Abstract Meaning of drilling fluid Types of drilling fluid Drilling fluid additives Rheological properties of drilling fluid The doctor of an oil well. The circulation system. References Questions

Jacob Ebere ( petroleum engineering AUST.)Date :Friday, March 30th, 2012. Venue: Zenith Hall, AUST Campus. Time 6.00pm Abstract.

Drilling fluid is a mixture of clay and chemicals at predetermined proportion, used in oil and gas well drilling operations. This presentation is aimed at explaining the meaning of drilling fluid, the types, functions, the additives that make up the drilling fluid and the rheological properties of a drilling fluid and why it is the “doctor” of an oil well.The discussion will cover the complete circulation process from the suction pit to the rotary hose to swivel to kelly hose, to the drill pipe to the bit nozzles through the annulus back to the shale shakers and finally back to the suction pit carrying bunch of information on the progress of the well as it performs so many functions.

mixture of clay and chemicals in a defined proportion, pumped through the bit nozzles to the wellbore to provide hydrostatic pressure , suspend and lift cuttings, cool and lubricate the bit and secure maximum hole information.

Drilling fluid

Water base mudOil mud

Low solid mud

Oil base mud

Low toxicity mud

Pseudo oil base mud

Native mud

Special mud

Air base mud

•Suspend and lift drilled cuttings to surface.• provides hydrostatic pressure.• Seal permeable formations.• Cool, lubricate, and support the drilling assembly. • Transmit hydraulic energy to tools and bit.

•To prevent or recover stuck pipes.• Minimize reservoir damage.• Inhibits sloughing or swollen shale.• Control corrosion.• Serves as means of communication with well.

•Considerations for purpose•Consideration for cost.•Plan for emergency

Base oil

Calcium chloride(in form of brine)

Lime

Viscosifier

Primary and secondary emulsifier

Fluid loss agent (usually called FLG)

Barite (weighting agent)

Pre-hydrated bentonite. Salt (KCL, NaCl, CaCl2). Filtration Control Agent ( soltex). Guar gum.(polymer). sodiumcarboxymethyl cellulose (polymer) XC-polymer (polymer). Custic soda (NaOH). Calcium carbonate(weighting agent).

plastic viscosity(PV) Yield point(YP) Gel strength(GS) Marsh funnel viscosity(MFV) apparent viscosity(AV)

Θ600 minus Θ300 = plastic viscosity(cp)

Θ300 minus plastic viscosity =yield point (lb/100ft2)

Θ600 /2 = Apparent viscosity

Θ3 at 10 secs and 10mins = gel strength(lb/100ft2)

remedy to kick. remedy to blown well. gas out measurement. telemetry system.

?S

ANA industries Drilling fluids Manuals, (2004).Ofite drilling fluids equipment manuals, (2010)http://www.ofite.com/products/110-10.asp