Study on Recycling of Fracturing Waste Fluid

Fracturing waste fluid samples from a horizontal well in Changqing Oilfield were analyzed for their compositions at different times during fracturing operation. Inorganic ions, solid particles and residue additives were studied for their influences on the recycling of the fracturing waste fluid. In the fracturing fluid samples, the content of Ca²⁺ and Mg²⁺ ions are low, and will pose no negative effect on the reuse of the waster fluid. The Fe²⁺ and Fe³⁺ ions, rich in the waste fluid, can be removed through "oxidization-flocculation to precipitate-filtration". The presence of residue crosslinking agent in the waste fluid made the re-produced fracturing fluid highly viscous, and was thus masked with a solution containing triethanolamine and glucose (triethanolamine:glucose=1:9). To avoid the effect of gel breaker on the stability of the re-produced fracturing fluid at elevated temperatures, the gel breaker is suggested to be used in modest concentrations in the original fracturing fluid. Through these steps, the fracturing waste fluid can be recycled.