How oil based muds helps in drilling a well effectively?
Oil-based muds are used for many reasons, including increased lubricity, enhanced shale inhibition, and greater cleaning abilities with less viscosity. Oil-based muds also withstand greater heat without breaking down.
Which of the following mud type is preferred during drilling shale formation?
Potassium muds are the most widely accepted water mud system for drilling water sensitive shales. K+ ions attach to clay surfaces and lend stability to shale exposed to drilling fluids by the bit. The ions also help hold the cuttings together, minimizing dispersion into finer particles.
What is the filtration area in HPHT fluid loss test?
These 3.5-in. ² (22.6-cm²) filtration area instruments have 175-mL, 250-mL, and 500-mL capacity test cells. Because the area of the standard API filter press is 7.1-in. ² (45.8-cm²), the volume obtained from the HTHP test is doubled before reporting.
On what base we choose the drilling fluid?
The base fluid may be fresh water, seawater, brine, saturated brine, or a formate brine. The type of fluid selected depends on anticipated well conditions or on the specific interval of the well being drilled.
How much back pressure is used for HPHT tests above 100 C?
As this temperature exceeds 212°F (100°C), the back pressure must be increased in order to prevent vaporization of the filtrate. The 500 PSI differential pressure must be maintained, so the top pressure will have to be increased accordingly. The table below shows the pressures recommended for various test temperatures.
What is API filtrate?
API filtrate is the filtrate volume in term of (ml) after 30 min. in API fluid loss test. API fluid loss test measures static filtration behavior of water-based mud at room temperature and 100 psi differential pressure.
Which type of drilling fluid would be best to use in unstable formations?
Synthetic-based drilling fluids Increase lubricity in directional and horizontal wells. Minimize wellbore-stability problems, such as those caused by reactive shales.
How does hot aging affect HTHP loss in drilling fluid?
After hot aging at 200 °C, the oil-based drilling fluid containing 1 w/v% SPM exhibited an API filtration loss decrease of 85%, and HTHP filtration loss decrease of 79% in comparison with the base fluid.
Can a HTHP test be used with water based mud?
The HTHP test is used mainly with Oil Based Mud although it may be used with water based mud under certain circumstances such as in high temperature wells or wells which exhibit a high risk of differential sticking. HTHP testing of water based mud is not routine and shall be specified in the Drilling Fluids Programme.
What kind of fluids are used in a HPHT well?
INVERT EMULSION FLUIDS Invert Emulsion fluids have been utilized for drilling HP/HT wells and the technology is adequate for temperatures up to 500 °F. Table 1 illustrates the generic name and functions of the specialty additives used in the formulation of HP/HT invert emulsion fluids.
Can a HTHP test be used for chemical analysis?
Filtrate collected during HTHP testing must not be used for subsequent chemical analysis. The HTHP fluid loss must be maintained within the programmed specification to limit potential for differential sticking and formation damage in the reservoir. HTHP Filter Press and heating jacket.
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