Viscosifiers - Week 2 Flashcards
Milgel - Composition
Premium grade bentonite. Not a pure bentonite
Milgel - Primary Function
Provides viscosity in water based muds
Milgel - Secondary Function
Aids in filtration control by reducing the permeability of the filter cake
Milgel - Features and Benefits
- There are API specifications for viscosity, filtration, moisture and particle size
- the specific gravity of bentonite clays are usually in the range of 2.5-2.65
- Clays are colloidal in size - less than 2 microns
Milgel - Limitations
- High total hardness and/or chloride concentrations in the base water will reduce the yield of smectite clays
- Prehydration of the clays in fresh water are recommended under these conditions
Milgel - Treatment
A concentration of 20 Ib/bbl in fresh water will provide a minimum apparent viscosity of 10 centipoise and a maximum API filtrate of 12.5 cc. Amounts will vary according to viscosity needs
Milgel NT- Composition
Premium grade natural Wyoming bentonite (Absorbent phyllosilicate)
Milgel NT- Primary Function
Provides viscosity in water based muds
Milgel NT- Secondary Function
- Aids in filtration control by reducing the permeability of the filter cake
- Lubricant
Milgel NT- Features and Benefits
Also aids in the high temperature/ high pressure filtration properties of water based mud
Milgel NT- Treatment
A concentration of 25Ib/bbl in frest water will provide a minimum apparent viscosity of 10 centipoise and a maximum API filtrate of 12.5 cc. Amounts will vary according to viscosity needs.
Milgel NT- Limitations
High total hardness and/or chloride concentrations in the base water will reduce the yield of smectite clays. Prehydration of the clays in fresh water are recommended under the conditions.
Salt Water Gel - Composition
Attapulgite Gel - magnesium aluminium phyllosilicate
Salt Water Gel - Primary Function
Provides viscosity for fresh to saturated salt water fluids
Salt Water Gel - Secondary Function
High solids squeeze plugs for loss of circulation
Salt Water Gel - Features and Benefits
- Specific gravity of 2.2- 2.4
- light tan to grey powder
- bulk density of 44 Ib/kg^3 (705 kg/m^3)