HOUSTON–Geosteering in horizontal wells involves correlating logging data to a type log from a nearby offset well to characterize the zone of interest. Correlating against a type log requires the bedding thickness and gamma character of the target well to be close to that of the type log, which can be offset by miles in some cases. If not, the resulting geosteering interpretation will have unreasonable bed dips that do not accurately reflect the target lithology being drilled, leaving the geosteering geologist running multiple simultaneous interpretations in the hope that one will start to make sense as new data come in during drilling.
