CONSISTOMER OIL AND HEAT TRANSFER FLUID IS CURRENTLY UNDER DISCUSSION ON API MONOGRAM PROGRAM COMMITTEE. Spec 10 A and RP10B2

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1 PLEASE FIND BELOW VARIOUS COMMENTS RECEIVED SINCE APRIL 2013 WHEN API RP 10B 2 WAS RELEASED. OTHER PROBLEMS OR ISSUES THAT HAVE BEEN UNCOVERED SINCE THE RELEASE ARE: CONSISTOMER OIL AND HEAT TRANSFER FLUID IS CURRENTLY UNDER DISCUSSION ON API MONOGRAM PROGRAM COMMITTEE. Spec 10 A and RP10B2 FLUID LOSS SCREEN REPLACEMENT ON STATIC FLUID LOSS TESTS OTHER ISSUES UNCOVERED IN Spec 10A that apply to 10B 2 OTHER ISSUES NOT YET DOCUMENTED OR PSSIBLE MISSED, ===================================================================================== DETERMINING GEL STRNGTH TOM DEALY API RP 10B, Twenty Second Edition, 1997 gives the following instructions for determining 10 sec and 10 min gel strength for cements: 12.7 Procedure for determination of gel strength The gel strength of a cement may be measured immediately after determining the rheological properties of the slurry sample, or as an independent observation. If increasing slurry gelation is observed during the rheological measurements a brief recondition of the slurry in the viscometer for 1 minute at 300 RPM may disperse the gels and allow better measurement of the gel strength. For all independent tests, the slurry should be prepared and loaded into the viscometer as outlined in through Shut off the viscometer for 10 seconds and record the slurry temperature Set the viscometer at the speed equivalent to 5.1 1/s and start rotation. Record the maximum observed reading immediately after turning on the instrument. Use this reading to calculate the 10 second gel strength per equation 20. Equation 20: Τ(lb/100 sq ft) = x F x θ Where: Τ =The shear stress in lb/100 ft 2 F = The instrument s torsion spring factor Θ = The viscometer reading in instrument degrees

2 Shut of the viscometer for 10 minutes and record the slurry temperature. Repeat the measurements as in to report the 10 minute gel strength After taking the readings, the temperature of the slurry in the viscometer cup should again be recorded The slurry gel strengths should be reported at the average of the recorded temperatures For improved reliability of the measurements, the entire procedure may be repeated several times using a freshly prepared sample of slurry each time. If the procedure is repeated several times, the gel strength values should then be reported as the average of all the acceptable measurements. At this time, there were no instructions for determining any gel strength tests at times other than 10 seconds and 10 minutes and the conditioning at 100 rpm was only performed before the 10 second gel strength determination. As Tom mentioned a 10 second gel strength measurement would not interfere with the 10 minute gel strength substantially so it was not reconditioned after the 10 second gel strength. In API RP 10B 2, First Edition, July 2005, the wording is basically unchanged. However, in the current version of API RP 10B 2, Second Edition, April 2013; it now contains information about performing the static gel strength at other times INSTEAD of 10 MINUTES. If another time is used (such as 30 or 60 minutes) the 10 second gel strength is not performed on the same slurry according to these procedures. If several gel strengths are desired, other tests will need to be performed for each static gel strength test. The rheological readings do not have to be performed on these other gel strength times, only condition the slurry at 300 rpm for 1 minute and then perform the 10 second and gel strength at the other time. It does not mention anything about determining several times on the same slurry Determination of Gel Strength The gel strength of a fluid may be measured immediately after determining the rheological properties of the sample or on a separate, freshly-prepared fluid. NOTE Gel strengths of a fluid are the measurements resulting of the application of the rheological property procedure described under These measurements are not comparable to static gel strength of a fluid measured under API 10B-6 or ISO and shall not be used for critical static gel strength determination Recondition the fluid in the viscometer for 1 min at 300 r/min to disperse the gels and allow better measurement of the gel strength. For tests on separate, freshly-prepared fluids, prepare, condition, and load the fluid into the viscometer as outlined in to and then condition the fluid for 1 min at 300 r/min Stop rotation of the rotor Set the viscometer at the speed equivalent to 5.1 s 1 (3 r/min with R1-B1 or 6 r/min with R1-B5) s after stopping the rotor, start rotation at 5.1 s 1 and record the maximum deflection of the dial observed immediately after starting rotation. Calculate the 10 s gel strength by multiplying the measured value by the factor for the applicable rotor, bob, and spring configuration found in Table Record the fluid temperature, then stop the viscometer for 10 min.

