Application of on-line recycling technology on fracturing flowback in Sulige gas field

With the in-depth exploration and development, horizontal well technology, volume fracturing technology, mixing water fracturing, and factory fracturing have been large-scale popularized and applied in Sulige gas field. These fracturing technologies use large amounts of sand and fracturing fluid, resulting in dramatic increase of fracturing flowback fluid. In particular, after the implementation of the new environmental laws, conventional sewage impermeable pits are prohibited. It is urgent to study and develop the non-landing flowback processing technology to achieve fast and efficient recycling. This article introduced the fracturing flowback recycling technology applied in Sulige gas field. Considering fracturing flowback fluid that often contains natural gas, fracturing sand and other solid particles, and known for elevated pressure and difficult to separate, on-line continuous processing technology on fracturing flowback fluid was optimized, which was composed of pipeline buck control module, high-pressure degassing module, low pressure degassing and desanding module, and fine filter module. These modules were filtered through the finest 10 μm filter to obtain the pure fracturing flowback fluid. After further chemical treatment, thickener was added for the next fracturing operation. The reusing ratio of flowback fluid could attain more than 90%, leaving the residual concentrate for evaporation process. The pilot field tests were carried out for 23 times and 44 649 cubic meters of flowback fluid was recovered, showing remarkable social and economic benefits. This technique provided a reference for the domestic innovation of fracturing flowback recycling technology innovation.