Destruction of the resins structure due to heating
This article considers a polymer composition based on acetone-formaldehyde (AFR) resin, which is used to reduce water influx into the well bore during the repair insulation work. Pumping into the well bore a composition, based on AFR resin, results in self-heating that causes destruction of its own structure and, therefore, the damage of the polymer blend structure. The purpose of the present article is to find the causes of AFR resin self-heating when injected into the well bore as part of the composite mixture that leads to the destruction of its structure. Author considers exothermic reaction between AFR resin and aqueous solution of sodium hydroxide during the curing of the polymer composition. The features of the given polymer structure are studied as well. The need for further studies of the resin structure is substantiated. Based on the study conducted, five possible reasons of the AFR resin self-heating, leading to destruction of resin structure, are revealed. Recommended practices that may decrease self-heating of the AFR resin are offered.
Stoke’s theory in problem solution of cementing slurry sedimentation in horizontal sections
The paper studies the application of Stokes theory in problem solution of cement slurry sedimentation in horizontal sections. As a rule, during the horizontal cementing of wells, due attention is paid to the composition of cement slurry. The final composition should ensure stable casing of the horizontal column - cement slurry - rock. A slight deviation in the fluid loss index can lead to a loss of contact between the cement stone and the rock. The study of the process of sedimentation of solution particles in horizontal sections is relevant. This paper assesses the application of Stokes theory in the solution of the above mentioned problem. The material described in this article will be useful during the study of this topic by students of Mining and Petroleum Faculty, the direction of drilling oil and gas wells, in order to improve the level of knowledge gained during the course of “Well casing” discipline.
Physical Processes in Inorganic Scintillators
BASIC PRINCIPLES AND PROCESSES Physical Mechanism of Scintillation Creation of Electron Hole Pairs Excitation and Emission of Luminescence Centers Scintillation Materials Halides Oxides and Oxide Systems Chalcogenides Glasses Interaction of Ionizing Radiation with Scintillators High Energy Photons Charged Particles Neutral Particles General Characteristics of Inorganic Scintillators Light Yield Duration of Scintillation Pulse Afterglow Temperature Response Optical Properties Radiation Hardness Density Emission Spectra Mechanical and Chemical Properties Physical Parameters Cost Consideration Scintillator Requirements in Various Applications High Energy Physics Intermediate Energy Physics Positron Emission Tomography Gamma Spectroscopy Energy Resolution Intrinsic Scintillator Resolution Nonproportional Response Time Resolution Low Energy Quanta and Electrons CONVERSION OF ELECTRONIC EXCITATIONS IN SOLIDS Charge Carrier Behaviors Delta Rays Secondaries Excitation of Luminescence Centers Effect of Ionization Density Energy Losses Simple Phenomenological Model Plasmon Model Polaron Model Scintillation Yield Spectra Vacuum Ultraviolet Region Ultrasoft X-Rays X-Rays Gamma Rays Heavy Ionizing Particles INTRINSIC LUMINESCENCE OF INORGANIC SCINTILLATORS Excitonic Luminescence Alkali Halide Crystals Alkaline-Earth Fluorides Ternary Halide Compounds Excitonic-Like Luminescence Cesium Iodide Tungstate and Molybdate Phosphors Core-to-Valence Transitions First Evidence for Radiative Core-to-Valence Transitions Excitation Spectra Emission Spectra Experiment Theory Luminescence Kinetics Experimental Theoretical Investigations Temperature Dependence of Luminescence Parameters Conditions of Detection Prospects for Research EXTRINSIC LUMINESCENCE OF INORGANIC SCINTILLATORS Thallium-Activated Halide Scintillators Crystals with NaCl-Type Structure Crystals with CsCl-Type Structure Other Thallium-Based and Thallium-Doped Crystals Crystals Containing Other ns2 Ions Bismuth Germanate (BGO) Sodium-Activated Cesium Iodide Rare-Earth-Activated Crystals General Considerations Europium-Activated Crystals Cerium-Activated Compounds Preliminary Comments LaF3-CeF3 Systems Cerium Chloride Barium Fluoride Gadolinium-Containing Crystals Lu- and Y-Containing Crystals Nd- and Pr-Activated Crystals DEFECT FORMATION BY IONIZING RADIATION Effect on Scintillator Characteristics Mechanisms of Defect Formation Efficiency of Defect Production Geometrical Factor Separation between F and H Centers Temperature Dependence of Production Efficiency Role of Halogen Ion Impurities Effect of Cation Impurities Formation Time of F-H Pairs Closing Comments References Index