Understanding the complexity and characterizing a carbonate reservoir with complex heterogeneity is a daunting task that various operators of the E&P industry are facing today. Though the most perfect and quantitative answer of the complexity of dynamics of the carbonates comes from full field dynamic simulation, the simulation approach is often time consuming and expensive. A quick and less expensive approach is qualitatively looking at the petrophysical and production data in an integrated way for reservoir characterization and applying the findings in further field development.
Often in the brown fields, a large amount of petrophysical and dynamic data in terms of production and pressure are available. Especially in the brown fields under extensive and prolonged water flood, studying the varying level of interaction of producer-injector pairs in the field combined with the variation in the static properties can give very useful insight in the reservoir heterogeneity and identification of preferentially water flooded areas. This interpretation can be used to improve efficiency of water flood by adding and/or relocating injectors. The above concept of integrated static and dynamic data analysis has been applied for the multilayered carbonate reservoir of Mumbai High South field.
The integrated approach of static properties validated with production-pressure data helped in identifying the in-homogeneity, interlayer communication, nature of seismic picked faults and existence of flow barriers. Also the production-injection interaction analysis helped in identifying the likely pathways of water flood and the areas lacking water injection support. The findings have been successfully validated with subsequent pressure surveys. The above study under taken for the first time for Mumbai High South field has helped in improving the water injection plan with confirmation of the planned injectors and identification of areas needing more injection support.
Although non-predictive, the technique has immense value in validation of ongoing water injection scheme, providing understanding of inter-well communication and quickly bringing out areas requiring review of the injection plan for improving its effectiveness.