Reducing Carbon Footprint with an Innovative Water Management in Workover Operations

Abstract

Workover operations in mature oilfields require significant volumes of freshwater for well control and tubing integrity testing, generating considerable environmental impact through water sourcing, transportation, and disposal activities. In environmentally sensitive regions, these practices contribute directly to operational carbon footprint and create additional logistical challenges. This paper presents a decade-long field implementation of an innovative water management strategy developed for a mature Ecuadorian oilfield characterized by depleted reservoirs and an extensive well intervention program. The proposed approach focused on two key initiatives: redesigning the well-control methodology to significantly reduce fluid control requirements and replacing freshwater used during tubing integrity testing with produced water available within the field. A structured implementation process was developed, including engineering validation, operational risk assessment, field pilots, and standardization across the asset. Between 2016 and 2025, the methodology was applied in more than 984 workover operations while maintaining operational safety, well integrity, and production objectives. Additionally, reductions in water transportation and disposal requirements decreased associated CO2 emissions by approximately 1,371 tons. This is equivalent to the estimated emissions from approximately 7 one-way long-haul commercial flights between Houston and London, based on typical aircraft fuel consumption and standard aviation fuel CO2 emission factors. The results demonstrate that targeted modifications to conventional workover practices can provide a practical pathway toward operational decarbonization while preserving operational efficiency and enhancing oil productivity.