The formation damage of water injection wells reduces the ability of the injected fluids (water) to flow through the formations in order to maintain the reservoir pressure and sweep the oil to producer, therefore it is common use the acid to remove theses damages and enhance well injectivity.
This paper describes the successful job in one water injection well in Libya by using an In-situ gelled acid as a diverter with acid treatments to remove formation damage and improve permeability along the whole interval.
The water injection well was suffering high skin damage along 27 ft of the total 42 ft interval; the remaining 16 ft took the entire volume of the injected water. The objective of the treatment was to remove the damage and improve the permeability in the damaged zone.
Use of the In-Situ gelled acid was decided to block temporary the high permeable zone and allow the regular acid to create worm hole in the damaged zone.
The In-situ gelled acid is tested at the laboratory before performing the job. The polymer was cross linked at pH 2 and the sudden rise in viscosity was to about 1000 m Pa S (cp).
The design, quality control and results are detailed in this paper.