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The first part of this article, published last month, was primarily concerned with a general approach to the problem and dealt with some of the materials used for corrosion resistant floors, including impervious membranes, PVC and polythene. This month, in concluding the article, the author gives details of several types of floor and their suitability in different industries.

The purpose of this paper is to investigate the mechanical properties changing of geopolymer cement under different brine salinity.

Geopolymer Cement of Class F Fly Ash and Class G Cement slurries were prepared according to API RP 10B. The optimum alkaline activator/cement and water/cement ratio of 0.44 was used for geopolymer and Class G cement samples, respectively. 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. The slurries were cured for 24 hours at 130^oC and 3,000 psi in HPHT Curing Chamber followed by coring process. Both cement sample were immersed in brine water salinity up to 28 days with different brine salinity up to 30 per cent of NaCl. The mechanical properties were investigated using OYO Sonic Viewer-SX and Uniaxial Compressive Strength. The surfaces of the cement samples were extracted for Scanning Electron Microscope (SEM) and EDS tests to evaluate the morphology and chemical compositions of the cured samples.

The paper shows that geopolymer samples experiences strength reduction in brine water but the reduction rate of geopolymer is about half of the Ordinary Portland cement based oil well cement. The finding was also verified by SEM and EDS result.

This paper investigates the mechanical property changes of emerging geopolymer cement due to different water salinity. The results provide potential application of geopolymer cement for oil well cementing.

The long‐term durability of cement becomes an important challenge in oil and gas wells due to the aggressive acid gas. H₂S has been found in more and more wells. The purpose of this research was to add polymer latex to the Class G cement in order to promote the H₂S corrosion resistance of oilwell cement.

The water loss and thickening time of cement slurry and compressive strength and gas permeability of bond cement were investigated to determine the cement formulation. The corrosion resistance of the polymer cement was compared to base Class G cement in solution with 1.8 MPa H₂S at 120°C.

The optimum concentration of polystyrene latex was determined as 5 percent. The permeability change, compressive strength loss and corrosion ratio of latex cement were all lower than for the base Class G cement. The electrochemical impedance spectroscopy results and microstructure details confirmed that the latex cement had stronger resistance to the aggressive medium. Thus, latex cement had excellent corrosion resistance to H₂S.

The findings of this study can further improve the sulfide resistance of Class G cement. Two roles of the polystyrene latex were observed in the cement, including interstitial in‐filling of the pore structure and packing around hydration products, which are proposed to properly explain the results.

Hardened cement paste is a heterogeneous system resulting from the grouping of particles, films, microcrystals and other solid structural elements bounded in a porous mass. The cement paste microstructure must be understood firstly due to its influence on concrete properties. The behaviour of concrete greatly depends on the conformation of localised special structures rather than on general structures found in the mass cement paste. The objective of this paper was to study the cement paste microstructure, as a function of the water–cement ratio, in order to interpret the variations of the steel–mortar bond strength and the developing of the corrosion process in steel–mortar specimens kept in tap water and 3 percent sodium chloride solutions for 1 year. A description of the steel–mortar interface was also provided.

In the carbon dioxide capture and storage (CCS) project, the integrity of CO₂ injection wells plays a vital role in the long‐term safety of CO₂ storage. The authors aim to practically investigate possible CO₂ leakage of a CO₂ injection well section during the injection operation and shut‐in by the thermomechanical FEM simulation. The application of numerical simulation to the CO₂ injection well deep underground is the first step that will help in the quantitative evaluation of the mechanical risks.

The injection of CO₂ at a temperature different from those of the well and the surrounding geological formation is likely to cause different thermal deformations of constitutive well materials. This could lead to cement cracking and microannuli openings at the interfaces of different materials such as casing/cement and cement/rock. In this paper, the possibility and order of magnitude of cement cracking and microannuli creation in the cross section of the well are assessed from a numerical case study within a classical thermomechanical finite element model framework.

The possibility of compressive failure and tensile cracking in the cement of the studied wells due to CO₂ injection is small unless a large casing eccentricity or an initial defect in the cement is present. Some microannuli openings are generated at interfaces cement/casing and/or cement/rock during the CO₂ injection because of different thermal shrinkage of each material. However, the width is not important enough to cause significant CO₂ leakage under the studied conditions. The use of “flexible” cement especially developed for oil well applications could mitigate the risk of cement cracking during CO₂ injection.

Numerous experimental studies on the chemical deterioration of the cement under severe conditions have been carried out. On the other hand, only a few investigations have focused on the mechanical behavior under thermal/pressure changes related to CO₂ injection. In this paper, the quantitative analysis to investigate cement cracking and microannuli formation is achieved to help in the identification of possible mechanical defects to cause CO₂ leakage. In addition, the discussion about the risk of the possible casing eccentricity and the application of flexible cement in the oil and gas field to CO₂ injection well could be practically useful.

Investigates the characterization of cement dust collected by electrostatic precipitators and fabric filters to study its ability to be used as a concrete material. The study includes 26 cement dust samples collected from different points on dry process lines in four of the major cement plants in the United Arab Emirates. The collected samples were subjected to detailed physical tests and chemical analyses. Results obtained were compared with the British Standard Specifications set for ordinary Portland cement. Finds that eight samples show comparable physical properties and chemical as well as mineral composition.

For the purposes of this article, adhesives, lutes and putties are excluded even though many of them have applications in the corrosion‐resistant field. Included are the pouring and mortar‐type cements based on bitumen or sulphur, sodium and potassium silicate solutions, silica sols, rubber or synthetic rubber latices, and synthetic resins. The author considers the composition and working properties of these cements and surveys present trends in their use in industry. Recent and possible future developments are covered.

The corrosion of concrete, and the factors causing or preventing it, present at least as complex a problem as metallic corrosion, and the two are frequently inter‐related. A vast tonnage of steel in all kinds of structures is protected by concrete from corrosion In the following article, the author outlines the various types of cement used in concrete, following this with a description of the chemical agents which can corrode concrete, such as organic acids, sulphates, etc. He then examines concrete as a means of preventing corrosion and also as a corrosive agent.

The purpose of this paper is to investigate the resistivity of geopolymer cement with nano-silica additive toward acid exposure for oil well cement application.

An 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.

The 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.

This 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.