3 Start rotation at 5.1 s 1 10 min after stopping the rotor and record the maximum deflection of the dial observed immediately after starting rotation. Calculate the 10 min gel strength by multiplying the measured value by the factor for the applicable rotor, bob, and spring configuration found in Table Gel strength measurements may be taken at other static times, as desired. For other static times, follow the procedure of and , substituting the desired static time for 10 min. Dennis Comment: To me, indicates that only the 10 second and 10 minute time are performed on the same slurry. If a 30 minute gel strength is desired, the 30 minute gel strength can be substituted for the 10 minute gel strength (10 minute gel strength not performed) or a new slurry mixed if additional times are desired, the 10 second and the other desired gel strength time can be performed, but not the 10 minute plus another time After taking the maximum deflection dial reading, again record the temperature of the fluid in the viscometer cup Report the fluid gel strengths at the recorded temperatures (note the rotational velocity, the rotor/bob configuration, and spring factor used in the test) For improved reliability of the measurements, the entire procedure may be repeated two times or three times using freshly prepared fluid each time. Report the gel strength values as the average of the measurements. The drilling fluid API RP 13B 1 and is for drilling fluids. For drilling fluids, they do re stir the fluid for 10 seconds (instead of1 minute) at 600 rpm (not at 300 rpm but) before the 10 second static period and before the 10 minute static period Procedure Place the sample in a container and immerse the rotor sleeve exactly to the scribed line. Measurements in the field should be made with minimum delay (within 5 min, if possible) and at a temperature as near as practical to that of the drilling fluid at the place of sampling, but not differing by more than 6 C (10 F). The place of sampling should be stated on the test report. DANGER Maximum recommended operating temperature is 90 C (200 F). If it is necessary to test fluids above this temperature, a solid metal bob or a hollow metal bob with a completely dry interior should be used. Liquid trapped inside a hollow bob can vaporize when immersed in a high-temperature fluid and cause the bob to explode Record the temperature of the sample With the sleeve rotating at 600 r/min, wait for viscometer dial reading to reach a steady value (the time required is dependent on the drilling-fluid characteristics). Record the dial reading for 600 r/min Reduce the rotor speed to 300 r/min and wait for the viscometer dial reading to reach a steady value. Record the dial reading for 300 r/min Stir drilling fluid sample for 10 s at 600 r/min. Stop the rotor Allow drilling fluid sample to stand undisturbed for 10 s. Slowly and steadily turn the hand-wheel in the appropriate direction to produce a positive dial reading. The maximum reading is the initial gel strength. For instruments having a speed of 3 r/min, the maximum reading attained after starting rotation at 3 r/min is the initial gel strength. Record the initial gel strength (10-second gel) in pounds per 100 ft2.

