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

Page 51 of 114

50 | P a g e

Petroleum Resources and shall remain unchanged. However, for factors that can
affect the quantities measured by the meter that must be changed, an approval shall
be granted by the Director of Petroleum, and adjustments must be retained in the
audit trail.
1.8.3.2 Meter factors shall be determined over a range of flow rates. The various meter
factors can then be used to linearize the output from the Ultrasonic flowmeter at
varying flow rates. If the meter is used to measure bidirectional flow, a meter factor
should be developed for each direction.

1.9 General Regulation
1.9.1 All meters at facilities shall be proved during every loading operation or at other
frequencies approved by the Department of Petroleum Resources while those at
other custody transfer points shall be proved fortnightly in accordance with the
procedure outlined in this guide. Production meters shall be proved monthly.
1.9.2 Meters shall be proved under their normal operating conditions with the same type of
liquid being measured by them.
1.9.3 Meter Linearity test shall be conducted annually during annual recertification exercise
or when the need arises and a performance (linearity) table and curve shall be
established for each meter as outlined in this guide.
1.9.4 All meters shall be proved before being put to use and also after maintenance.
1.9.5 Continued acceptance of a meter for use shall depend on its maintenance of
satisfactory performance during successive meter proving (or linearity) as adjudged
within the set down tolerance limits.
1.9.6 Each meter in the bank shall be equipped with adequate protection devices such as
valves, air eliminators, flow conditioning vanes and other measuring instruments as
indicated on the approved Detailed Engineering Design (DED).
1.9.7 The flow conditioning vanes shall be installed within a distance of 5D (5*internal
diameter) of the pipe upstream the meter where applicable.
1.9.8 The meter shall be in the same horizontal plane with the pipeline.
1.9.9 The meter bank shall be equipped with a dedicated prover preferably the pipe prover
type. Provisions shall be made for proving meters at other measurement points by any
of the methods specified in this guide.
1.9.10 Installation and commissioning shall follow appropriate reviews and approvals by the
Department of Petroleum Resources of factory calibration and on-site control
proving.
1.9.11 A control chart shall be established and maintained for each flow meter.
1.9.12 Results of all proving shall be carefully interpreted to identify the maintenance
requirements that are due. Determination of when to repair or inspect a meter shall
be by keeping a control chart of its meter factor values for each product or grade of
petroleum and petroleum products. Small random changes in meter factor will
naturally occur in normal operation, but if the value of such a change in meter factor