skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Hydrated Ordinary Portland Cement as a Carbonic Cement: The Mechanisms, Dynamics, and Implications of Self-Sealing and CO 2 Resistance in Wellbore Cements

Abstract

This report analyzes the dynamics and mechanisms of the interactions of carbonated brine with hydrated Portland cement. The analysis is based on a recent set of comprehensive reactive-transport simulations, and it relies heavily on the synthesis of the body of work on wellbore integrity that we have conducted for the Carbon Storage Program over the past decade.

Authors:
 [1];  [1];  [1];  [1];  [1];  [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1373519
Report Number(s):
LA-UR-17-24451
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; Earth Sciences; wellbore integrity, carbon sequestration

Citation Formats

Guthrie, George Drake Jr., Pawar, Rajesh J., Carey, James William, Karra, Satish, Harp, Dylan Robert, and Viswanathan, Hari S. Hydrated Ordinary Portland Cement as a Carbonic Cement: The Mechanisms, Dynamics, and Implications of Self-Sealing and CO2 Resistance in Wellbore Cements. United States: N. p., 2017. Web. doi:10.2172/1373519.
Guthrie, George Drake Jr., Pawar, Rajesh J., Carey, James William, Karra, Satish, Harp, Dylan Robert, & Viswanathan, Hari S. Hydrated Ordinary Portland Cement as a Carbonic Cement: The Mechanisms, Dynamics, and Implications of Self-Sealing and CO2 Resistance in Wellbore Cements. United States. doi:10.2172/1373519.
Guthrie, George Drake Jr., Pawar, Rajesh J., Carey, James William, Karra, Satish, Harp, Dylan Robert, and Viswanathan, Hari S. 2017. "Hydrated Ordinary Portland Cement as a Carbonic Cement: The Mechanisms, Dynamics, and Implications of Self-Sealing and CO2 Resistance in Wellbore Cements". United States. doi:10.2172/1373519. https://www.osti.gov/servlets/purl/1373519.
@article{osti_1373519,
title = {Hydrated Ordinary Portland Cement as a Carbonic Cement: The Mechanisms, Dynamics, and Implications of Self-Sealing and CO2 Resistance in Wellbore Cements},
author = {Guthrie, George Drake Jr. and Pawar, Rajesh J. and Carey, James William and Karra, Satish and Harp, Dylan Robert and Viswanathan, Hari S.},
abstractNote = {This report analyzes the dynamics and mechanisms of the interactions of carbonated brine with hydrated Portland cement. The analysis is based on a recent set of comprehensive reactive-transport simulations, and it relies heavily on the synthesis of the body of work on wellbore integrity that we have conducted for the Carbon Storage Program over the past decade.},
doi = {10.2172/1373519},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 7
}

Technical Report:

