In a number of fields in Oman thermal developments are being implemented. One of these fields is located in South Oman and contains an exceptional 200 m thick oil thick column of medium to heavy oil (200 to 800 cp). This sandstone reservoir is at a depth of 1050 m below surface and is underlain by a modestly strong aquifer. The field has been in production for 20 years, the main production mechanisms are pressure depletion and natural ingress of aquifer water. For the next phase of development a vertical pattern steam flood re-development is planned which will increase the ultimate recovery significantly. The extreme thickness of the heavy oil reservoir is unique for steam floods and poses both opportunities as challenges. There are no direct analogues and the normal practices of managing a steam flood need to be verified and adjusted. For that reason a range of numerical tools has been developed.

The tool box consists of: 1) An explicit well bore model to understand e.g. the internal well fluid dynamics and heat exchange between tubing, annulus liquids and reservoir fluids at the reservoir level as well as the overburden. Particular interesting is the impact of cool aquifer water inflow on condensation of steam in the annulus and near well bore area. 2) Radial models for detailed analysis of recently performed steam soaks. 3) Sector models (1/12 pattern) for capturing overall steam flood performance and to understand the impact of fine scale reservoir heterogeneity, 4) A single pattern model for analysis of the ongoing steam flood trial in the field and 5) A 10- pattern model cut-out of the geological model for understanding of pattern interference and impact of major reservoir features like faulting and structure. The models have been constrained by the long production history of the field. The performance of the tools is illustrated by the work-out of some specific well and reservoir management examples.

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