Micromodelling in a Complex Shaly Sand Reservoir: A Case Study in Greater Burgan Field, Kuwait

Abstract

Heterogeneity within the Cretaceous Upper Burgan sands was observed at multiple scales. Micromodelling for two different depositional environments i.e. Bay and Tidal Flat containing heteroliths were attempted. Objective of the work was to characterize this reservoir heterogeneity and analyze its impact on permeability tensor in the reservoir. The Bay Micromodel was constructed at the grid scale whereas the Tidal flat model was developed at whole core scale. The Bay Micromodel had its dimension limited to 100m x 100m x 3.5ft with a cell increment of 1m. The Tidal Flat Micromodel was developed using a slabbed core image 4 × 8 inches in size which was interpreted for bed forms and facies classification. The facies classified from high resolution core interpretation as well as borehole image were incorporated into the modeling software. For the Tidal Flat MicroModel, additional high resolution core minipermeameter data were also integrated. Streamline simulation was used to compute the equivalent permeability in the longitudinal, traverse and vertical directions. A pressure gradient was imposed in each direction at a time by keeping closed boundaries in the other two. From the total flow, the equivalent permeability was back calculated and permeability anisotropy ratios were computed. The Micromodelling simulation results were compared with analog reservoir information, core plug Kv/Kh data and statistical estimators from high resolution mini-permeameter grid. The permeability anisotropy ratios derived from the Micromodelling exercise were input into larger simulation models of areas of the Greater Burgan field.

AAPG Datapages/Search and Discovery Article #90217 © 2015 International Conference & Exhibition, Melbourne, Australia, September 13-16, 2015