Khoreyver Uplift (CKU) oilfields from 2009. So far, some of the oilfields have been put into production and are on the build-up or plateau stages. Other fields are going to be put into production in the next several years. The company drills both new deviated and sidetrack wells. Reservoir simulation model (RSM) is the main tool for making a decision on well pattern optimization and prediction of reservoir performance. Construction and continuous update of the models is a crucial task for the company. Productive reservoirs of CKU oilfields consist of a carbonate rock formation. Pores (matrix) form the most part of the reservoir void volume and contain almost all oil in place. The other part of the void volume is made up of secondary porosity: fractures and vugs. As a rule of thumb the dual porosity/permeability simulation model should be used in this case. However there are some disadvantages associated with this application of this approach for CKU fields. Firstly, the simulation time is dramatically increased in comparison with single porosity model. Secondly, the complexity of dual porosity/permeability models is not consistent with the availability and confidence level of the input data predominantly with the data about secondary porosity structures: areal distribution of fractures (vugs), porosity, fractures length and aperture. In this paper, we present the approach for construction and update of RSM, which is based on single porosity model with the effective properties of matrix and fractures (vugs). Fracture influence on fluid flow is modelled by implementation of non-neighbor connections (NNC) between cells. The transmissibility of NNC is adjusted during history matching. Well productivity index is matched by modifying effective permeability. Distribution of initial water saturation is based on J-function with the adjustment on initial well water cut. Application of the considered approach for construction and update of RSM of CKU fields results in obtaining the tool with high prognostic capability.
References
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