BLOCKAGE REMOVAL AND PERMEABILITY ENHANCEMENT METHOD FOR COALBED METHANE WELLS BY USING ELECTRIC PULSES

A blockage removal and permeability enhancement method for coalbed methane wells by using electric pulses is applicable to high-efficiency exploitation of coalbed methane wells. The blockage removal and permeability enhancement method includes: constructing a positive electrode coalbed methane wellbore and a negative electrode coalbed methane wellbore from the ground to a coal bed; when the gas yield declines because cracks in the coal bed are closed gradually or blocked by granular impurities as coalbed methane extraction goes on after hydrofracturing, injecting a conductive ion solution into the positive electrode coalbed methane wellbore to fill the coal bed between the positive electrode coalbed methane wellbore and the negative electrode coalbed methane wellbore with the conductive ion solution; placing a positive electrode and a negative electrode downwards to predetermined permeability enhancement portions of the coal bed in the positive electrode coalbed methane wellbore and the negative electrode coalbed methane wellbore respectively; and breaking down, by using high-voltage electric pulses discharge, the coal bed filled with the conductive plasma solution between the positive electrode and the negative electrode, where shock waves generated from a large amount of energy act on the coal bed to cause the closed cracks in the coal bed to be opened again and extend and to remove the granules blocking the cracks, such that the number of the cracks in the coal bed is effectively increased and crack connectivity is improved.