Research And Design Of Coalbed Methane Productivity Prediction System

The paper studied the characteristics of coal reservoirs,occurance, gas production mechanism, annlyses the influence factors and changes on pressure transmission, adsorption-desorption and permeability and the relationship among adsorption quantity of coal, pore radius and reservoir pressure. Based on it,the paper establish the model between pressure and adsorption radius,pore radius, adsorption quantity.According to gas, water two-phase stage of coal matrix’s positive effects and coal fracture system’s negative effects, coal bed methane adsorption-desorption, with permeability prediction model after fracturing,the paper established a permeability change model when two-phase pressure pass stabely and two-phase flow pressure only pass in some other direction. Based on Darcy’s law, considering the positive effects of the coal matrix and negative effects of row mining process, combined with the historical mining discharge data, applying normalization ideology and history fitting method,the paper established water production prediction model on low-yield water wells,middle-yield water wells and high-yield water wells. According to Darcy’s law, combined with gas production characteristics of coal bed methane wells, both water production and gas production predation model were established.And under the C#development environment,the paper achives the frame design on coalbed methane of production capacity of B/S structure by ASP.NET、ADO.NET,ect. Regarded the Panzhuang block as prediction object, the predicition curves of water production and gas production are created. Eventually conclusion is fitted with production capacity of Panzhuang block,and it shows the model is suitable.