Detecting and Modeling Cement Failure in High-Pressure/High-Temperature (HP/HT) Wells, Using Finite Element Method (FEM)

Shahri, Mehdi; Schubert, Jerome; Amani, Mahmood

doi:10.2523/iptc-10961-ms

Cited by 26 publications

(15 citation statements)

References 17 publications

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“…ξ 1 and ξ 2 are the dimensionless compressive wave velocity of the casing and the cement sheath, respectively. According to some literatures [11,[24][25][26][27], the Lame constants of casing ( λ c1 , μ c1 ) range from 2 to 10, while the Lame constants of cement (λ c2 , μ c2 ) are always lower than that of the stratum, ranging from 0.2 to 1. If the rock is like a kind of soil, the Lame constants can be much higher, for instance, the λ c1 and μ c1 can reach 100 or even a higher value [28], and in this case, the Lame constants of the cement can also reach beyond 1.…”

Section: Governing Equationsmentioning

confidence: 99%

Dynamic analysis of a cylindrical casing-cement structure in a poroelastic stratum

Xia

Jin

Chen

et al. 2017

Int. J. Numer. Anal. Meth. Geomech.

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Summary The transient response of a cylindrical casing–cement structure in a poroelastic stratum under dynamic radial tractions is one of the significant issues during the analysis of downhole operations and the selection of safe material. Based on the Biot theory and general elastic mechanics, this paper gives a set of exact solutions for radial displacement, stresses for the casing–cement system and the pore pressure of the infinite surrounding poroelastic stratum in the Laplace transform space. Solutions are presented for three different types of transient radial loadings acting on the surface of casing, i.e., suddenly applied constant load, gradually applied step load and triangular pulse load. Time domain solutions are obtained using a reliable numerical method of inverse Laplace transforms. A detailed parametric study about the transient response is presented both at the casing–cement interface and the cement–stratum interface, and the distributions of the pore pressure and the effective stresses in the stratum are also examined. Copyright © 2017 John Wiley & Sons, Ltd.

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Section: Governing Equationsmentioning

confidence: 99%

Dynamic analysis of a cylindrical casing-cement structure in a poroelastic stratum

Xia

Jin

Chen

et al. 2017

Int. J. Numer. Anal. Meth. Geomech.

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“…Although a three dimensional model can be more realistic for modeling the downhole environment, it is computationally complex and may lead to more errors (Rodriguez et al, 2003). In this study a 2D model was constructed based on the plain strain assumption which is valid when the dimension perpendicular to the cross section of the body is very large and the body is loaded by uniformly distributed forces perpendicular to the longitudinal axis (Rodriguez et al, 2003;Shahri et al, 2005).…”

Section: Finite Element Modelmentioning

confidence: 99%

“…In von Mises failure theory, failure is assumed to occur if the certain combination of the three principal stresses which is called von Mises stress exceeds the yield strength of the material. Due to the fact that under downhole conditions cement sheath exhibits more ductile behavior, this stress has been widely used in finite element modeling by several researchers (Berger et al, 2004;Fleckenstein et al, 2000;Shahri et al, 2005). In this study von Mises stress was also studied together with radial and tangential stresses in the cylindrical coordination system.…”

Section: Stress Profiles In Borehole Cross-sectionmentioning

confidence: 99%

“…They added in-situ stresses to the factors that influence the cement sheath integrity. Stress state inside and around the cement sheath in particular stages of well life was studied by a number of authors (Fleckenstein et al, 2000;Rodriguez et al, 2003;Shahri et al, 2005). Developed nonlinear finite element codes provided the ability of utilizing staged finite element approaches for analyzing downhole stresses.…”

Section: Introductionmentioning

confidence: 99%

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Finite Element Simulation of Downhole Stresses in Deep Gas Wells Cements

