Coal fines production in different drainage stages and its influence on productivity

Investigation about coal fines flow in different drainage stages and its influence on well productivity was based on parameters, such as the peak gas rate, the peak water rate, the peak change of producing fluid level (PFL) and duration of coal fine flow, and also combined with analysis of coal primary texture. It can be concluded that the key factor that influences well productivity is coal fines migration, deposition, and block in pore and fracture; coal fines production in different drainage stages is influenced both by coal structure and drainage system, and the latter determines quantity of coal fines in late production process; while continuous and steady drainage system will control coal fines flow and thus improve well productivity, by effectively avoiding pressure and velocity sensitivity induced by dramatic pressure change, and also Jamin Effect caused by coal fines accumulation.