scholarly journals The Use of Nanomaterials in Shaping the Properties of Cement Slurries Used in Drilling

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3121
Author(s):  
Marcin Rzepka ◽  
Miłosz Kędzierski
Keyword(s):  
Compressive Strength ◽  
Cement Matrix ◽  
Cement Stone ◽  
Calcium Aluminates ◽  
Innovative Solutions ◽  
Porosity And Permeability ◽  
Design Production ◽  
Calcium Silicates ◽  
The Given ◽  
Hydrated Calcium

For several decades, constant research has been performed in the world in order to obtain more durable, tighter, or less environmentally harmful binding materials which could be used to seal casing strings in boreholes. There is an increasing search for innovative solutions allowing the production of the highest possible class of binding cements. Since the beginning of the 21st century, one thing which has become synonymous with development is nanotechnology—a dynamically growing branch of science involving both the design, production, and testing of structures with the size of billionths of a metre. Among other things, a set cement stone is made of the grains of hydrated calcium silicates and calcium aluminates, between which there are pore spaces. Fine grains of nanoparticles can successfully settle inside these spaces, causing a decrease in the porosity and permeability of cement matrix. The paper presents the results of laboratory tests performed for formulas of cement slurries containing between 0.5% and 1% of nanosilica, between 1% and 3% of nanosized alumina and approximately 0.1% of carbon nanotubes. The resulting slurries had a density of approximately 1830–1920 kg/m3 and zero water settling. The thickening times of slurries were selected in accordance with the given geological and technical conditions. Early compressive strength amounting to 3.5 MPa (based on a test using an ultrasound cement analyser) was achieved by slurries after times between approximately 7 and 14 h. Upon setting of samples, cement stones produced from slurries featured a very low share of capillary pores. After 28 days of hydration, the compressive strength of the resulting cement stones took on very high values, reaching even up to 50 MPa. Photographs of cement stones containing nanomaterials (taken by means of scanning microscopy) are a confirmation of the exceptionally compact microstructure of the resulting samples.

scholarly journals The Effect of Weighting Materials on Oil-Well Cement Properties While Drilling Deep Wells

2019 ◽  
Vol 11 (23) ◽  
pp. 6776 ◽  
Author(s):  
Abdulmalek Ahmed ◽  
Ahmed Abdulhamid Mahmoud ◽  
Salaheldin Elkatatny ◽  
Weiqing Chen
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Density Variation ◽  
Cement Matrix ◽  
Oil Well ◽  
Cement Slurry ◽  
Deep Wells ◽  
Porosity And Permeability ◽  
Maximum Particle ◽  
Well Cement

In deep hydrocarbon development wells, cement slurry with high density is required to effectively balance the high-pressure formations. The increase in the slurry density could be achieved by adding different heavy materials. In this study, the effect of the weighting materials (barite, hematite, and ilmenite) on the properties of Saudi Class G cement matrix of vertical homogeneity, compressive strength, porosity, and permeability was evaluated. Three cement slurries were weighted with barite, hematite, and ilmenite, and cured at 294 °F and 3000 psi for 24 h. All slurries have the same concentration of the different additives except the weighting material. The amount of weighting material used in every slurry was determined based on the targeted density of 18 lbm/gal. The results of this study revealed that the most vertically homogenous cement matrix was the ilmenite-weighted sample with a vertical variation of 17.6% compared to 20.2 and 24.8% for hematite- and barite-weighted cement, respectively. This is attributed to the small particle size of the ilmenite. The medical computerized tomography (CT) scan confirmed that the ilmenite-weighted sample is the most homogeneous, with a narrow range of density variation vertically along the sample. Hematite-weighted cement showed the highest compressive strength of 55.3 MPa, and the barite- and ilmenite-weighted cement compressive strengths are each 18.4 and 36.7% less than the compressive strength of the hematite-weighted cement, respectively. Barite-weighted cement has the lowest porosity and permeability of 6.1% and 18.9 mD, respectively. The maximum particle size of ilmenite used in this study is less than 42 μm to ensure no abrasion effect on the drilling system, and it minimized the solids segregation while maintaining a compressive strength that is higher than the minimum acceptable strength, which is the recommended weighting material for Saudi Class G cement.

