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Mineralogy and Geochemistry |
Postgraduate Research Institute for Sedimentology, The University, P.O. Box 227, Whiteknights, Reading RG6 2AB, UK
The integration of wireline log information with other forms of geological data allows the recognition of certain diagenetic effects in sedimentary rocks. Diagenetic modification of a sandstone causes changes in the rock properties that will produce subtle shifts in the wireline log characteristics. Such shifts are often difficult to interpret. However, by reference to a now extensive diagenetic information base it is possible to construct models for processes controlling some types of diagenetic change. So it is possible both to model and predict the spatial distribution of diagenetic effects. To interpret diagenetic effects on wireline logs it is necessary to integrate existing geological databases with information derived from wireline logs in a form that can be handled by computer. Interactive modelling involves the iterative refinement of modelled features. This is done by comparing synthetic logs with actual logs over intervals from which core-derived information is available (Rotliegend and Sherwood sandstones provide ideal test-beds for this approach). Predictive models may then be generated by an interactive process of confirming or denying modelled features. This approach allows refinement of the interpretations made. Eventually we expect that a means of directly interpreting certain important diagenetic effects will be possible from wireline log data.
