Patent ID: 6955220
Filing Date: 2005-10-18
Classification: C04B,C09K,Y10S

Abstract:
1. A method for preventing water flows during the cementing of a borehole which penetrates a subterranean formation wherein the temperature of said formation is in the range of from about 40° F. to about 75° F., said method comprising forming a slurry of hydraulic cement in water, placing said slurry in said borehole adjacent said formation and permitting said slurry to set in said borehole; and wherein said slurry is comprised of water, hydraulic cement, a dispersant, and a set-accelerating admixture comprising an alkali or alkaline earth metal nitrate and an alkali or alkaline earth metal nitrite, wherein the slurry gel strength transitions from 100 to 500 lbf/100 ft 2 in a time period of up to about 90 minutes.