Save / Share:
  • As part of the study of hydraulic-cement system for use in possible underground isolation of nuclear wastes, this study was made to determine the temperature stability of ettringite and chloroaluminate. Either or both of these phases may be expected in a hydraulic cement system depending on the presence of salt (NaCl). The study of ettringite was made using 15 mixtures that contained portland cement, plaster, 2 levels of water, and in some mixtures, 1 of 6 pozzolans (3 fly ashes, 1 slag, a silica fume, a natural pozzolan), plus a 16th mixture with anhydrous sodium sulfate replacing plaster (CaSO4 .more » 1/2H20). Specimens were made and stored at 23, 50, and 75 C or 23, 75, and 100 C (all four temperatures in one case) for periodic examination by x-ray diffraction for phase compositiion and ettringite stability, and testing for compressive strength and restrained expansion. A more limited study of the stability of chloroaluminate was made along the same lines using fewer mixtures, salt instead of plaster, and higher temperatures plus some pressure. It was found that while some ettringette was decomposed at 75 C, depending on the composition of the mixture, all ettringite was undetectable by x-ray diffraction at 100 C, usually within a few days. The evidence indicates that the ettringite became amorphous and no significant test phases formed in its place. Since there was no corresponding loss in strength or reduction in volume, this loss of ettringite crystallinity was considered to be damaging. Based on much more limited data, chloroaluminate was found to decompose between 130 C at 25 psi and 170 C at 100 psi; no significant phases replaced it.« less
  • Ground water with a high concentration of magnesium ion is known to cause deterioration to portland cement concretes. A proposed mechanism for this deterioration process published previously involves an approximate 1:1 replacement of Ca ions by Mg ions in the crystalline phases of hydrated cement. The current study was undertaken to determine which ions, among magnesium, chloride, and sulfate, cause deterioration; whether their deleterious action is individual or interdependent; and to relate this mechanism of deterioration to the outlook for a 100-yr service life of concretes used in mass placements at the Waste Isolation Pilot Plant. Loss of Ca ionmore » by cement pastes was found to be strongly related to the concentration of Mg ion in simulated ground-water solutions in which the paste samples were aged. This was true of both salt- containing and conventional cement pastes. No other ion in the solutions exerted a strong effect on Ca loss. Ca ion left first from calcium hydroxide in the pastes, depleting all calcium hydroxide by 60 days. Some calcium silicate hydrate remained even after 90 days in the solutions with the highest concentration of Mg ion, while the paste samples deteriorated noticeably. The results indicated a mechanism that involves dissolution of Ca phases and transport of Ca ions to the surface of the sample, followed by formation of Mg-bearing phases at this reaction surface rather than directly by substitution within the microstructure of hydrated cement. Given that calcium hydroxide and calcium silicate hydrate are the principal strength-giving phases of hydrated cement, this mechanism indicates the likelihood of significant loss of integrity of a concrete exposed to Mg-bearing ground water at the WIPP. The rate of deterioration ultimately will depend on Mg-ion concentration, the microstructure materials of the concrete exposed to that groundwater, and the availability of brine.« less
  • Sulfate-attack and gamma-irradiation tests were carried out on three Portland cement mortars. For the sulfate attack work an accelerated test was used involving alternate immersion in Na/sub 2/SO/sub 4/ solution and oven drying of the samples. Attack was monitored through length-change measurements. Cement mortar containing silica fume gave unexpectedly poor resistance to attack. Reasons for this behavior are unclear. Gamma irradiation was found to cause losses in compressive strength at low doses in the 10/sup 7/ rad range. The irradiation time is a major factor in the strength-loss mechanism, whereas the dose rate is of secondary importance for the testingmore » conditions studied. 10 refs., 19 figs., 6 tabs.« less
  • X-ray diffraction methods developed for the determination of residual stress states in crystalline materials have been applied to study residual strains and strains because of mechanical loading of ordinary Portland cement paste. Synchrotron X-rays were used to make in situ measurements of interplanar spacings in the calcium hydroxide (CH) phase of hydrated neat Portland cement under uniaxial compression. The results indicate that strains on the order of 1/100000 can be resolved providing an essentially new technique by which to measure the phase-resolved meso-scale mechanical behavior of cement under different loading conditions. Evaluation of these strain data in view of publishedmore » elastic parameters for CH suggests that the CH carries a large fraction of the applied stress and that plastic interactions with the matrix are notable.« less
  • X-ray diffraction methods developed for the determination of residual stress states in crystalline materials have been applied to study residual strains and strains because of mechanical loading of ordinary portland cement paste. Synchrotron X-rays were used to make in situ measurements of interplanar spacings in the calcium hydroxide (CH) phase of hydrated neat portland cement under uniaxial compression. The results indicate that strains on the order of 1/100 000 can be resolved providing an essentially new technique by which to measure the phase-resolved meso-scale mechanical behavior of cement under different loading conditions. Evaluation of these strain data in view ofmore » published elastic parameters for CH suggests that the CH carries a large fraction of the applied stress and that plastic interactions with the matrix are notable.« less