ANSI API RP 10B-6-2010 pdf download.Petroleum and natural gas industries — Cements and materials for well cementing
6.2.1 If there is a batch mixing time being used for the job, the test schedule should include this segment. The slurry should be exposed to the anticipated temperature conditions during the batch mixing time. The pressure at this time shall be atmospheric. The stirring is typically maintained at 2,5 r/s ± 0,25 r/s (150 r/min ± 5 r/min). If there is no batch mixing time, omit this step. 6.2.2 Calculate the expected time to bottom and the expected placement time required to displace the cement to the flow zone. Ramp the cement slurry to bottom-hole circulating temperature (T PBHC ) and the bottom-hole pressure (P BH ) in the expected time to bottom. Then ramp to the circulating temperature and pressure at the flow zone. The time interval to ramp to the circulating temperature and pressure at the flow zone is the expected placement time to the flow zone, minus the expected time to bottom. After the circulating temperature at the flow zone is reached, hold at the specified temperature and pressure for 5 min ± 30 s to allow for temperature stabilization. Maintain paddle rotation at 2,5 r/s ± 0,25 r/s (150 r/min ± 15 r/min). In cases when an extended period of fluidity is expected, the test temperature may be increased to static temperature at the flow zone in 240 min after reaching the circulating temperature at the flow zone plus 5 min for temperature stabilization. During the placement simulation, the temperature and pressure shall be maintained within 3 °C (5 °F) and 2 MPa (300 psi) of the appropriate elapsed time versus temperature and pressure targets. Within 10 min after the end of the ramp, the temperature and pressure shall be within ± 1 °C (± 2 °F) and 0,7 MPa (100 psi) of the specified values. NOTE During the time of stirring at API/ISO rotational speeds [2,5 r/s ± 0,25 r/s (150 r/min ± 15 r/min)], the test gives an indication of slurry consistency. It is not an exact slurry thickening time consistency since the paddle does not conform to the required dimensions for determining thickening time.
6.2.3 For the SGS determination, at the end of the slurry placement simulation, the rotational speed is changed from the typical 2,5 r/s ± 0,25 r/s (150 r/min ± 15 r/min) to 0,000 009 2 r/s (0,2°/min) or other permissible rotational speed. Maintain circulating temperature and pressure at the zone of interest. During SGS determination the temperature and pressure shall be maintained within ± 1 °C (± 2 °F) and ± 0,7 MPa (± 100 psi) of the target values.
6.2.4 Record the initial SGS and the elapsed time when the sample is placed in SGS determination mode from the previous placement simulation. Record the time to 50 Pa (100 lbf/100 ft 2 ), 100 Pa (200 lbf/100 ft 2 ), 150 Pa (300 lbf/100 ft 2 ), 200 Pa (400 lbf/100 ft 2 ) and 250 Pa (500 lbf/100 ft 2 ) SGS and, CSGS. Where applicable, determine the critical static gel strength period (CSGSP) by measuring the time required for the cement to progress from the critical static gel strength (CSGS) value (see Annex A) to a SGS of 250 Pa (500 lbf/100 ft 2 ). The manufacturer, model and rotational speed of the apparatus used to make the SGS determination shall be reported.
8.1 Apparatus
The cement slurry being tested is maintained in a static condition in a pressure chamber at a controlled temperature and pressure. The SGS is calculated from the torque required to rotate a paddle of known geometry intermittently at very low speed. This apparatus typically operates intermittently at 0,000 16 r/s ± 0,000 005 r/s (0,01 r/min ± 0,003 r/min) for 6 s after an interval of time adjustable between 1 min and 10 min during the SGS- testing phase. Generally, an intermittent rotation every 3 min is used during the SGS-testing phase. The intermittent rotation-type static gel strength apparatus shall be calibrated according to the manufacturer’s instructions. During the test period, the temperature of the slurry in the test cell is increased in accordance with the appropriate well simulation test schedule (see 8.2.4). Determine the temperature of the cement slurry by use of an ASTM E220 classification “special” type J thermocouple located in the cement slurry. The temperature- measuring system shall be calibrated to an accuracy of ± 2 °C (± 4 °F). Calibration shall be performed no less frequently than every three months.ANSI API RP 10B-6-2010 pdf download
