Publications

Giant gas fields with complicated geological structures, such as faults and pinch-outs, require impractical time for fine-scale simulation for development planning and production forecasts. Therefore accurate coarse-scale simulation model is essentially required. To satisfy this requirement, we developed a new upscaling method and applied it to an actual field model. This new method is made up of two components: (1) transmissibility upscaling of fine model containing many inactive cells into a Cartesian coarse model and (2) non-Darcy flow upscaling for gas reservoirs.The developed upscaling method was tested in upscaling a fine model of 107 layers to a coarse model of 5 layers with the same areal gridding. The following results were obtained.1) Accuracy: The resultant coarse model reproduced the production performance of the finely gridded model. On the other hand, coarse-scale models generated by conventional methods show significant errors.2) Speed: Time required for simulation is dramatically reduced, for example, the speed-up factor of 200 with the scale-up factor of 20.Keyword: permeability upscaling, transmissibility upscaling, near-well upscaling, gas reservoir, flow simulation