| 摘要 |
Downhole measuring apparatus includes a gamma radiation source and at least two pairs of radiation detectors carried by a housing so that radiation may be emitted from the source and scattered by the environment of the housing and detected by the detectors. Each pair of detectors is arranged so that its detectors are positioned symmetrically on opposite sides of the longitudinal axis of the housing, and each pair of detectors, in combination with the radiation source, forms a different geometrical configuration so that, in general, the radiation counts obtained by the different pairs of detectors will not be redundant. The output signals from the detectors may be processed to provide data signals indicative of the radiation counts experienced by the detectors, and which may then be used to simultaneously obtain values for two or more downhole parameters. The addition of each new, independent pair of detectors permits the simultaneous solution of an additional downhole parameter.
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