INSTRUCTIONS: MINILAB 5 PART No

Transcription

1 OFI Testing Equipment Minilab 5 Instructions Page 1 of 5 INSTRUCTIONS: MINILAB 5 PART No DESCRIPTION: This kit is used in testing the chloride ion concentration, alkalinity and lime content, and the total hardness of drilling fluids and filtrates. The analysis of mud filtrate is required on all daily drilling mud reports in order to diagnose the performance of the drilling fluid and to determine salt contamination. These chemical analyses, in addition to ph determinations, are probably the most frequent checks made on a drilling mud. Calcium sulfate content of a mud can also be determined with the equipment provided. EQUIPMENT: Part No. Description Beaker, 50 ml Titration dish, 150 ml Graduated pipette, 1 ml Graduated pipette, 2 ml Graduated pipette, 5 ml Graduated pipette, 10 ml ph indicator strips, range 0 to 14 Spatula, No. 1 porcelain Stirring rod, 6 inch, glass Thermometer, 0 to 220 deg. F, pocket type Case, stainless steel Reagents: Buffer solution, strong, 2 oz Calcium carbonate, precipitated, CP grade, 2 oz Distilled water, 4 oz.

2 OFI Testing Equipment Minilab 5 Instructions Page 2 of Hardness indicator solution, manver, 2 oz Methyl orange indicator solution, 2 oz Methyl orange/bromocresol green indicator solution, 2 oz Phenolphthalein indicator solution, 2 oz Potassium chromate indicator solution, 2 oz Silver nitrate solution, N, 4 oz Silver nitrate solution, 0.282N, 4 oz Sulfuric acid solution, 0.02N, 6 oz Sulfuric acid solution, 0.1N, 6 oz Standard versenate solution, 0.01 molar EDTA, 6 oz. Accessories: Pipetter, Pi-pump, Filler/Dispenser, capacity 10 ml Chloride ion Concentration 1. Measure one or more milliliters of filtrate into the titration vessel. Add 2 or 3 drops of phenolphthalein. If the indicator turns pink, add acid drop by drop from a pipet, with stirring, until the color is discharged. If the filtrate is deeply colored, add an additional 2 ml of 0.02N sulfuric or nitric acid and stir. Then add 1g of calcium carbonate and stir. 2. Add 25 to 50 ml deionezed water and 5 to 10 drops of potassium chromate indicator. While stirring continuously, add the silver nitrate solution drop by drop from a pipet, until the color changes from yellow to orange-red and persists for 30 seconds. 3. Record the milliliters of silver nitrate solution required to reach the endpoint. If over 10 ml of silver nitrate solution are used, repeat the test with a smaller sample of filtrate. CALCULATIONS: Chloride, mg/1 = (ml of.0282n Silver Nitrate) x (1000) Ml of filtrate NOTE: If the chloride concentration of the filtrate exceeds 10,000 mg/1, 0.282N silver nitrate solution (equivalent to 0.01g chloride ion per milliliter) may be used. The calculation then becomes: Chloride, mg/1 = ml of 0.282N Silver Nitrate x 10,000 Ml of filtrate For any normality of silver nitrate, the following equation may be used: Chloride, mg/1 = ml silver nitrate x normality x 35,450 Ml of sample To convert units:

3 OFI Testing Equipment Minilab 5 Instructions Page 3 of 5 Chloride, ppm = Chloride, mg/1 Specific gravity of filtrate Salt (NaCl), ppm = 1.65 x Chloride, ppm Grains per gallon = x ppm Pf (phenolphthalein Alkalinity) 1. Using a 1.0 ml transfer pipette, measure 1.0 ml of filtrate into the titration vessel. 2. Using the 25 ml graduated cylinder, add 25 ml of deionized water. 3. Add 2 to 4 drops of phenolphthalein indicator solution. 4. If the solution turns pink, rinse and fill the 25 ml burette with the 0.02N hydrochloric acid. 5. Add the acid drop by drop, form the burette into the titration vessel, with stirring, until the pink color just disappears, or until the ph is 8.3, as measured by a glass-electrode ph meter. 6. Report the phenolphthalein alkalinity of the filtrate, Pf, as the number of ml of 0.02 normal acid requirement for one ml of filtrate. Mf (Methyl Orange Alkalinity) 1. To the same sample which has been titrated to the P end point, add 2 or 3 drops of Methyl Orange indicator solution. 2. Continue adding standard 0.02 normal Hydrochloric acid drop by drop from the burette, with stirring, until the color of the indicator turns from yellow to pink, or to a ph of 4.3 as measured by a glass electrode ph meter. 3. Report the methyl orange alkalinity of the filtrate, Mf, as the total ml of 0.02 normal acid per ml of filtrate required to reach the methyl orange end point (including that required to the P end point). NOTE: Standardized 0.02 Normal Sulfuric acid may be used instead of Hydrochloric acid. Methyl Orange Bromocresol green may be substituted for the Methyl Orange Solution. When MOBCG is added, the sample will turn green and the Methyl Orange end point is reached when the sample turns from green to yellow. Pm (Mud Alkalinity) 1. Measure 1 ml of mud into the titration vessel using the 1 ml pipette. 2. Dilute the mud sample with 25 to 50 ml of distilled water. 3. Add 4 or 5 drops of phenolphthalein indicator and while stirring, titrate with 0.02 normal acid or 0.1 normal acid until the pink color just disappears. If the sample is so colored that the color change of the indicator is masked, the end point is taken when the ph drops to 8.3 as measured with the glass electrode. 4. Report the phenolphthalein alkalinity of the mud, Pm, as the number of milliliters of 0.02N (N/50) acid required per milliliter of mud. If 0.1 normal acid is used, Pm = (5) (milliliters of 0.1 normal acid per milliliter mud). Lime Content

