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

 

 

 

 

Fracture model

Syringe pump

Air mass flow controllerFoam generator

Computer for recording pressure difference

Surfactant solution

Air

Transducer

Frit

               

 

HP digital camera

Experiment conditions

Surfactant: 0.5% C13-4PO+0.5% CS330Salinity: 0.23% NaCl, 0.07% CaCl2, 0.04%

MgCl2Aperture: 0.1mm, 0.2mm, 0.1 mm/0.2 mm

(1:2), 0.05 mm/0.15 mm (1:3)Fractional gas flow: 0~0.9Bubble diameter: 0.4 mm, 0.6 mm

Mechanisms affecting apparent viscosity in fracture system

Homogeneous parallel plates model

14 inch

12 inch

8 inch6 inch

Variable thickness

Effect of flow rate and gas fractional flow on apparent viscosity

aperture = 0.2 mm,mean bubble size DB= 0.6 mm

0.1

1.0

10.0

100.0

0.001 0.010 0.100 1.000

Flow velocity (m/s)

App

aren

t vis

cosi

ty (c

p)

fg=0.67fg=0.67 from theoryfg=0.5fg=0.5 from theoryfg=0.33fg=0.33 from theoryfg=0.2fg=0.2 from theoryfg=0.0fg=0.0 from theory

Re=30Re=0.5

Re=0.5 Re=30

Water front at different Reynold’s number

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 f low = 0.67, aperture = 0.2 mm

0.1

1.0

10.0

100.0

0.1 1.0 10.0

Mean bubble size (mm)

Appa

rent

visco

sity

(cp)

f low velocity=2.2 cm/s

flow velocity=2.2 cm/s fromtheory

Heterogeneous parallel plates model

14 inch

12 inch

8 inch6 inch

Variable thickness

10 inch

0.1 mm

Foam has higher apparent viscosity at larger thickness Match of apparent viscosity from theory and measurement

aperture = 0.05mm/0.15mm,DB=0.4mm,Re = 0.22

1

10

100

0 0.2 0.4 0.6 0.8 1Gas Fractional Flow

Ap

par

ent

visc

osi

ty (

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

0.05 mm thickness

Foam improves sweep of fractured system Less liquid is needed to sweep system with foam

LPV – Liquid Pore volume

Aperture = 0.05 mm / 0.15 mm, Re = 0.22, DB = 0.4 mm

fg=0.0

0.41PV 0.82 PV 1.23PV 1.64 PV 2.05 PV 6.56 PV

fg=0.9

0.04 LPV 0.08 LPV 0.12 LPV 0.16 LPV 0.21 LPV 0.66 LPV

Surfactant solution to sweep entire heterogeneous fracture at different aperture ratio in total pore volume

DB=0.4mm, Re=0.22

0.1

1.0

10.0

0.0 0.2 0.4 0.6 0.8 1.0

Gas Fractional Flow

To

tal P

ore

Vo

lum

e

1:3

1:2

Surfactant solution to sweep entire heterogeneous fracture at different aperture ratio in liquid pore volume

DB=0.4mm, Re=0.22

0.1

1.0

10.0

0.0 0.2 0.4 0.6 0.8 1.0

Gas Fractional Flow

Liqu

id P

ore

Vol

ume 1:3

1:2

The model to describe flow in heterogeneous parallel plates

P1

P2

P3

P4

P1=P2 P3=P4

ImpermeableDykstra-Parsons Model

DB=0.4mm, Re=0.22

aperture 0.05mm/0.15mmDykstra-Parsons model

0.1

1.0

10.0

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

Gas Fractional Flow

Tota

l Por

e V

olum

e

0.05mm aperture from experiment

0.05mm aperture from theory

0.15mm aperture from experiment

0.15mm aperture from theory

Injection to breakthrough in wide and narrow aperture

Calculation of sweep efficiency in fracture networkFracture apertures are with log-normal

distributionNo crossflowPressure difference is equal for each

layerGas 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