Improvement of Wood-Cement Composition Properties with Microsilica Additive

2020 ◽  
Vol 992 ◽  
pp. 162-167
Author(s):  
E.Yu. Gornostaeva ◽  
N.P. Lukuttsova ◽  
D.I. Dryazgov
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Silicon Dioxide ◽  
Cement Hydration ◽  
Cement Stone ◽  
Hydration Products ◽  
Maximum Increase ◽  
Calcium Hydrosilicates ◽  
Calcium Silicates ◽  
Composition Properties

The properties and microstructure of wood-cement compositions (WCC) with microsilica (MS) additive for the manufacture of small-pieces wall products are studied. The extreme dependences of mean density, thermal conductivity and compressive strength on the content of microsilica additive are established. The mechanism of microsilica effect on wood-cement compositions is offered. Two interrelated factors (chemical and physical) could be distinguished at that. The first factor includes mainly the interaction of silicon dioxide with lime having released during hydration of calcium silicates, i.e. pozzolatic process. The second factor lies in the compaction of wood-cement compositions and the cement stone structure by means of cement hydration products and silica particles. It is established that introducing 20% of microsilica in the composition results in the maximum increase in ultimate compression strength (3 times). It can be explained not only by forming calcium hydrosilicates, uniformly and densely covering the wood aggregate, but by compacting effect of spherical microsilica inclusions, filling the space between the new cement stone formations and wood aggregate.

scholarly journals Mechanical Properties and Enhancement Mechanism of Oil-Well Cement Stone Reinforced with Carbon Fiber Surfaces Treated by Concentrated Nitric Acid and Sodium Hypochlorite

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yongjin Yu ◽  
Jiawen Fu ◽  
Chi Zhang ◽  
Fengzhong Qi ◽  
Ming Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Nitric Acid ◽  
Sodium Hypochlorite ◽  
Ultimate Strain ◽  
Cement Matrix ◽  
Infrared Analysis ◽  
Cement Stone ◽  
Maximum Compressive Strength

In this study, carbon fibers (CFs) were used as toughening materials to improve the mechanical properties of cement stone. The surfaces of the CFs were treated with concentrated nitric acid and sodium hypochlorite to increase the interfacial adhesion between the CFs and the cement. The CFs subjected to surface treatment were evaluated by scanning electron microscopy and infrared analysis to find a significant increase in the number of oxygen-containing groups on the surface. The CFs subjected to surface treatment were added to the cement matrix. The effect of the modified CFs on the mechanical properties of the cement matrix was evaluated by testing the means of mechanical properties. The maximum tensile strength, maximum compressive strength, and ultimate strain of the enhanced cement stone of the CFs treated with sodium hypochlorite increased by 68.2%, 12.0%, and 4.4%, respectively. The maximum tensile strength, maximum compressive strength, and ultimate strain of the enhanced cement stone of the CFs treated with concentrated nitric acid increased by 72.7%, 14.7%, and 4.5%, respectively. The addition of CFs to the cement stone exerted no effect on the type of cement hydration products, as determined by infrared analysis and X-ray diffraction. The toughening mechanism of the modified CFs added to the cement stone was ultimately explored, and the bridging effect, deflection effect, and pull-out effect of cracks were evaluated.

scholarly journals Strength Performance and Microstructure of Calcium Sulfoaluminate Cement-Stabilized Soft Soil

2021 ◽  
Vol 13 (4) ◽  
pp. 2295
Author(s):  
Hailong Liu ◽  
Jiuye Zhao ◽  
Yu Wang ◽  
Nangai Yi ◽  
Chunyi Cui
Keyword(s):  
Soft Soil ◽  
Hydration Product ◽  
X Ray Diffraction ◽  
Calcium Sulfoaluminate Cement ◽  
Strength Performance ◽  
X Ray ◽  
Calcium Sulfoaluminate ◽  
Stabilized Soil ◽  
Calcium Silicates ◽  
Hydrated Calcium

