Experimental Study: Evaluating the Effect of Low High Viscosity Friction Reducer Concentrations to Transport Proppant Across Static and Dynamic Models
Authors: Biheri Ghith , Imqam Abdulmohsin , Dunn-Norman Shari , Elmaleh Khaled 
Published: August 2024

Hydraulic fracturing treatments may significantly improve the oil production from wells in unconventional reservoirs by enhancing the fracture conductivities. Fracture conductivity can be improved by efficiently transporting and distributing the proppant through the lengths of the fractures. The main target of this study is to evaluate the viscosity and elasticity of high viscosity friction reducer (HVFR) for the purpose of transport and suspend the proppant at a temperature of 25°C. This study an alyzes the settling of proppant across HVFR using two different concentrations, 0.5 and 1 gallon per thousand of gallon (gpt). The tests were conducted using two static models and three different spherical particle sizes (2,4, and 6 mm). Also, the settling of the proppant was performed using proppant size of 40/70 mesh size. The study also assessing the distribution of proppant using a dynamic model. Proppant transport evaluations inside the dynamic model were performed utilizing various concentrations of HVFR and a sand mesh size of 40/70. The findings demonstrated that the viscosity and elasticity of HVFR improved as the concentration increased from 0.5 to 1 gpt. Furthermore, the findings indicated that HVFR at a concentration of 1 gpt is capable of suspending the proppant for a significant time, when compared to the HVFR at a concentration of 0.5 gpt. The work exhibits the settling velocity of the proppant utilizing low HVFR concentrations and examines how the rheology may impact the proppant transport.

1. INTRODUCTION

The successful application of hydraulic fracturing techniques for obtaining oil from unconventional reservoirs has received considerable interest in recent years, due to its potential to enhance oil recovery. Thus, the main purpose of hydraulic fracturing operations is to provide an effective distribution of proppant within the fracture networks, which increases the conductivities of the formations. To keep the created fractures open during hydraulic fracturing, an effective fracture fluid with high viscosity and elasticity is employed to transport proppant. In recent years, various oil companies have begun employing HVFR in place of polysaccharides like linear guar or crosslinked gels due to the cost-saving benefits of HVFR in hydraulic fracturing operations. HVFR is a green alternative to regular processes that involve the use of linear guar or crosslinked gels. HVFR consumes less water, reduces chemical usage by over 30%, and minimizes the equipment needed on-site (Van Domelen et al., 2017; Dahlgren et al., 2018; Johnson et al., 2018). Furthermore, HVFR significantly decreases friction by over 70% (Shen et al., 2019; Xu et al., 2019; Song et al., 2020; Hazra et al., 2020; John et al., 2021). This might potentially result in a reduction in pressure at the surface and a possible increase in injection rates. Many research investigations were performed to evaluate the ability of HVFR. Several of these researches aim to analyze the rheology of HVFR (Gaillard et al., 2013; Hu et al., 2015; Aften, 2018; Shen et al., 2018; Biheri and Imqam, 2020, 2021; Kurdi et al., 2020; and Ge et al., 2023a). The results indicated that HVFR has superior viscosity and elasticity compared to linear guar, and HVFR exhibited excellent rheological properties even at lower fluid concentrations. Several studies have utilized static models to measure the settling of proppant through the friction reducer at low shear rates (Sanders et al., 2016; Shen et al., 2018; Zhao et al., 2018; Biheri and Imqam, 2021, 2022; and Ge et al., 2022a, 2023b). the research concentrated on studying the influence of proppant loadings and proppant sizes on the velocity of the proppant. The findings demonstrated that HVFR has a greater ability to improve the suspension of the proppant compared to linear guar. Furthermore, HVFR indicated a better capacity to hold up larger proppant sizes or higher sand concentrations in comparison to linear guar. The benefits of HVFR help the continuous injection of proppant, resulting in an increasing concentration of proppant during the hydraulic fracturing operations. In addition, other research has investigated the proppant transport utilizing a dynamic model employing HVFR to simulate the actual transport of the proppant in the real field conditions (Dahlgren et al., 2018; Drylie et al., 2018; Zhao et al., 2018; Biheri and Imqam, 2020; and Ge et al., 2022b). The results indicate that the HVFR performance reduces as the size or concentration of the proppant increases. However, HVFR exhibits superior proppant distribution in comparison to linear guar, even when there is an increase in the sizes or concentrations of proppant. However, the majority of the listed studies have limits when it comes to analyzing the rheology of the low concentrations of HVFR. Additionally, the influence of low concentrations of HVFR on the transport of the proppant within the dynamic system has not been evaluated. The first stage of this study analyzed the rheological characteristics of two low concentrations of HVFR using 0.5 and 1 gpt. This investigation focused on determining the viscosity and elasticity characteristics of two HVFR concentrations. The rheology measurement was performed to provide insight of how these characteristics assist the transportation of proppant in fracture networks. In the second stage of the study, the suspension of the proppant and spherical particles inside the static model was investigated by employing HVFR at the given two concentrations. Finally, the proppant transport within a dynamic system has been evaluated for determining the distribution of proppant under different conditions of HVFR using 0.5 and 1 gpt.