Analysis on production performances and influence factors of coalbed methane wells in Liulin Block

According to complicated dynamic influence factors of coalbed methane well production in Liulin Block,rational production increasing measures and other pr oblems were hard to be set up. The drainage and extraction dynamic law of over 50 wells within the block was analyzed and the influence factors of the output performance S in different type wells were discussed.The results showed that the wells within the block were medium and low production wells mainly,the gas production at the initial per iod was high and the gas production was seriously reduced at the late period.Related to the vertical well and cluster well,gas production of the horizontal well would be sta ble and high. The seam thickness and hydrological condition were the main geological parameters affected to the production capacity of seams in Shanxi Formation and Tai yuan Formation individually. The further analysis combined with the engineering factors showed that the coal reservoir within the block was high in sensitivity and the fractu re scale and reservoir damage were the main causes to cause the low production of the vertical well within the block. Meanwhile,the relevant index of the production increa sed parameters was provided: Sand added quantity would be over 35 m3 and the construction fluid quantity would be over 400 m3.A drop speed of the liquid level controlle d would be2 ~ 10 m/ d and a casing pressure after the gas production was 0.1 ~ 0.3 MPa.The number of the well to be closed should be reduced and the time to stop the d rainage and extraction should be less than 20 days.