© 2019 Department of Petroleum Resources. All rights reserved Department of Petroleum Resources (DPR) PROCEDURE GUIDE

Page 60 of 114
 
59 | P a g e 
 
 
2.6.5.5.1 During the certification of Master meters, repeatability shall check to 0.020%. 
2.6.5.6 Oil producing Companies shall on a monthly or quarterly basis, submit to the 
appropriate field office of the Department of Petroleum Resources, an acceptable 
schedule for the proving of all meters in use at their facilities. 
2.6.6 Rules Governing Meter Factors  
2.6.6.1 The difference between the meter factors calculated from each of the series of 
complete runs made for a meter in a proving operation should not exceed ±0.0015. 
Where this limit is exceeded, the proving should be regarded as unsuccessful, and 
the meter serviced. During servicing, the clearances are checked and wax or any 
foreign deposit is removed before the meter is re-assembled, ensuring minimum 
change in the set point (s) of the meter’s inner mechanism components/ accessories. 
A second proving is then carried out to establish a meter factor which would be 
regarded as base factor (as there could occur a change in the inner mechanism 
accessory). Thereafter, if subsequent meter proving yield meter factor which are out 
of tolerance, with other conditions remaining within acceptable range, the inner 
mechanism (including any other major accessory) is changed in the presence of a 
representative of the Department of Petroleum Resources.   
2.6.6.2 An initial meter factor shall be re-established for the meter before it is put back to 
use. 
2.6.6.3 The difference between the meter factors obtained for any two successive proving 
for a meter should not exceed ±0.0025.  
2.6.6.4 A meter performance chart (see attached specimen “Appendix V”) shall be kept for 
each meter in use in all facilities. 
2.6.6.5 The repeatability of five (5) consecutive proving runs of meter factor or K factor out 
of maximum of ten runs made for a meter proving operation should not exceed 
±0.020% (0.040%).   
 
 
Repeatability = 
𝑀𝑎𝑥𝑖𝑚𝑢𝑚 𝑀𝑒𝑡𝑒𝑟 𝐹𝑎𝑐𝑡𝑜𝑟 − 𝑀𝑖𝑛𝑖𝑚𝑢𝑚 𝑀𝑒𝑡𝑒𝑟 𝐹𝑎𝑐𝑡𝑜𝑟
𝑀𝑖𝑛𝑖𝑚𝑢𝑚 𝑀𝑒𝑡𝑒𝑟 𝐹𝑎𝑐𝑡𝑜𝑟
∗100 
 
Or                  = 
𝑀𝑎𝑥𝑖𝑚𝑢𝑚 𝐾 𝐹𝑎𝑐𝑡𝑜𝑟 − 𝑀𝑖𝑛𝑖𝑚𝑢𝑚 𝐾 𝐹𝑎𝑐𝑡𝑜𝑟
𝑀𝑖𝑛𝑖𝑚𝑢𝑚 𝐾 𝐹𝑎𝑐𝑡𝑜𝑟
∗100 
 
2.6.7 Quality Control Chart  
A quality control chart shall be established for each meter during the initial proving of 
the meter before it is put to use. The quality control chart shall be reviewed and 
revalidated after five consecutive operational proving of the flow meter. The quality 
control chart shall be re-established after every comprehensive overhaul or 
maintenance of a meter in which the inner mechanism set points or essential references 
have been altered.