Research on Nonionic Polyacrylamide Zirconium Gel Fracturing Fluids in Coalbed Methane Gas Wells

Active water and guar gum are widely used for coalbed methane fracturing in China.Nevertheless,the application of these two types of fracturing fluid was limited due to poor rheological properties of active water and severe formation damage of guar gum fracturing fluid.Considering the temperature and low permeability of coalbed,the formulation of nonionic polyacrylamide zirconium gel fracturing fluids suitable for coalbed mechane fracturing was selected based on the analysis on the effects of different factors on the zirconium gel.The formulation is 0.4%PAM+0.035%ZrOCl2.The performance of the optimized formulation of nonionic polyacrylamide zirconium gel fracturing fluids was evaluated through laboratory experiments,and the results showed that,the formulation had the characteristics of shearing resistance,low filter loss,easy breaking,good proppant carrying capacity,non-residue,low formation damage and easy flowback.It is suitable for the coalbed gas reservoirs fracturing.