| 摘要 |
A logging-while-drilling sensor includes a gamma ray source (114) and at lea st two Nal detectors (116, 118) spaced apart from the source for determining measurements indicative of the formation density. A magnetometer on the dril l collar measures the relative azimuth of the Nal detectors. An acoustic calip er is used for making standoff measurements of the Nal detectors. Measurements made by the detectors are partitioned into spatial bins defined by standoff and azimuth. Within each azimuthal sector, the density measurements are compensated for standoff to provide a single density measurement for the sector. The azimuthal sectors are combined in such a way as to provide a compensated azimuthal geosteering density. The method of the invention may also be used with neutron porosity logging devices.
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