Chemical resistance and mechanical properties of nanosilica addition in oil well cement (original) (raw)
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A methodology to improve nanosilica based cements used in CO2 sequestration sites
Petroleum, 2018
Attempts to reduce the amount of greenhouse gases released into the atmosphere in recent years have led to the development of Carbon Capture and Sequestration (CCS) technology. However, there have been many studies reporting leakages form CO 2 storage sites as a result of cement degradation induced by generation of an acidic environment in the storage site. Although there are a number of approaches proposed to enhance the efficiency of the cement, the degradation issue has not been totally resolved yet perhaps due to the excessive corrosives nature of carbonic acid and supercritical CO 2. The aim of this study is to propose a methodology to improve the physical and mechanical characteristics of the cement by nanomodification such that a consistent rheology, constant density and a good strength development can be achieved. A new dispersion technique was proposed to ensure that the cement formulation gives a consistent result. The results obtained indicated that unlike the literature mixing, cement slurries prepared by the new mixing technique are very consistent in their rheology, regardless of the sonication parameters chosen. The measurements of the compressive strength performed at the reservoir condition revealed that nanosilica contributes in the strength development up to a certain point. Thermogravimetric Analysis (TGA) conducted at the last stage indicated that the amount of Portlandite left in the cement by adding nanosilica is decreased due to the pozzolanic reaction, which would help the cement to have a higher chance of survival in a storage site. However, cautions must be taken to maintain a certain amount of Portlandite in the cement for slowing down the carbonation rate, as otherwise the matrix of the cement is attacked directly and the cement will be degraded very fast.
Cement and Concrete Research, 2018
Chemical reactions of class G oil well cement submerged in CO 2-saturated brine were experimentally investigated to evaluate the effects of nano-silica and curing conditions. The progression of depths of reaction zones (depletion, carbonation, and degradation zone) with reaction time up to 62 days were quantitatively measured based on 3D X-ray CT in conjunction with the chemical analysis. The results show that there were no significant difference in the progress of carbonation zone regardless of the curing conditions and nano-silica. The measure of reaction depth for tested specimens concludes that the curing at the high pressure and temperature is more effective to prevent the depletion zone from progressing into the cement interior than the addition of the nano-silica, supported by XRD and NMR results. Image-based measurements, coupled with chemical analyses, quantified the evolution of the reactive zones in the oil well cement, providing insights into the underlying reaction mechanism.
Cement degradation in CO2 storage sites: a review on potential applications of nanomaterials
Journal of Petroleum Exploration and Production Technology
Carbon capture and sequestration (CCS) has been employed to reduce global warming, which is one of the critical environmental issues gained the attention of scientific and industrial communities worldwide. Once implemented successfully, CCS can store at least 5 billion tons of CO 2 per year as an effective and technologically safe method. However, there have been a few issues raised in recent years, indicating the potential leakages paths created during and after injection. One of the major issues might be the chemical interaction of supercritical CO 2 with the cement, which may lead to the partial or total loss of the cement sheath. There have been many approaches presented to improve the physical and mechanical properties of the cement against CO 2 attack such as changing the water-to-cement ratio, employing pozzolanic materials, and considering non-Portland cements. However, a limited success has been reported to the application of these approaches once implemented in a real-field condition. To date, only a few studies reported the application of nanoparticles as sophisticated additives which can reinforce oil well cements. This paper provides a review on the possible application of nanomaterials in the cement industry where physical and mechanical characteristics of the cement can be modified to have a better resistance against corrosive environments such as CO 2 storage sites. The results obtained indicated that adding 0.5 wt% of Carbon NanoTubes (CNTs) and NanoGlass Flakes (NGFs) can reinforce the thermal stability and coating characteristics of the cement which are required to increase the chance of survival in a CO 2 sequestrated site. Nanosilica can also be a good choice and added to the cement by as much as 3.0 wt% to improve pozzolanic reactivity and thermal stability as per the reports of recent studies.
