Study On Mechanism Of Coal Powder Production And Migration Rule Of Coalbed Methane Wells

A large number of coal powder productions in the production process of coalbed methane wells not only cause such production accidents like stuck pump and plugging pump,and also will block prop fracture,make damage to the permeability of coal seam and the flow conductance of prop fracture,reduce gas production.At the same time the horizontal pipe column will be cause erosion damage by a large number of coal powder production.Based on the investigation of a large number of domestic and foreign literatures and data analysis in this thesis,the mechanism and reasons and characteristics of coal powder production in different stages are analyzed.Mechanical properties of coal rock are analyzed through the theory of discrete element method.Mechanics model of coal powder in solid-liquid two-phase flow is established and the stress state of single coal particle in two-phase flow is studied.Based on the establishment of turbulence model and two-phase flow coupling model,the simulation of the migration rules of coal particle in horizontal wellbore are simulated using FLUENT software.The effects of different factors on coal powder production and distribution of coal particle concentration are studied,the erosion location and erosion rate of horizontal well string caused by coal particles are researched.