Learning Objectives Reservoir Rock Properties Fundamentals Saturation and Contacts By the end of this lesson, you will be able to: Describe the concept of fluid contacts Describe how saturations change when crossing contacts 1
Oil-Water Contact Oil Water Contact Gas-Oil Contact Gas Oil Contact DATUM DEPTH OIL Oil Zone Aquifer Gas Cap DATUM DEPTH OIL 2
Gas-Water Contact Gas Water Contact No Contact DATUM DEPTH GAS Gas Zone GAS DATUM DEPTH OIL 3
Super-Critical Fluid LIQUID CRITICAL POINT Pressure Oil Reservoir Temperature VAPOR DATUM DEPTH OIL 4
Oil Zone Sand Grains Oil Connate Water Aquifer Sand Grains Connate Water 5
Gas-Cap Gas Cap Reservoir Sand Grains DATUM DEPTH OIL Gas Connate Water 6
Summary Gas Cap Oil Leg Oil Zone Water Leg Aquifer Gas Zone Please PAUSE pause the video. Learning Objectives Gas-Oil Contact Oil-Water Contact Gas-Water Contact Near Critical Fluids Geologic Time Describe the concept of fluid contacts Describe how saturations change when crossing contacts 7
Learning Objectives Reservoir Rock Properties Fundamentals Wettability By the end of this lesson, you will be able to: Describe wettability Describe interfacial tension Describe how residual oil saturation is controlled by the interplay of different forces 8
Water Wet Sand Grains Oil Connate Water Oil Wet Sand Grains Connate Water Oil 9
Rock Types Disappearing Trail Sandstone Limestone Potential Wettability Changes Diffusion of Mud Components Oxidation Storage Drying Pollution Handling Pollution Temperature and Pressure Drop Drilling Mud Invasion 10
Fatty Acids O HO trans-oleic acid HO O By Edgar181 Own work, Public Domain, https://commons.wikimedia.org/w/index.php?curid=2783717 Wettability Air cis-oleic acid Water Glass Plate Please PAUSE pause the video. 11
Non-Wetting Air Non-Wetting Please PAUSE pause the video. Mercury Glass Plate 12
Neutral Wet Air Surface Tension Surface film Meniscus Molecules Oil Glass Plate Surface molecules pulled toward liquid causes tension in surface Oil Internal molecules pulled in all directions 13
Surface Tension Interfacial Tension Water Oil 14
Effect of Gravity Water Effect of Rock Rock Oil Water Oil 15
Residual Oil Oil Wet Sand Grains Residual Oil Connate Water Residual Oil 16
Summary Oil wet with respect to water Water wet with respect to oil Sandstone wettability at room conditions Limestone wettability at room conditions Residual oil saturation Please PAUSE pause the video. Learning Objectives Fatty acids Naphthenic acids Surface tension Interfacial tension Adhesive forces Buoyancy forces Describe wettability Describe interfacial tension Describe how residual oil saturation is controlled by the interplay of different forces 17
Learning Objectives Reservoir Rock Properties Fundamentals Capillary Pressure By the end of this lesson, you will be able to: Define capillary pressure Explain how capillary pressure is a combination of several related phenomena Describe how capillary pressure can be used to explain macroscopic reservoir phenomena Show how collecting capillary pressure data can actually save money 18
Different Pressures Sand Grains Oil Connate Water Resolution of Forces Water Oil 19
Resisting Movement Water Adhesive Forces Water Oil Oil 20
Meniscus Surface Film Meniscus Molecules Oil Meniscus Surface Film Meniscus Molecules Surface Molecules pulled toward liquid causes tension in surface Internal molecules pulled in all directions Surface Molecules pulled toward liquid causes tension in surface Oil Internal molecules pulled in all directions 21
Unbalanced Forces Water Counter-Balance Water Oil Water 22
Counter-Balance Water Counter-Balance Capillary Pressure Water The pressure in the OIL blob is higher than the pressure in the water on either side. Water = The difference in pressure between two fluids sharing the same pore in equilibrium. Water 23
