A tiered, integrated platform for maximising the value of noisy 4D seismic data acquired over a carbonate reservoir
Wong, Lee Jean
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The success of time lapse seismic in hard carbonates has long since been debated. The main reason is due to the nature of its higher stiffness compared to sandstones, potentially reducing the strength of reflected 4D signals. In this research project, the main purpose is to develop an integrated interdisciplinary workflow to interpret a previously unusable noisy 4D seismic dataset with poor repeatability and update the existing simulation model provided by Petrobras for a field (Field-X) in Campos basin of Brazil. Thus, the project was conducted in three stages. The first stage involves independent analysis of production data, 4D seismic data and reservoir model. The second stage integrating these three data sources in pairs for designation of production related signal confidence flags around observed 4D anomalies. The final stage integrates all three types of data simultaneously for 4D seismic interpretation. The following are my contributions to this research project: (1) Establish inter-well connectivity metric for a summary of reservoir characteristics (2) Develop a mapping strategy for the observed 4D seismic responses (3) Using change of pressure and fluid saturations in the simulation model to predict 4D seismic responses (4) Launch preliminary 4D cross plots for 4D seismic responses prediction (5) Assignment of production related signal confidence flags around observed 4D seismic anomalies as a history matching reference (6) Establish a 4D seismic interpretation matrix as a common platform for interdisciplinary communication (7) Develop a rock typing method and conceptual diagenesis model with permeability prediction from water saturation in the oil column (8) Improve geological realism of simulation model and history match quality by almost 60% after incorporating observed 4D seismic data. In this study, following calibration of the 4D seismic data with production data, a resemblance of 71% between synthetic and observed 4D seismic response increased its interpretability, with identifiable water-flood front and channelling features. Location of sweet spots were then used as a basis for identifying potential infill well locations.