This paper describes the methodology and application of a number of new structural-geological techniques for analysing faults and fault systems. These are: firstly, fault-displacement analysis, which is used to establish the common fault-patterns for multiple horizons; secondly, analysis of horizon separations on correlated faults to evaluate reservoir connectivity; and thirdly, prediction of the fault-displacement population below the limit of seismic resolution. There exists a substantial methodology for achieving objectivity in the identification and mapping of geological horizons on seismic sections. By contrast, however, the mapping of faults and fault systems remains comparatively subjective with no firm methodology for deriving a 'correct' fault-map. Recent researc has demonstrated that displacement varies systematically on fault surfaces and that by an analysis of displacement patterns on putative fault-correlations objectivity and methodology are introduced into fault correlation. We analyse displacement patterns on faults using interactive-graphics software. Once a consistent fault-pattern is established for all mapped horizons, reservoir connectivity throughout the area can be evaluated from horizon-separation diagrams which are produced automatically by our fault-analysis software for any selected fault. Further recent research has shown that prediction of the displacement population of faults and fractures below the limit of seismic resolution can be made from the seismically-resolved, fault-displacement population. Additional calibration of the fault-displacement population can be obtained from measurements made on cores from wells. The integration of these techniques enables a detailed analysis and description of faults and fault systems during seismic interpretation and reservoir evaluation.

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