Slim-hole natural gamma spectrometry logging device

Abstract

The invention relates to a slim-hole natural gamma spectrometry logging device. In one embodiment, the slim-hole natural gamma spectrometry logging device comprises a probe, an analog circuit and a digital circuit, wherein the probe comprises a photomuitplier and a sodium iodide crystal with the diameter Phi being 38*300mm; the analog circuit is used for magnifying voltage pulses converted by the probe and converting peak value signals into digital signals when voltage pulse peak value signals are stable; the digital circuit comprises an FPGA (Field Programmable Gate Array) and a single chip microcomputer; the FPGA is used for controlling voltage pulse signal conversion, accumulating the digital signals to form gamma spectrometry and transmitting the gamma spectrometry to the single chip microcomputer through UART (Universal Asynchronous Receiver / Transmitter) protocols; and the single chip microcomputer transmits the gamma spectrometry to an upper computer through a CAN (Controller Area Network) bus. The embodiment has the advantages that the FPGA technology is adopted for realizing high integration of a data collecting circuit; the instrument volume is reduced; and the 60mm slim-hole natural gamma spectrometry logging measurement under the condition without a vacuum flask is realized.

Description

technical field [0001] The invention relates to the fields of FPGA technology and well logging, in particular to a 60mm slim hole natural gamma ray spectrum logging measurement system. Background technique [0002] There are different amounts of radioactive elements in the stratum. The decay of radionuclides produces gamma photons, and the interaction between gamma rays and matter produces secondary electrons. These electrons can cause ionization and excitation of atoms in the matter. These excited atoms are in the Excess energy is released in the form of fluorescent light during de-excitation, and the photomultiplier tube can convert light pulses into electrical pulses, and convert extremely weak light into larger voltage pulses in proportion. [0003] Natural gamma-ray spectroscopy logging converts the gamma photons emitted in the formation into voltage pulses through the probe, which is amplified and sent to ground instruments to determine the content of radionuclides ura...

AI Technical Summary

Problems solved by technology

However, the borehole diameter of the existing wells is getting smaller and smaller, and the gamma energy spectrum logging tool designed with a vacuum flask further reduces the diameter of the crystal in the probe, reduces the detection efficiency, and increases the statistical fluctuation, which has been unable to adapt to the existing drilling of slim holes

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