WorldWide Drilling Resource

17 WorldWide Drilling Resource ® AUGUST 2013 Drilling Fluid Updates by Ray McLarty Drilling Fluids & Grouts Questions & Answers Question We had problems mixing a high- yield bentonite drilling mud. We talked to someone with the manufacturer and they told us to check the pH of the water we used to mix with, and if it was below 9, to add soda ash. We did, but it still seemed like we used a lot more product than what whe were told we would. We had material floating on top of the water; and when emptying the pan, we had a lot of product on the bot- tom that did not get mixed up good. What should we have done differently? Answer There are four major factors affect- ing bentonite drilling mud performance: 1 - mix water 2 - mixing equipment 3 - time 4 - product used First and foremost is the mix water. Think about it, you’re adding around 25 pounds of high-yield bentonite drilling mud to 100 gallons (833 pounds) of water. So the mud is made of 97% water. If you have bad mix water, it makes sense you will have bad mud. So doesn’t it also make sense that the first thing you should check is your mix water? Of course it does. And you did check the mix water. And you did add soda ash to treat any hardness and raise the pH to the ideal reading of 8.5 to 9.0. The second factor we need to check to see why our mud did not perform as expected is the mixing equipment. A lot of people successfully mix mud by adding it directly into the suction. However, if you look at their mud pit, I would be will- ing to bet you will find lumps floating around on top of the mix. These lumps, buckeyes, or whatever you want to call them are dry material that did not get sheared and mixed, and is therefore going to waste. The same is true for gobs of material laying on the bottom of the mud pan that did not get dis- persed, sheared, and mixed into the system. It was wasted. The easiest, least expensive, and I think one of the best ways to mix drilling mud is through a jet hopper mixture. It is a simple piece of equipment made of 2-inch steel pipe, a 12-inch x 12-inch hopper or funnel, and a 3/8-inch jet inside the 2-inch pipe. The majority of the ones I see on jobsites are home- made. If you can’t find one or make one, e-mail me and I will get you info on availability and cost from manufac- turers, or I can send you a Baroid IDP jet hopper design we have been pro- viding to drill operators for years. In fact, the one I have on my desk says BAROID DIVISION NL Industries . It has been a long time since Baroid was a part of National Lead. The design shows a suggested layout, sizing, and place- ment of all parts of the jet hopper mixer. The third factor affecting mixing/ performance is time. Regardless of the type of mixer being used, you must allow time for the bentonite to be dis- persed, sheared, and then hydrated. It is not a rapid process. Slowly add the bentonite to the mix water, giving it McLarty cont’d on page 20.