In the process of coal-bed methane drainage,the formation liquid carries coal powder into the production pipe string.With the decrease of liquid production in the middle and late stages,if the coal powder cannot be carried from the pump barrel and oil pipe to the surface in time,it will precipitate in the pump barrel,so that the pump leakage cannot be restored,and even the accumulation of coal powder will cause underground faults such as stuck pump and buried pump,which will seriously affect the coal-bed methane mining efficiency.To solve the problem of pulverized coal deposition,a suspension with a certain proportion of active agent is injected into the wellbore.The suspension can adsorb on the surface of pulverized coal at a low concentration and make it suspended in water,thus reducing the critical pulverized coal carrying velocity.On this basis,the coal suspended in the shaft is returned to the surface as soon as possible by rod pump to reduce the damage to the shaft.Through the method,the maximum suspension rate of pulverized coal with particle size below 100 mesh(0.150 mm)can reach 27.33%under the action of different mass fractions of surfactants.Under the condition of constant drainage gas production flow,the performance of pulverized coal carrying is effectively improved,and the failure rate of the main production pump of oil and gas field caused by pulverized coal plugging is reduced.The long-term discharge and production of coalbed methane is of great significance to the stable and high production of gas fields.
Coal bed gasDrainage of liquid and gas productionSuspending agentPulverized coal control
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