Integrated Reservoir Analysis and Geomodeling on Shallow Zone of Handil Field, a Key to Identify Un-Swept Area for Future Development of Mature Oil Field

摘要

This paper describes a new methodology to identify the un-swept areas for future infill well location in Handil shallow zone. This methodology has been proven by more recent Handil shallow oil (HSO) wells results. Handil shallow oil zone plays an important role as it contributes to 60% of today’s Handil oil production. Shallow zone was initially produced in 1977, reached its peak of production 37,000 BOPD, in 1981 and continued to decline until the lowest level of 2,500 BOPD in 2005. The re-development project was started in 2005 to revive the contribution from shallow zone. The project has delivered 42 HSO wells to date with cumulative production of 26 MMstb and current average production of 10,000 BOPD. The reservoirs are fluvio-deltaic sand with strong aquifer support which maintains the reservoir pressure in hydrostatic level. The compartmentalization of the reservoir by faults and facies heterogeneity, combined with HSO wells production impact, resulted in variation of water movement within the same stratigraphic layer in one reservoir segment. The tilting oil water contact (OWC) was observed and it reveals the opportunity to find un-swept areas in mature field. This phenomenon was observed in HSO wells drilled since 2005 to 2015. The behavior of fluid contact was analyzed from log, confirmed by formation tester and from production logging tool (PLT) in existing production wells. A new methodology was introduced to identify the un-swept areas for future infill well location. Detail reservoir correlations within individual deltaic cycle of more than 400 wells, integrated with reservoir dynamic synthesis, were performed to define the reservoir architecture and to characterize the water movement (actual and future OWC). The 3D reservoir model was built according to these syntheses and an individual dynamic region with similar OWC movement within the same stratigraphic layer was created to honor the compartmentalization of reservoirs. This has led to the identification of un-swept areas in top structure and also in the flank areas with less production activity. The methodology has become a game changer in finding remaining oil. More infill well locations are identified by using this approach for future Handil field development.