Fundamental Surfactant Properties of Foamers for ...

Gas Well Deliquification Workshop Adams Mark Hotel, Denver, Colorado February 25 - 27, 2008

Fundamental Surfactant Properties of Foamers for Increasing Gas Production Part II: Modeling of Foamer Performance Duy T. Nguyen, Ph.D Nalco

Foaming Technology: Yesterday, Today and Tomorrow Yesterday

Today

Yesterday, foamer selection was a lot like fishing. It was an art.

Tomorrow

Modeling and prediction of foamer performance: a proactive approach

Investigation of key factors that govern the foaming performance and foaming mechanisms. *To be published in “Petroleum Science and Technology” Journal

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) Factors Temperature Oil Chloride Foamer dosage Oil type

Levels 25oC 70oC 0% 50% 2.4% 8% 400ppm 1000 ppm cycloalkane aliphatic

Performance Response % Unloading

Dynamic Foam Test Cell Wt=15 min % Unloading= X100 Winitial

One Factor Plot Effects of Temperature and % Chloride 100

85 70 55

% Oil = 0.00 % Chloride = 8.00 Foamer Dosage = 400 ppm

% Unloading

% Unloading

100

.

85 70 55

Temp = 25 C % Oil = 0.00 Foamer Dosage = 400 ppm

40

40 25.00 36.25 47.50 58.75 70.00

Temp, C

2.40 3.80 5.20

6.60 8.00

Chloride, %

Two-Factor Interaction Temperature and Chloride

% Unloading

100

% Chloride = 2.40 % Chloride = 8.00

85

% Oil = 0 Foamer Dosage = 400 ppm

8% chloride

70

55

2.4% chloride

40 25.00

36.25

47.50

58.75

Temp, oC

70.00

One Factor Plot Effect of Foamer Dosage

80

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

60

40 400 550 700 850 1000

Foamer Dosage, ppm

100

% Unloading

% Unloading

100

80 Temp = 25 C % Chloride = 8.00 % Oil = 0

60

40 400

550

700.

850

1000

Foamer Dosage, ppm

3-Factor Interaction Chloride, % Oil, Foamer Dosage

% Unloading

96

90

0% oil

0% oil 72

68

50% oil

50% oil 48

Temp = 25 C Oil Type = Aliphatic

24 Foamer Dosage = 1000 ppm

46 Temp = 25 C Decrease foamer 24 Oil Type = Aliphatic conc. Foamer Dosage = 400 ppm 0

0 2.40 3.80 5.20

6.60 8.00

Chloride, %

2.40 3.80 5.20

6.60 8.00

Chloride, %

% Unloading

Effects of % Oil and Oil Type 80

90

62.5

70

45

50

Temp = 25 C % Chloride = 8

27.5

% Oil = 50

Decrease % oil

30

Temp = 25 C % Chloride = 8 % Oil = 21 Foamer Dos. = 1000 ppm

Foamer Dos. = 1000 ppm 10

10 Cycloalkane

Oil Type

Aliphatic

Cycloalkane

Aliphatic

Oil Type

Cube Plot of % Unloading Effect of Oil Oil Type = Aliphatic

66.56

51.41

Foamer Dosage = 1000 ppm 87.80

2.4

55.68

61.05

79.74

25oC

%

85.11

Temp

70oC

il O

50

% Chloride

72.54

0

8.0

Prediction of Foamer Performance

Predicted % Unloading vs. Actual % Unloading 90.58

Predicted

2 2

65.16

39.75

R2 = 0.917 14.33

-11.08 -11.08

14.33

39.75

Actual

65.16

90.58

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

% Unloading @ 15 min

Conditions: 400 ppm active foamer; 10.2% NaCl, 3.7% CaCl2.2H2O 70 55% oil (v/v) 0% oil 60 50 40 30 20 10 0 Betaine

Alkyl ether sulfate

Configuration of oil at the air-liquid interface Pseudoemulsion Film

Air Oil

Water

Oil drop inside the solution

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

Oil Oil spreads at the solution surface and ruptures the bubble

Oil drop enters the gas phase and forms lens

Effect of Condensate on Foaming Performance 400 ppm active in 10.2% NaCl and 3.7% CaCl2.2H2O 90

% Unloading

80

Amphoteric

70 60

Alkyl ether sulfate

50 40

Olefin sulfonate

30 20 10

CAPB

0 0

20

40

60

80

% Condensate (wt%)

100

Effect of Condensate on Foaming Performance 400 ppm active in 10.2% NaCl and 3.7% CaCl2.2H2O

90

% Unloading

80

High Condensate Foamer B

70 60

High Condensate Foamer A

50 40 30 20 10 0 0

20

40

60

80

% Condensate (wt%)

100

% Corrosion Inhibition

Corrosion Inhibition Performance of a High Condensate Foamer A Conditions: CO2 saturated, 80oC, 24 hrs, sea water, 90% brine and 10% oil 100 95 90 85 80 75 70 0

10

20

30

40

Dosage, ppm

50

60

Foam Stability of Carried–Over Liquid

200 ppm α-olefin sulfonate

200 ppm betaine

200 ppm high condensate foamer (patent pending)

10 23 2 10 00 24 7 2 10 00 25 7 10 200 26 7 2 10 00 27 7 2 10 00 28 7 2 10 00 29 7 2 10 00 30 7 2 10 00 31 7 11 200 01 7 2 11 00 02 7 2 11 00 03 7 2 11 00 04 7 2 11 00 05 7 2 11 00 06 7 11 200 07 7 2 11 00 08 7 2 11 00 09 7 2 11 00 10 7 2 11 00 11 7 2 11 00 12 7 11 200 13 7 2 11 00 14 7 2 11 00 15 7 20 07

Gas Production, Mscf/D

Case Study #1

900

800

700

600

500

400

300

100

0 Untreated

200

Started Foamer

07 2 07 620 3 0 08 020 7 0 0 08 320 7 0 0 08 720 7 1 0 08 120 7 1 0 08 520 7 1 0 08 920 7 2 0 08 320 7 2 0 08 720 7 3 0 09 120 7 0 0 09 420 7 0 0 09 820 7 1 0 09 220 7 1 0 09 620 7 2 0 09 020 7 2 0 09 420 7 2 0 10 820 7 0 0 10 220 7 0 0 10 620 7 1 0 10 020 7 1 0 10 420 7 1 0 10 820 7 2 0 10 220 7 2 0 10 620 7 3 0 11 020 7 0 0 11 320 7 0 0 11 720 7 1 0 11 120 7 1 0 11 520 7 1 0 11 920 7 23 07 20 07

Gas Production, Mscf/D

Case Study #2

160

140

120 Started pump back up with foamer

foamer pump went down

100

80

60

40

20

0

Acknowledgements David Horsup Sean Taylor Thanh Bui Jason Hudson Lawrence Thomas ConocoPhillips

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