Feb. 6 - 10, 2012 2012 Gas-Lift Workshop 1

Gas-liquid flow optimization with a Bubble Breaker device

• Hendy T. Rodrigues, Petr. Eng. • Petrobras Research Center

35th Gas-Lift Workshop Houston, Texas, USA February 6 – 10, 2012

Feb. 6 - 10, 2012 2012 Gas-Lift Workshop 2

Petrobras R&D Center, Rio de Janeiro

Introduction

• Bubble breaker was first presented by Shell engineers (Schrama and Fernandes, 2005): – Experimental and field tests

• Objective is to break the bubbles into smaller diameters, or change the flow pattern

Motivation

• Smaller bubbles reduce hidrostatic pressure drop and delay the transition to slug flow

(Guet et. al., 2003)

Motivation

• Lower rise velocity → Greater void fraction → lower hidrostatic pressure gradient.

G

G

VAQα⋅

=( )αραρρ −+= 1LG

Motivation

• Bubble rise velocity increases with bubble diamenter.

D~1,5mm D~17mm (Celata et. al., 2007)

(Parkinson et. al., 2008) (Tomiyama et. al., 2002)

(Nguyen et. al., 1998)

Experiments

• This work presents experimental results to evaluate the device: – Pressure measurements:

• At four locations along the pipe. • Ratio of Pressure Gradients before and after the bubble

breaker. – R=(Press. Grad. After)/(Press. Grad. Before)

– Detailed videos: high-speed camera.

Experimental facilities

Bubble breaker

• 3 different geometries: 1 plate with orifices and 2 Venturi

Test conditions

• Test conditions: – QL = 6 – 21 L/min – QG = 9 – 90 L/min – Air and water

1

10

100

1000

1 10 100 1000

QG (L/min)

QL

(L/m

in)

Disperse bubbles

Slug

Videos

• Dispersed bubbles • One elongated bubble • Slug flow

Pressure loss results

QL=21 L/min

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80

QG local (l/min)

∆P

(kgf

/cm

2)

Orifícios 8x3mmVenturi 8,5mmVenturi 6mm

QL=6 L/min

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80

QG local (l/min)

∆P

(kgf

/cm

2)

Orifícios 8x3mmVenturi 8,5mmVenturi 6mm

QL=12 L/min

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80

QG local (l/min)

∆P

(kgf

/cm

2)

Orifícios 8x3mmVenturi 8,5mmVenturi 6mm

QL=16,8 L/min

0.0

0.2

0.4

0.6

0.8

1.0

0 20 40 60 80

QG local (l/min)

∆P

(kgf

/cm

2)

Orifícios 8x3mmVenturi 8,5mmVenturi 6mm

Pressure gradients ratio

QL=21 L/min

0.6

0.8

1.0

1.2

1.4

1.6

0 20 40 60 80

QG local (l/min)

R

Orifícios 8x3mmVenturi 8,5mmVenturi 6mm

QL=6 L/min

0.6

0.8

1.0

1.2

1.4

1.6

0 20 40 60 80

QG local (l/min)

R

Orifícios 8x3mmVenturi 8,5mmVenturi 6mm

QL=12 L/min

0.6

0.8

1.0

1.2

1.4

1.6

0 20 40 60 80

QG local (l/min)

R

Orifícios 8x3mmVenturi 8,5mmVenturi 6mm

QL=16,8 L/min

0.6

0.8

1.0

1.2

1.4

1.6

0 20 40 60 80

QG local (l/min)

R

Orifícios 8x3mmVenturi 8,5mmVenturi 6mm

Values of R lower than 1 indicates that the Bubble Breaker is effective!

Results

• Bubble breaker is more effective at the Disperse Bubbles flow pattern (higher liquid flow rates).

• Geometry should be studied for each application.

• Reduction in the Pressure Gradients must be compared to local pressure drop.

• Next works: Different geometries to enhance bubble breaking while reducing local pressure drop.

References

• 1 – Schrama, E. and Fernandes, R. “The bubble breaker: breaking up slug flow into dispersed bubbly flow using a passive mechanical device”. BHR Group 2005 Multiphase Production Technology 12

• 2 – Guet, S., Ooms, G., Oliemans, R. V. A. and Mudde, R. F. “Bubble Injector Effect on the Gaslift Efficiency” AIChE Journal, Vol. 49, No. 9, 2003.

• 3 – Celata, G. P., D´Annibale, F., Di Marco, P., Memoli, G. and Tomiyama, A. “Measurements of rising velocity of a small bubble in a stagnant fluid in one- and two-component systems” Exp. Thermal and Fluid Sciences, Vol. 31, 2007.

• 4 – Parkinson, L., Sedev, R., Fornasiero, D. and Ralston, J. “The terminal rise velocity of 10–100 μm diameter bubbles in water” Journal of Colloid and Interface Science, Vol. 322, 2008.

• 5 – Tomiyama, A., Celata, G. P., Hosokawa, S. and Yoshida, S. “Terminal velocity of single bubbles in surface tension force dominant regime” Int. J. of Multiphase Flow, Vol. 28, 2002.

• 6 – Nguyen, A. V. “Prediction of Bubble Terminal Velocities in Contaminated Water” AIChE Journal, Vol. 44, No. 1, 1998.

Feb. 6 – 10. 2012 2012 Gas-Lift Workshop 16

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Feb. 6 – 10, 2012 2012 Gas-Lift Workshop 17

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