993)
• Oseberg Field, Gas Injection w/o water flood• Coulummes-Vancouriois field, France (Denoyelle et al., 1986)
– N2 after CO2, well in pattern displayed a 4 fold production increase– 14 Mscf/STB Utilization was recorded
• Alberta Pinnacle Reef Floods (Wizard Lake, Westpem Nisku D), Reserve Growth of 15-40% OOIP. (Howes, B. J., 1988)
• West Hackberry, LA, Reported 30% OOIP Reserve Growth• Others include; Weeks Island, Bay St Elaine, Intisar Libia,
Handil, Borneo, Samaria Field Mexico, Cantarell• Hawkins, Tx, Exxon, Greater than 80% Recovery Efficiency
Immiscible Floods and Pilots• Dodan Field, Turkey, Turkish Pet.,
• 60 MMSCF/D ( 1998 production)• Carbonate reservoir, at 1,500 m (4,900 ft) depth• 9- 15 API, 300 -1000 cp
• Lick Creek Field• Ss, Arkansas, after 5 years CO2 injection = 14.1 BSCF & 1 MM STB oil
produced.• 17 API, 160 cp
• Willmington Field pilots• Fault block 3 tar zone• Fault Block 5, 14 API, 180-410 CP demonstrated incremental tertiary oil recovery
• Ritchie Field• Arkansas, CO2 utilization 6.0 Mscf/STB,• 16 API, 195 cp
• Huntington Beach Field• 14 API, 177 cp oil
• Denbury Resources, Mississippi USA• Brage Oil Field, Fensfjord Formation, (Skauge, A., and Berg, E., 1997)
From Ma and Youngren,1994 SPE # 28602
Kuparuk River IWAG Example• Production Results, 10 to 20% OOIP Increase
0
5
10
20
15
25
30
35
40
Summary/Conclusions• Reserve Growth Development is like playing Horse-
shoes, Close Scores You Points!• There are Fundamental Immiscible Displacement
Mechanisms that Produce Reserve Growth in Watered- out Rocks– Oil Swelling– Viscosity Reduction– 3 Phase Relative Permeability (Kr effects)– Improved Volumetric Sweep Efficiency
Summary/Conclusions• Experimental Data Indicates Why Immiscible Gas
Displacement Works– Immiscible Core Studies– Immiscible micro models– Immiscible simulations
• Fluid Characteristics Matter– Interfacial tension between fluids– Under Saturated and Heavy Oil Examples
• Wetability of The Rock Controls the 3• Pilot and Field Applications Have Proven Immiscible
Displacement
Thank You