Advances in Borehole Geology Interpretation using the new Dual Imager LWD Tool for Oil-Base Mud

Abstract

Summary Borehole imaging while drilling in oil-base mud (OBM) has been a challenge for a long time and the interpretation of borehole geology on these well has been more problematic compared with the wells drilled with water-base mud. Whereas wireline logging benefited of a new OBM generation tools with very high definition, released on the market in the last years, the logging while drilling (LWD) lacked the same kind of offer. The new dual physics LWD tool for OBM described in this work is focused on adding high resolution imaging measurements in the global marker offer. The tool provides detailed geological information from electromagnetic images and gives a geomechanical investigation of the near borehole by means of ultrasonic measurements. During the last two years, Eni has acquired this type of data in four wells from vertical to sub-horizontal trajectory. The quality was quite encouraging, permitting to have a better characterization of geological settings, including bedding and fractures and obtaining some geomechanical important information. The evolution through the several acquisitions has demonstrated the capability to deliver data from only recorded mode to real time. At the moment, the acquired image data appear to be treated and improved using special post-processing.