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Reservoir surveillance and integration of geological and reservoir engineering studies are essential in optimising waterflooded oil field recovery. Maintaining calibration of dynamic models can be difficult as fields mature and watercuts increase, particularly where there is significant geological complexity. This can be even more challenging if the field is multi-layered with commingled production and injection. This paper describes how the energy method (EM) and capacitance resistance method (CRM) used for inter-well communication analysis were successfully employed to provide valuable insights in two such waterflood case studies and compares their results at well and layer levels. In a preliminary step, classical waterflood surveillance and analytical techniques are combined with geological knowledge for a firm understanding of field performance. More detailed communication analysis is then performed to analyse inter-well and cross-fault communication. In a first case study, the EM technique was used to examine waterflood effectiveness in six separate panels in the most faulted area of a mature, geologically highly complex oil field. In a second case study, both the EM and CRM techniques were used to assess and optimise the waterflood in the panel of another mature oil field. The communication analyses provided a rapid route to understanding communication within complex, multi-layer fields using production data alone. In the first case study, results indicated significant communication between injectors and producers including across many of the faults separating reservoir compartments. Results identified areas of interest for infill drilling and possible workover targets. In the second case study, the combination of EM and CRM enhanced the overall understanding gained from the inter-well communication analysis. |
