WorldWide Drilling Resource

17 WorldWide Drilling Resource ® MAY 2015 Drilling Fluid Updates by Ray McLarty Drilling Fluids & Grouts Questions & Answers Question We have an environmental job com- ing up in Arkansas, and would like your help in calculating how much 3/8-inch Hole Plug, which is specified for this job, it will take to grout the holes. We have one bore that will be 60 inches with a 30-inch casing 30 feet deep. We have five 18-inch holes with 10.50-inch casing. They are also 30 feet. How much Hole Plug will it take for each 18-inch hole, how much for the 60-inch hole, and what kind of price are we looking at for the material? Thanks for your help. Answer Good to hear from you again. I am sending you information on who you need to call to get pricing and delivery information on the HOLEPLUG ® material you will need for the job. The easiest way to calculate the amount of product needed is to obtain a metric card from one of the bentonite manufacturers which shows the volume of various sized holes, including the cubic feet per linear foot of hole. Baroid IDP , CETCO ® , Wyo-Ben , and M-I SWACO all have these. In my Halliburton RedBook ® , it shows a 60-inch bore has 19.64 cubic feet per linear foot, and a 30-inch one would have 4.91 cubic feet per linear foot. Subtract the two and we have 14.73 cubic feet per linear foot. My silver-haired friend “Bentonite Bob” Oliver told me there was approximately 68 pounds of 3/8-inch HOLEPLUG ® in one cubic foot. So simple multiplication tells us a 60-inch bore with a 30-inch casing 30 feet deep will require 30,050 pounds or 601 50-pound bags of 3/8- inch HOLEPLUG ® . If you don’t have a metric card, one way to calculate it is as follows: Square the size of the bore by mul- tiplying it times itself. Divide the answer by 24.5. This gives you the gallons per foot of hole. Multiply the gallons per foot by 30, which is the depth of the hole. This gives you the total gallons. Divide the total gallons by 7.48, which is the number of gallons in a cubic foot. This gives you 19.64, which is the cubic feet per foot of hole. Do the same with the casing and the answer is 4.91. As you did above, subtract 4.91 from 19.64 and the answer is 14.73. 14.73 x 68 = 1001.64 x 30 foot depth = 30,049 pounds or 601 50-pound bags Example: 60 x 60 = 3600 gallons ÷ 24.5 = 146.94 gallons per foot ÷ 7.48 = 19.64 cubic feet per foot 30 x 30 = 900 gallons ÷ 24.5 = 36.73 gallons per foot ÷ 7.48 = 4.91 cubic feet per foot 19.64 - 4.91 = 14.73 x 68 pounds per cubic foot = 1001.64 x 30 feet = 30,049 pounds ÷ 50 = 601 50-pound bags Using the same formula as above, the amount of HOLEPLUG ® required for the 18-inch bores would be 48 50-pound bags per hole. For five holes, it will re- quire 238 50-pound bags. Therefore, total bags required for the job will be 839 bags. There are 912 bags on a truckload. You should be able to get a McLarty cont’d on page 18.