Improved 2228 lithologic density logging instrument with exemption sources

Abstract

The invention discloses an improved 2228 lithologic density logging instrument with exemption sources. The improved 2228 lithologic density logging instrument with the exemption sources comprises a long source distance detector and a short source distance detector. A sheath assembly of the long source distance detector and a sheath assembly of the short source distance detector are each internally provided with a crystal and a photomultiplier. A spring is arranged between each crystal and the top of the corresponding sheath assembly. The exemption sources are arranged on the outer side face, adjacent to the corresponding crystal, of the sheath assembly of the long source distance detector and the outer side face, adjacent to the corresponding crystal, of the sheath assembly of the short source distance detector correspondingly. By additionally arranging the exemption monitoring cesium sources of 0.25 microcuries for the long source distance detector and the short source distance detector, the instrument is free of control from a radioactive source in the using process, the effect that the radiation risk is reduced to the minimum is ensured, and stable operation and reliable technologies of the long source distance detector and the short source distance detector can be achieved.

Description

technical field [0001] The invention relates to the technical field of oil exploration well logging, in particular to an improved 2228 lithology density logging tool with an exempt source. Background technique [0002] The 2228 Lithology Density Logging Tool is one of the radioactive series logging tools and is widely used in petroleum engineering logging. Such as figure 1 As shown, the 2228 lithology density logging tool includes two detectors with a long source distance and a short source distance. The sheath assembly 2 of the long and short source distance detectors is equipped with a crystal 3 and a photomultiplier tube 4 inside. According to the technical characteristics of the instrument, in order to achieve automatic peak stabilization, a 0.8-1.2 microcurie radioactive 137 cesium source (peak stabilization monitoring source 6) is installed on the top of the long source distance detector sheath assembly 2 (one end of the crystal 3), Short source distance detectors ha...

AI Technical Summary

Problems solved by technology

Since the instrument itself has a radioactive 137 cesium source, it is subject to national Class A management restrictions during use, and its safety is limited in foreign labor logging. According to the requirements of safety measures, the instrument must be maintained during maintenance, storage, and logging transportation. Fill in the corresponding safety protection sheet for radioactive sources, the filling process is cumbersome

And because the short source distance has no cesium source, the output amplitude of the short source distance detector will change with the change of temperature due to the influence of temperature, which also affects the logging quality of the instrument

At the same time, when maintaining the long source distance detector of the instrument, the monitoring 137 cesium source should be removed from the front end of the probe crystal for inspection and maintenance before installing it. When inspecting and disassembling the crystal and photomultiplier tube or repairing the detec

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