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Wettability Alteration and Foam Mobility Control in a Layered 2-D Heterogeneous System. SPE 141462 Presented 2011 Rice Consortium on Processes in Porous Media 2011 International Symposium on Oilfield Chemistry
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Wettability Alteration and Foam Mobility Control in a Layered 2-D Heterogeneous System SPE 141462 Presented 2011 Rice Consortium on Processes in Porous Media 2011 International Symposium on Oilfield Chemistry Robert F. Li, George J. Hirasaki, and Clarence A. Miller, SPE, Rice University; and Shehadeh, K. Masalmeh, SPE, Shell Technology Oman April 2011
Outline • Introduction • Wettability Alteration and Gravity Drainage in a Layered Heterogeneous 2-D System • Foam Stability in Presence of Crude Oil • Foam Mobility Control in a Layered Heterogeneous System • Conclusions
Introduction Focus/Problem to Be Solved • Injected Water Bypass • High Remaining Oil Saturation in the Tight Layer • Heterogeneity – 19:1 Permeability Contrast • Rock Wettability – Oil-Wet Solutions • Wettability Alteration • Foam Mobility Control
Wettability Alteration and Gravity Drainage in an Oil-Wet 2-D System
Silica Surface Treatment with CTAB ½ CMC CTAB (hexadecyltrimethylammonium bromide) was used for wettability alteration Contact Angle Measurement Zeta Potential Conductivity 2.37~2.46 mS/cm, 1% wt solid in 0.02 mol/L NaCl.
Wettability Alteration and Gravity Drainage in a CTAB-Treated Oil-Wet 2-D System Waterflood, 2% NaCl, 5 ft/D (~0.1 psi), Cumulative Recovery: 49.1% original oil-in-place (OOIP) 4.0 PV (Pore Volume) Most oil in the lower layer was retained by capillary pressure (oil-wet) Alkaline/Surfactant flood, 0.2% NI, 2% NaCl, 1% Na2CO3, 1ft/D 0.5 PV NI is a blend of 4:1 (wt/wt) Neodol 67-7PO blending with internal olefin sulfonate IOS 15-18 Shut in at 0.5 PV
Gravity and Capillary Pressure Driven Counter-Current Flow Day 0 tDg Real tD,Pc Real 0 0 Day 3 53 0.5 Day 6 107 1.0 Day 10 178 1.6 Day 42 748 6.7 Dimensionless Time for Gravity Drainage Dimensionless Time for Capillary Pressure Richardson, J.G. et al., JPT 1971; Trans., AIME, 251. Ma, S., et al., J. Pet. Sci. & Eng. 18 (1997) 165-178.
Recovery as a Function of Dimensionless Times Aronofsky, J.S..et al., Trans. AIME 213,1958
Foamflood 0 TPV 0.2 TPV, IOS 15-18 0.7 TPV, IOS 15-18 1.0 TPV, Air
Foam Stability in the Presence of Crude OilAdding Lauryl Betaine as a Foam Booster
NI, IOS15-18 in Foam Drive 142 darcy; constant pressure ~1.2 psi/ft; 1% Na2CO3, 2% NaCl; 0.2% NI no polymer; 0.5% IOS15-18 in foam drive NI Air NI Air NI Air IOS Air IOS Air IOS Air IOS Air IOS Air IOS Total PV 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Liquid PV 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9
Qualitative Foam Stability Test with NIB-Blends Without Oil With SME Crude, WOR=1 NI only 5:1 NI:B 1:1 NI:B 1:2 NI:B 1:3 NI:B NI only 5:1 NI:B 1:1 NI:B 1:2 NI:B 1:3 NI:B All vials contain 0.5% LaurylBetaine (except NI only),1% Na2CO3 and 3.5% NaCl
NIB (1:2 NI:B), and IB (10:1 IOS:B) in Foam Drive 193 darcy; 1% Na2CO3, 3.5% NaCl; 0.25% NI, 0.5% lauryl betaine; 0.5% IOS15-18 and 0.05% lauryl betaine in foam drive NIB NIB Air NIB Air IB Air IB Air IB Air IB Air IB Air IB Air TPV 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Liquid PV 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 5ft/D SAG, fg=0.5, injection under constant pressure gradient ~1.4 psi/ft Effluent
NIB alone in Achieving Both Low IFT and Foam Mobility Control NIB and AOS was injected at 20 ft/D with fg=2/3; Black curve with NI foam was injected at 0.5 psi/ft with fg=0.5.
