| 摘要 |
A well logging tool (10) has a neutron source (16) for irradiating formation surrounding a borehole. Two detectors (20,22) are mounted in a spaced-apart vertical relationship within the tool pressure-resistant housing (12). Each detector detects capture gamma radiation across the entire gamma ray energy spectrum, windows are set in this spectrum to separate two distinct energy ranges, thereby generating a total of four independent sets of signals, two for each detector. One set of signals is indicative of the hydrogen content and insensitive to the chlorine content of the irradiated formation. The second set of signals is indicative of the hydrogen plus the chlorine content of the irradiated formation. By comparing the sets of signals in two proportional energy ranges, the logging tool allows to generate a log that helps determine the presence or absence of hydrocarbon or salt water in the formation. |
