Patent ID: 6170574
Filing Date: 2001-01-09
Classification: E21B

Abstract:
A method of forming a seal or plug in a downhole pipe comprising:positioning a dump bailer containing a predetermined amount of a cement slurry at a desired location in a pipe disposed downhole in an earth borehole;displacing said cement slurry from said dump bailer; andallowing said cement slurry to set and form said seal wherein said cement slurry comprises a pumpable slurry comprising a hydraulic cement, water, a water soluble salt of a metal selected from the class consisting of alkali metals, alkaline earth metals, zinc, and mixtures thereof, a dispersant comprising an anionic surface-active agent of the sulfonated naphthalene type, and magnesium chloride, said dispersant being in the form of an aqueous solution, said dispersant being present in said aqueous solution in an amount of from 88 to 95% by weight based on the weight of water in the aqueous solution, said aqueous solution being present in an amount of from 0.2 to 2 gallons per 94 lbs. of dry cement present in the slurry.