NIB (1:2 NI:B) Only 174 darcy; 1% Na2CO3, 3.5% NaCl; 0.25% NI, 0.5% lauryl betaine NIB NIB Air NIB Air NIB Air NIB Air NIB Air [1] Trapping Number 0-0.2 TPV, low-rate NIB, / >3 [2] Gravity Number TPV 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 Liquid PV 0.1 0.3 0.4 0.5 0.6 5ft/D SAG, fg=0.5, constant pressure gradient ~1.4 psi/ft 0-0.2 TPV, low-rate NIB, Ng= 7.0 >>1 0.3 TPV, high-rate Air, Ng= 0.09 <<1 0.4 TPV, high-rate NIB, Ng= 0.10 <<1 Effluent Cumulative Recovery: 97% from Residual Oil [1] Pope, G.A., et al., SPE Reservoir Eval. and Eng. 2000 3(2) 171-178 [2] Hirasaki, G. J., SPEJ , 1975, 39-50
NIB (1:2 NI:B) Only in Secondary Recovery 164 darcy; 1% Na2CO3, 3.5% NaCl; 0.25% NI, 0.5% lauryl betaine NIB NIB Air NIB Air NIB Air NIB Air NIB Air NIB Air NIB … TPV 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.8 Liquid PV 0.1 0.3 0.4 0.5 0.6 0.7 0.8 1.0 5ft/D SAG, fg=0.5, constant pressure gradient ~2.8 psi/ft Effluent Cumulative Recovery 99.6% of Residual Oil
AOS16-18 Only in Secondary Recovery 0.7 PV 0 PV 1.4 PV 156 darcy; 1% Na2CO3, 2% NaCl; 0.5% AOS16-18 (alpha olefin sulfonate) 1.7 PV 0.3 PV 1.0 PV 1.9 PV 0.6 PV 1.3 PV • Early gas break-through leading to poor sweep • Cumulative Recovery 69% OOIP – worse than waterflood
Foam in Presence of SME Oil in the Micro Model NIwithout Betaine NI with Betaine • Weak Foam Mobility M k / μ • Continuous gas channels – increased gas relative permeability • No lamellae – reduced apparent viscosity • Strong Foam Mobility M k / μ • Trapped gas bubbles – reduced gas relative permeability • Lamellae and bubble trains – increased apparent viscosity • Possible pseudo-emulsion films – keeping oil drops from entering gas/water surface • Weak Foam Mobility M k / μ • Continuous gas channels – increased gas relative permeability • No lamellae – reduced apparent viscosity
Foam Mobility Control in an Oil-Wet Layered System 34:1 permeability ratio between upper and lower layers 0 PV 0.1 PV 0.2 PV 0.3 PV 0.4 PV 0.5 PV 1.0 PV Untreated, Water-Wet, waterflood CTAB-Treated, Oil-Wet, waterflood • In the oil-wet sandpack, capillary pressure retained most oil in the lower tight layer. • In the water-wet sandpack, spontaneous imbibition displaced most oil from lower layer.
