METHOD FOR PLACEMENT OF A SCALE INHIBITOR IN A FORMATION

摘要

A method for placement of a long life scale inhibitor into a formation where variable density scale inhibitors are utilized. A substantially low density non-reactive fluid is loaded into the intervals (20, 22, 24, 26) of the formation to be treated. Afterwards, a high density first stage scale inhibitor (16) is injected into the interval (20). Thereafter, a low density spacer fluid (18) is injected into the well (10). Next, a second stage high density scale inhibitor having a density lower than the first stage inhibitor is injected into the interval (22). Subsequently, a low density spacer (18) is injected into the well (10). Volume increments are repeatedly injected with decreasing fluid densities until a desired zone has been treated. The entire treatment is then overflushed with an inert high density fluid. Use of this method allows even inhibitor distribution in intervals of a formation with permeability variations thereby preventing scale build-up.