WorldWide Drilling Resource

17 WorldWide Drilling Resource ® JANUARY 2014 Drilling Fluid Updates by Ray McLarty Drilling Fluids & Grouts Questions & Answers I want to start off this month by wish- ing everyone a prosperous and Happy New Year. I hope one and all had a great Christmas and old Santa was good to you. In late November, we had the newly-formed West Tennessee/Central Tennessee Drilling Conference at Pick Wick Inn in Pick Wick Dam, Tennessee. For years we had a West Tennessee Convention in December at Pick Wick Inn, and it was one of my favorite shows to attend. We always had a real good crowd. We had distributors/manufactur- ers booths set up, continuing education classes, a social hour and dance, and finally on Sunday we had what we called a Farewell Fellowship Breakfast. It has been close to 20 years since this show ended. Hopefully, we will continue hav- ing the new show in November and it will grow and we will have all the events we used to. This year we did not have the din- ner and dance, or the Sunday breakfast. Hopefully, we can do it in the future. A special thanks to Robert Gentry at Gentry Drilling in Leoma, Tennessee. Robert was instrumental in putting the new show together. We had continuing edu- cation classes, and the following two questions were asked and discussed during yours truly’s presentation: Question We have conflicting information about the addition of bentonite to cement grout. We have one state or region requiring drilling contractors to add 10% bentonite to cement prior to pumping and place- ment. A lot of operators say this is a waste of time; others say it makes the pumping and placement easier. What do you think? Answer This question has been debated and discussed for years. I never put much stock in the addition of bentonite to cement. Cement pretty well destroys all of the good characteristics of bentonite. It is true that heat of hydration is reduced when adding bentonite and additional mix water. However, the amount of water added reduces the solids content, strength, and integrity of the cement grout. I have heard some knowledgeable people defend the use of bentonite with cement. I know at the national event one year, I think when it was held in Washington, this was discussed heat- edly during a presentation on grouting, until Sam Geffen (Mr. Bentonite) made this statement: “The use of 10% ben- tonite added to a cement grout is a hell of a waste of a good bentonite.” I agree with everything he ever said in regard to the use of bentonite. I would like to invite anyone - drilling contractors, reg- ulators, etc. - who would like to com- ment on the use of bentonite in cement for grouting a well, to send your com- ments to me for a future article. Question How long do we have to wait prior to pumping cement on top of a ben- tonite plug? Answer As long as possible. If you can, wait overnight. If you cannot wait that long, at least give the bentonite plug a cou- ple of hours to hydrate and seal before adding the cement. You will get an ini- tial seal in 45 minutes to an hour. If it is possible, place a buffer, such as sand, above the bentonite plug. The statements and comments in this article are my own and are based on information and references believed to be true and factual. If you have a question or comment on this article, or on bentonite drilling muds, polymers, grouts, or additives, please forward them to me in care of WWDR . Ray Ray McLarty may be contacted via e-mail at admin@ worldwidedrillingresource.com &% ! "" * "(%$ ))) (" $( ' & $ %# # " (" $( $ ( " !" !! ! &% ! % ! (" $( & $ $ $ " ! $ $ ! ! $ ! $ # $ $ $ You have a great magazine. Burt Thomas International Directional Services Vernon, Utah