Estimation of Casing-Cement-Formation Interaction using a new Analytical Model

Teodoriu, Cătălin; Ugwu, Ignatius Obinna; Schubert, Jerome

doi:10.2118/131335-ms

Cited by 24 publications

(10 citation statements)

References 17 publications

(5 reference statements)

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“…where X i and Y i are two constants that can be determined by boundary conditions. Substituting equations (4) and 7into equation 5yields the expression of stress component:…”

Section: Cement Setting Stagementioning

confidence: 99%

“…is issue becomes more severe when exploiting deep resources in recent decades. High temperature and high pressure (HTHP) have to be dealt with at increasing depths, and more rigorous design is required to ensure the well integrity [4]. In addition, hydraulic fracturing has been employed more and more extensively for unconventional resources such as shale gas.…”

Section: Introductionmentioning

confidence: 99%

“…After drilling, a well sequentially experiences cement injection, cement setting, completion, and production stages. Main mechanisms causing the failure of well integrity in these stages include the shrinkage of cement sheath due to cement hydration [9], the increase in internal casing pressure during hydraulic fracturing [7], and the increase in casing temperature when producing deep oil/gas [4].…”

Section: Introductionmentioning

confidence: 99%

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Full‐Life‐Cycle Analysis of Cement Sheath Integrity

Wang

Feng

et al. 2019

Mathematical Problems in Engineering

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This paper addresses evaluating the evolution of stress inside the casing-cement sheath-formation system during the cement injection, setting, completion, and production stages of hydrocarbon recovery. This full-life-cycle analysis of cement sheath integrity gives rise to assessment of potential failure mode (i.e., tensile mode, shear mode, and microannulus) in different stages, and the prevention measures can be proposed accordingly. Considering the loading history, two regimes should be distinguished. Before the accomplishment of cementation, as the cement slurry can merely withstand its hydraulic pressure, the in situ stress and the wellbore pressure are withstood by the rock and the casing, respectively. Once the cementation process is completed, the stress increment (e.g., hydraulic fracturing pressure) is withstood by the casing-cement sheath-formation system. The autogenous shrinkage of cement adversely affects the resistance of the system to all types of failure, whereas a moderate swelling of cement is favorable to the cement sheath integrity. In addition, the cement sheath integrity is strongly influenced by the depth: the failure is encountered more easily at the shallow layer. Both the hydraulic fracturing pressure in the completion stage and the increase in casing temperature in the production stage may lead to tensile circumferential stress, and the hydraulic fracturing is the most critical stage for the integrity of cement sheath.

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“…where X i and Y i are two constants that can be determined by boundary conditions. Substituting equations (4) and 7into equation 5yields the expression of stress component:…”

Section: Cement Setting Stagementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Full‐Life‐Cycle Analysis of Cement Sheath Integrity

Wang

Feng

et al. 2019

Mathematical Problems in Engineering

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“…The dimension of the defect size allows the estimation of the effective permeability of the cement sheath. It is recommended that empirical correlations be used, which allows for estimation of the equivalent permeability on the basis of the characterization of the defects (Etiope and Martinelli 2001;Carey et al 2009;Huerta and Checkai 2009;Tran Viet 2012). For a defect of microannulus, the width of the interface controls the leakage rate.…”

Section: Mechanical-integrity Evaluationmentioning

confidence: 99%

Development of a Novel Method To Evaluate Well Integrity During CO2 Underground Storage

