MERCURIC NITRATE (AR)

CHLORIDE TEST for DRILLING FLUID
Drilling and Completion Fluids

Chlorides

First of all test pH value of Mud, If it shows alkaline then neutralized by using phenolphthalein indicator with Sulfuric Acid. Then titrated with standard silver nitrate solution, using potassium chromate as indicator. The results are reported as parts per million chloride ion, although actually measured in terms of mg Cl ion per 1000 cm3 of filtrate. To determine the chloride content of an oil mud, the sample is diluted with isopropyl alcohol and then mixed with distilled water, neutralized to the phenolphthalein end point, and then titrated in the usual way.

The end point is difficult to detect using the silver nitrate method, and the results depend to some extent on the operator. Titrating with mercuric nitrate, using bromophenol blue as an indicator, is an alternative. The method gives a much sharper end point, which is particularly advantageous when titrating whole mud, especially oil muds.