4 NOTE To convert the dial reading to pascals: 1 Pa 0,511 lb/100 ft Re-stir the drilling fluid sample at 600 r/min for 10 s, stop the rotor and allow the drilling fluid to stand undisturbed for 10 min. Repeat the measurements as in and report the maximum reading as the 10-minute gel in pounds per 100 ft2. NOTE To convert the dial reading to pascals: 1 Pa 0,511 lb/100 ft2. Below are a few thoughts from Dennis Gray: 1. I do not see any place in API RP 10B 2 or earlier versions that the slurry is re stirred at 300 rpm after taking the 10 second gel strength indication or that more than two gel strength times are recommended to be performed on the same slurry. a. My thought would be if a second gel strength time is to be performed (in addition to the 10 second gel strength) it would be performed on a newly mixed slurry as the current API RP 10B 2 suggests. 2. Cements and drilling fluids have different properties. 3. The drilling fluids are probably more stable and have less of a tendency to settle or centrifuge at 600 rpm as they are conditioned for 10 seconds. 4. Drilling fluids do not set over time, but cements begin reacting as soon as they are mixed. 5. Allowing for multiple gel strength readings from the same slurry may allow the gel strength to get into a portion of the hydration period which will not be a gel strength, but an actual setting indication. a. This may be the reason cement testing does not have the slurry conditioned at 300 rpm after determining the 10 second gel strength and before determining the 10 minute gel strength (or other at another time). 6. If the longer static gel strength tests are to try to reproduce the SGS measurement performed in a MACS II, there will not be an exact correlation because of several things and some of them are: a. Although the slurry is preconditioned in an atmospheric or HPHT consistometer, the slurry must be static for a while during transferring from the conditioning unit to the Fann 35 and the test is not performed at higher temperatures and pressures. 7. Drilling fluids do not request gel strength tests be performed past the 10 minute gel strength. 8. I don t have records of API gel strength testing for drilling fluids, but suspect they have been around for a much longer time than the ones for cement. 9. Actually the 10 minute gel strength is performed 10 minutes after determining the 10 second gel strength, which will be about 10 minutes and 15 seconds for cements and about 10 minutes and 25 seconds for drilling fluids. 10. I am not sure why cement is re stirred for 1 minute and drilling fluids for only 10 seconds. 1 minute seems like it would give the slurry a chance to centrifuge out or settle and offset the gel strength measurement. If you set the timer for 30 minutes in step 9, the fluid would be sitting static for 40 total minutes before taking a reading. Therefore, you would have to pre stir the slurry at 300 RPM for 1 minute to break the gel strength before allowing it to sit static for 30 minutes.

5 The current API RP 10B 2 instructs the operator to substitute 30 minutes for 10 sec and 10 min, which is ambiguous. Initiating a global lab best practice to pre stir the slurry at 300 RPM for 1 minute prior to beginning all static periods would remove the ambiguity. Dennis Gray will be back in the office on Tuesday, November 5. I am copying him for his comments. I am also copying Robert Darbe for his comments. Robert has served as API Committee 10 Secretary for several years and is possibly most familiar with discussions on procedures. I do not know of any testing done to compare one method vs. the other, but it would be very useful. The question would be what effect does pre stirring before each static period have on final results. Please advise if the following could be classified as the correct procedure 1. Finish API rheologies 2. Complete a 1 min condition at 300 RPM (this is what recommended in API 10B for reproducibility) 3. Set rheometer to 3RPM before shutting off, simultaneously at shutoff start 10 sec timer. 4. After 10sec, turn rheometer back on and record the torque value at highest deflection point. 5. Recondition for 1 min at 300 RPM. 6. Set rheometer to 3RPM before shutting off, simultaneously at shutoff start 10 min timer. 7. After 10min, turn rheometer back on and record the torque value at highest deflection point. 8. If running another SGS test, recondition for 1 min at 300 RPM. 9. Set rheometer to 3RPM before shutting off, simultaneously at shutoff start 30 min timer. 10. After 30min, turn rheometer back on and record the torque value at highest deflection point. This will give me 10 sec, 10 min and 30 min readings. API does not specify 300 rpm conditioning between 10 sec, 10 min, 30 min, etc. readings. Below is the procedure from the latest edition, April 2013: MIXER RPM =/= ALAN DEAN SEE FOLLOWING PDF FROM MIXING As attached, the April 2013 Edition has an anomaly in the mixer allowable error. I have chosen to go with the +/-250rpm limit as it is specifically mentioned in two places in the body of the Standard. Hopefully these was considered more carefully than the entry in Table B.2

