2 SIMPLE TIPS TO CONSIDER WHILE DRILLING ANHYDRITE / GYPSUM FORMATIONS
Anhydrite/Gypsum Drilling Problems

Introduction
Calcium sulfate occurs in nature as Gypsum (CaSO4 l H2O) or Anhydrite (CaSO4 ). It is found in thick sections, stringers, in make-up water, embedded in silts as in evaporite formations and sometimes in the caprock of a salt dome.
Causes of Anhydrite/Gypsum Contamination
Calcium sulfate causes aggregation and flocculation of a fresh water mud, resulting in thickening. The calcium sulfate causes an increase in apparent viscosity, yield point (check
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