Evaluation of Influence of Salt in the Cement Hydration to Oil Wells

Abstract

The influence of NaCl salt in the hydration of the Portland cement paste class G was studied using a Non Conventional Differential Thermal Analysis (NCDTA) on the first 24 hours of cement hydration. The mass of salt used corresponds to 0, 5, 10, 15 and 20% of mass of water used in the preparation of the pastes. The water/cement ratio (w/c) remained constant, being 0.46, and the pastes final volume was 99.9mL. Applying a deconvolution method to separate overlapped NCDTA peaks it was possible to estimate the energy released during the different stages of hydration and the effect of salt in cement hydration process. The presence of up to 10% of salt accelerated the hydration process and increased the hydration of C 3 S and C 3 A, while the 20% of the salt causes a delayed hydration and decreased the hydration of C 3 S and C 3 A. Futhermore, cement pastes with the same percentages of NaCl and with different hydration times were evaluated by Thermogravimetry (TG), Derivative Thermogravimetry (DTG) and Differential Thermal Analysis (DTA). After 28 days the presence of salt caused a greater increase in the formation of hydrated products.

Effect of viscosity modifier admixture on Portland cement paste hydration and microstructure

“…3 the salt crystals were observed using an Environmental SEM, and with the help of Energy-Dispersive X-ray Spectroscopy (EDS) measurements the presence of peaks of sodium and chlorine were found. It should be noted that NaCl accelerates OPC hydration [35,36], and leads to corrosion of steel reinforcement [37,38].…”

The effects of seawater on the hydration, microstructure and strength development of Portland cement pastes incorporating colloidal silica

“…This confirms the findings in previous works, which have argued that the presence of chloride ions in seawater promotes cement hydration in the early hours. NaCl, MgCl 2 , CaCl 2 have an accelerating effect on cement hydration, especially on calcium silicates (mainly tricalcium silicate-C 3 S), which results in faster formation of the C-S-H phase and decreases the setting time of the composite (Govindarajan and Gopalakrishnan 2011;Etxeberria et al 2016b;Fernanda et al 2017;Parthasarathy et al 2017).…”

“…Several studies have agreed that the salt quantity in seawater can improve the early strength of concrete, with later strength remaining similar or slightly higher in comparison to concrete made with tap water (Demir et al 2010;Wegian 2010;Otsuki et al 2012;Abdel-Magid et al 2016;Etxeberria et al 2016a). The chloride ion (Cl − ) content of seawater contributes to the acceleration of the cement hydration process, thus decreasing the setting time of cement (Govindarajan and Gopalakrishnan 2011) and fastening its hardening (Fernanda et al 2017). In addition, a decrement in the porosity of the cement matrix and the absorption capacity of concrete have been reported (Etxeberria et al 2016a;Adiwijaya et al 2017).…”

The effects of seawater and nanosilica on the performance of blended cements and composites

“…This confirms that a combination of seawater with slag-cement has a higher reaction rate than that of pozzolan-blended cement. The acceleration of cement hydration in the presence of seawater is enhanced due to the input of chlorides, which are known to be efficient accelerating agents in the cement hydration process, mainly the C 3 S phase (Govindarajan and Gopalakrishnan 2011;Otsuki et al 2015;Etxeberria et al 2016b;Fernanda et al 2017;Parthasarathy et al 2017). As has been widely reported (Li et al 2018a;Wang et al 2018;Younis et al 2018;Shaikh and Dobson 2019), the negatively charged Cl − on the surface of the cement, together with the presence of SCM particles, promotes cement compounds' dispersion and results in an enhancement in hydration.…”