شبيه سازي ابزار نوترون پالسي براي كاربرد چاه نگاري هسته¬اي با استفاده از كد MCNP

Drilling oil an‎d gas wells is one of the main an‎d integral part of the production an‎d extraction of hydrocarbon fluids. Nuclear well drilling tools are widely used in this field. We know that nuclear welllogging tools are classified into two types of neutron tools an‎d gamma tools, of which the neutron tools are far more widely used. Of course, these tools require tremendous technology an‎d are very economical. Since these tools are also needed in Iranʹs oil industry, in this project we will simulate an‎d design a compensated neutron tool. Am-Be neutron source an‎d neutron source with 14 MeV an‎d 2.45 MeV energy are used in this instrument. Also, the detectors that count thermal neutrons are two 3He an‎d Bf3 detectors, which are placed at far an‎d near distances from the detector. The way the tool works is that fast neutrons are emitted from the source an‎d collide with the formation, then due to interactions with the atoms of the formation, they are converted into thermal neutrons an‎d recorded by the detectors. Now, in the meantime, different parameters affect the measurement of the tool, so we will examine each of these factors.The way the instrument works is that fast neutrons are emitted from the source an‎d collide with the formation, then due to interactions with the atoms of the formation, they are converted into thermal neutrons an‎d recorded by detectors. In the meantime, different parameters affect the measurement of the instrument, an‎d we examine each of these factors. In fact, in this thesis, we use MCNP code to design an‎d simulate an optimally compensated neutron instrument. We also made changes to the type of springs an‎d the type of detectors, an‎d we saw very good results. We also made changes in the type of source an‎d the type of detectors an‎d we saw very good results. The trend of the graph related to the detector near the source was ascending an‎d at a further distance it was descending. The slope of the graph is because of the high cross-sectional area of boron, Bf3 detector records more thermal neutron flux than 3He, which have significant differences in thermal neutron counts due to different porosities. For Bf3 an‎d 3He detectors in all distances an‎d formations of Si 2 an‎d CaCo 3, MeV2.45 energy has the highest slope in the graphs.

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