Experimental Investigation on Low-damage Nanofracture Fluid System in a Tight Reservoir Based on Nanoemulsion

Abstract

A tight reservoir has low permeability, low porosity, poor pore-throat connectivity, and strong heterogeneity. Hydraulic fracture is an effective technology to develop such reservoirs. However, in the process of fracturing, fracture fluid will cause damage to the formation. This formation damage can be reduced by nanomaterials due to their nano-level structure. In this paper, experimental studies on the use of nanoemulsion to reduce formation damage caused by fracture fluid are performed through pressure conduction experiments. A low-damage nanofracture fluid system that is suitable for tight reservoirs is optimized, and the injection time is optimized. Finally, a high-efficiency and low-damage nanofracture fluid system that meets the development needs of tight reservoirs is formed. This system provides support for the application of nanomaterials in tight reservoir fracture fluid. Experimental results show that the nanoemulsion fracture fluid can reduce the permeability damage caused by conventional slick water fracture fluid with a removal rate of 16.36% and a recovery rate of 80.00%. The damage rate of nanoemulsion fracture fluid to the fracture surface is 20.33%. The damage rate of the fracture surface under the synergistic effects of nanoemulsion fracture fluid and conventional slick water fracture fluid is between 20.92% and 31.89%. The optimal injection time of nanoemulsion fracture fluid is 2 h.