Investigating temperature effect on degradation of well cement in HPHT carbonic acid environment

Omosebi, Omotayo; Maheshwari, Himanshu; Ahmed, Ramadan; Shah, Subhash; Osisanya, S.O.; Santra, Ashok; Saasen, Arild

doi:10.1016/j.jngse.2015.08.018

Cited by 46 publications

(11 citation statements)

References 48 publications

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“…The commonly used alkali solutions were sodium hydroxide, potassium hydroxide, sodium silicate and potassium silicate [5,6]. In the case of carbonic acid attack on cement system, calcium carbonate salt rapidly forms and cement loses its strength, porosity, and permeability and reside calcium silicate carbonate as an incomplete carbonation product of CÀSÀH gel [8]. Previous research found calcite, natron, and nahcolite as a carbonation product of alkali-activated fly ash samples after exposure to CO 2 [9].…”

Section: Introductionmentioning

confidence: 99%

The influence of CO₂ accelerated carbonation on alkali‐activated fly ash cement under elevated temperature and pressure

Ridha

Setiawan

Hamid

et al. 2018

Materialwissenschaft Werkst

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An alternative of wellbore cement system, formed through alkali-activation of fly ashes also knows as fly ash geopolymers, provides attractive properties due to its high compressive strength and durability against acidic conditions. However, changes in microstructure and mineralogical during accelerated carbonation affected by CO 2 alteration under elevated temperature and pressure have not been fully understood. This paper investigates and characterizes the alkali-activated binders fly ash based in the acidic environment under elevated temperature and pressure. The results found that scales such a layer was formed in the gel phase at the spherical surface of fly ash after carbonation process. The effect is that the surface of the gel phase became rough and porous. Carbonate and/or bicarbonate salts were identified as major phase in the sample after immersion test. In the activated fly ash cement, both calcium aluminate silicate hydrate (C-A-S-H) and sodium aluminosilicate hydrate (N-A-S-H) gels were formed; C-A-S-H gel was decalcified, forming calcium carbonate phase in the form of calcite, aragonite or vaterite. These findings were confirmed by the analysis and identification of Fourier-transformed infrared spectroscopy, X-ray diffraction and scanning electron microscopy tests on the changes in the cement system.

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Section: Introductionmentioning

confidence: 99%

The influence of CO₂ accelerated carbonation on alkali‐activated fly ash cement under elevated temperature and pressure

Ridha

Setiawan

Hamid

et al. 2018

Materialwissenschaft Werkst

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“…Comparing the compressive strengths of the samples in Figures 3c and 3b subjected to 260 °C and 21 MPa between 28 days and 7 days, the strengths of the samples with 43 % BWOC silica flour S1, S2 and S3 incorporation decrease 4.8 %, 11.6 % and 22.6 %, respectively. This result indicates that the optimal particle size of silica flour should be 63.13 µm (median particle size of S1), which is coarser than the universally adopted 325 mesh (45 µm) [1,8,26,27], suggesting that very fine silica flour may not be a good choice for the anti-retrogression performance of cement slurry in the HTHP environment. The samples with 43 % and 67 % BWOC silica flour S2 incorporation show 11.6 % and 31.8 % compressive strength loss after curing at HTHP from 7 to 28 days because the higher silica flour amounts exceed the amount required for the reaction [28].…”

Section: Compressive Strengthmentioning

confidence: 94%

“…In the petroleum industry, crude oil is continuously extracted from oilfields through oil wells. The performance of an oil well over its entire life is closely related to the integrity of the cement sheath [1]. As shown in Figure 1, the cement sheath formed between the casing and the formation is crucial for the well zonal isolation [2,3,4].…”

Section: Introductionmentioning

confidence: 99%

“…When silica flour is added into the cement paste to reduce the lime-to-silica (Ca/Si) ratio of hydration products, more thermally stable phases, such as 14 Å tobermorite and xonotlite, will be formed and mitigate the strength degradation under HTHP conditions [5]. According to previous research, when the Ca/ Si ratio is approximately 1.0 and the temperature is above 150 °C (302 °F), the main hydration product is xonotlite [1,5,8].…”

Section: Introductionmentioning

confidence: 99%

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Influence of the Particle Size Distribution of Silica Flour on the Mechanical and Microstructural Properties of Oil Well Cement Paste Exposed to HTHP Conditions

