Analysis on integrity of cement sheath in the vertical section of wells during hydraulic fracturing

Liu, Kui; Gao, Deli; Taleghani, Arash Dahi

doi:10.1016/j.petrol.2018.05.016

Cited by 57 publications

(16 citation statements)

References 21 publications

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“…E.g, since the production casing is cemented all the way up to the intermediate casing in the vertical section of the well, the in-situ stress can only act on the intermediate casing and not directly on production casing. Based on this situation, an analytical model considering the well completion steps is established to study the integrity of cement sheath as a two-layer casing-cement system [24].…”

Section: The Strength Adaptability Analysis Of the New Completion Stringmentioning

confidence: 99%

Mechanical Safety Analysis of the Gas Lift Completion String Used for a High-Pressure Sandwich Layer

Luo

Wen

et al. 2021

Scientia Iranica

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This study examines the mechanical safety of a gas lift completion string in a certain oilfield, Algeria 438B block, having complex geological characteristics (a high salt and highpressure sandwich). When an annulus is not supported within fluid column after unloading using conventional single-tube gas lift completion with positive lift oil production, inner pressure is so low that the pressure differential between the annulus and external casing is very large, which may damage the casing. Hence, a dual tube completion annulus filled with fluid that can resist pressure was used to overcome this problem, in the adjacent blocks using a gas lift production string with positive and reverse lift oil. However, this technology is complex and characterized by poor system reliability, large construction costs and maintenance difficulty. Considering the three aspects of a casing string, the squeeze strength, tensile strength and internal pressure strength, a gas lift completion string with dual concentric tubes and positive lift was preferably selected under conditions that have been verified as safe for production and a shut-in state. It was shown that this gas lift completion string design is feasible, and has no problem of completion string in adjacent blocks.

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Section: The Strength Adaptability Analysis Of the New Completion Stringmentioning

confidence: 99%

Mechanical Safety Analysis of the Gas Lift Completion String Used for a High-Pressure Sandwich Layer

Luo

Wen

et al. 2021

Scientia Iranica

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“…The details of deriving these equations are shown in our previous paper [17]. The k indices are used for simplification purposes [18].…”

Section: Stress On Interfacesmentioning

confidence: 99%

Impact of Casing Eccentricity on Cement Sheath

2018

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Sustained casing pressure (SCP) in shale gas wells caused by cement sheath failure can have serious impacts on safe and efficient gas production. Considering the fact that horizontal wells are widely used for production from shale, the cementing quality and casing centricity is barely ensured in these wells. Among other indications, the casing eccentricity is identified very often in wells with SCP problems in the Sichuan field in China. Hence, the objective of this study is to analyze the effect of the casing eccentricity on the integrity of the cement sheath. To better understand stress distribution in eccentric cement sheaths, an analytical model is proposed in this paper. By comparing the results of this model with the one’s with centric casing, the impacts of the casing eccentricity on the integrity of the cement sheath is analyzed. During fracturing treatments, the casing eccentricity has a little effect on stress distribution in the cement sheath if the well is well cemented and bonded to the formation rock. However, on the contrary, the casing eccentricity may have serious effects on stress distribution if the cementing is done poorly. The debonding of casing–cement–formation interfaces can significantly increase the circumferential stress in the cement sheath. At the thin side of the cement sheath, the circumferential stress could be 2.5 times higher than the thick side. The offset magnitude of the casing eccentricity has little effect on the radial stress in the cement sheath but it can significantly increase the shear stress. We found that the risk of cement failure may be reduced by making the casing string more centralized, or increasing the thickness of the casing. The results provide insights for design practices which may lead to better integrity in shale gas wells.

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“…Diante de tais fatos, deve-se procurar garantir que a execução desta etapa seja segura e economicamente satisfatória. Alguns trabalhos indicam que os custos de revestimento de poço podem atingir a 50% do orçamento total, conforme discutido em Correia & Santos (2017), Ezeakacha et al (2018), Liu et al (2018), Aadnoy (2010) e Xia et al (2015).…”

Section: Introductionunclassified

Desenvolvimento De Metodologia Para Gerenciamento De Projeto De Revestimento De Poço De Petróleo

Santos

Lima

Gouveia

et al. 2021

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O presente trabalho propõe-se a desenvolver uma estratégia de otimização de seleção de revestimento de poço combinando a avaliação de integridade mecânica de revestimento por meio de análise de tensões triaxial em estado limite de serviço e técnicas de otimização baseado no mínimo custo global. A formulação é desenvolvida em um sistema de aplicação web (SAEP) construída a partir de cálculo de esforços e cálculo de resistências, que permitem uma análise desacoplada do processo de dimensionamento de coluna de revestimento de poços de petróleo. O módulo de integração e análise permite avaliar de forma integrada as solicitações e resistência, verificando o atendimento aos critérios de projeto baseado em diretrizes normativas internacionais. A análise da integridade estrutural é realizada através da combinação da envoltória API com a curva limite de plasticidade, auxiliando ao usuário no processo de dimensionamento das colunas de revestimento.

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Analysis on integrity of cement sheath in the vertical section of wells during hydraulic fracturing

Cited by 57 publications

References 21 publications

Mechanical Safety Analysis of the Gas Lift Completion String Used for a High-Pressure Sandwich Layer

Mechanical Safety Analysis of the Gas Lift Completion String Used for a High-Pressure Sandwich Layer

Impact of Casing Eccentricity on Cement Sheath

Desenvolvimento De Metodologia Para Gerenciamento De Projeto De Revestimento De Poço De Petróleo

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