Cellulose Nanofibers as a Modifier for Rheology, Curing and Mechanical Performance of Oil Well Cement.

Xiuxuan Sun,Yiqiang Wu,Sunyoung Lee,Qinglin Wu,Yan Qing

doi:10.1038/srep31654

Abstract

The influence of nanocellulose on oil well cement (OWC) properties is not known in detail, despite recent advances in nanocellulose technology and its related composite materials. The effect of cellulose nanofibers (CNFs) on flow, hydration, morphology, and strength of OWC was investigated using a range of spectroscopic methods coupled with rheological modelling and strength analysis. The Vom-Berg model showed the best fitting result of the rheology data. The addition of CNFs increased the yield stress of OWC slurry and degree of hydration value of hydrated CNF-OWC composites. The flexural strength of hydrated OWC samples was increased by 20.7% at the CNF/OWC ratio of 0.04 wt%. Excessive addition of CNFs into OWC matrix had a detrimental effect on the mechanical properties of hydrated CNF-OWC composites. This phenomenon was attributed to the aggregation of CNFs as observed through coupled morphological and elemental analysis. This study demonstrates a sustainable reinforcing nano-material for use in cement-based formulations.

Highlights

Cementing plays a crucial role in the oil well drilling operation-protecting and supporting casing, preventing fluid migration, and sealing abandoned sections of a well
It is apparent that the addition of Cellulose nanofibers (CNFs) in the oil well cement (OWC) promoted the reaction between water and OWC
Our data suggested that the yield stress of fresh CNF/OWC slurries increased with the increased loading of CNFs in OWC composites

Summary

Introduction

Cementing plays a crucial role in the oil well drilling operation-protecting and supporting casing, preventing fluid migration, and sealing abandoned sections of a well. Various additives have been incorporated into cement matrix to improve the rheological and mechanical properties of cement, including the use of silica fume[4], fly ash[5], and natural fiber[6,7]. CNTs improved the durability properties of cement-based composites through decreasing the water permeability www.nature.com/scientificreports/. Cellulose fibers are widely used in composites to improve their mechanical properties[13]. Mònica Ardanuy et al reported the use of nanofibrillated cellulose (NFC) in the cement mortar composites[14] Both sisal fiber and NFC reinforced cement mortar composites demonstrated improved flexural properties. Cellulose nanofibers (CNFs) are another type of CNPs, which exhibit great advantages when being used in composites as a reinforcing agent to improve mechanical and thermal properties. Bilodeau and Bousfield used CNFs to improve mechanical properties of particleboard and the fracture toughness was doubled when 20 wt.% of CNFs were added[19]

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