The Performance Evaluation and Field Application of Low Temperature Coalbed Gas Clean Fracturing Fluid

Clean fracturing fluid has many advantages, such as strong sand carrying capacity, strong ability to high generation and low friction, etc. However, the temperature of coalbed gas in the shallow part is low (25°C to 35°C). And there are no liquid hydrocarbons or no large amount of free water in the reservoir, which can make fracturing fluid break. The difficulty to break the clean fracturing fluid could result in serious reservoir damage during fracturing. This paper introduces many breakers for cleaning fracturing fluid. And the performances of those breakers have been evaluated in the condition of low temperature. On the base of research, the breaker for clean fracturing fluid is recommended for coalbed gas in the shallow part. The breaker can break clean fracturing fluid completely in low temperature of 25°C. At the same time, the degree of damage caused by fracturing fluid is evaluated. The damage rate of fracturing fluid is only 11%. The system of cleaning fracturing fluid has been applied in Qinshui Basin of Shanxi Province. The field experiment has achieved good results.