Nabipour

Joodi²,

Sarmadivaleh

2010

All Days

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Deep gas reservoirs are going to play more important roles in meeting growing demand of natural gas throughout the world. Due to extreme conditions of downhole stresses, pressure and temperature that occur in deep gas wells, maintaining cement mechanical integrity and zonal isolation have become critical concerns of industry during drilling, completion, and production of such wells. Cement sheath is expected to provide a flawless annular seal between casing and formation along the wellbore. However; cement failure cases which are being reported regularly show that there is still need for understanding extreme downhole conditions and the behavior of cement sheath experiencing such an environment. Although Uniaxial Compressive Strength (UCS) of cement is commonly regarded as the most important mechanical property of cement, recent theoretical and experimental results show that other mechanical properties of cement can be even more determinative in its failure.In this study, Finite Element Method (FEM), a widely-used robust numerical tool, is used for simulation of the downhole environment by modeling temperature, pressures, stresses, downhole materials and their interactions. Using this approach magnitude, direction and type of induced stresses in casing, cement, and formation have been determined. Furthermore; a series of sensitivity analyses was performed to reveal the effects of variation of various parameters such as casing internal pressure, differential horizontal stress and casing eccentricity, on the induced stresses in the cement sheath.Radial, tangential and von Mises stress profiles in the deep gas wells cements were investigated. Furthermore, the effect of casing internal pressure, differential horizontal stress and casing eccentricity were studied in the model. Results show that deep gas wells' cements experience extreme amounts of thermal and mechanical stresses and special consideration is required in cement selection.

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“…Other researchers prefer to concentrate on the stress state at a particular stage of life-of-well such as pressure or temperature loading of the set cement, and apply finite element analysis techniques to model this stage [19][20][21]. However, without consideration of the previous loading and history of deformation, it is not possible to specify the initial state of stress, amount of plasticity and damage, interface conditions and other parameters necessary to accurately set-up the problem to be solved.…”

Section: Literature Reviewmentioning

confidence: 99%

Finite Element Studies of Near-Wellbore Region During Cementing Operations: Part I

Podnos

Becker

2007

All Days

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fax 01-972-952-9435. AbstractA wellbore cement sheath is expected to provide zonal isolation and borehole integrity during well construction and well life. Cement sheaths mechanically interact with other elements in the wellbore region to stresses from geological processes and operational activities. Quantifying these interacting physical components and processes has technical, economic, and environmental implications of great, and growing, significance.Staged finite element procedures during well construction sequentially consider the stress states and displacements at and near the wellbore. The model replicates complicated stress states arising from simultaneous action of far-field stresses, overburden pressure, cement hardening and shrinkage, debonding at the interfaces, and plastic flow of cement sheath and rock formation. Presently, temperature and flow are not included. The technique tracks the time-dependent behavior of cement slurry, curing (with or without shrinkage), and hardened cement during the critical period after slurry placement.Material models for casing, cement and rock formation, failure criteria for cement, formation and interface bonds were calibrated using published information and experimental data. Calculations were conducted for various loading and unloading scenarios, geometric configurations, properties of rock formations, and cement slurry formulations. Results are discussed in terms of field implications, for example: (1) interface micro-channels may or may not develop, depending upon shrinkage magnitudes; (2) simplifying modeling assumptions that are often used, such as 2-D stresses and/or deformations, may obscure critical casing, cement, and formation behavior in the wellbore region, and in the producing horizon.This paper, part of a series quantifying the interacting physical components and processes at and near the wellbore region, initiates useful comparisons of analytical results and field realities. The series illustrates and compares results and practical implications for simple to increasingly complex, but more realistic assumptions, such as isotropic/directional stress states, and isotropic/anisotropic casing, cement, and formation material parameters.

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Detecting and Modeling Cement Failure in High-Pressure/High-Temperature (HP/HT) Wells, Using Finite Element Method (FEM)

Cited by 26 publications

References 17 publications

Dynamic analysis of a cylindrical casing-cement structure in a poroelastic stratum

Dynamic analysis of a cylindrical casing-cement structure in a poroelastic stratum

Finite Element Simulation of Downhole Stresses in Deep Gas Wells Cements

Finite Element Studies of Near-Wellbore Region During Cementing Operations: Part I

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