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The chalk reservoir of the Gorm Field, southern North Sea is dome-shaped and faulted owing to a combination of salt diapirism and regional east–west extension. Fractures developed in the structure considerably enhance permeability. The dataset discussed here records fractures in horizontal wells from more than 10 km of image logs and provides a special opportunity to test theoretical models of fracture development with quantitative observations. In an effort to forecast fracture density and fracture orientation, we have estimated the strains in the structure using an elastic dislocation model that incorporates mechanical boundaries in the form of the tectono-stratigraphic interface with salt and tectonic faults. More than 50% of the angular differences between poles to the planes of simulated and observed fractures are less than 30°; 75% are less than 45°. Relative strain magnitude appears to be a useful indicator of fracture density. At the field scale, small strain magnitudes correspond with small non-zero fracture densities and relatively large strain magnitudes correspond with high fracture densities.

Automated image analysis and image processing techniques make possible the simulation of sandstone diagenesis and prediction of pore system modification. Diagenetic processes in real rocks are simulated using a combination of element X-ray maps and backscattered electron images.Processes can also be simulated for computer-generated sand packs by image analysis and image processing. Compaction is simulated by moving grain centers closer together; overgrowth-type cementation is simulated by dilation of free grain surfaces; mineral dissolution is simulated by selective removal of specific minerals identified by the combination of element X-ray maps and backscattered electron images. The original and modified images can be processed and analyzed to reveal all the parameters needed to predict permeability using a Kozeny-Carman type equation.The computer modeling and image analysis approach can also be used to determine the specific effects of various diagenetic processes on porosity. The results are encouragingly realistic by reference to the few available well-characterized empirical datasets.

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