6 SEE PDF FROM RP CONVERSION FACTORS BERNARD FRABOULET as per 3) Equation 55 coefficient need to be rounded to ( or ) > Up today we found to errors with 2 occurrences in 10B-2 which need a > correction > 1) I report thermometer/thermocouple accuracy which need to be > corrected in clause and 8.2 at +/- 1 C (+/- 2 F ) as per annex > table B-2 > 2) Schlumberger/ Simon report Clause high curing temperature > which should be 88 C (190 F) and not as shown 90 C (194 F). > > 3: I found an error in Tables 8 and 9 : Conversion factor between pascal to lbf/100 ft² should be and not or if you prefer with R1B1 configuration -F1.0 spring per degree of dial deflection Pa is equivalent to lbf/100 ft² and not and so on. Table 8 and 9 should be corrected for USC values ( i hope that SI are right need to be checked) Is it all?? need to read again all clauses as Simon reported that the ballot file was right and the changes was done with the edition file ( and proof file), so something else can be found if I miss it during the last proof reading. Plan to do that but not before mid January. Coaxial cylinder viscosimeter Calculations of coefficients for R1B1 Spring factor 1 RP 13B 1, RP 13 B 2, RP13D, RP10B 2 provide the following coefficients : RP 13 D RP 13 B 1 RP13 B 2 RP 10 B 2 Shear rate coefficient ( k 3 ) s 1 Shear stress coefficient per degree lbf/100ft² Shear stress coefficient per degree * Pascal Torsion Spring F1.0 coefficient Dyne/cm and degree * calculated

7 Between these 4 recommended practices, discrepancies are observed. It is the same apparatus, coefficient should be the same one s ( USC unit shear rate coefficient is generally simplified and taken as 1). Main discrepancies is related to the shear rate coefficient, if the value is generally reported as Pa ( 5.11 dyne/cm) the conversion of this value into USC unit should be lbf/100 ft². Mario Zamora reports a value of lbf/100ft² based on a handnote written by J.G Savins ( 6/29/92) with a shear stress constant of Pa ( conversion to USC units : rounded to 1.066) The purpose of this note is to review calculations of coefficients for R1B1 configuration with spring F1.0. based on available data. Calculations introduce an experimental coefficient (k 2 ), the effective shear rate surface for the bob. 1) Shear rate coefficient per degree of dial deflection Shear rate are culated using the following formula and a k 3 coefficient based on the geometry R1B1 Viscosimeters suppliers are providing a value for k 3 of s 1 per r/min This value can be calculated using the formula used to calculate shear rate : 4π N 60 1 ² N where is the shear rate in s 1 N is the rotor speed in r/min ri is the bob external radius [B1 diameter : mm (1.358 in.)] re is the rotor internal radius [R1 diameter : mm(1.450 in. )] As dimensions are always provided in metric calculations is done with metric unit for radius ( with inches result is s 1 ) k 3 = rounded to s 1 per r/min However considering the tolerance on the diameters [ ±0.02 mm (±0.001 in.)] it should be recommended to take a value of : k 3 = 1.70 s 1 per r/min 2) Shear Stress coefficients per degree of dial deflection, k 1 k 2 In USC unit values are betwwen and lbf/100ft². Viscosimeters suppliers are providing a value of 5.11 dynes/cm ( Pa). This value expressed in lbf/100ft² will be

