煤层气井产气阶段临界排采参数分析

Analysis on Critical Drainage Parameters of CBM Well in Gas Production Period

依据煤层气排采实际,基于煤岩破坏出煤粉机理,建立了煤层气井产气通道较近井地带、近井和远井地带破坏出煤粉模型。分析得出较近井地带主要是降压程度大引起的压实破坏,而近井和远井地带主要是流体拖拽引起的拉伸破坏,由此给出了产气通道破坏出煤粉的临界排采参数。结合井筒压力分布模型,建立了煤层气单井多层合采的井底压力和产水量模型,分析了单井多层合采井底压力和排水量,优选多层合采时排采参数。

According to CBM actual production and the mechanism of coal rock destructed to product pulverized coal, the productive pulverized coal models of nearer wellbore zone were established, near wellbore zone and far wellbore zone on CBM well gas channels. Analyzed nearer wellbore zone was compacted and damaged by large pressure drop, near wellbore zone and far wellbore zone were stretched and damaged by fluid traction. Based on this, critical drainage and mining parameters on gas channels damaged and produced pulverized coal was given, based on the condition of gas channels damaged and produced pulverized coal and the model of water discharge, Bottom hole pressure and water discharge of single well multilayer commingled production at the same time were analyzed.Drainage and mining parameters of optimizing multilayer commingled production at the same time were analyzed.