Calcium sulfoaluminate cement (CSA) was used to stabilize a type of marine soft soil in Dalian China. Unconfined compressive strength (UCS) of CSA-stabilized soil was tested and compared to ordinary Portland cement (OPC); meanwhile the influence of amounts of gypsum in CSA and cement contents in stabilized soils on the strength of stabilized soils were investigated. X-ray diffraction (XRD) tests were employed to detect generated hydration products, and scanning electron microscopy (SEM) was conducted to analyze microstructures of CSA-stabilized soils. The results showed that UCS of CSA-stabilized soils at 1, 3, and 28 d firstly increased and then decreased with contents of gypsum increasing from 0 to 40 wt.%, and CSA-stabilized soils exhibited the highest UCS when the content of gypsum equaled 25 wt.%. When the mixing amounts of OPC and CSA were the same, CSA-stabilized soils had a significantly higher early strength (1 and 3 d) than OPC. For CSA-stabilized soil with 0 wt.% gypsum, monosulfate (AFm) was detected as a major hydration product. As for CSA-stabilized soil with certain amounts of gypsum, the intensity of ettringite (Aft) was significantly higher than that in the sample hydrating without gypsum, but a tiny peak of AFm also could be detected in the sample with 15 wt.% gypsum at 28 d. Additionally, the intensity of AFt increased with the contents of gypsum increasing from 0 to 25 wt.%. When contents of gypsum increased from 25 to 40 wt.%, the intensity of AFt tended to decrease slightly, and residual gypsum could be detected in the sample with 40 wt.% gypsum at 28 d. In the microstructure of OPC-stabilized soils, hexagonal plate-shaped calcium hydroxide (CH) constituted skeleton structures, and clusters of hydrated calcium silicates (C-S-H) gel adhered to particles of soils. In the microstructure of CSA-stabilized soils, AFt constituted skeleton structures, and the crystalline sizes of ettringite increased with contents of gypsum increasing; meanwhile, clusters of the aluminum hydroxide (AH3) phase could be observed to adhere to particles of soils and strengthen the interaction.

scholarly journals Use of thermodynamic chemical potential diagrams (µCaO, µCO2) to understand the weathering of cement by a slightly carbonated water

Cerâmica ◽  
2008 ◽  
Vol 54 (331) ◽  
pp. 356-360 ◽  
Author(s):  
A. Blandine ◽  
G. Bernard ◽  
B. Essaïd
Keyword(s):  
Chemical Weathering ◽  
Chemical Potential ◽  
Chemical Elements ◽  
Continuous Solid Solution ◽  
The Core ◽  
Chemical Potentials ◽  
Knowing That ◽  
Cement System ◽  
Calcium Silicates ◽  
Hydrated Calcium

Cement is a ubiquitous material that may suffer hazardous weathering. The chemical weathering of cement in natural environment is mostly characterized by the leaching of CaO and the addition of CO2. The different weathering zones that develop at the expense of the cement may be predicted by the help of chemical potential phase diagrams; these diagrams simulate the behaviour of systems open to some chemical elements. Some components have a so-called inert status, that is to say the system is closed for these components, their amount in the system remains constant; some other components have a mobile status, that is to say these components can be exchanged with the outside of the system, their amount can vary from one sample zone to another. The mobile components are represented in the model by their chemical potentials (linked to their concentrations) that are variable in the external environment. The main features of the weathering of a cement system open to CaO and CO2 are predicted in a phase diagram with µCaO et µCO2 as diagram axes. From core to rim, one observes the disappearance of portlandite, ettringite and calcium monosulfoaluminate, the precipitation of calcite and amorphous silica, the modification of the composition of the CSH minerals (hydrated calcium silicates) that see a decrease of their c/s ratio (CaO/SiO2) from the core to the rim of the sample. For the CSH minerals, we have separated their continuous solid solution into three compositions defined by different CaO/SiO2 ratios and called phases 1, 2 and 3: CaO = 0.8, 1.1, 1.8 respectively for one mole of SiO2 knowing that H2O varies in the three compositions.

