Effects of Fly Ash and Superplasticizers on the Rheology of Cement Slurries

1984 ◽  
Vol 43 ◽  
Author(s):  
Elizabeth L. White ◽  
Maria Lenkei ◽  
Della M. Roy ◽  
Ferenc D. Tamas
Keyword(s):  
Fly Ash ◽  
Partial Substitution ◽  
Oil Well ◽  
Low Calcium ◽  
Chemical Admixture ◽  
High Calcium ◽  
High Calcium Fly Ash ◽  
Oil Well Cement ◽  
Large Particles ◽  
Well Cement

AbstractCementitious slurries composed of an oil well cement, a high calcium fly ash, a low calcium fly ash, and three commercially available superplasticizers (two different sulfonated naphthalene formaldehyde condensates and a sulfonated melamine formaldehyde condensate)were mixed to contrast the two fly ashes and to determine the effectiveness of each of the superplasticizing agents. Most commercial superplasticizers and cements are relatively expansive; therefore a partial substitution by fly ash and other by-products represents a substantial savings in both quantity of chemical admixture required and energy consumption for the manufacture of cement. In the cement/fly ash mixtures of 100/0, 90/10, 60/40, 40/60, and 10/90, with both high calcium fly ash and low calcium fly ash, the mixture containing the low calcium fly ash was consistently less workable. The rheological properties of the high vs. low calcium fly ash mixtures were controlled by the differences in fly ash particle size and the presence of irregular large particles, rather than by the differences in chemistry between the two. The low calcium fly ash was the coarser material.

Effect of Fly Ash and Slag on the Resistance to H2S Attack of Oil Well Cement

2009 ◽  
Vol 79-82 ◽  
pp. 71-74
Author(s):  
Qi Wang ◽  
Lin Qiao ◽  
Peng Song
Keyword(s):  
Fly Ash ◽  
Compression Strength ◽  
Blended Cement ◽  
Oil Well ◽  
X Ray Diffraction ◽  
X Ray ◽  
Curing Period ◽  
Oil Well Cement ◽  
Xrd Patterns ◽  
Well Cement

In this paper, the resistance to H2S attack of pastes made from slag-fly ash blended cement used in oil well (SFAOW) was studied, in which fly ash (FA) was used at replacement dosages of 30% to 60% by weight of slag. Samples of SCOW and SFAOW pastes were demoulded and cured by immersion in fresh water with 2 Mp H2S insulfflation under 130oC for 15 days. After this curing period, compression strength and permeability of the samples were investigated. The reaction mechanisms of H2S with the paste were carried out through a microstructure study, which included the use of x-ray diffraction (XRD) patterns and scanning electron microscope (SEM). Based on the obtained data in this study, incorporation of FA into SCOW results in the comparable effects in the resistance to H2S attack. When the replacement dosage of slag is about 40%, the paste exhibits the best performance on resistance to H2S attack with compression strength 36.58Mp.

Influence of sulfuric and hydrochloric acid on the resistance of geopolymer cement with nano-silica additive for oil well cement application

2018 ◽  
Vol 9 (5) ◽  
pp. 616-624 ◽  
Author(s):  
Syahrir Ridha ◽  
Afif Izwan Abd Hamid ◽  
Riau Andriana Setiawan ◽  
Ahmad Radzi Shahari
Keyword(s):  
Fly Ash ◽  
Hydrochloric Acid ◽  
Strength Increase ◽  
Oil Well ◽  
Nano Silica ◽  
Content Type ◽  
Oil Well Cement ◽  
Geopolymer Cement ◽  
Well Cement ◽  
Silica Additive

PurposeThe purpose of this paper is to investigate the resistivity of geopolymer cement with nano-silica additive toward acid exposure for oil well cement application.Design/methodology/approachAn experimental study was conducted to assess the acid resistance of fly ash-based geopolymer cement with nano-silica additive at a concentration of 0 and 1 wt.% to understand its effect on the strength and microstructural development. Geopolymer cement of Class C fly ash and API Class G cement were used. The alkaline activator was prepared by mixing the proportion of sodium hydroxide (NaOH) solutions of 8 M and sodium silicate (Na2SiO3) using ratio of 1:2.5 by weight. After casting, the specimens were subjected to elevated curing condition at 3,500 psi and 130°C for 24 h. Durability of cement samples was assessed by immersing them in 15 wt.% of hydrochloric acid and 15 wt.% sulfuric acid for a period of 14 days. Evaluation of its resistance in terms of compressive strength and microstructural behavior were carried out by using ELE ADR 3000 and SEM, respectively.FindingsThe paper shows that geopolymer cement with 1 wt.% addition of nano-silica were highly resistant to sulfuric and hydrochloric acid. The strength increase was contributed by the densification of the microstructure with the addition of nano-silica.Originality/valueThis paper investigates the mechanical property and microstructure behavior of emerging geopolymer cement due to hydrochloric and sulfuric acids exposure. The results provide potential application of fly ash-based geopolymer cement as oil well cementing.

