1. n. [Drilling Fluids]

An experimental test, or series of tests, used to predict mud behavior and guide future actions by the mud engineer. Rather than experimenting on the full mud volume and risking serious and expensive mistakes, pilot tests such as those listed below give valuable guidance:

• Weight-up tests evaluate how much mud weight can be increased.
• Dilution tests evaluate how much prior dilution is needed in order to weight up.
• Product tests evaluate similar additives for performance to select the best material.
• Heat-aging tests evaluate how a mud will react if exposed to high temperature while circulating or while static in the hole.
• Contamination tests evaluate how mud will respond to an expected contaminant.
• Contaminant-treatment tests evaluate how contaminated mud will respond to various amounts and types of treatments. 

Pilot test samples are formulated using the concept of barrel equivalent.

See: barite,  bottoms-up mud sample,  caustic extraction test,  flowline mud sample,  hematite,  jar test,  kill-weight fluid,  lag time,  mud,  mud cup,  mud engineer,  mud oven,  mud-aging cell,  mud-in sample,  mud-out sample,  rolling aging test,  shear-strength measurement test,  static aging test,  temperature stability