Greater Burgan Field: defining the Wara Formation reservoir architecture

Study aims: to refine the stratigraphic and depositional model, and to determine the reservoir architecture and heterogeneities.

Database: evaluation of >120 cored wells at various levels of detail calibrated with wireline logs and integrated with bio/chemostratigraphy and data from 3 partly cored imaged wells.

Approach: application of a hierarchical approach to description, with detailed core description and core-log calibration allowing interpretation of various genetic elements, major changes in depositional evolution and key surface definition for full-field sequence stratigraphic correlation. burgan sedimentology and analogues

Integrated results: definition of three SW/W to NE/E oriented sand-dominated incised valleys cutting into brackish bay deposits.

Upward-fining/muddying composite valley fill is associated with an upward reduction in permeability.

Complex internal make-up, but valley fills typically evolve up from channel-fill to heterolithic channel-fills to rare in-channel sandsheets and abandonment/floodplain deposits.burgan depo model

Successive valley-fills display increased abundance of heterolithic channels and reduction in overall grain size supporting a back step in the overall depositional system.

Permeability anisotropy and complex fluid flow is anticipated within the heterolithic channel-fills and abandonment elements. Also, the intra-valley depositional heterogeneities create risk for unswept reserves.burgan correlation