Patent ID: 8505630

Claim:
A method of displacing a drilling fluid disposed in a well bore annulus, comprising: providing a spacer fluid comprising a kiln dust, wherein the spacer fluid has at least one property at well bore conditions, wherein the property is selected from the group consisting of: (i) a yield point of from about 25 Pascals to about 250 Pascals, (ii) a static gel strength of from about 70 lbf/100 ft 2 to about 500 lbf/100 ft 2 , (iii) a yield limit in compression from about 1 psi to about 2,000 psi, (iv) an unconfined uniaxial compressive strength of from about 5 psi to about 10,000 psi, (v) a zero gel time of about 8 hours or less, and (vi) a transition time of about 45 minutes or less; using the spacer fluid to displace at least a portion of the drilling fluid from the well bore annulus; and allowing at least a portion of the spacer fluid to consolidate in the well bore annulus, and wherein the portion of the spacer fluid consolidates in the well bore to meet the property.