Abstract

A novel technique of refining relative dip (RDIP) and relative strike (RSTRIKE) extractions uses a geocentric approach to define the sectoring (angular partitioning) of LWD (logging-while-drilling) azimuthal log data. We define sector partitions based on geological factors rather than standard engineering-based settings. Stratigraphic up and stratigraphic down sectors are defined such that they are the closest possible measurements perpendicular to bedding, yielding improved RDIP calculations and enhanced bed boundary detection for more accurate reservoir navigation. Likewise, stratigraphic left and right sectors are defined such that they are parallel to bedding, yielding refined RSTRIKE log curve extractions for higher resolution petrophysical analysis versus use of traditional non-azimuthal (time averaged) LWD curves (Figs. 1 and 2). Before drilling, azimuthal sector partition settings could be pre-set from existing data (e.g., subsurface contour maps, seismic data) as a starting approximation of geocentric sectoring (Figs. 3-6), recognizing that real-time adjustments may be necessary due to the coarseness of these datasets (Figs. 7-11). During drilling, azimuthal log data would reveal if the sectoring varies from geocentric due to formational or wellbore orientation changes (Figs. 7, 9, and 11), with the acquisition system allowed to make azimuthal sectoring adjustments via downlink command to resume the geocentric sectoring (Figs. 8 and 10). Overall, this approach intends to improve the process of acquisition and interpretation of LWD azimuthal log data to optimize structural and stratigraphic positioning for reservoir navigation and enhanced petrophysical analysis.