Perfection and application of efficient flowback technology for fracturing wells

Gas reservoirs in west Sichuan are featured by low-permeability, tight and low pressure. Long flowback time after conventional fracturing and low fluid cleanup rate require for improving the flow back rate of the fracturing fluid to decrease the formation damage. A novel efficient flow back technology was developed that integrated liquid nitrogen cleanup, fibre sand control with open flow optimization technology through many years’ exploration and research. This paper discusses the mechanism of filtration reducing and cleanup with liquid nitrogen and sand consolidating and carrying with fibre. The amount of liquid nitrogen and fibre and choke size are optimized and adding method of liquid nitrogen is studied deeply as well. Thus flow back technology is improved. Field application in 6 wells in west Sichuan achieved operation success ratio of 100%, returning efficiency of 68％ in 24 hours, with no sand during flowback and stimulation effect was remarkable.The perfection and application of this technology offer a good clue for efficiently developing similar gas reservoirs.