Counter-Balance The capillary force is a function of the interfacial tension between the oil and the water and the differences in adhesive forces between the oil-rock interface and waterrock interface. Gravity Water Water 24
Capillary Forces Surface tension Angle between interface and pore walls Buoyancy Forces Difference in density between oil and water Distance to the elevation 2 cos 2 cos Radius of the pore Acceleration due to gravity Engineering Oil Water Contact 25
Oil Wet Engineering Oil Water Contact Has to be negative Interfacial Tension Greater than 90 2 cos 2 cos 26
Interfacial Tension Curvature 2 cos 2 cos 27
Curvature Bundle-of-Tubes X Y OIL 2 cos WATER 28
Measurement Bundle-of-Tubes X OIL P C OIL Y 100% S W FREE WATER LEVEL WATER WATER SATURATION 0 100% OIL SATURATION 100% 0 SMALL PORE RADIUS BIG 29
Capillary Pressure Curves Oil Pressure Capillary Pressure Curves Capillary Pressure Water Saturation Water Saturation 30
Threshold Pressure P e Capillary Pressure Threshold Pressure Sand Grains Water Saturation P e Connate Water 31
Irreducible Water Saturation S wi S wi Capillary Pressure Irreducible Water Saturation Sand Grains Water Saturation Oil Connate Water Please PAUSE pause the video. 32
Hysteresis Imbibition Capillary Pressure Residual Oil Saturation S orw Capillary Pressure Drainage Water Saturation S orw Water Saturation 33
Residual Oil Saturation Applications Residual Oil 34
Saturation-Height Capillary Pressure Capillary Pressure How High? Water Saturation Depth Depth Water Saturation OWC (G) Water Saturation OWC (E) Water Saturation 35
Capillary Pressure Curves Please PAUSE pause the video. How Low? P C Kg f /cm 2 150 100 h m 112.5 75.0 30% S W 50 37.5 41 m HIGHEST ELEVATION 100% WATER 0 0 20 40 60 80 WATER SATURATION 0 100% 36
Capillary Pressure Curves Sample Number Porosity (%) Perm. (md) A 21.1 430.0 B 18.8 116.0 C 13.9 13.4 D 12.2 1.2 E 4.6 0.3 Please PAUSE pause the video. Tilted Contacts OWC (G) LOW PERMEABILITY WELL NO. 1 MEDIUM PERMEABILITY WELL NO. 2 HIGH PERMEABILITY WELL NO. 3 P C OR H S W P C OR H S W P C OR H S W OWC (E) 37
Active Aquifers Active Aquifers (A) WATER (B) (C) GAS OIL (A) WATER (B) (C) 38
Summary Active aquifers Tilted oil-water contacts Saturation-height functions Capillary pressure curves Free water level Engineering oil-water contact Geological oil-water contact Buoyancy forces Meniscus Please PAUSE pause the video. Learning Objectives Capillary forces Adhesive forces Interfacial tension Hysteresis Drainage Imbibition Threshold pressure Irreducible water saturation Residual oil saturation Bundle-of-Tubes Define capillary pressure Explain how capillary pressure is a combination of several related phenomena Describe how capillary pressure can be used to explain macroscopic reservoir phenomena Show how collecting capillary pressure data can actually save money 39
Learning Objectives Reservoir Rock Properties Fundamentals Relative Permeability By the end of this lesson, you will be able to: Describe how oil saturation affects the flow of water in the reservoir Describe how water saturation affects the flow of oil in the reservoir Describe how liquid saturation affects the flow of gas in the reservoir Describe how rock properties affect the flow of multiple phases through the reservoir 40
Water not Moving Sand Grains Oil Connate Water Absolute Permeability Sand Grains Oil Connate Water 41
Absolute Permeability Sand Grains Oil Relative Permeability to Oil Oil effective permeability Absolute permeability 42
Increasing Water Saturation Rock Rock Irreducible Water Oil Irreducible Water Rock Residual Oil Saturation Rock Irreducible Water Oil Irreducible Water Moveable Water Oil Moveable Water Irreducible Water Rock Rock Rock Irreducible Water Water Moveable Water Oil Oil Irreducible Water Rock Moveable Water Irreducible Water Rock 43
