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

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.

2018 ◽  
Vol 9 (5) ◽  
pp. 616-624 ◽  
Author(s):  
Syahrir Ridha ◽  
Afif Izwan Abd Hamid ◽  
Riau Andriana Setiawan ◽  
Ahmad Radzi Shahari

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.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Neeraj Jain

Investigations carried out to study the effect of Cr (VI) (1000–3000 mg/l) on solidification and hydration behavior of Ordinary Portland cement (OPC) and rice husk ash (RHA) blended (10%, 20%, and 30%) cement show that addition of RHA accelerates final setting as compared to control samples (OPC) and retardation in setting time has been observed on increase in rice husk ash concentration (10%–30%). Solidification studies show that the compressive strength of controls and rice husk ash blended samples increases with increase in the curing period and maximum strength was observed with 20% RHA blended samples. With the increase in Cr (VI) concentrations, the strength of OPC and RHA blended samples decreases as compared to controls (without chromium). The results of Toxicity Characteristics Leaching Procedure (TCLP) test, (pH≅3), show that the retention capacity of OPC and RHA blended samples was in the range of 92% to 99% and the leached Cr (VI) concentration was under the allowable limit (5 mg/l) of U.S. EPA. The chemistry of influence of Cr (VI) on hydration of cement was examined by X-ray diffraction which shows the formation of various crystalline phases during solidification in rice hush ash blended cement.


2019 ◽  
Vol 26 (4) ◽  
pp. 1238-1244 ◽  
Author(s):  
Edmundo Fraga ◽  
Jesus D. Zea-Garcia ◽  
Armando Yáñez ◽  
Angeles G. De la Torre ◽  
Ana Cuesta ◽  
...  

In situ research of materials under moderate pressures (hundreds of bar) is essential in many scientific fields. These range from gas sorption to chemical and biological processes. One industrially important discipline is the hydration of oil well cements. Existing capillary cells in this pressure range are static as they are easy to design and operate. This is convenient for the study of single-phase materials; however, powder diffraction quantitative analyses for multiphase systems cannot be performed accurately as a good powder average cannot be attained. Here, the design, construction and commissioning of a cost-effective spinning capillary cell for in situ powder X-ray diffraction is reported, for pressures currently up to 200 bar. The design addresses the importance of reducing the stress on the capillary by mechanically synchronizing the applied rotation power and alignment on both sides of the capillary while allowing the displacement of the supports needed to accommodate different capillaries sizes and to insert the sample within the tube. This cell can be utilized for multiple purposes allowing the introduction of gas or liquid from both ends of the capillary. The commissioning is reported for the hydration of a commercial oil well cement at 150 bar and 150°C. The quality of the resulting powder diffraction data has allowed in situ Rietveld quantitative phase analyses for a hydrating cement containing seven crystalline phases.


Author(s):  
Mtaki Thomas Maagi ◽  
Gu Jun

This study evaluates the wellbore shear bond strength of oil-well cement pastes containing nano-SiO2 and nano-TiO2 particles with an average of 20 ± 5 nm particle sizes. The nanoparticles were selected by weight of cement at proportions equivalent to 1, 2, 3 and 4%. The findings demonstrated that nanoparticles significantly increased the shear bond strength, and the strength increase was dependent on the nanoparticle types, dosage and curing period of the specimens. Due to effective pozzolanic activity, nano-SiO2 provided higher shear bond strength compared to nano-TiO2. The specimens containing 3% nano-SiO2 cured for 28 days displayed the utmost shear bond strength results (0.553 MPa). The optimal replacement dosage was 3% for all nanoparticles. The particle type did not affect the optimum nanoparticles replacement content. To examine the influence of nanoparticles on cement-formation bonding, a Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), and thermogravimetric technique were used.


2020 ◽  
Vol 38 (2A) ◽  
pp. 143-151
Author(s):  
Doaa M. Abdullah ◽  
Alaa A. Abdullalhameed ◽  
Farhad M. Othman

A proper slurry design is critical to cementing work success. In the present investigation, a ball mill method was utilized for preparing a nano powder from a cement dust material, supplied via Al-Kufa Cement Factory, to reinforce the oil well cement by utilizing it as a partial replacement of oil well cement class (G) using different weight percentages (0.25%, 0.5%, 0.75% and 1%). A mixture having water to cement ratio of (0.44) was produced. The produced samples characterizations were achieved via the Atomic Force Microscope (AFM), the X-Ray Diffraction (XRD) as well as the density and compressive strength. Results showed that the structural characteristics were enhanced with the phase formation of the calcium silicate hydration (C-S-H), and both density and compressive strength were improved. Accordingly, obtained results suggest that the modified cement is suitable for the oil well uses.


2020 ◽  
Vol 185 ◽  
pp. 106656 ◽  
Author(s):  
Roger Braun Ledesma ◽  
Natália Feijó Lopes ◽  
Katryanne Georg Bacca ◽  
Martimiano Krusciel de Moraes ◽  
Giovanni dos Santos Batista ◽  
...  

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