A recently developed treatment technique has significantly increased injectivity rates of injection wells which had been damaged by near-wellbore polymer blockage.
Polymer blockage can be caused by incompletely dissolved solid polymer, improperly inverted emulsion polymer, and/or deposition and adsorption of the polymer on the rock. Strong oxidizers such as hydrogen peroxide or sodium hypochlorite are typically used to clean up polymer deposits left after polymer injection; however, both of these chemicals present significant handling hazards. The treatment technique presented in this paper utilizes a solid oxidizer which releases a peroxide to dissolve the polymer deposits.
Field tests in Hockley County, TX, yielded injectivity rates more than double those recorded before treatment. The wells consisted of open-hole San Andres sections, at 4,850 to 5,050 ft (1,478.3 to 1,539.2 meters), with a bottom-hole temperature of 100°F (37.8°C). The polymer project was conducted from 1984 to 1986.
This paper discusses the solid oxidizer treatment technique and presents case histories and laboratory results.