Title: A Rheological Criterion for Fracturing Fluids to Transport Proppant during a Stimulation Treatment
Author(s): Naval Goel, and Subhash Shah, The University of Oklahoma
Presentation: 2001 SPE Annual Technical Conference and Exhibition
Date:
September 30-October 3, 2001
Abstract: One of the primary functions of a fracturing fluid is to transport proppant through a fracture and to keep the particles suspended till reservoir closes on the fracture. The proppant when suspended and uniformly distributed in the fracture improves the productivity of the reservoir. Therefore, a question is frequently asked regarding the minimum fluid viscosity required for satisfactory proppant transport through a fracture. The knowledge of this viscosity value is useful for evaluating fluids prior to their use in the stimulation treatment, and for demonstrating the effectiveness of new fluid formulations for fracturing applications. The present study addresses this question.
The study was performed by characterizing crosslinked guar gels for their viscoelastic properties. Then, the gels were evaluated for their proppant transport capabilities in two slot models using a field-scale test facility. The result shows that the proppant transport capability of crosslinked gels correlates with the fluid's elasticity, not with the fluid's viscosity. Based on these results, this investigation proposes a minimum elastic modulus criterion required for a satisfactory performance of the crosslinked fluids in a fracturing treatment. The criterion was developed from characterizations of borate-crosslinked gels, and then validated with zirconate-crosslinked gel.
The criterion proposed in this work was developed from the proppant transport behavior evaluated on a large-scale test facility. Thus, this criterion provides a useful and simple method to evaluate fracturing fluids in a laboratory, without the need for extensive fluid testing.