Gas Well Deliquification WorkshopAdams Mark Hotel, Denver, Colorado

February 25 - 27, 2008

Fundamental Surfactant Properties ofFoamers for Increasing Gas ProductionPart II: Modeling of Foamer PerformanceDuy T. Nguyen, Ph.D

Nalco

Foaming Technology: Yesterday, Today and Tomorrow

Yesterday, foamer selection was a lot like fishing. It

was an art.

Investigation of key factors that govern the foaming performance and foaming

mechanisms.*To be published in “Petroleum Science and Technology”

Journal

Modeling and prediction of foamer performance: a

proactive approach

Yesterday Today Tomorrow

Outline

• Impact of input variables on foaming performance– Input variables: temperature, brine, foamer dosage,

condensate, nature of condensate,…

• Modeling and prediction of foamer performance• New product:

– Novel high condensate foamer (patent pending)

• Case study/field data

“What Factors Influence Foaming Performance”

25 Factorial Design ( a 2 level with 5 factors)

with two replicates (64 experiments)

Temperature 25oC 70oCOil 0 % 50% Chloride 2.4% 8%Foamer dosage 400ppm 1000 ppmOil type cycloalkane aliphatic

Factors Levels

Performance Response% Unloading

Dynamic Foam Test Cell

X100W

W Unloading%initial

min 15t==

One Factor PlotEffects of Temperature and % Chloride

% Chloride = 8.00% Oil = 0.00

Foamer Dosage = 400 ppm

25.00 36.25 47.50 58.75 70.00

40

55

70

85

100

Temp, C

% U

nlo

ad

ing

Temp = 25 C% Oil = 0.00

Foamer Dosage = 400 ppm

2.40 3.80 5.20 6.60 8.00

40

55

70

85

100

Chloride, %

% U

nlo

ad

ing

.

Two-Factor InteractionTemperature and Chloride

% Oil = 0Foamer Dosage = 400 ppm

% Chloride = 2.40% Chloride = 8.00

% U

nlo

ad

ing

Temp, oC

25.00 36.25 47.50 58.75 70.00

40

55

70

85

100

8% chloride

2.4% chloride

One Factor PlotEffect of Foamer Dosage

Temp = 25 C% Chloride = 2.40% Oil = 0

400 550 700 850 1000

40

60

80

100

Foamer Dosage, ppm

% U

nlo

ad

ing

Temp = 25 C% Chloride = 8.00

% Oil = 0

400 550 700. 850 1000

40

60

80

100

Foamer Dosage, ppm

% U

nlo

ad

ing

3-Factor Interaction Chloride, % Oil, Foamer Dosage

% U

nlo

ad

ing

Temp = 25 COil Type = Aliphatic

Foamer Dosage = 1000 ppm

Chloride, %2.40 3.80 5.20 6.60 8.00

0

24

48

72

96 0% oil

50% oil

Decrease foamer conc.

Temp = 25 COil Type = Aliphatic

Foamer Dosage = 400 ppm

Chloride, %2.40 3.80 5.20 6.60 8.00

0

24

46

68

900% oil

50% oil

Effects of % Oil and Oil Type

Foamer Dos. = 1000 ppm

Temp = 25 C% Chloride = 8% Oil = 21

Oil TypeCycloalkane Aliphatic10

30

50

70

90

Oil TypeAliphatic

Temp = 25 C% Chloride = 8

% Oil = 50

% U

nlo

ad

ing

Cycloalkane10

27.5

45

62.5

80

Foamer Dos. = 1000 ppm

Decrease % oil

Cube Plot of % UnloadingEffect of Oil

Oil Type = AliphaticFoamer Dosage = 1000 ppm

Temp25oC 70oC

79.74 85.11 % Oil

0

5

0

61.0555.68% Chloride

2.4

8.0 87.80 72.54

51.4166.56

Prediction of FoamerPerformance

Predicted % Unloading vs. Actual % Unloading

2222

Actual

Pre

dic

ted

-11.08

14.33

39.75

65.16

90.58

-11.08 14.33 39.75 65.16 90.58

R2 = 0.917

CONCLUSIONS

• % Unloading modeled well (r2=0.917)(0.01% chance that effects occurred due to noise)• Eight significant terms in model• % Oil had the largest effect on % unloading• Oil type had the next largest effect, followed by the

foamer dosage• Temperature had an interaction with % chloride• Three-way interaction occurred between % chloride,

foamer dosage, and % oil

CONCLUSIONS

• Prediction and modeling of foamer performance with confidence– A proactive approach to manage program

• “No touch” foaming testing• Quick response when process variables change• Foamer mapping

Effect of Oil on Foaming Performance

0

10

20

30

40

50

60

70

Betaine Alkyl ether sulfate

% U

nlo

ad

ing

@ 1

5 m

in

55% oil (v/v)0% oil

Conditions: 400 ppm active foamer; 10.2% NaCl, 3.7% CaCl2.2H2O

Configuration of oil at the air-liquid interface

Oil Water

Air

Oil drop inside the solution

Oil

Oil drop enters the gas phase and forms lens

Oil spreads at the solution surfaceand ruptures the bubble

Oil

Pseudoemulsion Film

Oil drop at the surface separated by a pseudo-emulsion film from the air

Effect of Condensate on Foaming Performance

400 ppm active in 10.2% NaCl and 3.7% CaCl2.2H2O

% U

nlo

ad

ing

0

10

20

30

40

50

60

70

80

90

0 20 40 60 80 100% Condensate (wt%)

Amphoteric

CAPB

Olefin sulfonate

Alkyl ether sulfate

Effect of Condensate on Foaming Performance

400 ppm active in 10.2% NaCl and 3.7% CaCl2.2H2O

0

10

20

30

40

50

60

70

80

90

0 20 40 60 80 100% Condensate (wt%)

% U

nlo

ad

ing

High Condensate Foamer A

High Condensate Foamer B

Corrosion Inhibition Performance of a High Condensate Foamer A

70

75

80

85

90

95

100

0 10 20 30 40 50 60

Dosage, ppm

% C

orr

osi

on

In

hib

itio

nConditions: CO2 saturated, 80oC, 24 hrs, sea water, 90%

brine and 10% oil

200 ppm α-olefin sulfonate

Foam Stability of Carried–Over Liquid

200 ppm betaine 200 ppm high condensatefoamer (patent pending)

Case Study #1

0

100

200

300

400

500

600700

800

900

1023

2007

1024

2007

1025

2007

1026

2007

1027

2007

1028

2007

1029

2007

1030

2007

1031

2007

1101

2007

1102

2007

1103

2007

1104

2007

1105

2007

1106

2007

1107

2007

1108

2007

1109

2007

1110

2007

1111

2007

1112

2007

1113

2007

1114

2007

1115

2007

Untreated

Started Foamer

Gas

Pro

du

ctio

n,

Msc

f/D

Case Study #2

0726

2007

0730

2007

0803

2007

0807

2007

0811

2007

0815

2007

0819

2007

0823

2007

0827

2007

0831

2007

0904

2007

0908

2007

0912

2007

0916

2007

0920

2007

0924

2007

0928

2007

1002

2007

1006

2007

1010

2007

1014

2007

1018

2007

1022

2007

1026

2007

1030

2007

1103

2007

1107

2007

1111

2007

1115

2007

1119

2007

1123

2007

foamer pump went down

Started pump back up with foamer

Gas

Pr o

du

ctio

n,

Msc

f/D

160

140

120

100

80

60

40

20

0

Acknowledgements

David Horsup

Sean Taylor

Thanh Bui

Jason Hudson

Lawrence Thomas

ConocoPhillips

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