The document describes a mud weighting experiment where barite was added to bentonite mud to increase its density. Barite is commonly used to weight muds because it is inexpensive, readily available, and chemically inert, allowing mud weights to reach 20 ppg. The experiment involved preparing bentonite mud, measuring its initial density, then adding 117.6g of barite and measuring the final density. Some potential sources of error included barite powder being lost or sticking to surfaces during mixing and imprecise electronic balance measurements.

1. Supervised by:
Mr. Pshtewan T. M. Jaf
Mr. Muhammed Jamal
Prepared by:
Muhammed Hassan Aziz
Ahmad Jalal Hassan
Muhammed Fuad Rashid
Safwan Tofiq Ameen
Muhammed AbdulWahab
Group: B
Date of submit: Oct 28,2020
Koya University
Faculty of Engineering
Petroleum Engineering Department
Third stage
Drilling lab
Exp. No:2
Mud Weight
©2020

2. 2
Contents
1.0. Aim of the experiment.....................................................................................................3
2.0. Theory.............................................................................................................................4
3.0. Test equipment ...............................................................................................................5
4.0. Calibration.......................................................................................................................6
5.0. Test procedure ................................................................................................................7
6.0. Calculation.......................................................................................................................8
7.0. Discussions......................................................................................................................9
7.1. Discussion by: Muhammad Hassan Azeez.....................................................................9
7.2. Discussion by Ahmad Jalal Hasan ...............................................................................11
7.3. Discussion by Muhammed Fuad Rashid......................................................................12
7.4. Discussion by: Muhammed AbdulWahab ...................................................................13
7.5. Discussion by: Safwan Tofiq Ameen ...........................................................................14
8.0. Referencing ...................................................................................................................15

3. 3
1.0. Aim of the experiment
The main aim of the experiment is to prepare a typical mud with known density
and then modify its physical properties (density) by adding a limited amount of
barite to it and increase the muds density, and this procedure is called the mud
weighting.

4. 4
2.0. Theory
The density of a mud is increased by adding barite, a commercial grade of barium
sulphate. Barite is used as a standard weighting agent because of its low cost,
high specific gravity, inertness, and low abrasiveness. Commercial barite is a
mined product that undergoes very little processing other than grinding. Its specific
gravity averages about 4.25. Pure barium sulphate has a specific gravity of 4.5,
indicating that some impurities are present in the commercial grade. Applying
weighting process to increase the hydrostatic pressure, at that time kick and
blowout not happen.
And mud weighting with barite has many advantages such as:
1. Ease to use
2. Density increases to (21pound per gallon) & 𝑆. 𝐺 (2.52)
3. Achieve high densities in a low addition rate
4. Formation pressure controlling
5. Improve the boreholes stability
6. Inert chemically
7. Doesn’t react with the other additives
8. Particle break down limited

5. 5
3.0. Test equipment
1. mud balance apparatus
2. electronic balance
3. syringe
4. beaker
5. electric mixer
Figure 1mud balance apparatus Figure 2 electronic balance
Figure 3 syringe
Figure 4 electric mixer Figure 5 Beaker

6. 6
4.0. Calibration
1- Cleaning the cup and removing the lid from it and then completely filling the
cup with the fresh water, Wipe dry and replace the lid.
2- Water should come out from the lids hole
3- Set the rider on 8,33ppg or 1 specific gravity
4- Add or remove the steel shot from the shot well until the instrument is in balance
and the bubble in the level rests in the center of the glass.

7. 7
5.0. Test procedure
1- By mixing bentonite and water prepare a mud.
2- By mud balance apparatus measure the density of the mud.
3- Adding (117.6gm) of the barite to the mud.
4- Repeat measuring the density of the mud, as you see the density of the
mud has been increased.

8. 8
6.0. Calculation

9. 9
7.0. Discussions
7.1. Discussion by: Muhammad Hassan Azeez
Weighting materials are substances with a high specific gravity which can be
added to the mud to increase its density usually to control the formation pressure.
Barium sulfate (𝐵𝑎𝑆𝑂4) or barite is the most common weighting material used in
drilling fluids. It has an API defined specific gravity of 4.2, which makes it possible
to increase the mud weight up to 21ppg. It’s cheap and readily available.
Question1/ what is the barites chemical composition?
Answer/
(𝐵𝑎𝑆𝑂4)
Q2/ why barite is the most common weighting material?
A/
 It’s applicable in deep, high temperature wells.
 By increasing slurry density, it helps improve the muds displacement and
restrain the high formation pressure.
 The environmental protection agency (EPA) does not classify barite additive
as a hazardous waste.
Q3/ what are the barites application?
A/
 Increase the density of the mud up to 21ppg (2.5gm/cc).
 Stabilize the bore hole.
 Controlling the formation pressure.
 Prepare solids-laden for well control application.

10. 10
Q4/ during the mud weighting what are the common errors that we face?
A/
When we adding the barite powder to the bentonite mud some of the powder is
lost in the air and some of it sticks to the steel vessels. And our electronic balance
was not reading the points so maybe we gain some errors here because we don’t
know if we added the exact amount of the barite or bentonite.
Q5/ what are the differences between the mud density and mud weighting
experiment?
A/
Mud density Mud weighting
1- We are doing two density tests in
this experiment first for the mud
balance apparatus it means testing the
waters density which is knowable to
calibrate the mud balance, second for
measuring the muds density which is
the bentonite mud.
1- We are doing three density tests in
this experiment first for the mud
balance apparatus it mean testing the
waters density which is knowable to
calibrate the mud balance , second for
measuring the first muds density which
is bentonite mud, third for measuring
the final muds density which is the
mixture of the barite and bentonite.
2- We only prepare one mud. 2- We prepare two muds.
3- We use only one substance in the
mud barite or bentonite because we
prepare one mud.
3- We use two substances in the muds
barite and bentonite because we
prepare more than one mud.

