AAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain
Maximising Recovery from Thin Oil Columns Part 3: Maintaining from ‘Evergreen’ Subsurface Model to Optimise a Waterflood Development
(1) PDO, Muscat, Oman.
Over the last three years the first stages of a waterflooding project comprising 200 horizontal producers and injectors were implemented in a thin oil column (20m) transition zone carbonate field (Shuaiba formation) in the Sultanate of Oman. The reservoir is composed of a high porosity, low permeability matrix. Porosity and rock quality vary across the field to such a degree that wells in some areas of the field are not economic. Therefore prediction of reservoir quality is critical to a successful field development. The field development plan (FDP) that underpins this project utilised sequence stratigraphy, acoustic impedance and production behaviour of existing wells to create static and dynamic models which formed the basis for the development well patterns.
This paper focuses on the updates made to the static model since the FDP model, integrating drilling results from the first 60 wells of the project and continued reservoir characterisation and modelling work, to ensure that the planned wells remain economic and the well sequencing and placement optimised. Automated workflows were established to incorporate drilling data on a day to day basis for improved reservoir performance predications and well design. Information from appraisal wells and production behaviour from the production wells was used for improved well sequencing and property model rebuilding. Updated methodologies for rock typing, permeability and saturation height functions were established. The overburden model is updated to give accurate formation top predictions for the drillers.
Keeping an ‘evergreen model’ has proven a best practise to ensure continuously optimised drilling and recovery from the field.