Experimental investigation of rheological properties of fiber-laden crosslinked fracturing fluids

Abstract

Proppant settling is a critical issue in hydraulic fracturing and this is found to be a strong function of rheological properties (viscosity and elasticity) of fracturing fluids. In order to improve proppant-suspension capacity of fracturing fluids, fiber materials are often added into fracturing fluids, such as in FiberFRAC and channel fracturing. However, only few studies have currently dealt with the rheological properties of crosslinked fracturing fluids containing fiber. In this paper, a comprehensive study was performed to investigate the influence of fiber on the rheological properties (apparent viscosity and viscoelasticity) of borate crosslinked hydroxypropyl guar (HPG) gels by using a HAAKE MARS Ⅲ rheometer with different geometries (a concentric-cylinder geometry, a vane geometry and a parallel-plate geometry). It was found that the addition of fiber did not have a significant influence on the apparent viscosity of crosslinked fracturing fluid, which was due to the high viscosity of borate crosslinked fracturing fluids and low dosage of fiber. However, the addition of fiber caused an obvious increase in the elastic modulus of crosslinked fracturing fluid. Significant increment in elastic modulus was observed at high fiber concentration and long fiber length.