Oil Behavior 1.0 0.9 Relative Permeability [dimensionless] 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Relative Permeability to Water Water Saturation [no units] kro Water effective permeability Absolute permeability 44
Increasing Water Saturation Rock Irreducible Water Moveable Water Oil Moveable Water Irreducible Water Rock Increasing Water Saturation Rock Irreducible Water Oil Rock Irreducible Water Moveable Water Oil Irreducible Water Rock Moveable Water Irreducible Water Rock 45
Residual Oil Saturation WATER IN Residual Oil Saturation WATER IN Residual Oil WATER OUT WATER OUT Residual Oil 46
Water Behavior 1.0 Relative Permeability [dimensionless] 0.9 k ro 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Water Behavior Relative Permeability [dimensionless] 1.0 0.9 0.8 0.7 0.6 0.5 k ro Water Saturation [no units] krw kro k rw 0.4 0.3 k rw 0.2 0.1 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Water Saturation [no units] krw kro 47
Water Behavior 1.0 Relative Permeability [dimensionless] Aquifer 0.9 k ro 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Sand Grains Water Saturation [no units] krw Practical Maximum Water Relative Permeability kro k rw Connate Water 48
Aquifer Correction 1.0 Relative Permeability [dimensionless] k ro 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Measurement Water Saturation [no units] krw kro k rw 49
Pressures vs. Pressure Drops Presentation Relative Permeability [dimensionless] Where: k ro = Oil relative permeability Δp = Pressure drop in flow direction k rw = Water relative permeability ΔL = Length in flow direction k = Absolute permeability μ o = Oil viscosity A = Cross sectional area perpendicular to flow μ w = Water viscosity Please PAUSE pause the video. Water Saturation [no units] k rw k ro 50
Moderate Permeability RELATIVE PERMEABILITY 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Low Permeability RELATIVE PERMEABILITY k ro 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 WATER SATURATION (%) k ro k air : 440 md k air : 175 md k air : 132 md k rw k air : 440 md k air : 175 md k air : 132 md 0.1 k rw 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 WATER SATURATION (%) 51
Low Permeability 1.0 1.0 0.9 0.8 k ro k air : 440 md k air : 175 md k air : 132 md 0.9 0.8 k ro k air : 440 md k air : 175 md k air : 132 md RELATIVE PERMEABILITY 0.7 0.6 0.5 0.4 0.3 Relative Permeability [dimensionless] 0.2 k rw 0.1 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 WATER SATURATION (%) Please PAUSE pause the video. Water-Wet k ro k rw RELATIVE PERMEABILITY 0.7 0.6 0.5 0.4 0.3 0.2 0.1 k rw 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 WATER SATURATION (%) Water Saturation [no units] 52
Water-Wet vs. Oil-Wet k ro k rw Relative Permeability [dimensionless] Hysteresis k rw Water Saturation [no units] Relative Permeability [dimensionless] k ro Oil Saturation [no units] k ro imbibition k ro drainage k rw Relative Permeability [dimensionless] Water Saturation [no units] 53
Hysteresis Hysteresis Relative Permeability [dimensionless] Relative Permeability [dimensionless] k ro drainage Water Saturation [no units] k ro imbibition k ro drainage Water Saturation [no units] 54
Hysteresis k rw Gas k ro & k rg Relative Permeability [dimensionless] k ro imbibition k ro drainage Water Saturation [no units] k rg k ro 0.93 0.60 S Wirr TOTAL LIQUID SATURATION = (s o + s w ) (%) 55
Three-Phase Relative Permeability Ternary Diagram 56
Vertices 100% Gas 100% Water Sides 100% Gas 0% Oil 0% Water 100% Oil 100% Water 0% Gas 100% Oil 57
Contours k ro 100% Gas 100% Water Three-Phase 0% Oil 0% Water 0.3 0.4 0.5 0% Gas 0.6 0.7 0.8 0.9 100% Oil 58
Three-Phase Applications 59
