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Water management challenge turned into a friendly environmental response resulting from successful stimulations with coiled tubing in water injection wells: Chichimene field case study in Colombia

Abstract:

Two producer wells in the Chichimene field of Colombia were converted to injector wells as part of a water management and pressure control strategy. Because of zero injectivity in these wells, the operator desired to stimulate for a successful disposal-type reinjection to decrease the 70,000 bbl of water being discharged. This paper describes the planning and performance of stimulation operations in these two injector wells. A proper diagnostic helped to identify damage to be attributed to fines migration. Based on a consideration of petrophysical properties and corresponding logs, an acid system was designed and tested in the laboratory. Diversion options during stages of sequenced acid preflush, hydrofluoric acid, and postflush were reviewed. The desire to minimize the tubular exposure to acid in the wellbore and to place the open end of the tubing in front of the perforations made the option of coiled tubing appealing. With this option, the placement of the necessary sequential stages of the sandstone acid treatment would be possible across discrete intervals. Both wells experienced an injectivity index of zero before the acid treatment. The average daily injection of well CH-182 dramatically increased to 19,000 BWPD after the acid treatment. The average daily injection of well CH-183 dramatically increased to 20,000 BWPD after the acid treatment. These two wells currently have higher injection capacities than any other wells in the Chichimene field; combined, they inject 43,000 BWPD at maximum peak. The discharged water volume before the stimulation treatments was 70,000 bbl. After stimulation of the injector wells, the discharged volume is 30,000 bbl, representing an approximately 60% reduction in discharged volume.