Abstract In S-Field, first oil was in 1975, and the field is undergoing a redevelopment project. Integrated operations (IO) has been identified as part of the redevelopment initiative aiming at providing an asset decision support system. The S-Field operator has identified gravity-assisted simultaneous water and gas injection (GASWAG) as the suitable enhanced oil recovery (EOR) method for the field's reservoir. In implementing a digital oilfield solution addressing the GASWAG performance in S-Field, only the EOR field development plan exists as a guidance. S-Field is the first of its kind to implement EOR GASWAG. This increases the uncertainty of the agreed metrics for measurement and formulas to monitor and implement control of the effectiveness of GASWAG (sweep efficiencies and volume displacement). The scope given is to implement an EOR GASWAG-compatible digital solution that allows flexibility for the users to update their established analysis methods and that uses a web application as a basis for periodic assessment and monitoring within the asset team. The current implementation of IO at the software level has minimum flexibility to change a workflow. Any changes that are not considered during workflow development and deployment require a specialist from the development team to implement. The described system addresses the challenges in implementing digital solutions for EOR, including introducing more flexibility in adapting to changes in workflows. The EOR applications include a reservoir simulator to assist the estimation of vertical and areal sweep efficiencies and residual oil displacement in each formation; a geomodel application: to provide graphical interface of the oil, gas, and water distribution in S-Field MN reservoir model; and a data analysis application to provide classical reservoir analysis and method. To bring the applications together as digital solutions, only applications with application programming interfaces (API) are selected. This is to minimize the development effort. The analysis of EOR GASWAG can be maintained by any user through the current software. This means any changes in the analysis method can be implemented within the existing software interface without affecting the overall solutions. The changes will then be reflected in the corporate-wide implementation (web application) without the presence of a specialist and lengthy administration process. Applications with API allow extensibility that minimizes the data extraction effort and drives higher utilization time and effort that can be invested in geological models and engineering analysis. In addition, the system minimizes the change management effort because the process leverages current business processes and reduces the cost of investment by using the existing centralized powerful processing computer. Developing the solution through an analysis application that has the extensibility (API) to other third-party applications has significantly reduced the project implementation duration by half of the initial estimated effort (benchmarked with current project alike).