Relative Permeability Ratios k ro / k rw CURVES FOR WATER-WET ROCKS CEMENTED SANDSTONES, OGLITE LIMESTONES, OR ROCKS WITH REGULAR POROSITY POORLY SORTED UNCONSOLIDATED SANDS WELL SORTED SANDS Water-Oil Ratios k ro /k rw k ro /k rw Where: q w = Oil rate q o = Water rate k ro = Oil relative permeability k rw = Water relative permeability μ o = Oil viscosity μ w = Water viscosity B o = Oil formation volume factor = Water formation volume factor B w WATER SATURATION, % WATER SATURATION, % 60
Saturation-Height Depth [length units] Depth [length units] Water Saturation [no units] WOR-Height k ro /k rw k ro / k rw CURVES FOR WATER-WET ROCKS CEMENTED SANDSTONES, OGLITE LIMESTONES, OR ROCKS WITH REGULAR POROSITY POORLY SORTED UNCONSOLIDATED SANDS WELL SORTED SANDS Water Saturation [no units] WATER SATURATION, % 61
Summary Water-oil ratios Transition zones Rel. perm. ratios Ternary diagrams Gas dominance 3-phase rel. perm. Oil-water rel. perm. Gas-oil rel. perm. Gas-water rel. perm. Irreducible water saturation Please PAUSE pause the video. Learning Objectives Residual oil saturation Hysteresis Oil-wet rel. perm. Water-wet rel. perm. Aquifer adjustments Effect of texture Effect of sorting Effective vs. absolute permeability Describe how oil saturation affects the flow of water in the reservoir Describe how water saturation affects the flow of oil in the reservoir Describe how liquid saturation affects the flow of gas in the reservoir Describe how rock properties affect the flow of multiple phases through the reservoir 62
Learning Objectives Reservoir Rock Properties Fundamentals Laboratory Procedures Relative Permeability By the end of this lesson, you will be able to: Discuss the various choices available for measuring relative permeability in the laboratory 63
Permeability Core Sample Permeability d Diameter x Length 64
Permeability Gas in Darcy s Law δp Gas Out Pressure drop Where: q g = Gas rate k g = Gas effective permeability d = Diameter of core sample = Circle constant (~3.14) p = Pressure drop in flow direction x = Length in flow direction g = Gas viscosity 65
Relative Permeability Relative Permeability Relative Permeability Relative Permeability Steady State Unsteady State Centrifuge Steady State Unsteady State Centrifuge 66
Relative Permeability Core Sample Relative Permeability d Diameter x Length 67
Relative Permeability (Steady State) Oil in Water in Oil in Water in Water in Relative Permeability (Steady State) Oil out Water out δp Pressure drop 68
Relative Permeability (Steady State) Relative Permeability (Steady State) Oil in Water in 1. Wait for steady state 2. Measure the pressure drop 3. Measure the mass 4. Repeat workflow 69
Apparatus STEADY STATE FLOW TECHNIQUE Darcy s Law P OIL IN WATER IN OIL OUT WATER OUT PORCELAIN PLATE Where: q o = Oil rate k o = Oil effective permeability d = Diameter of core sample = Circle constant (~3.14) p = Pressure drop in flow direction x = Length in flow direction o = Oil viscosity 70
Darcy s Law (2 Phase) OIL rate and OIL viscosity WATER rate and WATER viscosity 2 Where: k o = Oil effective permeability k w = Water effective permeability d = Diameter of core sample = Circle constant (~3.14) p = Pressure drop in flow direction x = Length in flow direction o = Oil viscosity w = Water viscosity Effective Permeabilities Run k o K w No. [md] [md] 1 150 0 2 97 3 3 56 8 4 39 19 5 19 35 6 8 58 7 2 84 2 Please PAUSE pause the video. 71
Relative Permeability to Oil Relative Permeabilities Run k o K w No. [md] [md] 1 150 0 2 97 3 3 56 8 4 39 19 5 19 35 6 8 58 7 2 84 0 0 161 72
Relative Permeability to Water Relative Permeabilities Run k o K w K ro k rw No. [md] [md] [ ] [] 1 150 0 0.932 0.000 2 97 3 0.602 0.019 3 56 8 0.348 0.050 4 39 19 0.242 0.118 5 19 35 0.118 0.217 6 8 58 0.050 0.360 7 2 84 0.012 0.522 0 0 161 0.000 1.000 Please PAUSE pause the video. 73
Saturations Saturations Mass of saturated core sample Mass of oil in saturated core sample 74
