Study on Corrosion Mechanism of Sour Gas to Cement Stone

One of the main tasks in the construction of oil and gas wells is to ensure the high quality of well casing. It is especially difficult to get it in wells, in sections of which there are salt-bearing strata. From the salts, the most dangerous are magnesia salts, which can lead to the destruction of the stone based on portland cement within a few months. The report presents the results of experimental studies on the corrosion of cement stone in aggressive magnesia media.The quantitative indicators reflecting the degree of damage to the stone are taken as the thickness of the damaged layer and the coefficient of stone resistance, characterized by the ratio of the ultimate strength of stone samples for compression or bending stored in an aggressive environment to the strength of control samples at the same time of hardening. In the course of the research, the corrosion resistance of the cement stone to the magnesian corrosive environment was assessed, after 8 weeks in a medium with a constant concentration of MgCl2. In addition, the effect of MgCl2 concentration on the cement stone corrosion mechanism was investigated. The use of the palygorskit additive and the reduction of water cement ratio to reduce the porosity of the cement stone and reduce the rate of corrosion damage are proposed. The kinetics and the main factors affecting the corrosion process are considered, and the x-ray structural analysis of corrosion products and unaffected cement stone is carried out.

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Compressive Strength Changing Law of Oil Well Cement Paste under Corporate Corrosion of HCO3- and SO42-

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.229-231.95 ◽

2012 ◽

Vol 229-231 ◽

pp. 95-99 ◽

Cited By ~ 2

Author(s):

Yu Wang ◽

Yu Feng Chen ◽

Yan Lu ◽

Hui Fang Zhang ◽

Zhi Guo Sun

Keyword(s):

Compressive Strength ◽

Influence Factors ◽

Ion Concentration ◽

Solution Temperature ◽

Cement Stone ◽

Corrosion Mechanism ◽

Oil Well ◽

Experimental Conditions ◽

Oil Well Cement ◽

Well Cement

On the basis of analyzing the oil well cement corrosion mechanism by SO42- and HCO3-, the corrosion products, microstructure and compressive strength of cement stone were measured and the changing regularity and influence factors of compressive strength were analyzed under different experimental conditions. The following conclusions can be drawn. Under the interactive corrosion effect of SO42- and HCO3-, Ca(OH)2 in cement stone was dissolved out and consumed, the calcium silicate hydrate was decomposed, ettringite, gypsum, calcite and thaumasite were produced which destroyed the structure and components of cement stone primary products and led the compressive strength of corrosion cement stone decline. With the increases of ion concentration of corrosive solution, temperature and corrosive time, the compressive strength was decreased gradually, even collapsed completely.

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Research on the corrosion mechanism of CO2/H2S mixture to cement stone

Proceedings of OilGasScientificResearchProjects Institute SOCAR ◽

10.5510/ogp20140200194 ◽

2014 ◽

pp. 12-21

Author(s):

Sh. Zhou ◽

◽

G. Li

Keyword(s):

Cement Stone ◽

Corrosion Mechanism

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Aging processes of cement stone during thermal degradation and their control

Proceedings of Gubkin Russian State University of Oil and Gas ◽

10.33285/2073-9028-2020-1(298)-155-161 ◽

2020 ◽

pp. 155-161

Author(s):

Sh.M. Rakhimbayev ◽

◽

T.V. Anikanova ◽

I.M. Kolesnikov ◽

◽

...

Keyword(s):

Thermal Degradation ◽

Cement Stone

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Study Of Structure Formation Of Organic-Mineral Compositions With Fibrous Filler By Electron Microscopy Method

Promyshlennoe i Grazhdanskoe Stroitel stvo ◽

10.33622/0869-7019.2019.12.41-47 ◽

2019 ◽

pp. 41-47

Keyword(s):

Electron Microscopy ◽

Structure Formation ◽

Mineral Composition ◽

Bending Strength ◽

Cement Stone ◽

Hydrated Cement ◽

Fibrous Filler ◽

Organic Mineral ◽

Microscopy Method ◽

Mineral Compositions

The article presents the study of processes of structure formation of cement stone and products of hardening of organic-mineral compositions with fibrous filler (shavings) by the electronic scanning microscopy method. It is established that the additive-free cement stone at the age of 28 days has a dense and homogeneous structure, consists of calcium hydro-silicates, Portlandite and calcite - newgrowths characteristic for cement systems. Cellulose fibers, which make up the bulk of the substance of shavings, are sufficiently active, which determines the high adhesion of the hydration products of the cement binder to their surface. It is shown that the introduction of shavings into the organo-mineral composition leads to inhibition of cement hydration processes. Organo-mineral compositions with different shavings content (two compositions) were analyzed. The first composition is characterized by a fairly dense structure, the cement stone consists of globular nanoscale nuclei of hydrosilicates, Portlandite and calcite. The second composition has a loose porous structure, cement stone consists of non-hydrated cement grains, newgrowths are represented by calcite and vaterite. The structure of the contact zone "osprey fiber-cement stone" in the organo-mineral composition of the first composition indicates a good adhesion of the filler surface with the phases of hydrated cement. The use of shavings as a fibrous filler (the first composition) increases the tensile and bending strength, as well as the wear resistance of organo-mineral compositions. The data obtained by scanning electron microscopy are confirmed by the results of studying the processes of structure formation of cement stone by quantitative x-ray phase analysis.

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