DOAJ (DOAJ: Directory of Open Access Journals), 2021
Soil cement is a mixture of Portland cement, soil and water, in which hydration of cement and compaction causes the materials' constituents to bond together makes a dense and durable composition with low permeability and abrasion resistant. Since most of the recent researches are focused on the addition of nano-SiO2 on concrete, in this paper it has been attempted to use nano-SiO2 particles in soil-cement and observe the effects. Due to the fact that in concrete there are no particles passing sieve 200 and this restriction does not apply to soil-cements, some tests were carried out on the nano-SiO2 + soil-cement matrix because of the meaningful difference between concrete and soil-cement. The test procedure consists of moisture-dry density, unconfined compressive test and hydraulic conductivity. In these tests, silica fume (with specific surface area of 21 m 2 /g), nano-SiO2 (with specific surface area of 200 and 380 m 2 /g) were added to soilcement. The results show that adding certain amounts of nano-SiO2 particles to the soilcement matrix can improve the compressive strength and reduce permeability and speed hydration reactions in the matrix in presence of nano-SiO2 particles.
International Journal of Engineering Research and Technology (IJERT), 2015
https://www.ijert.org/enhancing-physical-and-mechanical-properties-of-cement-based-morters-and-corrosion-resistance-of-reinforcing-steel-using-nano-sio2 https://www.ijert.org/research/enhancing-physical-and-mechanical-properties-of-cement-based-morters-and-corrosion-resistance-of-reinforcing-steel-using-nano-sio2-IJERTV4IS030899.pdf This paper investigates the effect of replacement of cement with different percentages of Nano-SiO2 and with constant percentage of silica fume. Nano-Sio2 is used to reduce the corrosion in reinforcement bars. The physical and mechanical properties of cement mortars and corrosion resistance property was studied to estimate the effect of Nano-SiO2 additive. A control specimen is prepared without Nano-SiO2. Further, four more specimens are prepared by replacing the amount of cement with different percentages of Nano-SiO2 with silica fume. In these four specimens, the amount of Nano-SiO2 are varied by 0%, 1%, 2%, 3% and 4%, respectively with constant 10% silica fume. The specimens are treated with different types of water as tape water and Qarun lake water. Comparing the observed responses, it is found that the addition of Nano-SiO2 with silica fume is effective in increasing the compressive and flexural strengths of cement mortar in addition to decreasing permeability and corrosion (with different mixing and type of treatment water). Thus this paper presents the recent progress and advancement in Nano-engineering and Nano modification in cement concrete.
The Effect of Nano Silica on Cementitious Materials
2017
Nano silica is a relatively new product that has come to markets in limited parts of the world. Its production and thus characteristics vary significantly in the absence of clear specification and guides for its use. This study aims at achieving better understanding of the performance of cementitious mortar prepared using imported Nano silica when compared with mixtures made with silica fume. The testing program included physical properties, chemical analysis as well as the compressive and flexural Strength. Another set of tests included water permeability, rapid chloride permeability, resistance of the mortar to sulphates, sulphuric acid. Results reveal that the Nano silica used enhances some of the cementitious mortar properties while substantial enhancement was not witnessed when compared to silica fume mixtures. Recommendations are provided to better utilize this innovative material and projects that are likely to make best use of its application.
The effect of carbon dioxide on β-dicalcium silicate and Portland cement
Chemical Engineering Journal, 2006
Carbonation of silicate-based minerals and industrial residues can help to reduce CO 2 emissions as well as produce useful materials. However, until a full understanding of the chemistry and microstructural development of carbonation products is obtained, their utilization in engineering applications may remain limited. In respect of this, the present work examines microstructural properties of accelerated carbonated dicalcium silicate and Portland cement by using the complementary analytical techniques of XRD, SEM, TG-DTA, and NMR MAS. It was found that carbon dioxide reacts with calcium silicates to form calcite and aragonite and a polymerized silicate product comprised of cross-linked Q 3 co-ordinated silicon and fully polymerized Q 4 co-ordinated silicon. The extent of silicate polymerization was higher in carbonated dicalcium silicate, however, in the Portland cement-derived product, Al substitution in the Si-framework was detected. The amount of CO 2 that reacted with dicalcium silicate and Portland cement was 48 and 37% by mass, respectively.
