Deployment of a Scale Squeeze Enhancer and Oil-Soluble Scale Inhibitor To Avoid Oil Production Losses in Low Water-Cut Well

Abstract

Summary This paper outlines the development of an effective treatment strategy for production wells that suffered significant performance impairment at water cuts of less than 5% caused by carbonate scale deposited within the electrical submersible pumps (ESPs). These Alaskan production wells had been treated for a couple of years with aqueous-based scale-inhibitor squeezes. Many of these treatments resulted in a significant reduction (10 to 20%) in the oil production rate following the squeeze. The damage mechanism was investigated by coreflooding and was revealed to be a combination of water block and relative permeability effects. Following the coreflood damage investigation, a second study was undertaken to investigate a chemical treatment to remove the damage already present within the near wellbore and to prevent further deposition of scale. The result of this test program was the development of a treatment strategy that used a solvent package followed by an oil-soluble scale inhibitor. Field results of this type of treatment suggest that the wells treated with this chemical system did not suffer any reduction in the oil production rate and were effectively protected from carbonate scale. Wells that had been damaged by the previous aqueous treatments could be stimulated, and the lost oil production could be recovered. Reference is also made to the development of improved, aqueous-based squeeze treatments for the treatment of higher water-cut wells.