Effect of Fluid Rheology on Sand Production: Comprehensive Study
Authors: Omirbekov Sagyn , Zhaidarbek Balnur , Amanbek Yerlan 
Published: August 2024

ABSTRACT:
This study presents a new analytical model for power-law fluids and investigates its application in examining sand production. A xanthan gum (XG) based polymer solution is injected into the artificially made sandstone, with characteristics similar to the Kazakhstani oil field, to evaluate the effect of polymer flooding on sand production. The examined rheology of the polymer solution fitted with a power-law model was used as input for the new analytical model. We observed sand production during the injection of the polymer solution, but no sanding was noticed during the injection of brine at a similar flow rate. The derived analytical model was used to compare the cumulative mass of produced particles with the results of laboratory experiments. The model fits well with the experimental data, except for the initial stage, where approximately half of the sand volume was produced at the first pore volume of XG solution injection.

1 INTRODUCTION
Sand production is one of the severe problems in the petroleum industry, causing serious operational issues by damaging equipment due to erosion, clogging wellbores, and destroying surface facilities. Hence, understanding, preventing, and controlling sand production is under the scrutiny of operating companies. Most of the world's oil and gas reserves, about 70 %, are located in weakly consolidated sandstone reservoirs (Saghandali et al., 2022), where sand production commonly occurs with hydrocarbons. Unconsolidated sandstone oil reservoirs can also be found in Kazakhstan, especially in the pre-Caspian regions, and issues related to sand production also exist in local operating companies.
Numerous sand prediction models have been developed to understand better the complex process of sand production in hydrocarbon extraction. These models use theoretical (Weingarten and Perkins, 1995), empirical, and numerical methods (Kazidenov et al., 2023a,b; Omirbekov et al., 2023), taking into account hydro-mechanical mechanisms such as tensile and shear failure, as well as factors like pressure depletion. However, accurately forecasting sand production is challenging due to the complexity of assessing parameters such as rock mass properties and stress distribution. Researchers have employed plasticity, mixture, or micromechanics theories to simplify modeling sand production, but these approaches have limitations in capturing sudden changes or discontinuities. Mixture theory has been used to model sand production, considering factors such as fluid injection, hydrodynamic forces, and erosion. Distinguished researchers such as Bratli and Risnes (1981); Vardoulakis et al. (1996); Skajrstein et al. (1997); Papamichos et al. (2001); Chin and Ramos (2002); Detournay et al. (2006); Isehunwa and Olanrewaju (2010); Fjaer et al. (2008) have proposed various models that incorporate a range of parameters, such as fluid flow rate, porosity, solid density, plastic strain, and erosion criteria. These parameters are essential in describing the complex process of sand production during hydrocarbon extraction (Ranjith et al., 2014). Previous sand production models were only dedicated to Newtonian fluids, while models to describe the impact of non-Newtonian fluids (like polymer injection) on sand production were not presented before.