Improving the fracturing fluid loss control for multistage fracturing by the precise gel breaking time design

• The effect of APS concentration on the fluid loss and damage rate was studied.
• A novel gel breaking formula was developed through encapsulated APS.
• The APS releasing time for different encapsulated breakers was studied.
• A pilot field case was included which presented a positive effect on the production rate.

Tight gas and oil explorations have gained more and more attention across the world recently, and the hydraulic fracturing is considered the main approach to develop such resources. Previous fieldwork showed that in the micro-fracture reservoir development, serious liquid leakage would damage the formation dramatically. Furthermore, the situation can be aggravated due to the improper gel-breaking process. According to these problems, this study aims to improve the fluid loss control technology. In this paper, the Ammonium Persulfate (APS) releasing time of three encapsulated gel breakers were evaluated. A novel gel breaking formula was developed by combining APS and encapsulated breakers. The pilot case was conducted which exhibited a positive effect on the hydrocarbon production. Owing to the accurate fluid loss control, the formation damage was also relieved.