Research On The Pulse Generator Of Coal Bed Methane Well Fracturing

With the development of coal bed methane pressure fracturing technology in China,the problem of single and uncompacted fracture appears gradually,which is not conducive to the exploitation of coal bed methane.In order to solve the problem,a new underground fracturing pulse device is needed.When fracturing operation is carried out,the fracturing fluid is allowed to impact the rock stratum in the form of pulse in the underground,so as to extend the fracture,which can effectively improve the production of coal bed methane.After analyzing the common fracturing methods and the fracturing pulse devices at home and abroad,aiming at the shortcomings of the existing methods and devices,according to the parameters of the underground fracturing operation,the piston type fracturing pulse generator is designed,and the characteristics of the reversing limit device and the operation process are described in detail.The pressure drop loss of the piston type fracturing pulse generator is calculated by hydrodynamics analysis,and the reasonable main channel diameter and flow rate of the piston type fracturing pulse generator are determined.According to the design scheme,the shell of the piston type fracturing pulse generator is checked by finite element strength,which meets the strength requirements.The program flow chart is drawn and the pressure data acquisition system is designed by using LabVIEW.Finally,set up the experimental device,carry out the test in the experimental site,collect the pressure value before and after the mud enters the piston fracturing pulse generator.Then,the collected data is analyzed preliminarily and the wave chart is drawn,and then the Origin data analysis software is used to filter the wave chart.The maximum accurate pulse pressure of piston type fracturing pulse generator is 1.4MPa,the pulse frequency is about 3.3Hz.In this thesis,a new underground piston fracturing pulse generator is designed,which provides experience for the development of domestic coal bed methane fracturing equipment,and provides basis for the later prototype production and optimization.