8 In conclusion shear rate coefficients should be recalculated based on B1 geometry and F1.0 spring torsional stiffness. 2.1 calculation using spring torsional stiffness and R1B1 effective geometry 2 ² where τ is the shear stress expressed in pascals (dynes/cm) for a dial deflection θ in degree k 1 is the spring F1.0 torsionnal stiffness : as per suppliers dynes/cm per degree of dial deflection or 3.86 Pascal per degree of dial deflection ri is the radius of the bob ( m) h is the height of the bob (0.038 m) ε is a correction factor on height for effective surface coefficient k 2 is the shear stress constant for effective bob surface. k 2 experimental value is provided by viscosimeter suppliers : cm 3 Then k 1 k 2 = x = dynes/cm rounded to Pa or Pa as given by suppliers. In USC units : k 1 k 2 = which is rounded to or lbf/100ft² 2.2 Calculation of Spring F1.0 torsional stiffness through dead weight calibration This value given at dynes/cm can be determined experimentally based on viscosimeter dead weight calibration measurement. It allows to verify the value k 1 torsional stiffness of spring F1.0 Where k 1 is the spring F1.0 torsional stiffness expressed in dynes/cm per degree of deflection M is the mass used for calibration in grams g is the gravitational constant : m/s² = cm/s² R is the radius of the calibration mandrel : cm : θ is the dial deflection in degree

9 With a mass of 100 g dial deflection should be 254 with a factory deviation of ± 0.5 k 1 = dynes/(cm. ) ±0.08 dynes/(cm. ) then shear stress coefficient per degree of dial deflection would be k 1 k 2 = ( ±0.08 ) x = dynes/cm ± dynes/cm or Pa ± Pa in USC k 1 k 2 = lbf/100ft² ± lbf/100ft² 2.3 Calculation based on overall viscosimeter coefficient Overall coefficient K is provided equal to it is used to determine viscosity with the relation θ N And K = 100 x k 1 k 2 / k 3 k 1 k 2 = ( x 300.0) /100 = dynes /(cm. ) or lbf/100ft² 2.4 Conclusion Considering the results and the incertainties of measurements the following coefficents should be recommended Shear rate coefficient per rpm : 1.70 s 1 Shear stress coefficient per degree of dial deflection : In SI units : Pa generally rounded to Pa In USC units :1.066 lbf/100 ft² to be rounded to lbf/100 ft² CALIBRATE DEFINITION DENNIS GRAY The first section below deals with the word calibrate. In one of the dictionaries I looked at, it states: to determine, check, or rectify the graduation of (any instrument giving quantitative measurements). Although calibrate can mean to make adjustments (rectify) in the definition; some are not including it can also mean check which will be to verify the accuracy. Since I and a few others mistook (and didn t look up) the actual definition of Calibrate, I would assume others may also. A suggestion is to make a statement in Annex B somewhere (possibly at the beginning or a note) that: Calibrate is a verification of an instrument or to actually make adjustments to the instrument if it is out of calibration. If a verification shows the instrument to be in calibration, the date and verification data will be the calibration. In this Calibration section, the word Verification pertains

