pH in drilling mud

pH is a value representing the hydrogen ion concentration in liquid. We use it to indicate acidity or alkalinity of drilling mud especially water base mud. Let’s talk about general of the pH. The pH is presented in a numerical value (0-14) which means an inverse measurement of hydrogen concentration in the fluid.

The pH formula is listed below;

pH = -log10[H]

Where: H is the hydrogen ion concentration in mol.

According to the pH formula, the more hydrogen atoms present, the more acidity of substance is but the pH valve decreases. Generally speaking, the pH of 7 means neutral. Fluids with a pH above 7 are considered as alkaline. On other hand, the fluids with pH below 7 are defined as acidic.

In the drilling mud, there are three main chemical components involving in Alkalinity of drilling fluid which are bicarbonate ions (HCO₃-), hydroxyl ions (OH-), and carbonate ions (CO₃-2). As you may not know about what is the Alkalinity. The Alkalinity means ions that will reduce the acidity.

So as to get accurate measurements for the pH, you need to use a pH meter instead of using a pH paper because it can give you more accurate figures. However, you need to ensure that the pH meters should be calibrated frequently.

Reference Drilling Mud blog

Tags: drilling, in, mud, pH

Comment by Drilling Ahead on April 14, 2011 at 2:12pm: I think to a derrickman it would be good to understand the role that pH plays in drilling muds. For instance when making a sweep in areas with hard water soda ash should be added to the water to lower the "hardness" of the water-this allows the gel to work much better-THEN a sack of lime may be added AFTER the gel-if you add the lime 1st you are increasing the "Hardness AND alkalinity.
( "Hardness" is actually a measure of calcium in the water but it is true that hard water is naturally likely to also have a high pH, because it is also high in carbonates that buffer the pH toward the alkaline side)

Many dispersants require a high pH to actually work well so if you are dispersing your mud and the pH is low then you are just spinning your wheels. You really need a pH of around 11 ( in my opinion) although 9.5 is whats advertised for most dispersants to work well.

Also a pH of at least 9.5 is preferred for protection of drill pipe.
Adding dispersants to a low pH mud is just wasting the product with few exceptions. "Desco" is a brand of thinner that can be added to water based muds of low pH and would be the product to use when low pH mud is coming back "flocked"

I could add more-but these are just my opinions from a derrickmans perspective and experience-maybe someone else will add more to the blog remarks,

Thanks again Rachain for another great addition to our website!

Comment by Marek on December 8, 2011 at 6:16am: I ask for more information about the mud.

Thanks

Comment by Khalil Ferris on April 23, 2013 at 2:33am: Good point above but i would like to add that Hardness is an indication of Total dissolved minerals Using Hardness indicator and Titraver 400/4000. To get Calcium levels A Mud Engineer must use CalVer 2 tabs and Titrated using Titraver 400/4000 to get an end point. This is especially important when Running a High Calcium System or when Magnesium is present. Also when using CalVer 2 tabs the Filtrate in the dish should turn purple/pink color and blue when an end point is reached but if the color turns a greyish black color that can be an indication of Co² present in Mud.

Comment by Khalil Ferris on April 23, 2013 at 2:40am: Calcium Hydroxide (used in Cement jobs) Can have a pH source since Hydrogen is present ( As mentioned above). Calcium Nitrate does and should be Alkaline. Usually this is an issue when drilling out cement. Just food for thought

AREA	LAST COUNT DATE	COUNT	CHANGE FROM PRIOR COUNT	DATE OF PRIOR COUNT	CHANGE FROM LAST YEAR	DATE OF LAST YEARS COUNT
UNITED STATES	5/17/13	1769	+0	5/10/13	-217	5/18/12
CANADA	5/17/13	118	+5	5/10/13	0	5/18/12
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INTERNATIONAL	04/2013	1301	+33	3/2013	+123	4/2012

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pH in drilling mud

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