Study On Simulation Model Of Coalbed Methane Fracturing

In the 21st century, with the exhausted of normal natural gas and the increasing of energy demand, in particular the stringent requirements of environmental protection and safety production, Coalbed methane plays an more important role in development resources than ever before as potential and huge resources. The coalbed methane exploitation in our country is just at the initial stage. CBM (Coalbed Methane) is a self generating and self preserving unconventional natural gas which from the coal seam, and it is a new kind of clean energy. Development and mining of coalbed methane can not only to relieve pressure on energy supply but also to protect environment, and to make sure the production safety, which are all of great significance.In my thesis, based on the literature research at home and abroad, reservoir characteristics,migration and production mechanisms of CBM are analyzed, mechanisms of the desorption, percolation and diffusion are studied, combination of heat, conduction, fluid mechanics and linear elastic fracture mechanics, and study of CBM fracturing methods, including a numerical model of temperature, extension of cracks in three-dimensional model, proppant the model of proppant sedimentation and productivity formulas for the fractured CBM well,the following results are obtained:(1) Established the mathematical model of the three dimensional, which considered in the different situation of rock corporeal character, stratum stress, construction parameter and fracturing fluid performance.(2) Has established the model for the temperature in the mineshaft and fracture, the model of proppant sedimentation, then can accurately calculate the rate of proppant sedimentation in the crack, then it can calculate the thickness of proppant in the different position and the time, then can calculate the pressure drop under the different proppant thickness along the fracture length.(3) Has established the productivity formulas for the fractured CBM well, according to the characteristics of coal development, divided CBM flow process into three pieces, and then calculated the productivity of the fractured CBM well.(4) According to the above established models, a computer calculation is developed, and simulated the results of the fractured CBM well.In this paper, made a thorough study in the fractured CBM well with four aspects about stimulation techniques and technology, which is useful both in practice and theory for the technology to be used in coal bed methane development in the field.