Xie¹

2019

Ceramics - Silikaty

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Silica flour is used to mitigate the strength retrogression and microstructure degradation problems of oil well cement paste in high temperature wells. This study investigates the effects of the particle size distribution of silica flour on the thermal stability of cement paste. After 7 days of hydrothermal curing at 80 °C, the cement paste was exposed to further aging for 7 or 28 days under high temperature and high pressure (HTHP) conditions in a sealed chamber at 260 °C (500 °F) and 21 MPa (2900 psi). The results show that 43% silica flour by weight of cement (BWOC) mitigates the strength degradation of silica-stabilized Portland cement (SSPC), and course silica flour (63.13 and 48.25 µm) maintains the strength stability of SSPC better than fine silica flour (3.25 µm). The transformation of C-S-H gel to xonotlite in SSPC was influenced by the silica particle size. The relatively fine silica flour (d 50 = 3.25 µm) accelerates the consumption of calcium hydroxide during the pozzolanic reaction, resulting in a poorer strength stability of SSPC than the courser silica flour (d 50 = 63.13 and 48.25 µm). The silica flour with an average particle size of 48.25 µm is more conducive to crystallization of xonotlite on the crystal plane corresponding to a diffraction angle of 25.5° than the other size silica flour.

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“…Long-term integrity of Portland cement has been studied quite extensively in CO 2 -environments, due to the current focus on carbon capture and storage (CCS), and the carbonation process and degradation mechanisms of cement by CO 2 are relatively well-known (Kutchko et al, 2007, Barlet-Gouédard et al, 2009, Brandl et al, 2011, Omosebi et al, 2015. There have been some long-term integrity studies of cement in other relevant downhole environments as well (Noik and Rivereau, 1999, Lecolier et al, 2006, Lecolier et al, 2007, Garnier et al, 2012, but the findings from these few studies are so far inconclusive.…”

Section: Introductionmentioning

confidence: 99%

Long-Term Integrity of Well Cements at Downhole Conditions

Vrålstad

Todorović

Saasen

et al. 2016

Day 1 Wed, April 20, 2016

Self Cite

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The objective of plug and abandonment of wells can be described as Љrestoring the cap rockЉ. In that respect, the long-term integrity of the plugging material is crucial. I.e. it is important that the plugging material can resist downhole chemicals and otherwise withstand downhole conditions. In this paper, we have performed ageing tests with cement samples at relevant downhole conditions to determine the long-term integrity of well cement as plugging material. Portland cement samples with and without silica flour as additive have been separately exposed to crude oil, brine and H 2 S (in brine) at 100°C and 500 bar for 1, 3, 6 and 12 months. The long-term integrity of the samples was determined by measuring changes in weight, volume, mechanical strength and permeability, as well as physical appearance.It is seen from the results that the addition of a pozzolan such as silica has a significant impact on the long-term integrity of Portland cement, especially in a corrosive environment such as H 2 S. All the samples were affected by most of the different chemical environments, but the cement samples without silica were considerably more affected than the samples with silica as additive. Furthermore, the exposure to H 2 S in brine resulted in the formation of an unexpected white deposit, which precipitated both inside and outside the samples.

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Investigating temperature effect on degradation of well cement in HPHT carbonic acid environment

Cited by 46 publications

References 48 publications

The influence of CO₂ accelerated carbonation on alkali‐activated fly ash cement under elevated temperature and pressure

The influence of CO₂ accelerated carbonation on alkali‐activated fly ash cement under elevated temperature and pressure

Influence of the Particle Size Distribution of Silica Flour on the Mechanical and Microstructural Properties of Oil Well Cement Paste Exposed to HTHP Conditions

Long-Term Integrity of Well Cements at Downhole Conditions

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Investigating temperature effect on degradation of well cement in HPHT carbonic acid environment

Cited by 46 publications

References 48 publications

The influence of CO2 accelerated carbonation on alkali‐activated fly ash cement under elevated temperature and pressure

The influence of CO2 accelerated carbonation on alkali‐activated fly ash cement under elevated temperature and pressure

Influence of the Particle Size Distribution of Silica Flour on the Mechanical and Microstructural Properties of Oil Well Cement Paste Exposed to HTHP Conditions

Long-Term Integrity of Well Cements at Downhole Conditions

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The influence of CO₂ accelerated carbonation on alkali‐activated fly ash cement under elevated temperature and pressure

The influence of CO₂ accelerated carbonation on alkali‐activated fly ash cement under elevated temperature and pressure