Use of nano-silica in cement based materials—A review
The research nowadays is mainly focusing on the basic science of cementitious material at nano/atomic level. Further, researchers are continuing to improve the durability and sustainability of concrete and have realized significant increment in mechanical properties of cementitious materials by incorporating nano-silica. The review paper summarizes the effect of nano-silica addition on mechanical, durability and microstructure characteristics of paste, mortar and concrete. It provides the current development of application of nano-silica in paste, mortar and concrete. Finally, the future trend/potential and implication of nanosilica in cement-based materials is discussed. Their areas of interest include use of nanosilica in concrete, its study of mechanical and durability properties. High-performance concrete, self-compacting concrete, their performance and durability aspects incorporating industrial by-products. Cement is one of the most energyconsuming materials widely used globally. Efforts are being made mainly to use supplementary cementitious materials in mortars and concrete directed towards the reduction of carbon footprint. The present research work is one such effort towards attaining the above goal.
Cement and Concrete Research, 2021
This study explored the reactive processes of atmospheric carbonation and the consequences with respect to cementitious materials. Two model pastes were used: hydrated C 3 S (including C-S-H and portlandite) and a paste prepared by hydrating a blend of C 3 S and nanosilica (including C-S-H only). The two pastes were carbonated under accelerated conditions in the laboratory. The resulting mineralogical assemblage was examined using Xray diffraction, thermogravimetric analysis and nuclear magnetic resonance. The microstructural changes were studied by X-ray tomography and porosimetry, and their macroscopic impacts were evaluated through gas diffusion and shrinkage measurements. The use of model pastes allowed for the evaluation of the change in solid volume induced by the carbonation of C-S-H. C-S-H decalcification and subsequent silica chain polymerisation were found responsible for carbonation shrinkage (and potentially cracking). Finally, the results highlight the protective role of portlandite: portlandite helped in limiting C-S-H decalcification and then reducing carbonation shrinkage and cracking.
CHEMICAL AND PHYSICO-MECHANICAL PROPERTIES OF COMPOSITE CEMENTS CONTAINING MICRO- AND NANO-SILICA
Portland cement is one of the most used materials in the world. Due the environmental problems related to its use, such as CO 2 emission and use of non-renewable raw materials, new materials are being researched. In the recent years, there is a great interest in replacing a long time used materials in concrete structure by nanomaterials (NMs) to produce concrete with novel function and better performance at unprecedented levels. NMs are used either to replace part of cement, producing ecological profile concrete or as admixtures in cement pastes. The great reactivity of NMs is attributed to their high purity and specific surface area. A number of NMs been explored and among of them nanosilica has been used most extensively. This work aims to study, the chemical and physico-mechanical properties of composite cements containing silica fume (SF) and nanosilica (NS). Different cement blends were made from OPC, SF and NS. OPC was substituted with SF up to 15.0 mass, %, then the SF portion was partially replaced by NS (2.0, 4.0 and 6.0 mass, %). The hydration behavior was followed by determination of free lime (FL) and combined water (Wn) contents at different curing ages. The required water for standard consistency (W/C), setting times (IST&FST), bulk density (BD) and compressive strength were also estimated. The hydration products were analyzed using XRD, DTA and SEM techniques. The results showed that, both of SF and NS improve the hydration behavior and physico-mechanical properties of composite cements. But, NS possesses higher improvement level than SF. This is due to that, both of them behave not only as filler to improve the microstructure, but also as activator to promote pozzolanic reaction, which enhances the formation of excessive hydration products. The higher beneficial role of NS is mainly due to its higher surface area, filling effect and pozzolanic activity in comparison with SF. The composite cement containing 85.0 % OPC, 11.0 % SF and 4.0 % NS gave the optimum mechanical properties at all ages of hydration.