API MPMS 17.3:2009 pdf download
API MPMS 17.3:2009 pdf download.Manual of Petroleum Measurement Standards Chapter 17–Marine Measurement Section 3- -Guidelines for ldentification of the Source of Free Waters Associated with Marine Petroleum Cargo Movements.
General Statements
A.1 .1 Comparisons of sample patterns and major-ion to minor-ion ratios provide identification of source waters.
A.1 .2 In order to establish a uniform basis of comparison, each sample component in a series must be analyzed using the same test method.
A.1 .3 The volume of sample should not be diluted or extended in order to perform a more extensive battery of tests. Destroying the natural buffering that exists in these samples changes the solution parameters or ion concentration, and large errors result.
A.2 Expression of Analytical Results
A.2.1 Milligrams per liter (mg/L) is the most common weight-to-volume relationship used to express concentration of dissolved components. Milligrams per liter can be converted to parts per million (ppm) using the expression ppm = (mg/L)/density (kg/L). However, within normal analytical precision and accuracy of these analyses, ppm = (mg/L)/(specific gravity).
A.2.2 Milliequivalents per liter (meqlL) is a weight-to-volume relationship obtained by dividing the weight of the component by its milliequivalent weight.
Note: See API Recommended Practice 45 for values to be used in this computation.
A.2.3 All data except pH, resistivity, and relative density shall be reported in milligrams per liter and milliequivalents per liter.
A.4 Interpretation
Although some of these tests used individually are excellent indicators of the origin of a certain water, there is the possibility of pollution, contamination, or mishandling of samples. It is therefore recommended that several of the test parameters be used to establish a data base and that each water sample be examined on the basis of a battery of tests rather than one individual test.
A.4.1 SPECIFIC GRAVITY
Specific gravity must be used in calculating concentrations of components, and several samples in a series with essentially the same gravity should be from the same source.
Note: Immediate on-site determination of sampled water gravities can provide early indication that the waters being detected may or may not be of a shipbome source. A Specific Gravity Hydrometer in the range of 1.000 to 1.220 in 0.002 divisions is recommended for the on-site investigation of free water samples withdrawn from beneath cargoes of crude oil petroleum.
A.4.2 RESISTIVITY
Resistivity is a measure of total ion concentration. Several samples in a series with essentially the same resistivity should be from the same source.
A.4.3 CHLORIDES
Chlorides are present in seawater at some 19,000 to 21,000 ppm by weight and vary near shorelines due to freshwater discharge or to oceanic basins having high evaporation rates. However, chlorides are consistent in specific areas. Reservoir waters, salt dome, and formation waters have higher concentrations, but concentrations vary near the edges of the formation. Formations other than salt domes may have water fresher than seawater.
A.4.4 SULFATES
Sulfates in sea water have concentrations of about 2500 to 3000 ppm by weight, while in reservoir water, concentrations are considerably less, usually 1000 ppm by weight or less. See A.4.9 for applicable comments.
A.4.5 CARBONATE, BICARBONATE, HYDROXIDE, AND pH
Carbonate, bicarbonate, hydroxide, and pH must be evaluated concurrently, as a unit. The pH of seawater is very consistent but may vary due to changes in local conditions and handling. The pH should be determined as soon as possible after the sample is taken because oxygen can be introduced due to aeration during sampling, samples can be subjected to temperature changes during shipment, and the water layer below a head of oil is under some pressure and therefore may contain entrained gases.