Bai

Song

et al. 2015

SPE Journal

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A safe and ecologic underground storage of carbon dioxide (CO 2 ) requires long-term integrity of the wells affected by the injected CO 2 , including both active wells and abandoned wells. In line with other investigators, technical integrity is assumed if there is no significant leak in the subsurface system from the storage reservoir. The evaluation of integrity of abandoned wells over a long time frame during CO 2 underground storage can only be performed indirectly and requires a comprehensive understanding of relevant thermal/hydraulic/mechanical/chemical processes affecting well integrity. This paper presents an integrated approach coupling qualitative features, events, and processes (FEPs) and scenario analysis with quantitative-model development and consequence analysis. The qualitative analysis provides a solid and comprehensive study on all the FEPs that affect well integrity. The mechanical model presents the stress distribution of the casing/cement/rock composite system and provides a quantification of the defect dimension caused by different load conditions. The defect dimension can be used to compute equivalent permeability of the cement sheath by use of empirical correlations, which is an important input parameter for the following CO 2 -leakage simulation, provided it is considered that CO 2 can only migrate through the defects instead of the cement matrix. When integrity is compromised, the storage reservoir will leak CO 2 . For this leakage, a numerical model is presented to simulate the flow of CO 2 along abandoned wellbores during the storage period, such as 1,000 years. It is found from the FEP analysis that the most-critical system components are caprock, casing/cement/rock composite system, and abandonment elements. By building a geomechanical model and a leakage model, it is also found that in the simulated scenarios the CO 2 -leakage rate is very small except for when using cement sheaths of very poor quality, which can lead to a leakage rate exceeding the maximum-allowable value. The sensitivity analysis shows that the vertical permeability of the cement sheath plays the most critical role. In comparison with previous studies, this method is comprehensive and easy to implement.

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“…Li et al [24] established a mechanical model coupling effect of temperature and pressure and researched the behavior of the cement sheath in non-uniform in-situ stress fields. Teodoriu et al [25] proposed a casing-cement-formation interaction analytical model considering radial uniform temperature change. Bois et al [26] also developed a mechanical model of cement sheath and simulated its failure mode from casing deformation owing to wellbore temperature change.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Thermal Stress of Cement Sheath for Geothermal Wells during Fracturing

Peng

et al. 2018

Energies

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Geothermal energy development has increasingly been studied in recently decades because of its renewable and sustainable features. It can be divided into two categories: traditional geothermal (hydrothermal) systems and enhanced geothermal systems (EGS) based on the type of exploitation. The hot dry rock (HDR) in the EGS incorporates about 80% of all thermal energy, and its value is about 100–1000 times that of fossil energy. It is pivotal for geothermal wells to improve the flow conductivity of the HDR mass, enhance the communication area of natural fractures, and constitute the fracture network between injection and production wells by hydraulic treatments. While the wellbore temperature significantly decreases because of fracturing, fluid injection will induce additional thermal stresses in the cement sheath, which will aggravate its failure. Considering the radial nonuniform temperature change, this paper proposes a new thermal stress model for a casing-cement sheath-formation combined system for geothermal wells during fracturing based on elastic mechanics and thermodynamics theory. This model is solved by the Gaussian main elimination method. Based on the analytical model, the thermal stresses of cement sheath have been analyzed. The effects of the main influencing parameters on thermal stresses have also been investigated. Results show that the radial and axial tensile thermal stresses are both obviously larger than tangential tensile thermal stress. The maximum radial and axial thermal stresses always occur at the casing interface while the location of the maximum tangential thermal stress varies. Generally, thermal stresses are more likely to induce radial and axial micro cracks in the cement sheath, and the cement sheath will fail more easily at the casing interface in fracturing geothermal wells. For integrity protection of the cement sheath, a proper decrease of casing wall thickness, casing linear thermal expansion coefficient, cement sheath elasticity modulus, and an increase of the fracturing fluid temperature has been suggested.

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Estimation of Casing-Cement-Formation Interaction using a new Analytical Model

Cited by 24 publications

References 17 publications

Full‐Life‐Cycle Analysis of Cement Sheath Integrity

Full‐Life‐Cycle Analysis of Cement Sheath Integrity

Development of a Novel Method To Evaluate Well Integrity During CO2 Underground Storage

Investigation of Thermal Stress of Cement Sheath for Geothermal Wells during Fracturing

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