ABSTRACTPH or hydrogen ion concentration is used todetermine whether a substance is leaning towards acidity or alkalinity. Sinceit is important that your drilling mud is alkaline, it is necessary todetermine the PH of your mud before sending it downhole. This is becausehaving a high concentration of hydrogen ions in our drilling mud, poses seriousproblems.
The viscosity of bentonite will be least affected if the PH is within the range of 7 to 9.5. Above this, theviscosity will increase and may give viscosities that are too high for gooddrilling properties. Also, for reducing shale problems, a PH of 8.5 to 9.5 gives the best hole stability andcontrol over mud properties. Corrosion is also another disadvantage of low PH. The corrosion of metal is increased if it comesinto contact with an acidic fluid.
So, a higher PHwould be desirable to protect pipe and casing from corrosion. TABLE OF CONTENTTITLE PAGE Abstract – – – – – – – – – 2Table of content – – – – – – – – 3Introduction – – – – – – – – 4Experimentapparatus/diagram – – – – – 5Colorimetric Method – – – – – – – 7o Procedure:Sample 1o Results: Sample1o Procedure:Sample 2o Results: Sample2o PrecautionElectrometric Method – – – – – – – 8o Procedure:Sample 1o Results: Sample1o Procedure:Sample 2o Results: Sample2o PrecautionDiscussion – – – – – – – – – 10Conclusion – – – – – – – – – 10References – – – – – – – – – 11 INTRODUCTION The term PH is used to express the concentration of hydrogenions in aqueous solution. PH is the logarithm of the reciprocal of thehydrogen ion concentration in gram moles per litre. In a neutral solution (e.
g.pure water), the hydrogen ion (H+) and the hydroxyl ion (OH-) concentrationsare equal, and each is equal to 10-7. A PHbelow 7 shows an increase in acidity, while an increase in PHabove 7 shows an increase in alkalinity. The PHcan be determined either by using the colorimetric methodor the electrometric method. EXPERIMENTAL APPARATUS/DIAGRAM. ColorimetricMethod1. PHpaper 2.
Mixer3. Spatula4. Measuringcylinder5. Weighingscale Electrometric method1. PHmeter2. Mixer3. Spatula4.
Measuringcylinder5. Weighingscale Fig 6.1 showing a PH meterFig 6.2 showing a mixer Fig 6.
3 showing PH paper Fig 6.4 showing a weighingbalanceUSING THE COLORIMETRICMETHOD (PH PAPER) The PH paper is impregnated with dyes that exhibitdifferent colours when exposed to solutions of varying PH. High concentration of salt in the sample mayalter the colour developed by the dyes and cause the estimate of PH to be unreliable. PROCEDURE: SAMPLE 11. Inorder to prepare my Sample 1, I measured and mixed 350 ml of water (H2O) and 25gof Bentonite.2. Ithen tore off a short strip of litmus paper and placed it on the surface of mySample 1.3.
Afterthe colour of the test paper had stabilized, I matched the changed colouragainst the standard colour chart. RESULTS: SAMPLE 1 Valueof PHas read using the standard colour chart =9 PH PROCEDURE: SAMPLE 21. In order to prepare my Sample 2, I measuredand mixed 350 ml of water (H2O), 25g of Bentonite and 5g of CaCl.2.
Ithen tore off a short strip of litmus paper and placed it on the surface of mySample 1.3. Afterthe colour of the test paper had stabilized, I matched the changed colouragainst the standard colour chart. RESULTS:SAMPLE 2 Valueof PHas read using the standard colour chart = 7 PHPRECAUTION1. Iavoided sticking the PHpaper into the sample.2.
Imade sure the colour of the test paper was stabilized before matching itagainst the standard colour chart. USINGTHE ELECTROMETRIC METHOD (PH METER) The PH meter is an instrument that determines the PH of an aqueous solution by measuring theelectropotential generated between a special glass electrode and a referenceelectrode. The electromotive force (EMF) generated across the speciallyformulated glass membrane has been found empirically to be almost linear with PH of the solution. The meter has a range of 0 to 14 PH unit, with accuracy and repeatability = 0.1 PH unit. PROCEDURE: SAMPLE 11. Inorder to prepare my Sample 1, I measured and mixed 350 ml of water (H2O) and 25gof Bentonite.2.
I poured the mixture into a sample cup andturned the PH meter on.3. Ipushed the PH/mv key until the annunciators indicated thedesired mode.4. Iset the temperature compensation manually by adjusting the temperature over arange of 0?to 100?C.
5. Irinsed the probe with distilled water and immersed the probe into the mixture.6. Ileft the probe in the mixture for 60 to 90 seconds until the reading stabilizedand then took my reading. RESULTS: SAMPLE 1Value of PH as read using the PHmeter= 9.
2 PH Temperature of the sample 1 tested = 26.4°C PROCEDURE: SAMPLE 21. In order to prepare my Sample 2, I measuredand mixed 350 ml of water (H2O), 25g of Bentonite and 5g of CaCl.2. Ipoured the mixture into a sample cup and turned the PH meter on.3.
Ipushed the PH/mv key until the annunciators indicated thedesired mode.4. Iset the temperature compensation manually by adjusting the temperature over a rangeof 0?to 100?C.5.
Irinsed the probe with distilled water and immersed the probe into the mixture.6. Ileft the probe in the mixture for 60 to 90 seconds until the reading stabilizedand then took my reading.
RESULTS:SAMPLE 2 Valueof PHas read using the PH meter = 7.3 PH Temperature of the sample 2 tested = 26.7°C PRECAUTION1. Inever let the probe tip become dry. I always kept the glass bulb of the probemoist for fast response.2. Afterusing the electrode, I covered it with the rubber cap. DISCUSSION In my results for Sample 1, it shows that the PH will have no significant effect on the viscosityof the mud since the PHis within the range of 7 – 9.
5 PH.Also, the PH of Sample 1 will provide good hole stability andmud property control when used to minimize shale problems. Theaddition of salt (CaCl) to the mud (Sample 2), which is a contaminant that canbe encountered by the mud during drilling operations, affected the mud bycausing a decrease in the PHvalue. If the value had been further decreased, it could corrode the casing anddrilling equipment when used. CONCLUSION Determining our PHis very important because it helps us to prevent or minimize corrosion and tocontrol other mud properties like viscosity. The optimum control of some mudsystems is based on PH,as is the detection and treatment of certain mud contaminants. Other reasonsfor PH control include maintenance of lime-treated muds,effective use of thinners, and corrosion mitigation.
REFERENCES- DrillingMud Laboratory Manual.- Pet315 Lecture Note.
