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AUS-TEX
FLUID LOSS CONTROL AGENT
DESCRIPTION
AUS-TEX is sodium asphalt sulphonate-based product and is more than 60% soluble in both fresh and hard water. When mixed in the mud system, it functions as a shale stabiliser, cuttings dispersion inhibitor and contributes to high temperature fluid loss control. It helps to form a thin and tough wall cake, the small particles can effectively plug micro-fractures and shale pores. It also reduces torque and drag, aids in the emulsification of oil and assists in the prevention of differential sticking.
APPLICATIONS/FUNCTIONS
AUS-TEX can be used in all types of drilling applications especially micro-fractured and troublesome shales. AUS-TEX is added to water based drilling fluids to help control troublesome shales, reduce HPHT filtration loss, reduce torque and drag, and improve overall mud condition and performance. The dispersed resinous phase of AUS-TEX coats the surface of the borehole with a layer which deforms with heat and pressure, forming a continuous, tough, thin film. Some particles also bridge the openings of micro fractures, deforming to seal off these fractures to prevent invasion of mud or filtrate. AUS-TEX contributes inhibitive compounds to the drilling fluid, while acting to satisfy positively-charged (cationic) sites on exposed shale edges.
ADVANTAGES
- Excellent shale and clay stabilisation performance
- Helps form a thin, tough wall cake
- Lubricates thereby reducing torque and drag of the drilling string
- Improves filter cake quality and helps to seal micro fractures
- Helps inhibit cuttings dispersion
- Seals small fractures in stressed shale formations
- Temperature stable up to 450°F (232°C)
- Compatible with all water based mud systems
TYPICAL PROPERTIES
- Appearance: Brown to black powder
- Specific gravity: 1.24 – 4.45
- pH (1 % solution): >8.5
- Solubility: Partly soluble in water and partly soluble in organic solvent
RECOMMENDED TREATMENT
AUS-TEX should be mixed through a mud hopper at between 2 to 6 ppb (5.7 – 17.1 kg / m3). When using in hard water, pre mixing with fresh water will enhance performance. Best results are achieved by treating the system with AUS-TEX before penetrating an interval of swelling or sloughing shale. AUS-TEX should be added daily after the initial concentration has been established in the system, the product concentration will be depleted as it is used to coat on the wellbore wall and cuttings.
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