Applications DuraFoam™ Foam Drilling System Specifications

DuraFoam Foam
Drilling System
Weatherford’s DuraFoam foam drilling system is an economical, highfoam,
corrosion-inhibitive system that protects downhole tubular goods
in aerated applications, such as underbalanced drilling. The system
protects against oxygen-, chloride-, and acid-induced corrosion to
extend tubular life. The comprehensive system consists of the unique
DuraFoam foaming surfactant and Weatherford’s CORRFOAM ®
corrosion inhibitor, a class 1 anodic inhibitor.
The system can be adapted to many conditions, including performance
and reservoir drilling with low- to high-salinity fluids, and environments
with acid gases, hydrogen sulfide (H 2 S), and carbon dioxide. The
system can also be adapted for drilling in reactive shale by incorporating
Weatherford’s DIONIC ® 900 water-soluble polymer, NCL-100 quaternary
chloride compound, or CC-120 shale inhibitor.
The system can be applied as a mist or fully integrated foam. The mist
can absorb up to 500 bbl/hr (79 m 3 /h) of water and coat drill cuttings
to prevent mud-ring formation in the annulus. As foam, the system can
stabilize downhole pressures and reduce cutting-bed formation because
the DuraFoam surfactant extends the foam stability and half-life at low
concentrations. Foam stability is critical for cutting transport in extendedreach
horizontal drilling.
In mist and foam underbalanced drilling, compressed air is usually
injected into the drilling fluid. Consequently, the high oxygen
concentration of the fluid increases the potential for oxygen-induced
corrosion in downhole equipment and drillpipe.
The DuraFoam system can be continuously injected or batch treated into
the drilling-fluid stream. The DuraFoam component extends the foam
stability, and the CORRFOAM inhibitor reacts with available oxygen to
form a protective passivation layer on metal surfaces.
In high-angle and horizontal drilling, cuttings can collect on the low side
of the wellbore and damage the formation. The extended foam stability
provided by the DuraFoam system helps to coat the cuttings for easier
removal from the wellbore.
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© 2008-2010 Weatherford. All rights reserved. 4794.01

DuraFoam Foam Drilling System
Applications
The DuraFoam system can be adapted to many drilling conditions:
• Mist, foam, and reactive shale
• Acid gases and high chlorides
• Low-pressure reservoirs
• Extended-reach horizontal wells
Features, Advantages and Benefits
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• The economical system can be adapted to many drilling conditions, eliminating the need for multiple
foaming surfactants.
• The system can be easily injected into the fluid stream without special mixing or handling, providing a
safe, simple application on the rig.
• The biodegradable, nonflammable system enhances health, safety, and environmental performance.
Specifications
Concentration*
(% volume/volume)
Shale Stabilization
(DIONIC 900, CC-120, or Weatherford’s WFT 9801
Application DuraFoam System CORRFOAM Class 1 NCL-100)
Hydrogen Sulfide Scavenger
Mist 0.1 to 0.5 0.05 to 0.2 — —
Foam 0.25 to 1.0 0.1 to 0.5 — —
Shale 0.1 to 1.0 0.05 to 0.5 0.25 to 2.0 —
Acid gas 0.1 to 1.0 0.05 to 0.5 — Depends on H S concentration
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*The pH of the system is maintained at 9.5 to 10.5 with caustic soda, soda ash, potassium carbonate, and lime. For shale drilling, the pH is maintained at neutral (~7.0)
to reduce reactive shale swelling.
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© 2008-2010 Weatherford. All rights reserved. 4794.01

DuraFoam Foam Drilling System
Specifications
Corrosion Rate (mil/yr)
700.0
600.0
500.0
400.0
300.0
200.0
100.0
0.0
weatherford.com
320.3
Comparison of an Uninhibited Fluid System to DuraFoam System
24-hr Corrosion Rates at 250°F (121°C) in a 10,000-mg/liter Chloride Fluid
573.9
118.8
Uninhibited Fluid
10,000 mg/liter Cl 2
No Foamer or Corrosion Inhibitor
201.1
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DuraFoam System
0.5% DuraFoam surfactant
0.2% CORRFOAM Class 1
23.8
10.7 13.2 19.2 23.8
10.7 13.2 19.2
7.0 7.7 5.0 3.6
Compressed Air (20% O 2 ) Membrane N 2 (4% O 2 ) Cryogenic Nitrogen (0.0001% O 2 )
25% Quality Uninhibited 50% Quality Uninhibited 25% Quality DuraFoam System 50% Quality DuraFoam System
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© 2008-2010 Weatherford. All rights reserved. 4794.01

DuraFoam Foam Drilling System
Specifications
Foam Height (ml) and half-life (sec)
900
800
700
600 600
500 500
400
300
200 200
100
00
weatherford.com
725
DuraFoam System Foam Properties
1.0% DuraFoam Surfactant and 0.2% CORRFOAM Class 1
480
675 675
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© 2008-2010 Weatherford. All rights reserved. 4794.01
Weatherford products and services are subject to the Company’s standard terms and conditions, available on request or at weatherford.com. For more information contact an authorized
Weatherford representative. Unless noted otherwise, trademarks and service marks herein are the property of Weatherford. Specifications are subject to change without notice. Weatherford
sells its products and services in accordance with the terms and conditions set forth in the applicable contract between Weatherford and the client.
780
550
500 16,000 110,000
4
Chloride Content (mg/liter)
Foam Height Foam Half-Life
840