This paper describes key factors related to intelligent horizontal well completion systems and surveillance activities for a polymer field trial within a sandstone reservoir in the South of Oman. The existing field predominantly comprising of horizontal producer wells drilled and located at the crest of the reservoir to ensure optimum oil production rates via artificial lift techniques. Many wells have encountered early water breakthrough, resulting in large volumes of un-swept oil. Improved sweep efficiency, hence improved oil recovery is expected by polymer flooding using a horizontal well approach .
The polymer field trial location consists of: 4 horizontal producers each completed with wire wrap screens, blanks and external zonal isolation packers within the reservoir section for segmentation and isolation. Each producer has a downhole gauge for real-time pressure and temperature monitoring. Three horizontal smart injectors each consisting of 4 zones completed with 7 inch pre-drilled liners, blanks and external zonal isolation packers across the reservoir section for segmentation and zonal isolation. These injectors are internally completed with intelligent completion systems with remote access and control whereby each of the 4 zones consists of a mechanical retrievable packer for zonal isolation, on-off intelligent flow control valve with hydraulic multi-drop module system for conformance control, quartz pressure-temperature gauge, double ended pump down DTS system for real-time monitoring and internally lined GRE tubulars in order to prevent polymer degradation. Two horizontal observation wells each completed with GRE casings and predrilled liner joints for logging along with downhole gauges for real-time pressure-temperature monitoring. One vertical observation well completed with GRE casing and carbon steel casing below the oil water contact for surveillance purposes.
A detailed surveillance plan for the current producers, injectors and observation wells is of utmost importance for pre and post injection data gathering in order to successfully evaluate key subsurface risks and uncertainties associated with the polymer flood technique. The field trial has been designed and executed with an optimum approach to ensure continuous real-time surveillance. This is facilitated by remote access and control thereby minimizing well interventions for surveillance activities for the duration of the trial.