High permeable layers are one of the key factors of heterogeneity in the Mauddud carbonate reservoir. The objective of this study is to use a field scale definitive approach to characterize high permeable layers with limited data control and derisk their presence at pilot scale using multi-disciplinary data sets acquired from EOR pilot wells
An appropriate definition is assigned to characterize high permeable layers based on core and log data. High permeability layers thus defined were indexed as facies logs at well locations. The indexed facies logs were correlated with different data sets in connection with from NMR, FMI, mud logs and tracers. Before incorporating surveillance data, a base case facies model was generated out of multiple distribution runs using facies index logs from pilot wells. The geological uncertainty associated with high permeable facies identified at pilot wells was decreased by incorporating previously acquired PNL logs, C/O logs, tracer, ILTs, PLTs and SNL-HPT data.
It is found that there is no mud loss or any fractured core detected in pilot wells, thus indicating that there is no interference with faults or fracture networks. Tracer test data show short breakthrough times and are correlatable to identified high permeable intervals in the reservoir. The correlation of TDT log saturations, RFT fluid samples and cooling anomalies behind the casing based on SNL-HPT data matches with interpreted Hi Perm layers. This explains a preferential movement of water into the pilot area resulting from potential connection between Hi Perms and surrounding water injector wells outside the pilot area. Finally, the modelling of identified high permeable layers as imprinted facies established quantification of high permeable layers in terms of areal extension, thickness and connectivity between the pilot wells. This multi-disciplinary approach is useful to de-risk the geological uncertainty associated with high permeable intervals in carbonate reservoirs.
Early detection and characterization of high permeable layers within a selected EOR pilot area is beneficial to mitigate preferential sweep and maximize the ultimate oil recovery as a result of chemical EOR depolyment.