drilling engineering lab

1. Drilling Engineering-I
Pet-E-211L
Lab Instructor :
Engr. Muhammad Awais Qureshi
Department of Petroleum &
Gas Engineering 5/5/2021

2. Experiment # 06
• Objective:
1) Measurement of yield point of drilling mud sample using
viscometer.
5/5/2021

3. Apparatus
• Rotational viscometer,
• Bentonite,
• Water,
• Graduated Cylinder,
• Stirring Rod,
• Balance,
• Beakers
• PPE’s (Personal Protective Equipments)
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4. Related Theory
• Yield Point:
• A parameter of the Bingham plastic model.
• YP is the yield stress extrapolated to a shear rate of zero.
• A Bingham plastic fluid plots as a straight line on a shear rate (x-
axis) versus shear Stress y-axis) plot , in which YP is the zero-
shear-rate intercept.(PV is the slope of the line.)YP calculated from
300- and – 600 rpm viscometer dial readings by subtracting PV from
the 300-rpm dial reading.
• YP is used to evaluate the ability of a mud to lift cuttings out of the
annulus.
• A high YP implies, non-Newtonian fluid, one that carries cuttings
better than a fluid of similar density but lower YP.
• YP is lowered by adding deflocculant to a clay based mud and
increased by adding freshly dispersed clay or a flocculant, such as
lime.
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5. Rotational Viscometer
• Rotational viscometer uses the
idea that the torque required to
turn an object in a liquid is a
function of the viscosity of that
liquid.
• It measures the torque required
to rotate a disk or bob in a liquid
at a known speed.
• Rotational viscometers are
commonly used for measuring
viscosity of Non-Newtonian fluids
.
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6. OFITE-8 SPEED
VISCOMETER
• The Model 800 8-Speed Electronic Oilfield Viscometer is
designed and exclusively manufactured by OFI Testing
Equipment, Inc. It is extensively used worldwide in both
the field and laboratory for precisely measuring the
rheological properties of drilling fluids and cement.
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7. Features
• Speeds are easily changed with a control
knob
• Shear stress values are displayed on a
lighted magnified dial for ease of reading
• Suitable for both field and laboratory use and
uses a motor-driven electronic package to
provide drilling fluid engineers with an
extremely accurate and versatile tool
• Operates anywhere in the world without
flipping switches or re-wiring
• Threaded rotor - mechanically attaches to
the unit the same way every time
• Available with retractable legs for placement
in kits
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8. 5/5/2021

9. Measurement Procedure
1) Mix the sample on the “STIR” setting for 10 seconds.
2) Set the speed to 600 RPM. Wait for the reading to
stabilize and then record the dial reading and
temperature.
3) Set the speed to 300 RPM. Wait for the reading to
stabilize and then record the dial reading and
temperature.
4) YP = 300 RPM Reading- PV
Units:
1) PV is measured in centipoise
2) YP is measured in lbf/100 sq. ft.
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10. Demonstration
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11. Observation and
Calculations
• PV = 600 RPM Reading — 300 RPM Reading .
• YP = 300 RPM Reading- PV
• PV = 600 RPM Reading — 300 RPM Reading .
• PV = ____________ cp
• YP = ______________
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RPM (on viscometer) Viscometer Readings
300
600

12. Precautions
1. Sleeve and bob should be washed after each operation.
2. The rotor bob assembly should be lowered slowly into
the beakers up to the mark.
3. Wear relevant Personal Protective Equipment (PPE)
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13. Viva Voce
Q1) Which is Yield point ?
Q2) What is the physical meaning of the yield Point? Q3)
Why a high Yield Point value is prederable?
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