Foam EOR in a Layered Oil-Wet Heterogeneous System Oil-Wet; Permeability Ratio 34:1 CTAB-Treated Oil-Wet Silica, NIB, SAG, fg=1/3 1% Na2CO3, 3.5% NaCl; 0.25% NI, 0.5% lauryl betaine Waterflood remaining condition 1.0 PV 2.0 PV 3.5 PV • Remaining Sor_w= 61.5% • Recovered by Foam: 88.7% of waterflood remaining oil
Conclusions • In an oil-wet 2-D heterogeneous sandpack with 19:1 permeability contrast, waterflood recovered only 49.1% OOIP. After NI was injected gravity- and capillary pressure-driven, vertical, counter-current flow occurred during a 42-day system shut-in. This and a subsequent foamflood recovered 89.4% of the waterflood remaining oil. Overall recovery (waterflood+ASF) was 94.6% OOIP. • NI alone is not a good foaming agent. The addition of lauryl betaine made NIB (NI:B=1:2) a strong foaming agent with and without SME crude oil, and a good IFT reducing agent. • In an oil-wet, layered sandpack with 34:1 permeability contrast, NIB foam was able to mobilize and recover remaining oil from the lower, low-permeability layer.
Acknowledgment • The financial support of Shell International E&P B.V. is gratefully acknowledged. • Shell is also acknowledged for donation of the 2-D sandpack and the glass micro model.
2-D CTAB-Treated Silica SandpackOilfloodArrows show locations of injection ports 0.1 PV 0.5PV 1.0PV 16.6PV • Injection rate: 5 ft/D. Soi=62.4%
Movie… Day 2 Day 3 Day 4 Day 5 Day 6 Day 7 Day 8 Day 1 Day 9 Day 11 Day 12 Day 13 Day 14 Day 15 Day 16 Day 17 Day 10 Day 18 Day 19 Day 20 Day 22 Day 23 Day 24 Day 25 Day 26 Day 27 Day 28 Day 21 Day 29 Day 31 Day 32 Day 33 Day 34 Day 36 Day 37 Day 38 Day 30 Day 42 Day 0
Movie of Foamflood… 0.1 TPV, IOS 0.2 TPV, IOS 0.3 TPV, Air 0.4 TPV, IOS 0.5 TPV, IOS 0.6 TPV, Air 0.7 TPV, IOS 0.8 TPV, IOS 0.9 TPV, Air 1.0 TPV, IOS 1.1 TPV, IOS 1.2 TPV, Air 1.3 TPV, IOS 1.4 TPV, IOS 1.5 TPV, Air 1.6 TPV, IOS 1.7 TPV, IOS 1.8 TPV, Air 1.9 TPV, IOS 2.0 TPV, IOS 2.1 TPV, Air 2.2 TPV, IOS 2.3 TPV, IOS 2.4 TPV, Air 2.5 TPV, IOS 2.6 TPV, IOS 2.7 TPV, Air 2.8 TPV, IOS 2.9 TPV, IOS 3.0 TPV, Air 0.0 TPV
Effluent from Foamflood 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 TPV IOS IOS Air IOS IOS Air IOS IOS Air IOS 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 TPV IOS Air IOS IOS Air IOS IOS Air IOS IOS 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 TPV Air IOS IOS Air IOS IOS Air IOS IOS Air
Foam Apparent Viscosity Low, because of oil breaking foam
Introduction of Foam Flow in Porous Media Gas injected into 0.5% IOS15-18 1 mm
Viscosity with IOS15-18 and LaurylBetaine Blendsin 1% Na2CO3 and 3.5% NaCl 10:1 AOS:B was picked because it had highest viscosity as a clear single phase solution
NIB (1:2 NI:B) Only Cumulative Recovery: 97% from Residual Oil
NIB (1:2 NI:B) Only in Secondary Recovery Cumulative Recovery 99.6% from Residual Oil
NIB (1:2 NI:B) Only in Secondary Recovery Foam was not as strong as NIB in the tertiary recovery process due to higher initial oil saturation
Untreated Silica, NIB, SAG, fg=1/3 Overall 88 darcy; Permeability ratio 36:1; 1% Na2CO3, 3.5% NaCl; 0.25% NI, 0.5% laurylbetaine 0.1 PV 0.5 PV 1.0 PV 1.5 PV