Research on Rational Stable Production Point of High-rank Coalbed Methane Horizontal Wells——A Case Study of Zhengzhuang Block in Southern Qinshui Basin
Based on the Langmuir isothermal adsorption equation,this paper accurately divides the sta-ges of desorption during production.With the decrease of coal reservoir pressure,the desorption efficien-cy transitions from basically unchanged to slowly increasing,then rapidly increasing,and finally sharply increasing.The point at which the desorption efficiency transitions from basically unchanged to slowly in-creasing is referred to as the starting pressure,and the point from rapidly increasing to sharply increasing is termed the sensitivity pressure.The analysis of production data from horizontal wells in Zhengzhuang Block shows that the sensitive pressure is positively correlated with the time to reach the peak gas produc-tion time.Finally,with the desorption stage as the main criterion,and the ratio of stable production pres-sure to sensitive pressure as the secondary one,it is verified that it will achieve better gas production effects when the coalbed methane wells enter stable production during the rapid desorption stage.Moreo-ver,a higher stable sensitivity ratio indicates a better gas production effect.
Stages of desorption during productioncoalbed methane wellssensitivity pressureextrac-tion systemfield application
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