Buenos Aires, 7 al 10 de agosto de 2012 OPTIMIZING DEFOAMER
USAGE IN DRILLING & CEMENTING APPLICATIONS: TECHNOLOGY REVIEW
& TESTING METHODOLOGIES Luciana Bava, Amir Mahmoudkhani, Robert
Wilson, Leanne Levy, Patricia De Palma and Henry Masias Atlanta
R&D Center, Atlanta, Georgia, USA
Slide 2
Foam is a colloidal dispersion of gas in a liquid or a solid.
Pure liquids do not foam Tap water, in spite of being aerated, does
not foam Bubbles collapse immediately on the surface To generate
foam, it is necessary to have a surface active component that
stabilize the inclusion of dissolved and entrained gasses. 2 Foam
Generation
Slide 3
Water-based Drilling Muds Cement Slurries Foam Drillings /
Cementing Aqueous Systems Oil & Gas Separators Oil-based
Drilling Muds Non-aqueous Systems Examples of foaming/defoaming
systems in upstream Oil & Gas industry under dynamic fluid
conditions Foaming/Defoaming Systems
Slide 4
Cement Well Completion
Slide 5
Most common additives used to modify the behavior of drilling
and cement systems are surface active molecules that cause the
working fluid to foam during mixing Such additives include: Cement:
retarders, dispersants, fluid loss control additives, gas migration
control agents and ductility improvement additives. Water base
drilling muds: salinity chemicals, dispersants, lost circulation
materials and gelling agents and viscosifiers Drilling and
Cementing Additives Cement G + Gas Migration Additive Blend, 1800 i
kg/m 3 - without defoamer (left), with defoamer (right)
Slide 6
Excessive slurry foaming can have several undesirable
consequences: Loss of hydraulic pressure during pumping can occur
owing to cavitation in the mixing system Air entrainment may cause
higher than desired slurry densities Air entrainment also increases
the risk of gas permeability and of improper wetting and mixing
Liquid or Dry Defoamers are used Foam in Drilling and Cementing
Operations
Slide 7
Recirculating Centrifugal Pumps (max 4000 L /min) Slurry Tubs:
1000 8000 L Well Cementing Cement Mixing
A B Time Sparge Foam Test Blender Foam Test Simple &
inexpensive Good for initial screening Measurements based on foam
height May not accurately represent system under study (A vs. B)
Single point data Single shear rates and fix mixing time Difficulty
in replicating field conditions Non-Systematic Testing Methods Foam
Height
Slide 11
Modified Blender Test Mahmoudkhani et al., An Innovative
Approach for Laboratory Evaluation of Defoamers for Oilfield
Cementing Applications, SPE 143825, Brasil Offshore Conference and
Exhibition, Brazil, June 2011
Slide 12
P DFM Variable Rate Pump Density & Flow Meter Temp
Controller Foam Cell Data Recording Drain Ancillary Gas 12 Foam and
Entrained Air Test (FEAT)
Slide 13
Data collected every 0.5 second At precision of 0.00005 g/mL
Data collected every 0.5 second At precision of 0.00005 g/mL Fluid
composition may be altered by addition of chemical components at
any point during the test Foam and Entrained Air Test (FEAT)
Slide 14
Cement Slurry Solids+Liquids Liquids Mix: Water + Water-Soluble
Additives Solids Mix: Cement + Additives Defoamer performance FEAT
Study Blender Test This comprehensive study approach (FEAT +
Blender) is needed for proper laboratory validation and
qualification under simulated field conditions (accounting for
different dosage practices, additives, mixing regimes, etc.)
Dispersant-Salt System FEAT analysis of silicone and
non-silicone chemistries on 4% sodium polynaphthalenesulfonate +
30% salt solution.
Slide 17
Dispersant-Salt System Blender foam test data in the
dispersant-salt system, 4% sodium polynaphthalenesulfonate + 30%
salt solution. All defoamers are dosed at 0.20% BWOC (by weight of
cement)
Slide 18
Latex System FEAT analysis of silicone and non-silicone
chemistries on latex solution. Silicone A Blank Non-Silicone D
Slide 19
Latex System Blender foam test data in latex system. All
defoamers are dosed at 0.20% BWOC (by weight of cement)
Slide 20
PVA (fluid loss additive) System Blender foam test data in
latex system. All defoamers are dosed at 0.20% BWOC (by weight of
cement)
Slide 21
Dry vs. Liquid Defoamers Cement Slurry Solids + Liquids Mixing
Liquids: Water + Water-Soluble Additives Mixing Solids: Cement +
Additives Liquid Defoamers Dry Defoamers Dry Defoamers are prefer
for better stability, ease of handling and storage Dry Defoamers
are suitable for harsh climate areas Cannot be used as trimmer, a
second (and liquid) defoamer is required
Slide 22
Improved / Fast Release Dry Defoamers Conventional Dry
Defoamers (silica) Improved / Fast Release Dry Defoamers High
Surface Area Solids AdsorptionRelease High adsorptionSlow /
incomplete release Substrate Defoamer
Slide 23
Fast Release vs. Conventional Dry Defoamers Fast Release Dry
Defoamers: Outperform conventional Dry Defoamers with a performance
level comparable to Liquid Defoamers Reach maximum performance at
lower dosages Fast Release Dry Defoamers: Outperform conventional
Dry Defoamers with a performance level comparable to Liquid
Defoamers Reach maximum performance at lower dosages FR Dry: fast
release dry defoamer Dry: conventional dry defoamers Liq: liquid
defoamer FR Dry: fast release dry defoamer Dry: conventional dry
defoamers Liq: liquid defoamer
Slide 24
1. What cause foaming? Additives: Dispersants, Salt, PVA,
Latex, etc. 2. Where foaming is created? 3. Test Methods Blender
(static, single point data) FEAT (dynamic / multipoint data)
Summary 1: Foam Generation and Testing
Slide 25
Summary 2: Choice of Defoaming Chemistry
Slide 26
Summary 3: Form of Defoamer (Liquid, Conventional Dry or Fast
Release)