The Use of Internally Consistent Models in Seal Analysis

Seal presence is required for hydrocarbons to be accumulated, and the quality of the seals will often directly determine the fluid contact levels and hence the trapped hydrocarbon volumes. It is therefore crucial that a proper seal analysis always is included in prospect evaluation. A complete seal analysis includes evaluations of both cap rocks and faults. Sometimes also bottom and side seals need to be evaluated. Various tools and methods for evaluating several of these aspects of seal analysis exist. Despite this, an overall work procedure that describes how all the individual tasks of seal analysis should be integrated and prioritized is currently not readily available to the explorationist. Through recent research and case studies we have experienced that it is difficult to apply a standardized work flow for seal analysis. This is so because the relevance of the individual tasks commonly included in such analysis will vary significantly between different areas and between individual traps. However, we have found that the concept of “Internally Consistent Models” (ICM) can be very useful for such analyses regardless of the geological setting. The use of such models will aid integration and provide a basis for risking hydrocarbon volumes in prospect evaluation.