10 to instruments that cannot be changed if they are inaccurate and the word Calibrate pertains to instruments that if they are out of calibration as seen by the Verification of the instrument may be adjusted to get them into calibration. 1. Paragraph B.2 and Table B.1 Equipment Calibration Requirements a. In this table there are a lot of components that show that they need to be calibrated. However after thinking about it, should these be verifications and if the verification is inaccurate then do the calibration? The way it is written, it does not indicate that if it is already calibrated that the previous calibration is acceptable with a new date, but the component must have the complete calibration performed. When we were going through this part of the document, I just took it for granted that if it was in calibration there was no need to calibrate it again. However, like many things there are more than 1 way to look at things and I think if it is unclear to some, it should be made clear. b. I visited with one person at the meeting and they do a verification of the calibration of the instrument and if it is still within the accuracy tolerance specifications, they consider it to be calibrated and use the old calibration for the calibration and date it was verified and in calibration at the new date. c. In the past we typically used the previous calibration but now some are asking if they need to do a new calibration although it is not needed. d. If the component is in calibration, I do not see any benefit in performing a new calibration. Sometimes a new calibration can get the component a little closer to the extreme for the tolerances than it already is (closer to being out of tolerance). e. I suggest all calibrations are changed to verification/calibration (V/C) in the table (with a note at the bottom stating V/C indicates the verification of calibration needs to be performed and only if it is not in calibration does the calibration need to be performed and the verification values are accepted at the time it is verified) and in B.2 one the calibration records contain a statement that if the component is in calibration during the as found verification, the as found verification be used as the calibration and a new calibration does not have to be performed. i. As well as in the two tables being changed to Verification/Calibration, I feel the written portion of Section B should have all the places that state shall be calibrated (or similar) be changed to verified and if out of calibration be calibrated. If in calibration, the date of the verification should be documented along with the verification values. ii. When we have a person in to test our load machine for breaking compressive strengths, they only check the accuracy of the load machine and do not make any adjustments if it is in calibration and certify it as is. I feel the same is done for our weighing scales also. f. A full calibration takes time and I feel it is a waste of time and money if the component is already in calibration as shown by the verification. 2. Paragraph B.3.5 Temperature Devices g. Basically this section recommends calibrations of the thermocouples and temperature instruments. There are some instruments (atmospheric consistometer and atmospheric water bath and possibly others) that I would suggest a different method that does not include verifying the calibration accuracy of the thermocouple. iii. Atmospheric consistometer 1. It is difficult, time consuming, can create a mess, possibly cause other operational problems and possible safety issues to calibrate the thermocouple. This is due to the bath typically being filled with oil and having to drain it, location of the thermocouple and difficulty getting to it and compactness of components in the electrical compartment where the indicator/controller resides. 2. My proposal is to allow the verification and calibration of this instrument to be accomplished by having one cell in place and rotating it to provide circulation within the bath to distribute the heat evenly, or to devise a paddle system that will fit one of the holes for the slurry cup to keep the bath at a uniform

11 temperature. Then a certified thermocouple be placed in the bath close to the tip of the atmospheric consistometer s thermocouple and connected to a certified temperature instrument calibrator to indicate the temperature of the bath. If changing the temperature results in temperatures on the certified temperature instrument calibrator and the indicator/controller on the unit are within the specified ±2 F it is in calibration. However if it is not within ±2 F the instrument/controller shall be calibrated so it reads within the specified ±2 F of the certified digital temperature calibrator. iv. Water bath with digital temperature indicator/controller and thermocouple/rtd. 3. The baths are made so it is extremely difficult to get to the thermocouple or RTD of a water bath. 4. My proposal is to allow the verification and calibration be performed with a stirring device in the water bath (if it doesn t already have one built in) to circulate the water for uniform temperature. Then a certified thermocouple be placed in the bath and connected to a certified temperature instrument calibrator to indicate the temperature of the bath. If changing the temperature results in temperatures on the certified temperature instrument calibrator and the indicator/controller on the unit within the specified ±2 F it is in calibration. However if it is not within ±2 F the instrument/controller shall be calibrated so it reads within the specified ±2 F. 3. Table B.2 Calibration and Verification of Well Cement Testing Equipment h. Digital Hand Held Thermometer v. I am not sure they have the capability to be calibrated or if they can only be verified, but it states in the table they are to be calibrated. If they can t be calibrated in the lab, I suggest they be verified for accuracy and if not within the ±2 F it be replaced. vi. I am also hearing some use this as an instrument to calibrate temperature for other instruments (such as those above). Since the accuracy of the digital thermocouple is typically no better than ±2F, I think there should a statement (possibly in the description area) stating it is only for checking temperature of a process and not an instrument to be used to calibrate another instrument. 4. Any changes that may be made, should be included when the calibration section is placed into the next version of API Specification 10A. DENNIS GRAY I was just sent an e mail about the new API RP 10B 2 where there may need to be some modifications. The problem is the weight sets are to have a tolerance of 0.1% of the stated weight for the weight (below). Table B.2 Calibration and Verification of Well Cement Testing Equipment Equipment and Calibration/ Check Points Tolerance Fr Component/Function Verification Weight sets Calibration Each piece 0.1 % of nominal value A Then when you go to the tolerances for the HPHT potentiometer weight sets they are all 0.1 gram. However if the weight sets are calibrated/verified to 0.1% of their weight, they do not meet the requirements for use in calibrating the potentiometer since at weights above 100 grams they will be out of tolerance for calibrating the potentiometer. At 150 grams the weight may be 1.5 grams at 0.1% tolerance and at 400 grams it may be at 0.1% tolerance. Does the info in Table B 2 need to have a tolerance of 0.1 grams or is there another way to make the two places so they are usable. The potentiometer weight information is below.

