Gamma ray logging is a method of measuring naturally occurring gamma radiation to characterize the rock or sediment in a borehole or drill hole. It is a wireline logging method used in mining, mineral exploration, water-well drilling, for formation evaluation in oil and gas well drilling and for other related purposes. [ 1 ]

The spectral gamma ray log is displayed as three curves of thorium (ppm), uranium (ppm), and potassium (%), while the gamma ray track records two gamma ray curves, the standard (SGR) and computed gamma ray (CGR).

The gamma ray log measures the total natural gamma radiation emanating from a formation. This gamma radiation originates from potassium-40 and the isotopes of the Uranium-Radium and Thorium series. The gamma ray log is commonly given the symbol GR.

2025年1月28日 · Gamma ray log character is one of the primary methods used to correlate the stratigraphic section. For most engineering and geophysical applications, the gamma ray log is primarily used to extract lithologic, mineralogic, or fabric estimates. The log response depends on the radiation, tool characteristics, and logging parameters.

The Gamma Ray log is the simpler of the two and only measures the total radioactive count rate in API units. Whereas the Spectral Gamma Ray log is able to differentiate between the different radioactive elements (K, Th, U) and outputs the abundance of each in parts per million (ppm).

2025年3月4日 · Natural- and spectral-gamma logs can produce “total gamma-ray” logs that display the total-gamma emissions in CPS or APIu as a function of depth. Basic spectral-gamma tools count the number of each potassium, uranium, and/or thorium energy window in real time to produce “KUT” logs.

2019年2月24日 · Spectral gamma logging builds on a fundamental understanding of nuclear geophysics. In the spectral gamma tool, gamma radiation is measured by converting gamma rays (or "gamma photons") to electronic pulses that are then measured and counted.

Gamma-ray logging has evolved from a qualitative estimation of the variation of natural radioactivity with depth in a borehole, using a Geiger-Müller detector, to a sophisticated quantitative logging technique which yields information on the identification and amount of the radioelements present, as well as data on the likely geologic history ...

2023年8月28日 · Gamma-ray logs are essential tools in geophysics and petrophysics, utilizing natural gamma radiation to reveal rock composition and characteristics underground. These logs find applications in hydrocarbon exploration, mineral prospecting, and environmenta

Gamma rays have longer penetrations than either alpha or beta rays, and can be measured by simple counter devices. The earliest detectors on logging tools were Geiger counters, but these have been replaced by scintillation detectors in most modern tools.