The most important function of a drilling mud is to suspend and
remove cuttings from the bit and take them to the surface. This process depends
mainly on the rheological properties of the mud.
The experiment was done in order to determine the rheological
properties of bentonite mixed with water only (sample 1) and bentonite mixed
with barite and water only (sample 2). The readings were recorded after
conducting the experiment and the plastic viscosity, yield point, and apparent
viscosity of both samples were gotten after much calculations were done.
For sample 2: 52 ÷ 2= 26cp
For sample 1: 40 ÷ 2= 20cp
For sample 2: 50 – 2= 48lb/100ft2
For sample 1: 33 – 7= 26lb/100ft2
sample 2: 52 – 50= 2cp
For sample 1: 40
– 33= 7cp
GEL STRENGTH FOR SAMPLE 2
GEL STRENGTH FOR SAMPLE 1
b. I ensured that the line on the rotor
sleeve was in contact with the sample.
a. I avoided error due to parallax while
taking RPM readings.
experiment I ensured the following precautions:
removed the splash guard and wiped down the bob shaft and cleaned all parts
with soap and water dry
removed the bob.
the test, I removed the sleeve from the rotor.
12. For sample 2, I repeated the same procedure above.
11. I re-stirred the mud and waited for 10minutes before
recording the maximum dial deflection for the 10minute gel strength.
10. I waited for 10 seconds after the sleeve stopped rotating
and turned the power on while looking at the dial. Then I recorded the maximum
dial deflection before the gel breaks at the 10-second gel strength.
rotated the speed selector knob to the gel setting and turned the power switch
returned the speed selector knob back to the stir setting and re-stirred the
sample for a few seconds.
rotated the speed selector knob to the 300 RPM setting, waited for the dial to
reach a steady reading and recorded the 300 RPM setting.
rotated the speed selector knob to the stir setting and mixed the sample for a
few seconds. I rotated the knob to the 600 RPM setting and waited for the dial
to reach a steady reading and recorded the 600 RPM reading
turned the power switch behind the panel on.
poured the mixture into a sample cup on the platform and elevated the platform
until the line on the rotor sleeve was in contact with the sample. Then I tightened
the nut on the platform.
used the electric mixer to mix the sample until I had smooth mixture.
added 70g of bentonite into the mixing cup along with my already measured
sample 1, I measured 350ml of water in the measuring cylinder.
20g of barite.
700ml of water
70g of bentonite
For sample 2
700ml of water
70g of bentonite
For sample 1
SAMPLES USED FOR THE EXPERIMENT
Fig1.0. rotary viscometer
The test speeds observed in this experiment are 30, 60, 300,
600. While the range of gel strength test observed are for 10seconds and
Viscosity is defined as the internal resistance to flow and
gel strength, the minimum shear stress required to produce slip-wise movement.
The aim of this experiment is to determine the viscosity and gel strength of
Bentonite mixed with water alone (sample 1) and bentonite mixed with barite and
water alone (sample 2). The instrument used to ascertain the measure of these
properties is the rotary viscometer. The rotary viscometer determines the flow
characteristics of drilling mud in terms of shear stress and shear rate over
different time and temperature ranges, at atmospheric pressure.
USED FOR THE EXPERIMENT. 6
The rheological properties of a mud such as viscosity and gel
strength are very instrumental in the success of a drilling operation. They are
responsible for the suspension and removal of drill cuttings which results in
adequate hole cleaning. If these properties are not optimum, there will be an
accumulation of cuttings downhole which could lead to stuck pipe and a host of
Date Submitted: 21-01-2018.
Date Performed: 19-01-2018.
NWOGBO CHINEDU BRIGHT
A REPORT ON EXPERIMENT 1-DETERMINATION OF RHEOLOGY OF A GIVEN VOLUME OF MUD.
PETROLEUM ENGINEERING LABORATORY
COVENEANT UNIVERSITY, CANNANLAND OTA, OGUN STATE, NIGERIA.
DEPARTMENT OF PETROLEUM ENGINEERING