scholarly journals Strength Time–Varying and Freeze–Thaw Durability of Sustainable Pervious Concrete Pavement Material Containing Waste Fly Ash

2018 ◽  
Vol 11 (1) ◽  
pp. 176 ◽  
Author(s):  
Hanbing Liu ◽  
Guobao Luo ◽  
Longhui Wang ◽  
Yafeng Gong
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Pervious Concrete ◽  
Early Age ◽  
Pavement Materials ◽  
Freeze Thaw ◽  
Replacement Method ◽  
Porosity And Permeability ◽  
Volume Method

Pervious concretes, as sustainable pavement materials, have great advantages in addressing a number of environmental issues. Fly ash, as the industrial by-product waste, is the most commonly used as cement substitute in concrete. The objective of this paper is to study the effects of waste fly ash on properties of pervious concrete. Fly ash was used to replace cement with equivalent volume method at different levels (3%, 6%, 9%, and 12%). The control pervious concrete and fly ash modified pervious concrete were prepared in the laboratory. The porosity, permeability, compressive strength, flexural strength, and freeze–thaw resistance of all mixtures were tested. The results indicated that the addition of fly ash decreased the early-age (28 d) compressive strength and flexural strength, but the long-term (150 d) compressive strength and flexural strength of fly ash modified pervious concrete were higher than that of the early-age. The adverse effect of fly ash on freeze–thaw resistance of pervious concrete was observed when the fly ash was added. The porosity and permeability of all pervious concrete mixtures changed little with the content of fly ash due to the use of equal volume replacement method. Although fly ash is not positive to the properties of pervious concrete, it is still feasible to apply fly ash as a substitute for cement in pervious concrete.

scholarly journals AN EFFECTIVE WAY TO RECYCLE 3D PRINTING CONCRETE SCRAP

2021 ◽  
Vol 4 (2) ◽  
pp. 12-18
Author(s):  
D.A. Tolypin ◽  
N. Tolypina
Keyword(s):  
Compressive Strength ◽  
3D Printing ◽  
Portland Cement ◽  
Quartz Sand ◽  
Raw Materials ◽  
Electricity Consumption ◽  
Cement Matrix ◽  
Fine Aggregate ◽  
Fine Grained ◽  
Control Samples

the article proposes a rational method for processing 3D printing concrete scrap using vibration equipment, which allows obtaining a multicomponent building material with minimal electricity consumption. As a crite-rion for the degree of grinding of concrete scrap, it is proposed to use the specific surface area of the finely dispersed part of concrete scrap, which should correspond to 400-500 m2/kg. The possibility of reusing the resulting product instead of the traditional fine aggregate of quartz sand is shown. It was found that the con-crete scrap without the addition of Portland cement hardens, reaching up to 48% of the compressive strength of the control samples by 28 days. When 10% of the binder CEM I 42.5 N was added to the concrete scrap processing product, the compressive strength of fine-grained concrete increased by 106.6%, and 20% of Portland cement - by 112.2 %, compared to the strength of control samples of a similar composition on tra-ditional quartz sand after 28 days of hardening. It is noted that this is primarily due to the weak contact zone of quartz sand and the cement matrix of concrete. The use of the product of processing concrete scrap al-lows obtaining building composites based on it with the complete exclusion of natural raw materials

The Effect of Filler Based on Calcium Silicates оn Strength of Lime Composites

2016 ◽  
Vol 835 ◽  
pp. 531-534 ◽  
Author(s):  
Valentina Ivanovna Loganina ◽  
Ludmila V. Makarova ◽  
Roman V. Tarasov
Keyword(s):  
Mathematical Model ◽  
Compressive Strength ◽  
Properties Of Coatings ◽  
Synthesis Conditions ◽  
Influence Of Water ◽  
Calcium Silicates

The article shows the results of studies on the effect of calcium silicates-based fillers on the properties of coatings based on dry building mixes. The authors propose a mathematical model of the influence of water-lime ratio, filler ratio and filler synthesis conditions on the compressive strength of lime composite.

Sign in / Sign up

Export Citation Format

Share Document