Instructions - OFI Testing Equipment, Inc.

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OFI Testing Equipment – 146-00 Instructions – Workover and Completion Fluids Test Kit Page 14 of 17 A. Add at least 1.0 mL of sample to the Beaker. If the filtrate is colorless or is only slightly colored, omit steps B - E. B. Add 10.0 ml of Sodium Hypochlorite solution and mix. C. Add 1.0 ml of Glacial Acetic Acid and mix. D. Boil the sample for 5 minutes and maintain the sample volume by adding distilled water as required during boiling. Boiling removes excess Chlorine and this may be verified by immersing a strip of Ph paper in the sample. If the paper is bleached white, continue boiling. A sufficiently boiled sample will have a pH of 5.0. E. Cool the sample and wash the sides of the beaker with distilled water. F. With distilled water, dilute the sample to approximately 50 ml. G. Add 10 to 15 ml of Calcium Buffer solution, or sufficient Buffer solution to produce a pH of 12 - 13. H. Optional: The presence of soluble Iron may interfere with the endpoint determination. If this is suspected, a mixture of Triethanolamine: Tetraethylenepentamine : Water (1:1:2 by volume) is a suitable masking agent. I. Add sufficient Calver ® II Indicator powder (0.1 to 0.2 grams) to produce a pink to wine-red color if Calcium is present. Too much indicator will obscure the endpoint. Note: Adding several drops of Methyl Orange Indicator solution may improve the visibility of the endpoint. J. While stirring, titrate with Hardness Titration solution (EDTA), to the end point. Calcium indicators produce a Red-to-Blue change and the endpoint is best described as that point where additional Titration solution will produce no further Red-to-Blue color change. The Titration solution volume will be used in the calculation procedure. 3. Using the 1 ml pipette, add 1.0 ml of the original undiluted mud filtrate to the titration dish. Titrate with EDTA titration solution to the calcium endpoint, as above. Call this volume EDTA V f . 4. Retort the whole mud. Determine the volume fraction of water in the mud by using the volume percent of water from the liquid and solids determination based upon the following equation. Volume Fraction of Water, F w = Volume Percent Water 100 Calculation: Total Calcium Sulfate, lb/bbl = 2.38 ( EDTA V t ) The excess undissolved Calcium Sulfate content of the mud in pounds per barrel may be calculated as follows: Excess Calcium Sulfate, lb/bbl = 2.38 (EDTA V t) – 0.48 [EDTA V f x (F w )] Procedure: MAGNESIUM CONTENT The Hardness Titration test and the Calcium Titration test must be performed first. The total milliliters of Versenate Titration solution (EDTA), 1 mL = 400 mg/L Ca ++ used in the determination of total hardness, minus the milliliters of Versenate Titration solution (EDTA) used in the determination of calcium ion, times 243 equals the mg/L of Magnesium. OFITE • 11302 Steeplecrest Dr. • Houston, TX 77065 USA • Phone (832) 320-7300 • http://www.ofite.com Version 1.1 Date 03-04-03
OFI Testing Equipment – 146-00 Instructions – Workover and Completion Fluids Test Kit Page 15 of 17 Calculation: Mg ++ , mg/L = (mL EDTA, Total Hardness – mL EDTA, Ca++) x 243 mL of Filtrate POTASSIUM & POTASSIUM CHLORIDE OFI Part No. 285-09 Centrifuge Method: > 5000 Milligrams per Liter KCl (1% KCl) Potassium ion is used in drilling fluids to aid in the stabilization of shales and to control swelling clays. The accurate determination of the potassium ion content is necessary to control the properties of the drilling fluid. This procedure is used to measure the potassium ion content in mud filtrates at levels above 5000 milligrams per liter or 3.5 pounds per barrel KCl. The procedure is most accurate in the range between 10,000 mg/L (2%) and 40,000 mg/L (8%) KCl and is suspect below 10,000 mg/L (2%) KCl. Potassium is precipitated in a centrifuge tube as the perchlorate salt, and then the precipitate volume is measured. The potassium ion content is then read from a prepared standard curve. Equipment: #153-21 Centrifuge Tube, Kolmer, 10 ml (2 supplied) #153-25-2 *Centrifuge, Hand Crank, with dual head and shields #153-38 Pipette, 5 ml x 1/10 ml, glass Reagents: #206-02 Distilled Water, 16 oz #285-10 *Sodium Perchlorate sol'n, 16 oz (UN1502) #285-11 Potassium Chloride sol'n (standard), 4 oz Procedure - Generating a Standard Calibration Curve: 1. A standard calibration curve is required for each type of centrifuge. A minimum of three points or test procedures (3.5, 10.5 & 17.5 pounds per barrel) is required to obtain an accurate graph. 2. Samples can be prepared by using the standard potassium chloride solution where 0.5 ml of standard potassium chloride solution is equivalent to 3.5 pounds per barrel KCl. 3.5 ppb KCl = 1 % KCL = 5000 mg/L ≅ 0.5 ml standard KCl solution. Therefore - A. To obtain 3.5 ppb equivalent KCl or 1% KCl use 0.5 ml of standard potassium chloride. B. To obtain 10.5 ppb equivalent KCl or 3% KCl use 1.5 ml of standard potassium chloride. C. To obtain 17.5 ppb equivalent KCl or 5% KCl use 2.5 ml of standard potassium chloride 3. Dilute the samples in the centrifuge tube to the 7.0 ml mark with distilled water and agitate the mixture. 4. Add 3 ml of standard sodium perchlorate solution to each centrifuge tube and do not agitate. 5. Centrifuge at a constant speed of approximately 1800 revolutions per minute for one minute and read the precipitate volume immediately. It will be necessary to counterbalance the centrifuge tube with another tube and 10 ml of liquid of the same weight. A fairly constant 1800 revolutions per minute can be obtained by determining the number of revolutions of the rotor per each turn of the crank. Move the crank very slowly and count the number of revolutions of the rotor head during one turn of the crank. For example, 15 revolutions of the rotor per one turn of the crank. Calculate the number of crank turns required to obtain 1800 revolutions of the rotor head. In the example to obtain 1800 revolutions of the head would require 120 turns of the crank (1800/15). Thus the crank must be turned 120 times in one minute to obtain the rate of 1800 OFITE • 11302 Steeplecrest Dr. • Houston, TX 77065 USA • Phone (832) 320-7300 • http://www.ofite.com Version 1.1 Date 03-04-03
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Instructions - OFI Testing Equipment, Inc.

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