Saturations Saturations Mass of water in saturated core sample Mass of rock (solid material) in saturated core sample 75
Saturations Where: m s = Mass of saturated core sample m o = Mass of oil in saturated core sample m w = Mass of water in saturated core sample m r = Mass of rock (solid material) in saturated core sample o = Oil density = Water density w 1 2 Please PAUSE pause the video. Saturations 1 2 r s w = Rock (solid material) density = Core sample water saturation φ = Core sample porosity d = Diameter of core sample x = Length in flow direction π = Circle constant (~3.14) 1 2 Please PAUSE pause the video. 76
Saturations 1 2 1 1 2 Please PAUSE pause the video. Saturations 1 2 Run k o K w K rw m s No. [md] [md] [ ] [g] 1 150 0 0.000 2.601 2 97 3 0.019 2.605 3 56 8 0.050 2.609 4 39 19 0.118 2.614 5 19 35 0.217 2.618 6 8 58 0.360 2.623 7 2 84 0.522 2.627 0 0 161 1.000 2.636 77
Saturations Run k o K w K ro k rw m s o 0.850 [g/cc] No. [md] [md] [ ] [] [g] w 1.000 [g/cc] 1 150 0 0.932 0.000 2.601 r 2.650 [g/cc] 2 97 3 0.602 0.019 2.605 0.250 [ ] 3 56 8 0.348 0.050 2.609 d 1.000 [cm] 4 39 19 0.242 0.118 2.614 x 1.500 [cm] 5 19 35 0.118 0.217 2.618 6 8 58 0.050 0.360 2.623 7 2 84 0.012 0.522 2.627 0 0 161 0.000 1.000 2.636 Complete Table Run k o K w K ro k rw m s o 0.850 [g/cc] s w No. [md] [md] [ ] [ ] [g] w 1.000 [g/cc] [ ] 1 150 0 0.932 0.000 2.601 r 2.650 [g/cc] 0.200 2 97 3 0.602 0.019 2.605 0.250 [ ] 0.300 3 56 8 0.348 0.050 2.609 d 1.000 [cm] 0.400 4 39 19 0.242 0.118 2.614 x 1.500 [cm] 0.500 5 19 35 0.118 0.217 2.618 0.600 6 8 58 0.050 0.360 2.623 0.700 7 2 84 0.012 0.522 2.627 0.800 0 0 161 0.000 1.000 2.636 1.000 78
Normalization Normalized Run k o K w K ro k rw m s o 0.850 [g/cc] s w k ro k rw No. [md] [md] [ ] [] [g] w 1.000 [g/cc] [ ] [] [ ] 1 150 0 0.932 0.000 2.601 r 2.650 [g/cc] 0.200 1.000 0.000 2 97 3 0.602 0.019 2.605 0.250 [ ] 0.300 0.647 0.020 3 56 8 0.348 0.050 2.609 d 1.000 [cm] 0.400 0.373 0.053 4 39 19 0.242 0.118 2.614 x 1.500 [cm] 0.500 0.260 0.127 5 19 35 0.118 0.217 2.618 0.600 0.127 0.233 6 8 58 0.050 0.360 2.623 0.700 0.053 0.387 7 2 84 0.012 0.522 2.627 0.800 0.013 0.560 0 0 161 0.000 1.000 2.636 1.000 0.000 1.073 Plot Please PAUSE pause the video. Relative Permeability [ ] k ro k rw Water Saturation [ ] 79
Relative Permeability Relative Permeability Relative Permeability (Steady State) Oil in Steady State Unsteady State Centrifuge Oil in Water in δp Pressure drop 80
Relative Permeability Relative Permeability Relative Permeability (Centrifuge) HEAVIER FLUID GRADUATED TUBE CENTRIFUGE SYSTEM CORE SAMPLE Steady State Unsteady State Centrifuge LIGHTER FLUID AXIS OF ROTATION 81
Relative Permeability Relative Permeability Measures capillary pressure concurrently with relative permeability Relative Permeability Relative Permeability More math 1 fluid injecteded Steady State Unsteady State Centrifuge Steady State Unsteady State Centrifuge 82
Summary Absolute permeability measurement Steady state relative permeability measurement Unsteady state relative permeability measurement using a permeameter Unsteady state relative permeability measurement using a centrifuge Please PAUSE pause the video. Back to Work Suggestion Search for as many relative permeability tests as you can find in your well files that apply to your reservoir Compare them to the capillary pressure tests Are they consistent? 83
Learning Objectives Discuss the various choices available for measuring relative permeability in the laboratory 84
Learning Objectives Reservoir Rock Properties Fundamentals Laboratory Procedures Capillary Pressure By the end of this lesson, you will be able to: Discuss the various choices available for measuring capillary pressure in the laboratory 85
Capillary Pressure Capillary Pressure Mercury Injection Porous Plate Centrifuge Mercury Injection Porous Plate Centrifuge 86
