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

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2.5.5.4 The date logged above shall be used to determine the validity of sample collected 
and will reflect the performance efficiency of the sampler to ascertain when any equipment 
failure may have occurred. Appropriate corrective action shall be taken whenever a failure 
is observed. 
 
 2.5.6 Maintenance and Proving of Automatic Sampler 
2.5.6.1 The sampling system shall be proved before installation and annually thereafter by 
injecting known quantity of water into the petroleum and petroleum product’s stream 
passing through the sampler. Alternatively, the grab efficiency of the sampler shall be 
determined. 
2.5.6.2 Analysis of the samples taken from the stream is then compared with the total value 
of initial BS&W content of the petroleum and petroleum product and the additional water 
injected. 
2.5.6.3 The detailed procedure for carrying out the exercise shall be as outlined in ASTM 
D4177/API MPMS Chapter 8. 
2.5.6.4 An official of the Department of Petroleum Resources shall be present during the 
proving and shall countersign the official record of the result of the exercise which shall 
then be sent to the Director of Petroleum Resources for approval. It should however be 
noted that for water injection method, the acceptance shall conform to ASTM D4177. 
2.5.6.5 No new sampling equipment shall be commissioned for operations without the 
approval of the Department of Petroleum Resources and any existing sampler that fails to 
be approved after a proving exercise shall be decommissioned immediately and appropriate 
corrective action taken by the operator. 
2.5.6.6 The associated flow meter serving as the pacing device of the sampler shall be 
calibrated monthly by the normal procedure for proving such measuring devices. All relief 
valve installed on the sampler receiver shall be checked and cleaned after every six months 
of operation. 
2.5.6.7 For every custody transfer operation, the auto sampler grab performance factor shall 
be between 1 ± 0.10, which shall be calculated as follows: 
 
Performance factor  = 
𝑆𝑎𝑚𝑝𝑙𝑒 𝑉𝑜𝑙𝑢𝑚𝑒 𝐶𝑜𝑙𝑙𝑒𝑐𝑡𝑒𝑑 (𝑚𝑙)
𝑆𝑎𝑚𝑝𝑙𝑒 𝑉𝑜𝑙𝑢𝑚𝑒 𝐶𝑎𝑙𝑐𝑢𝑙𝑎𝑡𝑒𝑑 (𝑚𝑙)