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Introduction of Gamma Ray Log

Introduction of Gamma Ray Log
    Gamma Ray Log

    Introduction of Gamma Ray Log 


    مقدمه عن اشعه الجاما ودورها فى تسجيلات الابار
    Is the measurement 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 a shaly sand and used for stratigraphic correlations

    Gamma ray is a radioactivity log which measured natural radioactivity in the rock

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    Properties Of Gamma Ray



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

    All gamma-ray encountered in the earth is emitted by uranium

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    ? The similarity 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

    because sp are used only in fresh mud and don't use in salt mud

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    Theory 

    Gamma-ray are high energy electromagnetic waves produced by the  decay of radioactivity isotopes such as 
    k40-th-u

    The rays pass from the formation and enter the borehole .the gamma ray detector registers incoming gamma rays as an electronic pulses


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


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    Interpretation


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


    shale have abundant 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

    thus


    shales have high radioactivity 


    sandstone, quartz, carbonates have strong bonds and generally don't allow impurities to occupy the composition 
    thus
    sandstone and carbonates have low radioactivity

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


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    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 a layer


    Describe of radioactive and nonradioactive minerals


    مقدمه عن اشعه الجاما ودورها فى تسجيلات الابار