Mercury Injection Apparatus N 2 Bottle 250kg Hg In Pc Hg mano Hg Windows Sample Volumetric mercury pump 87
Air Injection Capillary Pressure Air In Mercury Injection Porous Plate Centrifuge H 2 O Out 88
Apparatus Capillary Pressure Mercury Injection Porous Plate Centrifuge 89
Water Expulsion Water Out Apparatus CENTRIFUGE SYSTEM LIGHTER FLUID HEAVIER FLUID GRADUATED TUBE CORE SAMPLE Oil In AXIS OF ROTATION 90
Comparison Comparison Capillary Pressure Mercury Injection Porous Plate Centrifuge Method Wetting Phase Non-Wetting Phase Mercury Injection Air Mercury Porous Plate Water Air Centrifuge Water Oil 91
Conversion Conversion Where: Pc res = Capillary pressure reservoir conditions Pc lab = Capillary pressure laboratory conditions Where: Pc res = Pc lab = res = lab = res = lab = Capillary pressure reservoir conditions Capillary pressure laboratory conditions Interfacial tension reservoir conditions Interfacial tension laboratory conditions Contact angle reservoir conditions Contact angle laboratory conditions 92
Summary Mercury Injection Porous Plate Centrifuge Corrections Back to Work Suggestion Search for as many capillary pressure tests as you can find in your well files Compare them against each other Compare them to the relative permeability data Are they consistent? 93
Learning Objectives Discuss the various choices available for measuring capillary pressure in the laboratory 94
Learning Objectives Reservoir Rock Properties Fundamentals Laboratory Procedures Wettability By the end of this lesson, you will be able to: Discuss the various choices available for measuring wettability in the laboratory 95
Wettability Wettability Contact Angle Amott Contact Angle Amott USBM USBM 96
Step 1 Water Step 2 Solid Rock Water Solid Rock 97
Step 2 Water Step 3 Solid Rock Water Oil Oil Solid Rock 98
Contact Angle Water Solid Rock Interpretation Old School Oil Contact Angle <90 Contact Angle >90 Water Wet Oil Wet 99
Wikipedia Please PAUSE the video. Wikipedia Please PAUSE the video. 100
Interpretation Contact Angle < 60 Water Wet New School 60 < Contact Angle < 120 Old School Contact Angle < 90 o Contact Angle >90 o Interpretation Water Wet Oil Wet New School Contact Angle > 120 Contact Angle < 60 Neutral Wet Oil Wet Water Wet 60 < Contact Neutral Neutral Wet Angle < 120 Wet Contact Angle < 90 o Water Wet Old School Contact Angle >90 o Oil Mixed Wet? Contact Angle > 120 Oil Wet 101
1. Cloudy Water 2. Porous Rock Wikipedia 1. If produced water is cloudy: Change wavelength of the light to one not scattered by suspended solids in the water Filter the water 2. If rock sample is porous and permeable Non-porous rock samples are used Wikipedia 102
Contact Angle Wettability Amott USBM Step 1 103
Step 2 Oil Step 3 Displaced Water (Spontaneous) V 2 Displaced Water (Forced) V 3 104
Step 4 Displaced Oil (Spontaneous) V 4 Step 5 Displaced Oil (Forced) V 5 105
Calculations Oil Index Calculations Where: I o = Oil Index V 2 = Oil spontaneously entering core V 3 = Oil entering core under force 106
Calculations Oil Index Calculations Oil Index Water Index Where: I o = Oil Index V 2 = Oil spontaneously entering core V 3 = Oil entering core under force I w = Water Index V 4 = Water spontaneously entering core V 5 = Water entering core under force 107
Calculations Oil Index Variations Water Index Amott-Harvey Index Step 1 Where: I A = Amott Index I w = Water Index I o = Oil Index Start Step 2 Step 3 Step 1 Step 3 Start Step 4 Step 4 Step 5 Step 5 Step 2 End Step 3 End 108
Example 0.45 0.4 0.35 Jadhunandan and Morrow, 1991 Owolabi and Watson, 1993 Chen et al, 2004 S or 0.3 0.25 0.2 0.15 0.1 0.05 From Anderson, 2006 0-1 -0.75-0.5-0.25 0 0.25 0.5 0.75 1 I A w Totally Oil Wet Totally Water Wet Water Wet (left) vs. Oil Wet (right) 109
