Application of Clear Slick Water Fracturing Fluid on Changning-H26 Platform

Slick water fracturing fluids presently in use have some shortages, such as incompatible with the flowback water and severe damage to reservoirs etc. Based on the characteristics of the Longmaxi shales of the Lower Silurian system in the south of the Sichuan Basin and field operational requirements, a clear slick water fracturing fluid has been developed for use in Block Changning. Laboratory evaluation of the slick water fracturing fluid shows that the main additive, JHFR-2, in the fracturing fluid has good drag reducing performance. Slick water formulated with the flowback water and JHFR-2 has drag reducing efficiency of 70%, and it only takes 30 s or shorter time for JHFR-2 to dissolve. The optimum treatment of JHFR-2 is 0.07%-0.10%. Percent permeability recovery of cores flowed with the formulated slick water is 91.9%. The clear slick water fracturing fluid is non-toxic and easy to flow back. Application of the clear slick water fracturing fluid on well H26-4 and well H26-5 proved that the fracturing fluid had good drag reducing performance. Continuous mixing of the slick water fracturing fluid for direct use completely satisfied the needs of long time fracturing of shale gas wells which consumed large volume of fluid and large amount of sands. The easily formulated low cost clear slick water fracturing fluid is believed to have good application prospect.