Influence of Cellulose Nanoparticles on Rheological Behavior of Oil Well Cement-Water Slurries.

Zhengjie Tang,Xiuqiang Zhang,Changtong Mei,Runzhou Huang,Qinglin Wu,Xiuxuan Sun,Dingguo Zhou

doi:10.3390/ma12020291

Abstract

Performance of hardened oil well cement (OWC) is largely determined by the rheological properties of the cement slurries. This work was carried out to investigate the effect of water- to-cement ratio (WCR) and cellulose nanoparticles (CNPs), including cellulose nanofibers (CNFs) and cellulose nanocrystals (CNCs), on rheology performance of OWC-based slurries using a Couette rotational viscometer coupled with rheological models. The yield stress and viscosity of neat OWC slurries had a decreasing trend with the increase of WCRs. The suspension became increased unstable with the increase of WCRs. The properties of CNPs, including rheological behaviors, surface properties and morphology, determine the rheological performance of CNP-OWC slurries. In comparison with CNC-OWC slurries, the gel strength, yield stress and viscosity of CNF-OWC slurries were higher as CNFs were more likely to form an entangled network. The gel strength, yield stress and viscosity of CNP-OWC slurries increased with reduced CNF size through regrinding and the proportion of CNFs in the mixture of CNFs and CNCs, respectively.

Highlights

Oil well cementing operations play a vital role in the petroleum industry
The results showed that the flexural strength of cellulose nanofibers (CNFs)-cement composites increased 40% and nearly twice compared with cement composites enhanced by sisal fiber, but the fracture toughness was half of sisal fiber-cement composites
The initial and final gel strength of CNF-oil well cement (OWC) slurries slightly decreased first and increased when the amount of cellulose nanocrystals (CNCs) increased from 0.05% to 0.2% (Figure 6 b)

Summary

Introduction

Oil well cementing operations play a vital role in the petroleum industry. Oil well cement (OWC) is mainly constituted by Portland cement and other additives including accelerators, retarders, extenders, heavy weight agents, fluid loss additives, lost circulation additives, expansion additives, dispersants and antifoam agents [1,2]. The cementing operation is to form a ring-shaped space between the oil well casing and the structure surrounding the oil well bore, to support and protect the casing, to isolate abandoned sections of well and to cut out the lost circulation zones [3]. For the special case of the oil industry, OWC slurries are sometimes pumped down to in excess of several thousand meters into the ground and face additional challenges compared to ordinary cementing work on the surface. The rheological properties of OWC slurries determine the character of the hardened. Accurately characterizing the rheology of OWC slurries is critical

Objectives

Methods

Discussion

Conclusion