Summary Contact Angle Neutral Wet Mixed Wet Amott Spontaneous vs. Forced Oil vs. Water Index Amott-Harvey Residual Oil Saturation Relative Permeability Please PAUSE pause the video. Back to Work Suggestion Search for as many wettability tests on your reservoir as you can find Is the data consistent? If not, how do you explain the inconsistencies? How are you going to resolve the inconsistencies? 110
Learning Objectives Discuss the various choices available for measuring wettability in the laboratory 111
Learning Objectives Reservoir Rock Properties Fundamentals Modeling By the end of this lesson, you will be able to: Show how reservoir engineers model relative permeability Show how reservoir engineers model capillary pressure 112
Relative Permeability Water Relative Permeability Modified-Corey Equation 113
Water Relative Permeability 2-phase water relative permeability end-point 2-phase water saturation exponent Relative Permeability [ ] Water Relative Permeability Relative Permeability [ ] k rw Water Saturation [ ] k rw Water Saturation [ ] 114
Water Relative Permeability Relative Permeability [ ] Normalized water saturation Critical water saturation Oil Relative Permeability k ro Relative Permeability [ ] k rw Water Saturation [ ] Water Saturation [ ] 115
Oil & Water k ro Relative Permeability [ ] End Point Changes Water Saturation [ ] Relative Permeability [ ] k rw k ro k rw Water Saturation [ ] 116
End Point Changes k ro End Point Changes Relative Permeability [ ] Relative Permeability [ ] Water Saturation [ ] k rw k ro k rw Water Saturation [ ] 117
Exponent Changes k ro Exponent Changes Relative Permeability [ ] Relative Permeability [ ] k rw Water Saturation [ ] k ro k rw Water Saturation [ ] 118
Exponent Changes k ro Relative Permeability [ ] 3-Phase Relative Permeability Oil Water Water Saturation [ ] Gas Oil k rw 119
3-Phase Relative Permeability Stone Where: k ro = 2-phase oil relative permeability k rw = 2-phase water relative permeability k row = 2-phase oil relative permeability from oil-water table k rog = 2-phase oil relative permeability from gas-oil table k rg = 2-phase gas relative permeability Please PAUSE pause the video. 3-Phase Relative Permeability Stone @ S w @ S g @ S w @ S g Where: k ro = 2-phase oil relative permeability k rw = 2-phase water relative permeability k row = 2-phase oil relative permeability from oil-water table k rog = 2-phase oil relative permeability from gas-oil table k rg = 2-phase gas relative permeability 120
Thomeer Capillary Pressure Water Saturation Interporosity Coefficient Capillary Pressure Threshold Pressure Where: P c = Capillary pressure S w = Water saturation G = Interporosity coefficient P d = Threshold pressure 121
Thomeer P c Fit The original version of this equation used bulk volumes instead of saturations. The results are equivalent, so we ll keep things simple by using saturations. Thomeer (68,948) (6,895) (689) Fit to Data Where: P c = Capillary pressure S w = Water saturation G = Interporosity coefficient P d = Threshold pressure P c Fit Capillary Pressure [psi] (kpa) (69) Oil Saturation [ ] 122
Thomeer (68,948) Threshold Pressure Where: P c = Capillary pressure S w = Water saturation G = Interporosity coefficient P d = Threshold pressure Thomeer Where: P c = Capillary pressure S w = Water saturation G = Interporosity coefficient P d = Threshold pressure (6,895) (689) (69) (68,948) P c Fit P d P c Fit Oil Saturation [ ] Infinite Pressure (6,895) (689) Capillary Pressure [psi] (kpa) Capillary Pressure [psi] (kpa) (69) Oil Saturation [ ] 123
Thomeer (68,948) Raw Data P c Fit Where: P c = Capillary pressure S w = Water saturation G = Interporosity coefficient P d = Threshold pressure Thomeer Where: P c = Capillary pressure S w = Water saturation G = Interporosity coefficient P d = Threshold pressure (6,895) (689) (69) (68,948) Oil Saturation [ ] P c Raw Increase Threshold Pressure P c Fit (6,895) (689) Capillary Pressure [psi] (kpa) Capillary Pressure [psi] (kpa) (69) Oil Saturation [ ] P c Raw 124
