Introduction of Gamma Ray Log

Gamma Ray Log

Is the measurment of the natural radioactivity of formation in general shales tend to have high radioactivity while sandstone-limestone-salt-anhydrite have low radioactivity

Its tools used to determine shae content in ashaly sand and used for stratigraphic correlations

Gamma ray is aradioactivity log which measured natural radio activity in the rock


Properties Of Gamma Ray

Gamma rays burst of high energy electro magnetic waves that are emitted by radioactive elements

All gamma ray encountered in the earth is emmitted by uranium


? The similarty between Gamma Ray and  SP

The gamma ray is similar to sp and gamma ray is replace the sp in salt muds and in air filled holes and when Rmf=Rw

becous sp are used only in fresh mud and dont use in salt mud



Gamma ray are high energy electromagnetic waves produced by the  decay of radioactivity isotopes such as 

The rays pass from the formation and enter the bore hole .the gamma ray detector registers incomming gamma rays as an electronic pulses

The pulse are sent to the uphole computer where they are counted and timed



The interpretation of gamma ray curve is based on the assumption that

shale have abundent potassium 40 in their composition the open lattice structure and waves bonds in clays encourage incorporation of impurities the most common of these impurities are uranium-thorium


shales have high radioactivity 

sandstone,quartz,carbonates have strong bonds and generally dont allow impurities occupy the composition 
sand stone and carbonates have low radioactivity

limestone undergo rearrangement of crystal structure and addition magnesium to become dolomite

Advantage of Gamma Ray

Good shale indicator

Good correlations

Gamma ray can be run in open and cased hole

Used to determine the top and the bottom of layer

Discribe of radioactive and nonradioactive minerals

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