Alkali metal tungstate compositions and uses thereof

3 The composition of claim 1, wherein said chelating agent is at least partially ionic.

A method to remove scaling deposits present on a well bore surface comprising contacting said scaling deposits with an aqueous-based composition comprising at least one alkali metal tungstate and optionally at least one chelating agent, wherein said composition is introduced while recovery of hydrocarbons is occurring from said well bore

36 The method of claim 33, wherein said alkali metal formate comprises cesium tungstate, sodium tungstate, potassium tungstate, or combinations thereof.

A spent completion fluid comprising at least one alkali metal tungstate, a dissolved or solubilized filter cake, and optionally at least one chelating agent.

94 The method of claim 90, wherein said completion fluid reaches a temperature of at least 50° C. in the well bore.

A drilling fluid or mud comprising at least one alkali metal tungstate.

112 The drilling fluid of claim 111, further comprising at least one hydrocarbon-based fluid or synthetic mud fluid.

The drilling fluid of claim 112, wherein said hydrocarbon-based fluid comprises diesel oil.

The drilling fluid of claim 112, wherein said hydrocarbon-based fluid comprises at least one synthetic oil.

A method to reduce the solids content in a drilling fluid comprising substituting at least a portion of said solid weighting material with an aqueous solution comprising at least one alkali metal tungstate, and optionally at least one alkali metal formate.

A drilling fluid or mud made by mixing at least one alkali metal tungstate and at least one emulsifier, and optionally at least one alkali metal formate.

A drilling fluid or mud made by mixing at least one alkali metal tungstate, at least one emulsifier, at least one hydrocarbon-based fluid or synthetic mud fluid, and optionally at least one alkali metal formate.