Build the water envelope
Use complete analyses for source water, produced water and planned blends, including calcium, magnesium, iron, pH and temperature.
TDS alone cannot describe every polymer-water interaction.
Preserve sample condition
Record settling, oil, suspended solids, treatment chemicals and storage time before testing.
A changed water sample can create a false product comparison.
Screen rapid response
Measure early and final differential pressure under matched injection and mixing.
The field decision often depends on performance developed before the fluid reaches the high-pressure pumps.
Challenge credible variability
Repeat finalists in normal and difficult brine windows and with planned additives.
A narrow laboratory optimum is difficult to control during water blending.
Inspect downstream effects
Review filter response, deposits, incompatibility and cleanup requirements beside friction reduction.
One pressure metric does not define whole-system suitability.
Write a bounded release
State water chemistry, temperature, product code, addition, equipment and acceptance trace.
Do not extend the result to untested brines.