PET 327 GROUP E
Hydrogen Ion Concentration
26TH January, 2018
Hydrogen ion concentration ( pH ) is the percentage or ratio of hydrogen ion present in a given solution. The analysis of the pH value help us to determine the general nature of the solution whether it be acidic, alkaline or neutral. This analysis is done using a pH scale ranging from 0 to 14.The nature is truly determined by the ratio of the hydrogen content to that of the hydroxyl ion, where a solution is neutral; it contains equal concentration of hydrogen ion and hydroxyl ion and has a pH value of 7. An acidic solution contains a higher percentage of hydrogen ion to that of hydroxyl and so occupies the values of 0 to 6, where a solution of 0 pH is more acidic than that of 6. Same goes to an alkaline or basic solution contains more of the hydroxyl ion to that of hydrogen ion with pH value of 8 t0 14. When a solution is with 14 as a pH value is more alkalinic than that of 8 as its pH value.
It is important to monitor the pH value of our mud to avoid wellbore instability which may result from the pitting of our drill pipes and other metallic components of our drilling system or eroding our casing strings.
The pH of our mud could either increased or decreased when drilling by contaminants encountered down hole. An effective or concise drilling mud is basic in nature and a reduction of its ph could result in shale swelling or make our drilling mud flocculate.
TABLE OF CONTENT
2. TABLE OF CONTENT
The pH of a solution is the concentration of hydrogen ions present in that solution which is the logarithm of the reciprocal of the hydrogen ion concentration measured in grams per litre. The pH scale is used as a reference to determine if a solution is acidic, basic or neutral, which ranges from 1 to 14. Where solutions that falls between 0 to 6 is said to be acidic and those above 7 to 14 is basic while those with 7 is neutral.
The pH could be measured using the
1. Colorimetric method
2. Electrometric method
In this method a pH paper is used. This paper changes to different colours when exposed to solution with regards to the measure of its hydrogen ion concentration
FIG 1. pH paper
This is done by placing a strip of this paper on the surface of the sample to be analyzed .After the colouration stabilizes then u match against the standard colour chart for analysis.
ELECTROMETRIC METHOD :
Here a pH meter is used to the pH of the solution by measuring the electropotential generated between a special glass electrode and a reference electrode
BENTONITE + WATER
1. Measure a 350ml of water and pour into the electric mud mixer cup
2. Measure 25g of bentonite
3. Turn on the electric mud mixer
4. Gently turn the measured bentonite into the mud mixer cup containing water to avoid lumps
5. Mix until your solution becomes homogeneous
6. Place your pH paper on the surface of your sample
7. Match the strip of paper to the standard chart and record the observed pH
8. Rinse the probe of the electrometer with distilled water and then place it into our sample
9. Leave for about 2 minutes and then take your reading
BENTONITE +WATER + SALT
1. Measure 5g of salt ( calcium chloride )
2. Place the mud back into the mud mixing machine
3. Turn on and gently pour your salt into the mixture
4. Mix for a while
5. Place your pH paper on the surface of your sample
6. Match the strip of paper to the standard chart and record the observed pH
7. Rinse the probe of the electrometer with distilled water and then place it into our sample
8. Leave for about 2 minutes and then take your reading
Colorimetric method: 9 pH
Electrometric method:9.2 pH at 26 degree celcius ,-111nv
Colorimetric method:7 pH
Electrometric method:7.25 pH AT 26 degree celcius,- 44nv
1. I ensured that I did not stick the pH paper into the sample
2. I ensured I rinsed the probe of the electrometer with distilled water before use
3. I ensured that my mud was homogenous before I stopped mixing
From the experiment I was able to show the effect of contaminants like salts (cacl) on the pH value of our drilling mud. It was observed that after the addiction of our salt to the mud , we recorded a slight decrease in the pH our mud.
From my experiment it shows that proper steps should be taken to maintain the pH of our mud due to contamination and avoid instance of wellbore instability as a result of change in pH
Fig 1; gotten from unitedsci.com
Fig 2 ; gotten from specmeter.com