(26*fit&i13 



WATER 

 ANALYSIS 



J. F. Sage 



The analyses of representative formation water samples from drill-stem 

 tests on exploration, or from field development wells, can prove very valuable 

 to geologists. 



SAMPLING Nonrepresentative samples of formation waters 



can lead to unnecessary analytical work and 

 erroneous correlations. For these reasons it is important that uncontaminated 

 formation water samples be collected whenever possible, and that contamination 

 be detected when it takes place. The best way to accomplish this is to use what 

 is known as the Chloride Ion Titration Method. In this method, the first sample 

 for titration is taken of the filtrate from the mud stream just prior to the drill- 

 stem test. Additional samples are taken from the drill pipe as it is being re- 

 moved from the well. The number of samples that should be taken depends on 

 the depth of the formation being tested (fig. 13-1). At least three samples 

 should always be taken near the bottom: one approximately 100 feet above the 

 tool, one approximately 50 feet above the tool, and the last as close to the tool 

 as possible. All samples are titrated for their chloride-ion content, and the 

 results are plotted in milligrams per liter against the corresponding depth of 

 interval of drill pipe (fig. 13-1). 



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