12 We had a comment from one of the users of the Apr 2013 edition of 10B 2 about an inconsistency. I have listed it below. Simon followed up and checked the ballot edition which was actually correct. Is there a way to correct the published version? From the user: I am looking at the new API 10B 2 second edition that just came and noticed this inconsistency: Curing at Pressures Above Atmospheric For samples cured at or below 88 C (190 F), maintain test temperature and pressure until 45 min ( 5 min) prior to testing. For test temperatures above 90 C (194 F), discontinue heating and allow samples to cool at such a rate that the sample temperature is 90 C (194 F) or less 45 min prior to testing. Maintain test pressure on the curing vessel during the cooling process. Release the pressure gradually and remove the molds from the curing vessel. Immediately remove the samples from the molds and immerse them in a water cooling bath at 27 C 3 C (80 F 5 F) for 45 min ( 5 min) until the samples are tested. Ref: API 10B-2 2 nd Edition Seems like in the whole document there is a switch from 90degC (194degF) temp reference to 88 degc (190degF) temp reference. My opinion this is due to SI vs. Imperial unit rounding. It was more convenient to reference 190degF than 194degF for Imperial unit user and easier for SI user to quote 90degC rather than 88 degf. However the gap on the quote above still stands (although the gap is not big ).

13 From: Simon James Sent: Friday, April 19, :08 AM To: Gunnar DeBruijn Subject: FW: API 10B-2 second edition Gunnar, We need to raise this to the API. The ballot version was correct: For samples cured at or below 88 C (190 F), maintain test temperature and pressure until 45 min (±5 min) prior to testing. For test temperatures above 88 C (190 F), discontinue heating 45 min (±5 min) before the end of the required curing period and cool samples as fast as possible to 88 C (190 F) or less. Maintain test pressure on the curing vessel during the cooling process. Release the pressure gradually and remove the moulds from the curing vessel. Immediately remove the samples from the moulds and immerse them in a water cooling bath at 27 C ±3 C (80 F ±5 F) for 45 min (±5 min) until the samples are tested. Simon From: Labinot Mahmuti [mailto:lmahmuti@slb.com] Sent: Thursday, April 18, :40 PM To: cembb@slb.com Subject: API 10B-2 second edition Dear Community, I am looking at the new API 10B 2 second edition that just came and noticed this inconsistency: Curing at Pressures Above Atmospheric For samples cured at or below 88 C (190 F), maintain test temperature and pressure until 45 min ( 5 min) prior to testing. For test temperatures above 90 C (194 F), discontinue heating and allow samples to cool at such a rate that the sample temperature is 90 C (194 F) or less 45 min prior to testing. Maintain test pressure on the curing vessel during the cooling process. Release the pressure gradually and remove the molds from the curing vessel. Immediately remove the samples from the molds and immerse them in a water cooling bath at 27 C 3 C (80 F 5 F) for 45 min ( 5 min) until the samples are tested. Ref: API 10B-2 2 nd Edition Seems like in the whole document there is a switch from 90degC (194degF) temp reference to 88 degc (190degF) temp reference. My opinion this is due to SI vs. Imperial unit rounding. It was more convenient to reference 190degF than 194degF for Imperial unit user and easier for SI user to quote 90degC rather than 88 degf. However the gap on the quote above still stands (although the gap is not big ).