This document describes an experiment to measure the pH of a water-based mud (WBM) using a pH meter. It provides background on how pH is measured and its importance in drilling operations. The student calibrated the pH meter using water with a pH of 7 and acid with a pH of 4.01. They then measured the pH of the WBM and found a reading of 7.89, but after accounting for the calibration error of 0.27, the actual pH of the mud was 8.16. The experiment demonstrated how to properly calibrate and use a pH meter to determine the pH of a drilling mud.

1. Soran University
Faculty of Engineering
Department of Petroleum Engineering
Drilling Engineering I
Title: PH Meter Measurement
Experiment No.: 9
Name: Muhammad Sulaimon Rasul
Group: B2
Date: 18/NOV/2019
Supervisors: Mr. Jagar Ali, Mr. Fouad, Mr. Rawezh

2. Contents
Aim………………………………………………………………………………………….…….1
Theory…………………………………………………………………………………….…….…1
Apparatus…………………………………………………………...…………………………..…2
Calibration………………………………………………………………………………………...3
Procedure………………………………………………………………………………………….3
Calculation………………………………………………………………………………...………4
Result and Discussion……………………………………………………………………………..5
Conclusion………………………………………………………………………………………...5
References…………………………………………………………………………………………6
List of Figures
Figure 1 Lab Spatula………….……………………………………………...….….……….….…2
Figure 2 Beaker. …………………………………………….………..........…………….….…….2
Figure 3 Weighting Material ……………….…….….…………….………………………......….2
Figure 4 Cylinder …………………………………………………………………………………2
Figure 5 Water/Acid …...………………..…………….………………………………….………2
Figure 6 Electronic Mud Mixture ………………………………………………………………...2
Figure 7 pH meter …...…………………………………….………………...….……....…..…….2
List of Tables
Table 1 Experimental and Theorical Results……………………………………………………..5

3. Aim
This experiment tends to measure pH of mud using a pH meter.
Theory
The hydrogen ion concentration (pH), is measure of degree of acidity or alkalinity of the drilling
mud. The pH value ranged between 0-14, while 0.6 beng acid, 7 is neutral, and 8-14 being alkaline.
In the drilling fluid, there are three alkalinity composition in a drilling mud involving bicarbonate
ions (HCO-3
), hydroxyl ions (OH-
), and carbnate ions (CO3-2
) which are reducing the acidity of
the drilling fluid. Usually, the pH of mud falls between 8 to 11 depending on mud type excep salt
muds (Kate, 1998).
As usuall, the pH measured by pH meter which measures the potential differnce which gives a
derect deal reading of the pH. The most common one is pH paper, which change its color according
to the acidity or alkality. Always, the pH meter shows more accurate reading of pH. pH has a big
role in controlling the well stability, corrosive damage, amount of mud filtrate, gel strength of a
mud, and especially solubility of calicium (Kruse, 1975).
At hight pH values, the active clays in mud tends to disperse and the solubiliy of calicuim become
very limited; which makes a high pH of mud suitable for driling in carbonate formations.
Controlling corrosion is another situation related to pH, a minimum value of 9.5 should be
maintained in order to prevent oxygen corrosion of casing, drille pipe and etc (Azar et al., 2007) .
1

4. Apparatus and Materials
Apparatus
• Electronic Mud Mixer: Is a device used to mix liquid-solid particles. Shown in Figure 6.
• Lab Spatula: Used to mix mud and water manually. Shown in Figure 1.
• Beaker or Graduated Cylinder: Is a cylindrical container used to measure volume of a
liquid. Shown in Figure 2.
• pH meter: Is a device used to measure pH of a mud. Shown in Figure 7.
• Mud Balance: Is a device used to measure fluid density. Shown in Figure 6.
Materials
• Water with pH of 7 and Acid with pH of 4.01 which used to calibrate pH meter. Shown in
Figure 5.
• Bentonite: Is a weighting material used to create a WBM.
• Mud: Is a mixture of weighting material and water.
• Barite: Is a weighting material used to rise a density of mud.
2
Figure 1 Lab Spatula Figure 2 Beaker Figure 3 Weighting
Material
Figure 4 Graduated
Cylider
Figure 5 Acid / Water Figure 6 Mud Mixer Figure 7 pH meter

5. Calibration
1. Bring a distillated water and put a side of calibration of pH meter inside.
2. Put the probe of the meter into the acid. And the meter should read 4.01.
3. If the reading was smaller than 4.01 then should find the difference between the shown pH
and 4.01 then add the difference to the PH of the mud sample and vice versa if the pH of
the acid is greater than 4.01.
Procedure
1. Ready a mud with specified density and put it to beaker.
2. Bring the mud in beaker and put probe of pH meter inside.
3. Make sure other part of probe inside the water.
4. Read the pH.
5. Record it and ± error from the calibration.
3

6. Calculation
4

7. Result and Discussion
Table 1 Experimental Results
According to Table 1, the water and weighting materials has prepared to create a water base mud
as usual as Lab 2 in previous experiments. The pH meter was used to measure the pH of mud
which calibrated with Acid at pH of 4.01, while the pH meter read the pH of acid; showed that the
pH is 3.74 which its less than actual pH of acid. This will cause error if the differential pH does
not measure between actual and pH read from pH meter. The actual has been subtracted from the
pH read which was calculated in the calculation, equaled to 0.27. After the pH of mud has been
measured, 0.27 should be added to read pH from the pH meter. The pH meter read 7.89 and after
adding 0.27 from the calibration, the actual pH of mud becomes 8.16.
.
Conclusion
This experiment can conclude that, A Venturi meter can be used to determine the flow rate in the
pipelines and the pressure loss that occurring in order to control the discharge fluid addition to the
discharge coefficient of a Venturi meter.
Materials Mass(gm) Volume(cc) Density(ppg) pH
Water - 200 8.33 7
Bentonite 15 - 20.8 -
Barite 2 - 35 -
Acid - - - 4.01
WBM - - - 8.16
5

8. References
Azar, J. J. & Samuel, R., 2007. Drilling Engineering. Tulsa, Oklaoma: PennWell Corporation.
Kate, V.D. (1998): Drilling Fluids, Mud Pumps and Conditioning Equipment.
Kruse, C.F. (1975): Lessons in Rotary Drilling, Unit II-Lesson 2 “Drilling Mud”. 12th Edition.
Published by Petroleum Extension Service Industrial and Business Training Bureau Division of
Extension, The University of Texas.
6