1. Emulsion Deposition in Porous Media : Impact on Well Injectivity
S. Buret, L. Nabzar, IFP - Rueil-Malmaison, France
A. Jada, ICSI - Mulhouse, France

2. Frame of work Oilfield applications Enhanced oil recovery (EOR)
ASP or emulsion flooding
PWRI operations
Conformance... 2
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

3. Aim of the work Industrial viewpoint Frame of work
Better understanding of emulsion behavior in porous media
Deposition behavior
Industrial viewpoint
Residual emulsion management (PWRI)
Real impact on well injectivity? 3
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

4. Theoretical background
Rule of thumb
Jamming ratio Jr : pore to particle size ratio
In-depth invasion for Jr>3
RSA theory
Random Sequential Adsorption
Deposition of suspension of hard spheres (opposite charges)
Maximal surface coverage θ=54%
with 0,8<x<1 4
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

5. Experimental parameters
Unconsolidated sandpacks
Sharp-edged grains of SiC
Average diameter : 80 µm
Average porosity : 40%
Average permeability : 2.4 µm²
Direct (O/W) emulsions
Dodecane in brine of various salinities
Average diameter of droplets : 0.35 µm
Jr>40 5
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

6. Deposition mechanisms
Objectives
Deposition mechanisms
physico-chemical aspects : salinity
hydrodynamic aspects : flow rate
Impact on permeability
Practical implication 6
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

7. Characterization of emulsions
ζ-potential
Size stability
salinity, g/l
0.6 3 30
ζ – potential, mV
from -13 to -10
from -8 to -6
N/A
size variation around 4% 7
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

8. Breakthrough curves Adsorption q = 80% > qRSA
0.6 g/l
3 g/l
30g/l
30 g/l NaCl:
G = 2.34 mg/g of SiC
 surface coverage:
q = 80% > qRSA
two deposition kinetics
 surface heterogeneity?
 monolayer compaction?
Droplets behavior similar to the one of charged colloidal spheres 8
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

9. Desorption Irreversible deposition Desorption of droplets
at the injection salinity
partially reversible at a lower salinity
Desorption of droplets
no surface coalescence : unchanged droplets 9
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

10. Droplets behave like charged colloidal spheres
Summary
Droplets behave like charged colloidal spheres
They deposit as individual
Deposition is irreversible
for θ>54%
deposit compaction
for θ<54%
RSA-like deposition 10
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

11. Hydrodynamics Main parameters Collection efficiency
Grain Peclet's number
Colloidal scaling power laws:
DLD regime (Diffusion Limited Deposition)
RLD regime (Reaction Limited Deposition)
Cin
Cin
Cout
with 11
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

12. Droplets obey the scaling deposition kinetics
Kinetic aspects
First mechanism
close to DLD regime
Second mechanism
close to RLD regime
Droplets obey the scaling deposition kinetics 12
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

13. Impact on permeability
Permeability reduction
RSA theory
Entrance section
Internal section
Whole core
Homogeneous and in-depth piston like deposition
Hydrodynamic thickness of deposition layer
close to droplet diameter : monolayer
Droplets behave like individual colloidal spheres 13
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

14. For surface coverage below 54%
Summary
For surface coverage below 54%
permeability reduction (and deposition) fits the RSA theory
For surface coverage over 54%
no more permeability reduction
compaction of the deposited layer
no change in the mean hydrodynamic thickness 14
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

15. Practical consequences
Possible injectivity loss
up to 95%! Jr
Rk (RSA)
injectivity loss 40
1.17
15% 10
2.01
50% 3
21.1
95% 15
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia

16. T =25°C dodecane/ brine PC fraction collector He data logging unit
BYPASS
T =25°C PC
data logging unit
1 cm
5 cm
9 cm
GRANULAR PACK D
P 1-5
spectrophotometer
fraction collector
Pump He P
0-10
P 0-1
OUT
dodecane/ brine
EMULSION
BRINE 16
IEA Collaborative Project on EOR – 30th Annual Workshop and Symposium – September 2009, Canberra, Australia