Experiment and Micro-Mechanism Study on Mechanical Properties and Durability of High-Calcium Fly Ash Concrete

2011 ◽  
Vol 480-481 ◽  
pp. 59-65
Author(s):  
Shuang Xi Li ◽  
Tuan She Yang ◽  
Zhi Ming Wang ◽  
Quan Hu
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Frost Resistance ◽  
Strength Development ◽  
Hydration Reaction ◽  
Optimal Dosage ◽  
Fly Ash Concrete ◽  
Low Calcium ◽  
High Calcium ◽  
High Calcium Fly Ash

Low-calcium fly ash is paid much attention for its wide use in engineering, the research and application technology of it are very mature, but as to high-calcium fly ash concrete, the researches on stability, mechanical property and durability of it are very less , The existing researches are still inadequate for practice of engineering. As to this problem, using small shek kip hydropower project as example, the volume stability of high-calcium fly ash concretes with different fly ash dosages are tested, then the optimal dosage of the high-calcium fly ash is determined; based on this, the impacts of high-calcium fly ash on the performance of mechanical properties , impermeability and frost resistance of concrete are studied; Finally, macro performance is analyzed from a micro-mechanism point of view through taking the electron micrograph. As the study shows, the optimal dosage of high-calcium fly ash should be taken as 20% -25%; for the concrete with special requirements, the dosage can be relaxed to 30% when the high-calcium fly ash achieves high quality. The compressive strength of high-calcium fly ash concrete is higher than the low-calcium fly ash concrete. Strength development advantage of high-calcium fly ash concrete reflects at the early age, this advantage takes the trend of weakening as the development of age. Concrete mixed with high-calcium fly ash has good performance in impermeability. The high-calcium fly ash has high activity, the high-calcium fly ash and secondary hydration reaction products can be filled into the pore capillary and cracks of the concrete structure, improving the pore structure, thereby increasing the density of cement paste. High-calcium fly ash concrete has good performance in frost resistance. The destructive effects of freeze-thaw cycles on cement structure has connection with the microstructure of cement and impermeability , the improvement of impermeability avoids the water entering into the concrete, reduces the risk of destruction caused by frost heave.The study on micro-mechanism proves well the macro-phenomena above.

Zeolite and fly ash in the composition of oil well cement: Evaluation of degradation by CO2 under geological storage condition

2020 ◽  
Vol 185 ◽  
pp. 106656 ◽  
Author(s):  
Roger Braun Ledesma ◽  
Natália Feijó Lopes ◽  
Katryanne Georg Bacca ◽  
Martimiano Krusciel de Moraes ◽  
Giovanni dos Santos Batista ◽  
...  
Keyword(s):  
Fly Ash ◽  
Storage Condition ◽  
Oil Well ◽  
Geological Storage ◽  
Oil Well Cement ◽  
Well Cement

Investigation of Dehydroxylated Sodium Bentonite as a Pozzolanic Extender in Oil-Well Cement

2021 ◽  
pp. 1-8
Author(s):  
Stephen Adjei ◽  
Salaheldin Elkatatny ◽  
Pranjal Sarmah ◽  
Gonzalo Chinea
Keyword(s):  
Heat Treatment ◽  
Compressive Strength ◽  
Fly Ash ◽  
Atmospheric Pressure ◽  
High Stability ◽  
Oil Well ◽  
Sodium Bentonite ◽  
Pozzolanic Material ◽  
Oil Well Cement ◽  
Well Cement

Summary Fly ash, which is a pozzolan generated as a byproduct from coal-powered plants, is the most used extender in the design of lightweight cement. However, the coal-powered plants are phasing out due to global-warming concerns. There is the need to investigate other materials as substitutes to fly ash. Bentonite is a natural pozzolanic material that is abundant in nature. This pozzolanic property is enhanced upon heat treatment; however, this material has never been explored in oil-well cementing in such form. This study compares the performance of 13-ppg heated (dehydroxylated) sodium bentonite and fly-ash cement systems. The raw (commercial) sodium bentonite was dehydroxylated at 1,526°F for 3 hours. Cement slurries were prepared at 13 ppg using the heated sodium bentonite as partial replacements of cement in concentrations of 10 to 50% by weight of blend. Various tests were done at a bottomhole static temperature of 120°F, bottomhole circulating temperature of 110°F, and pressure of 1,000 psi or atmospheric pressure. All the dehydroxylated sodium bentonite systems exhibited high stability, thickening times in the range of 3 to 5 hours, and a minimum 24-hour compressive strength of 600 psi. At a concentration of 40 and 50%, the 24-hour compressive strength was approximately 800 and 787 psi, respectively. This was higher than a 13-ppg fly-ash-based cement designed at 40% cement replacement (580 psi).

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