| 摘要 |
<p>A gamma ray density sub and method useful for measurementwhile-drilling applications utilizing a gamma ray source and detector located on the rotating sub and computation of the product of the counting rates obtained from at least three locations in the formation sample, the locations being located in an azimuthally symmetric pattern about the sub therefore indicating the average density location in the formation sample surrounding a borehole traversing an earth formation. Alternatively, a gamma ray density sub utilizing three pairs of gamma ray sources and detectors located symmetrically about the axis of the sub and computation of the product of the counting rates obtained from the three detectors to indicate the average density of a formation sample surrounding a borehole traversing an earth formation. The sub is able to measure the density of the sample, independent of the location of the sub within the borehole and the chemical composition of the interfering materials lying between the formation sample and the detectors.</p> |
