Look behind the Borehole Wall. Resistivity Images while Drilling

Special characteristics of carbonate formations, i.e. complex structure of pore space, inhomogeneity of reservoir properties, etc. determine the processes of geological reserves allocation, field development and oil and gas production. For each perspective formation, it is necessary to adopt its own drilling strategy with optimized suit of geosteering methods. In this paper, several examples of well placement jobs for different stratigraphic units (Bashkirian stage, Tournai stage and the Famennian) with usage of resistivity images while drilling service were discussed. Trajectory change decisions depending on the position of sweet spots and in accordance with identified by the images structural dips were analyzed. Resistivity imaging while drilling service provides an opportunity of acquisition of high quality borehole wall images that could be used for a variety of tasks, such as for geological model adjustment in real-time, trajectory changes while drilling, etc. That method is very suitable for thin laminated formations (such as carbonates) and is irreplaceable in the palette of geosteering techniques.