This paper describes key aspects related to conceptual well completion design and surveillance planning for an evolving polymer field trial in the South of Oman. An existing field was developed with mostly horizontal production wells drilled at the top of the oil column to deliver high oil production rates. The production of this medium-heavy oil is supported by a strong bottom drive. However, many wells have observed premature water breakthrough resulting in high water cuts and large volume of unswept oil. Polymer flooding using a horizontal well approach is proposed to improve sweep efficiency. If successful, this alternative approach has the potential to significantly improve oil recovery in the subject field.

Because of the significant investment required and novelty of the process (i.e. heavy oil, strong bottom water drive combined with the use of horizontal wells), a field trial is planned to address some of the development risks. Key subsurface risks and uncertainties include: possible polymer losses to the underlying aquifer, loss of effective matrix polymer injectivity, lack of polymer injection conformance along the horizontals and poor sweep efficiency. A number of activities were performed to help design the field trial and reduce some key risks and uncertainties i.e. laboratory coreflood, subsurface study, injectivity test and field visit to analogue field.

The study concluded horizontal polymer injectors placed between the existing producers and slightly deeper than the centre of the oil column is optimum to recover the unswept oil. Polymer injector with Smart completion is proposed to mitigate the lack of conformance along the horizontals. A detailed surveillance plan is critical to identify the required tools and technologies to facilitate data gathering and well intervention activities during the field trial. Proposed surveillance technologies are DTS, Multi Pressure Sensors (MPS) and saturation logging. Observation wells with glass reinforced epoxy (GRE) pipe are planned to get a higher accuracy and deeper investigation of the formation saturation. These activities will be supported by calibrated subsurface simulation models as new data is available to address the trial performance, as well as, better predict full-field performance.

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