A New Environmentally Safe Crosslinked Polymer for Fluid-Loss Control

Abstract

Abstract The adverse effects of inadequate fluid-loss control associated with gravel-packed completions is well known. Controlling fluid losses to the formation before and after pack placement is critical to ultimately achieving optimum productivity from a given well for the following two reasons: Fluid-loss control is necessary to prevent losses of expensive high-density brines, sometimes used for well control in high-permeability, unconsolidated formations. The costly loss of expensive brines can also lead to critically unsafe well conditions, where high overbalance pressures are required to control highly geopressured zones. Dense brines have been reported as being difficult to unload from formations once losses have occurred.1 Calcium and zinc-bromide brines can form highly stable, acid-insoluble compounds when reacted with some formation brines. Because of the high density of these brines, stratification tends to further inhibit their removal. The most effective means of preventing the formation damage described is to limit completion brine losses to the formation.