Performance analyses of hydroxyethyl cellulose (HEC) polymer as gelling agent in gravel-pack carrier fluid formulation for sand control of hydrocarbon production wells

Abstract

This study considers the performance of 40ppt and 60ppt hydroxyethyl cellulose (HEC) polymer used as a gelling agent in the formulation of carrier fluids for gravel pack transport in sand control operations in oil and gas wells. The gravel pack carrier fluid was prepared by adding adequate amounts of sodium persulfate (SP) used as gel breaker, Fe-2 used as an iron control agent, KCL brine as mixed fluid, K-35 used as pH buffer, BE-6, and BE-35 used as biocides, HEC used as a gelling agent, and distilled water. The effects of temperature, gel loading, and breaker fluid concentration on the rheology, gel break time, and sand settling of the formulated HEC carrier fluid were considered. The results showed that shear stress, plastic viscosity and yield point and consistency factor decreased with an increase in bottomhole temperature for both 40ppt and 60ppt HEC gels. Furthermore, flow behaviour index was observed to be within the range of 0.45±0.1 40ppt and 0.5±0.04 for 60ppt HEC of gel loading, respectively and showing shear-thinning characteristics. Good gravel settling was observed for the HEC gels when in contact with gravel, addition of breaker fluid greatly improved the sand/gravel suspension for 40ppt and 60ppt gel loadings. Gel break time of the HEC gel increased with increasing gel loading, and at higher breaker fluid concentrations, HEC gel degradation becomes more critical as temperature increases. The results highlight the adequate performance of HEC polymer as gravel pack fluid in sand control operation.