Study On Theory Of Coal Bed Methane Underground Drainage Project Technology And Economy Evaluation

With the development and utilization of CBM(Coal Bed Methane)resources spread rapidly in worldwide, China has recognize the importance of CBM resources increasingly. But the Chinese CBM development starts relatively late, technical and economic evaluation of the CBM projects didn't form a corresponding standard, especially underground boreholes extraction of CBM project technical economic evaluation, there only a small amount of this kind of research, and research methods are simple. In this paper, theoretical analysis, numerical simulation and field observation by means of underground drilling coal bed methane extraction project technical and economic evaluation carried out a systematic research, the research contents and results are as follows:(1)It summed up the three prerequisites of CBM output: resource extent, coal reservoir permeability and desorption ability through the analysis of CBM occurrence. CBM resources is the material guarantee, the size of the coal reservoir permeability is connected to the gas space and the occurrence of an important link between the external environment, reflecting the strength of the desorption extraction and ease of extraction rate high or low.The output of CBM are divided into two parts included underground geological factors and mining factors.(2)Analysis of various factors on the impact of underground coal bed methane rules. Analysis of various factors on the impact of underground coal bed methane rules Toolbox Partial Differential Equations using MATLAB to model, the study draws extraction time, extraction aperture size and extraction of negative pressure on the impact of CBM extraction rule: the longer the drainage holes, the higher the amount of coal bed methane extraction ; with the time increasing, decreasing gas extraction flow rate, the greater the aperture, the greater the amount of coal bed methane extraction; with vacuum extraction increases, the amount of gas extraction increased.(3)Various factors will be the basic parameters as input model, using the BP neural network mainly to rough set theory and gray theory, giving the advantages and disadvantages of three kinds of prediction theory and the rationality of the model, and then established based on rough set Grey relational analysis of the neural network model, referred to CGB model. Validate the model with an example, validation by model forecasts, forecast accuracy relative to the gray prediction model and BP neural network model of high operation speed.(4)Through underground methane drainage drilling technology and the economic situation analysis, the use of CGB forecasting model to predict the pumping rate. Pumping rate is calculated based on the economic evaluation. The fuzzy evaluation method and the hierarchical structure of the Combination of three underground coal bed methane extraction technology solutions for technical and economic evaluation, can be used during a variety of technical programs underground drainage bed methane extraction, the individual has strengths and weaknesses.(5)1126 under the moon face coal field geological data field conditions, the use of hierarchical fuzzy evaluation and analysis of three extraction technology program, a comprehensive assessment of the coal seam borehole mining obtained technical solution is the best extraction technology program. 18 months after the extraction of statistical data and CGB pumping rate predicted by the model for comparison, the 1126 face CGB model forecast of CBM extraction rate is more accurate, according to projections pumping rate in a series of technical and economic evaluation of the site has a reference value.