Transcript Foam in Fracture Systems

Foam Enhancement of
sweep in Fracture System
Wei Yan
George J. Hirasaki
Clarence A. Miller
Chemical Engineering Department,
Rice University
Objective
•
Study the diversion of liquid in
heterogeneous fracture network with foam
Foam flow in fractures experiment setup
Transducer
Surfactant solution
HP digital camera
Syringe pump
Frit
Fracture model
Air
Foam generator
Air mass flow controller
Computer for
recording pressure
difference
Experiment conditions
Surfactant: 0.5% C13-4PO+0.5% CS330
 Salinity: 0.23% NaCl, 0.07% CaCl2, 0.04%
MgCl2
 Aperture: 0.1mm, 0.2mm, 0.1 mm/0.2 mm
(1:2), 0.05 mm/0.15 mm (1:3)
 Fractional gas flow: 0~0.9
 Bubble diameter: 0.4 mm, 0.6 mm

Mechanisms affecting apparent
viscosity in fracture system
Homogeneous parallel plates model
Variable thickness
12 inch
14 inch
6 inch
8 inch
Effect of flow rate and gas fractional flow on apparent viscosity
100.0
Apparent viscosity (cp)
aperture = 0.2 mm,mean bubble size DB= 0.6 mm
10.0
fg=0.67
fg=0.67 from theory
fg=0.5
fg=0.5 from theory
fg=0.33
fg=0.33 from theory
fg=0.2
fg=0.2 from theory
fg=0.0
fg=0.0 from theory
1.0
Re=0.5
0.1
0.001
Re=30
0.010
0.100
Flow velocity (m/s)
1.000
Water front at different Reynold’s number
Re=0.5
Re=30
Effect of bubble size on apparent viscosity
0.5% C13-4PO+0.5% CS330,
0.23% NaCl, 0.07% CaCl2, 0.04% MgCl2,
gas fractional flow = 0.67, aperture = 0.2 mm
Apparent viscosity
(cp)
100.0
10.0
flow velocity=2.2 cm/s
flow velocity=2.2 cm/s from
theory
1.0
0.1
0.1
1.0
Mean bubble size (mm)
10.0
Heterogeneous parallel plates model
Variable thickness
0.1 mm
12 inch
14 inch
10 inch
6 inch
8 inch


Foam has higher apparent viscosity at larger thickness
Match of apparent viscosity from theory and measurement
aperture = 0.05mm/0.15mm,D B=0.4mm,
Re = 0.22
100
Apparent viscosity (cp)
0.05mm aperture from measurement
0.05mm aperture from theory
0.15mm aperture from measurement
0.15mm aperture from theory
0.15 mm thickness
10
0.05 mm thickness
1
0
0.2
0.4
0.6
Gas Fractional Flow
0.8
1

Foam improves sweep of fractured system
 Less liquid is needed to sweep system with foam
Aperture = 0.05 mm / 0.15 mm, Re = 0.22, D B = 0.4 mm
fg=0.0
0.41PV
0.82 PV
1.23PV
1.64 PV
0.08 LPV
0.12 LPV
0.16 LPV
2.05 PV
6.56 PV
0.21 LPV
0.66 LPV
fg=0.9
0.04 LPV
LPV – Liquid Pore volume
Surfactant solution to sweep entire heterogeneous
fracture at different aperture ratio in total pore volume
DB=0.4mm, Re=0.22
10.0
Total Pore Volume
1:3
1.0
1:2
0.1
0.0
0.2
0.4
0.6
Gas Fractional Flow
0.8
1.0
Surfactant solution to sweep entire heterogeneous
fracture at different aperture ratio in liquid pore volume
DB=0.4mm, Re=0.22
Liquid Pore Volume
10.0
1:3
1.0
1:2
0.1
0.0
0.2
0.4
0.6
Gas Fractional Flow
0.8
1.0
The model to describe flow in
heterogeneous parallel plates
Dykstra-Parsons Model
Impermeable
P1
P3
P2
P4
P1=P2
P3=P4
Injection to breakthrough in wide and narrow aperture
Total Pore Volume
10.0
DB=0.4mm, Re=0.22
aperture 0.05mm/0.15mm
Dykstra-Parsons model
1.0
0.05mm aperture from experiment
0.05mm aperture from theory
0.15mm aperture from experiment
0.15mm aperture from theory
0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
Gas Fractional Flow
0.7
0.8
0.9
1.0
Calculation of sweep efficiency in
fracture network
Fracture apertures are with log-normal
distribution
 No crossflow
 Pressure difference is equal for each
layer
 Gas fractional flow is equal in each
layer

Calculation of foam/water sweep in heterogeneous
fractures with log-normal distribution apertures
Set bubble diameter=0.1mm
Simulation of foam/water sweep in heterogeneous
fractures with log-normal distribution apertures
Set bubble diameter=0.1mm
Conclusions

The foam apparent viscosity in heterogeneous
fracture is from two contributions-bubble
deformation and liquid slugs between bubbles.
The measurement corresponds to the theory.
 Gas fractional flow and fracture thickness ratio
can greatly affect the sweep efficiency.
 Foam can greatly improve the sweep efficiency
in heterogeneous fracture.
 Dykstra-Parsons model can be applied to
simulate the transient state foam flow in
heterogeneous fractures
Future work
Test surfactants’ ability to generate foam
in alkaline-surfactant EOR process
 Study the foam stability with the presence
of oil
