Evaluation and application of low damage guar gum fracturing fluid in deep coalbed methane reservoirs

An evaluation of low damage guar gum fracturing fluid system based on deep coalbed methane reservoir stimulation was carried out, its on-site application research was conducted. The results indicate that the gel breaking time decreases with increasing temperature. Low damage guar gum fracturing fluid has a significant breaking expression in a short period of time at temperature above 40 ℃, which is not obvious at 20 ℃ and 30 ℃. The permeability of coal core is sensitive to temperature, which leads to an increase in core damage rate, but the amplitude of change is relatively small. For low damage guar gum fracturing fluid, the increase rate of temperature sensitivity of coal core to damage rate is much lower than the decrease rate of guar gum fracturing fluid damage rate to coal core with the increasing temperature from 20 ℃ to 40 ℃. Overall, the damage rate of guar gum fracturing fluid to coal core significantly decreases with the increase of temperature. For active water, the damage rate of active water to coal core increases when the temperature rises from 20 ℃ to 40 ℃. The backflow fluid viscosity reaches 5 mPa·s of guar gum fracturing in 2 hours at temperatures above 40 ℃, meeting the needs of on-site construction. By comparing the fracturing results of low damage guar gum fracturing and active water in the same well and horizontal well at the same layer, low damage guar gum fracturing fluid can achieve a fracturing process with less injection volume, larger sand volume, higher sand ratio, and smoother pressure.