Applicability of High Resolution Resistivity LWD Image Logs in Field Development

LWD resistivity imagers offer a unique real-time image of the reservoir while drilling. Realtime transmission is, however, constrained by telemetry and the images are down-sampled from the full data acquired. The full dataset recorded in memory is used to produce high resolution images with the latest generation of tools capable of imaging geological features that are smaller than half an inch. As these LWD imagers emulate conventional open hole micro-resistivity images, we compare several datasets from deviated wells in carbonate reservoirs, where both LWD and conventional images were acquired. Our aim was to benchmark the LWD imager capabilities for reservoir characterization purposes, to determine whether under certain circumstances they offer a direct alternate to the conventional image logs. Comparisons showed that the differences in the apparent resolution between the two technologies is dependent on factors such as, geological conditions, feature orientation, operational mode and post acquisition processing. We conclude that, at present, the LWD images do not offer a direct alternate to the conventional open hole images for high resolution reservoir characterization purposes. In some cases, for instance, where operational circumstances dictate, or in areas where the reservoir characteristics are already well established, they might offer a reasonable alternative.