11. 11
7.2. Discussion by Ahmad Jalal Hasan
Mud Weight is one of the important tasks that every petroleum engineer should
know about it, because it’s very important to control the High overburden pressure
in the sub surface which we encounter while drilling a well, if the hydrostatic
pressure (𝑃ℎ) of the mud is not greater than the formation pressure (𝑃𝑓) While
Drilling then the mud will be kicked out from the well and blow out occurs.
so it’s necessary to increase the density of the mud in order to Balance Formation
pressure, therefore the only way is by adding a weighting material, there is different
materials with different characteristics like Calcite (CaCO3) or Hematite (Fe2O3),
but we used Barite in our experiment because its widely used and its chip also it
doesn’t increase the viscosity so stuck pipe won’t happen.
Barite is a mineral composed of barium sulphate (BaSO4). It receives its name
from the Greek word "barys" which means "heavy." This name is in response to
barite's high specific gravity of 4.5, adding Barite to the mud does two Main things
which are:
1. Increases density of the mud (to Balance Formation Pressure).
2. it cools the drill bit.
3. the high-density barite mud suspends the rock cuttings produced by the drill
and carries them up to the surface.
in previous experiment we made a mud with Density of 8.6 ppg and we tried to
make it 10, but there was a tiny difference between the theoretical and the practical
result, it was due to some reasons which properly are:
1. we used fresh water instead pure water so it affected specific gravity of the
liquid (mud) which is proportional to density.
2. The temperature wasn’t standard that should be in room temperature to get
accurate results.
3. The quality of barite wasn’t perfect.
There is some question that could be asked like below so we answered them:

12. 12
Q 1 why we used syringe for water measurement?
A because the cylinder has big scales which would be difficult to measure it
correctly so we used syringe which is small scaled.
Q 2 when whitening of barite why we reset the device on zero when we put
barite on a paper?
A because the paper itself has a weight to avoid wrong measurements.
7.3. Discussion by Muhammed Fuad Rashid
QWhy we use Barite to mud weighting?
ans -Barite increases the hydrostatic pressure of the drilling mud allowing it to
compensate for high-pressure zones experienced during drilling.
-The weighing agents are added in mud to counter the formation pressure. Any
formation has to counter the overburden pressure and as a result develops some
pressure off its own.
Q What are the problems with interpreting pressure from mud weight?
Ans Different operators have different policies about how much margin to allow
between formation pore pressure and mud pressure; the range in margin is quite
large. Also, the well bore can penetrate a pressure seal for many hundreds of feet
without penetrating a permeable zone, in which case mud weight may not reflect
the presence of abnormal pressure below the seal. In general, mud weight should
be a clue to be confirmed by other evidence.
Q Barite is chosen worldwide as the weighing agent of choice?
ans because
a) it is inexpensive
b) Easy to get

13. 13
c) Has high specific gravity (4.1-4.2 sg) which can provide a mud weight up to 2.4
sg (20 ppg)
d) Chemically inert to the formation and other drilling fluid additives
e) Non- abrasive f) Nontoxic.
Q What were the errors in the experiment?
Ans 8.6 ppg was required from bentonite-water mixture, result from mud balance
was 8.52.
10ppg was required by adding barite to the mud, but result from mud balance was
9.9.
Qwhat’s the factor get you error?
Ans/ a-if you don’t use pure water content a many impurities that effected on
density.
b-accuracy on mud balance
c-loss (barite and Bentonite) when add to mixer.
d- Mud loss from steel vessels and water loss from beaker and during balance test.
7.4. Discussion by: Muhammed AbdulWahab
What will happen if the mud weight is too high?
Lost circulation
If the hydrostatic pressure from mud column exceeds formation strength, it will
cause a formation to break. Once the formation is broken, drilling fluids will be lost
into the induced formation fractures.
Decrease in rate of penetration

14. 14
Heavier mud weight will result in slower ROP because of hold down effect.
Practically, while drilling, low mud weight is used at the beginning and mud weight
will be increased, as the well is drilled deeper in order to optimize ROP and mitigate
well control.
Deferentially Stuck Pipe
Since there are differences between formation pressure and hydrostatic pressure,
there will be a lot of chances that a drill string will get deferentially stuck across
permeable rocks.
Formation damage
The more mud weight that is in the well, the more mud filtration invades into porous
formations. The invaded mud will cause damage to formation rocks.
7.5. Discussion by: Safwan Tofiq Ameen

15. 15
8.0. Referencing
1- Mohammed,P.,2014. Drilling Engineering Laboratory Manual
2- Society for Mining, M. and Kogel, J., 2009. Industrial Minerals & Rocks:
Commodities, Markets, And Uses (Industrial Minerals And Rocks). Society
for Mining, Metallurgy and Exploration Incorporated.
3- King, H., 2020. Barite Mineral | Uses And Properties. [online] Geology.com.
Available at: <https://geology.com/minerals/barite.shtml> [Accessed 27
October 2020].
4- Cormack, D. (2007). An introduction to well control calculations for drilling
operations. 1st ed. Texas: Springer.