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

Page 30 of 114

29 | P a g e

3.2.2 Procedure
3.2.2.1 Extract a reasonable quantity of the petroleum and petroleum product sample after
a thorough mixing into a clean glass cylinder.
3.2.2.2 The hydrometer is then gently lowered into the sample while the thermometer is
used to stir the sample until the temperature reading becomes steady. The temperature at
this point is read and noted and the gravity of the sample is read from the hydrometer at
the meniscus cut on the hydrometer stem while it is stationary and freely floating in the
sample. The reading is then adjusted with appropriate meniscus correction applicable to
that instrument to give the accurate SG or API Gravity of the sample to the equivalent value
at 60/60oF using the appropriate ASTM table.
3.2.3 Precautions
3.2.3.1 Any air bubbles on the surface of the sample in the cylinder should be mopped up
with clean filter paper before readings are taken.
3.2.3.2 There should be no air current in the environment in which the test is being carried
out.
3.3 Procedure for Determining the Base Sediment and Water Contents (BS&W) of
Petroleum and Petroleum Product Sample
3.3.1 Approved Method
3.3.1.1 The approved method for determining the BS&W of petroleum and petroleum
product sample shall be with the use of the distillation equipment or any other method as
approved by the Director of Petroleum Resources. The steps to follow shall generally
conform to those outlined in ASTM D4006 and D95. In crude oil, the amount of water as
determined by this method (D4006) shall be used to correct the volume involved in the
custody transfer of the petroleum batch under test.
3.3.2 Equipment Specification
3.3.2.1 The apparatus shall be as shown in the figure in Appendix I. It shall consist of a glass
distillation flask, a condenser, a graduated glass trap and a heater. Other types of
distillation apparatus will be acceptable for this method provided they can be
demonstrated to operate within the precision established with the preferred apparatus.
3.3.3 Preparation of Test Samples
3.3.3.1 The sample size shall be selected such that the higher the expected water content
of the petroleum batch under test, the smaller the sample quantity. Hence sample sizes will
be inversely proportional to the expected water cut. As a general rule, the following
proportional sizes shall be adopted: