Well completion and workover method

In a well completion and workover method wherein a subterranean formation is contacted with a treating fluid, the improvment wherein said treating fluid comprises a saturated aqueous solution of calcium chloride having finely divided particles of sodium chloride suspended therein, said particles of sodium chloride being added in sufficient quantities to substantially increase the density of said treating fluid, and minor amounts of xanthomonas gum and a polyphosphate acid ester to prevent settling of said sodium chloride particles.

In a well completion method wherein a drilling fluid is circulated through a drill string and contacted with a subterranean formation, the improvement wherein said drilling fluid comprises a saturated aqueous saline solution having a density of at least about 1.2 g/cc at 10.degree. C. and having finely divided particles of a water soluble salt suspended therein, and minor amounts of xanthomonas gum and a polyphosphate acid ester to prevent settling of said salt particles, said drilling fluid having sufficient density to provide a hydrostatic head capable of preventing influx of fluids from said formation.

In a workover method wherein a subterranean hydrocarbon bearing formation is contacted with a nondamaging well treatment fluid, the improvement wherein said nondamaging well treatment fluid comprises a saturated aqueous saline solution having a density of at least about 1.2 g/cc at 10.degree. C. and having finely divided particles of a water soluble salt suspended therein, and minor amounts of xanthomonas gum and a polyphosphate acid ester to prevent settling of said salt particles, said well treatment fluid having sufficient density to provide a wellbore pressure at least about 100 pounds per square inch above the pressure of said formation.