Thomeer (68,948) Restore Threshold Pressure P c Fit Where: P c = Capillary pressure S w = Water saturation G = Interporosity coefficient P d = Threshold pressure Thomeer Where: P c = Capillary pressure S w = Water saturation G = Interporosity coefficient P d = Threshold pressure (6,895) (689) (69) (68,948) P c Fit Oil Saturation [ ] Increase G-Factor (6,895) (689) P c Raw Capillary Pressure [psi] (kpa) Capillary Pressure [psi] (kpa) (69) Oil Saturation [ ] P c Raw 125
Thomeer (68,948) Restore G-Factor P c Fit Where: P c = Capillary pressure S w = Water saturation G = Interporosity coefficient P d = Threshold pressure (6,895) (689) (69) Please PAUSE pause the video. Summary Threshold pressure Interporosity coefficient Saturation exponent Relative permeability endpoint Normalized saturation Thomeer Corey Oil Saturation [ ] P c Raw Capillary Pressure [psi] (kpa) Please PAUSE pause the video. 126
Back to Work Suggestion Learning Objectives Build a relative permeability and capillary pressure model for your reservoir using correlations How does it compare with the laboratory data? If you have no laboratory data for your reservoir, how do you decide what parameters to use? Show how reservoir engineers model relative permeability Show how reservoir engineers model capillary pressure 127
Learning Objectives Reservoir Rock Properties Fundamentals Saturations By the end of this lesson, you will be able to: Describe how reservoir engineers define saturations 128
Water Saturation Relative Permeability [dimensionless] 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Irreducible water saturation Initial water saturation Critical Connate water saturation Critical water saturation 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Water Saturation [no units] krw kro 129
1.0 Relative Permeability [dimensionless] 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 Sand Grains Water Saturation [no units] krw Oil kro Irreducible Connate Water 130
Sand Grains Connate Water Water Saturation Initial water saturation Connate water saturation Irreducible water saturation Critical water saturation 131
Oil Saturation Oil Saturation Where: S o = Oil saturation = Residual oil saturation 132
Oil Saturation Residual oil saturation to water Water Displacing Oil Water In Residual oil saturation to gas Water Out Residual Oil 133
Gas Displacing Oil Sand Grains Residual Oil Connate Water Gas Out Gas In Gas Saturation 134
Gas Saturation Where: = Gas saturation S g Gas Saturations Residual gas saturation Critical Critical gas saturation Where: S g = Gas saturation Residual 135
Summary S w S wi S or S orw S wc S wirr S wcr S o Please PAUSE pause the video as needed. Learning Objectives S org S g S gc S gr Describe how reservoir engineers define saturations 136
PetroAcademy TM Applied Reservoir Engineering Skill Modules Properties Analysis Management This is Reservoir Engineering Core Reservoir Rock Properties Core Reservoir Rock Rock Properties Fundamentals Reservoir Fluid Core Reservoir Fluid Fundamentals Reservoir Flow Properties Core Reservoir Flow Properties Fundamentals Reservoir Fluid Displacement Core Reservoir Fluid Displacement Fundamentals Reservoir Material Balance Core Reservoir Material Balance Fundamentals Decline Curve Analysis and Empirical Approaches Core Decline Curve Analysis and Empirical Approaches Fundamentals Pressure Transient Analysis Core Rate Transient Analysis Core Enhanced Oil Recovery Core Enhanced Oil Recovery Fundamentals Reservoir Simulation Core Reserves and Resources Core Reservoir Surveillance Core Reservoir Surveillance Fundamentals Reservoir Management Core Reservoir Management Fundamentals 137