High resolution FMI interpretation and upscaling to seismic

In addition to gathering and manipulating dip data, the detailed analysis of image logs can provide abundant detailed information about the style of bedding, sedimentary and biogenic structures, fractures and sediment heterogeneity in general. At Fugro Robertson we have been integrating detailed image log interpretation with core description and wireline logs since 1987 and have developed a very flexible approach to analysis and, where appropriate, modifying interpretation and integration procedures and products to suit the requirements of particular clients. Using this approach we often gain almost as much sedimentary facies and bedding information from the image logs, in conjunction with cuttings and conventional logs, as could have been obtained from cores.

Sandstone injection structures in FMI

Our ideal approach begins with detailed core description (typically 1:50 or 1:100 scale), followed by comparison and calibration between cores and images to determine what the images are showing in terms of sedimentological and/or diagenetic features. We then have the option to record and visually summarise all sedimentary structures, bedding planes, fractures, spots, vugs, etc. identifiable on the images irrespective of whether or not such features can be recorded as dipping planes. The resulting charts are referred to as 'borehole structures logs' and can include 'pseudo core descriptions' (derived from the images), the core logs themselves and core photographs, all depth-matched to the images, together with practically any other depth-defined data (including well logs, mud logs, detailed interpreted lithologies, petrophysical interpretation data, dip tadpoles, facies breakdowns, text interval descriptions etc.). The ability to produce with much higher confidence a facies breakdown through uncored sections is of considerable value where facies input is required for reservoir modelling software/simulation etc.