Abstract
Logging while drilling (LWD) resistivity imaging was typically deployed to provide real-time LWD images to identify critical geological information, e.g., bedding dip changes, lithology changes and large faults to allow optimum geosteering. During the past decade, there has been a progressive increase in the along hole resolution of LWD images, and today's highest resolution tools achieve nominal along hole resolutions of approximately 0.5-in. with full 360° azimuthal borehole wall coverage.
The focus of this study is the high-resolution LWD resistivity images recorded downhole as the memory mode data and their direct comparison with images from conventional open hole ("wireline") resistivity images, to illustrate the similarities and differences between images from the two technologies for fracture characterization and vuggy porosity partitioning in carbonate reservoirs.
Fracture types, distribution and their orientation can be determined from LWD image logs. Proportion of vuggy porosity can be estimated from LWD images by applying porosity-partitioning technique. This study shows that the images generated from the new generation of high-resolution LWD resistivity imagers have sufficient effective along hole resolution to offer an alternate to the conventional open hole images for carbonate reservoir characterization.
