The Mechanism Research To Increase Production By Ultrasonic Extraction For Coalbed Methane(CBM)

Coal-bed methane production generally through the drainage,gas production process,in the drainage and gas production process,because the rock matrix is ??very brittle,very easy to break,easy to collapse,coal and coal and other particles will be with the coal layer fluid Migration of coal seams,reducing reservoir permeability,affecting the production of coalbed methane wells,reducing the recovery rate of coalbed methane.The ultrasonic effect of coal on the coal production is very important for the actual production.In this paper,the mechanism of coalbed methane adsorption,desorption and transport is first explored,and then a variety of coal and rock models are constructed.The physical parameters of each model are measured.Then,by using the experimental equipment,the coal samples are measured under different water content The change of methane desorption capacity,the time of ultrasonic action and the change of coal sample permeability under different ultrasonic power.Through the methane step-down mining experiment,the effects of different ultrasonic power,the time of action and the recovery of coalbed methane The final study of the mechanism of action of ultrasound,the following conclusions:The water content of coal samples has a significant effect on methane desorption.The desorption of methane in 10% of coal samples is 10-20% lower than that in non-water-containing coal samples.The modified model Langmuir exponential desorption can better describe the desorption curve,reveal the law of pressure drop and desorption of coalbed methane,which has certain guiding significance for the exploitation of coalbed methane.In the case of the same ultrasonic power,different ultrasonic action time,there is an increase in the limit permeability,and the rate of increase in permeability is in the range of 40 to 60%.Under laboratory conditions,the optimal ultrasonic action time is 10 minutes.In the case of the same ultrasonic action time,different ultrasonic power,the rate of increase inpermeability is in the range of 50-60%,and the ultrasonic power is proportional to the rate of increase of the permeability of the coal sample.At the same mining time,the ultrasonic effect of 10 minutes faster than the ultrasonic effect of 5 minutes of recovery rate,and the role of ultrasound 10 minutes than the role of 5minutes of recovery is higher.With the higher the ultrasonic power,the more it produces,the more methane is produced and the higher the final recovery.The effect of ultrasonic wave in the middle stage of mining is higher than that of the initial ultrasonic recovery.