4 OFI Testing Equipment Minilab 5 Instructions Page 4 of 5 1. Determine the phenolphthalein alkalinity of the filtrate and the mud, Pf and Pm, as described above. 2. Determine the Volume Fraction of water in the mud, Fw, using the value for volume percent water form the liquid and solids determination in the following equation: Fw = Volume percent Water Report the lime content of the mud in lb per bbl calculated form the following equation: Lime, lb/bbl = 0.26 (P Fw Pf) Lime, kg/m (3) = (Pm Fw Pf) If liquid and solids determinations are not made, approximate values for Fw based on mud gradient are given below for muds containing no oil and for muds containing 10 and 15% oil by volume. Fw for muds containing other percentages may be obtained by subtracting 0.01 for each 1.0% oil from the value for Fw with no oil. APPROXIMATE VALUES FOR Fw Mud Gradient Mud Density 10 percent 15 percent Psi/M ft Lb per Gal Lb Cu Ft No Oil Oil Oil Note: For other percentages of oil, subtract 0.01 for each 1 percent oil from the value of Fw for no oil. PROCEDURE #1 Total Hardness 1. Add approximately 20 ml of deionized water to titration vessel. 2. Using a graduated pipette, add 1 or 2 ml of water or filtrate to be tested. 3. Add 1 ml of strong buffer solution. 4. Add 6 drops of Manver Indicator and mix with a stirring rod. A wine color will develop if calcium and/or magnesium are present. 5. Using a graduated pipette, titrate with the standard Versenate solution, stirring continuously, until the sample first turns blue with no undertint of red remaining. Record ml of standard Versenate used. (If magnesium is needed to be determined, call this value a ml).

5 OFI Testing Equipment Minilab 5 Instructions Page 5 of 5 CALCULATIONS: Total Hardness (CaCO3,ppm) = (ml of Standard Versenate) x 1000 M/ of sample Calcium, ppm = (CaCo3ppm) (0.4) PROCEDURE #7 Calcium Sulfate API 1. Add 5 ml of mud to 245 ml of deionized water. Stir the mixture for 15 minutes and then filter through hardened filter paper. Discard the first cloudy portion of filtrate. 2. To approximately 50 ml of deionized water in a titration vessel, add about 2 ml of strong buffer solutions and sufficient calmagite indicator solution to give a strong color (2 to 6 drops). If a red color develops, indicating hardness in the water, add Versenate solution dropwise until the water first turns blue. Do not include this volume of Versenate Solution in the calculations. 3. Add 10 ml of clear filtrate from a pipette, stirring continuously, until the sample first turns to blue. In filtrates colored reddish-brown by chemical thinners, the masking effect of the thinner tint may cause the color change to be from brownish-purple to slate gray. Record the number of ml of Standard Versenate used as Vt. 4. Titrate 1 ml of filtrate of the original mud to the versenate end point using the same procedure described in Steps 2 and 3. Use 1 ml of filtrate from original mud instead of 10 ml from diluted mud, in Step 3. Record the number of ml of Standard Versenate used as Vf. CALCULATIONS: Total calcium sulfate, lb/bbl = 2.38 Vt Undissolved calcium sulfate, lb/bbl = 2.38 Vt 0.48 Vf Fw Where: Vt = ml of Standard Versenate solution to titrate 20 ml of the filtrate of the diluted mud. Vf = ml of Standard Versenate solution to titrate 1 ml of filtrate of the original mud. Fw = Volume fraction of water in the mud Fw = Volume percent water 100

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