| 摘要 |
<p>A composition comprising water, a water soluble alkali metal silicate, and a water soluble metal compound capable of releasing a multivalent metal cation to react with the soluble silicate to form a pumpable gel is employed as a spacer for displacing a drilling mud from a borehole, particularly immediately preceding injection of a fluid, such as a cement slurry, containing compounds capable of detrimentally reacting with the mud. Optionally, the composition may contain one or more of: a water dispersible cellulose compound and an inert particulate which cooperate to provide fluid loss control; a chelating agent for polyvalent metal cations; a weighting material; a material to minimize lost circulation, and a salt to stabilize fresh water sensitive sandstones and shales.</p> |
