Three-dimensional analysis of boreholes considering spatial variability of properties and poroelastoplasticity

Müller, A.; Vargas, Eurípedes do Amaral; Vaz, Luiz Eloy; Gonçalves, Clemente

doi:10.1016/j.petrol.2009.06.021

Cited by 11 publications

(6 citation statements)

References 32 publications

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“…The constitutive model chosen to represent the elastic-plastic behavior of the material was the Bogdanova-Bontcheva-Lippmann constitutive model, which was specifically developed to represent the behavior of granular materials. The basis for the development of this work was a finite element program previously developed by the authors [29,30], one which allows analysis of poroelastoplasticity problems. Numerical procedures were therefore implemented in that computer program in order to simulate the erosion processes associated with the sand/solids production.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis of sand/solids production in boreholes considering fluid-mechanical coupling in a Cosserat continuum

Müller

Vargas

Vaz

et al. 2011

International Journal of Rock Mechanics and Mining Sciences

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Sand/solids production is a serious problem faced by the petroleum industry during production stages. Particles/groups of particles of the formation rock are produced together with pumped oil or gas causing highly damaging effects on pipes and valves. This phenomena can be caused by several factors including the stresses developed around the boreholes/perforations and fluid flow, which break and erode the rock, respectively. Numerical simulation of sand/solids production presents a considerable challenge as intricacies of failure processes must be correctly simulated. This paper presents a finite element based procedure for simulating the process of sand/solids production, considering fluidmechanical coupling in an elasto-plastic Cosserat continuum. It is believed that the enhanced deformation modes included into Cosserat continua may contribute for proper modeling of the deformational behavior and failure modes of the cemented/non-cemented granular materials involved. Bogdanova-Bontcheva and Lippmann's constitutive model was implemented in order to model the granular materials involved. Finally, the work presents the analysis of sand/solids production in a hypothetical borehole. For comparison purposes, different characteristic lengths of the material are adopted and analysis is also performed using standard continua.

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Section: Introductionmentioning

confidence: 99%

Numerical analysis of sand/solids production in boreholes considering fluid-mechanical coupling in a Cosserat continuum

Müller

Vargas

Vaz

et al. 2011

International Journal of Rock Mechanics and Mining Sciences

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“…On the other hand, soft rocks may have experienced plastic deformation before fracturing caused by high mud pressure, which is not considered in the traditional elastic model. Thus, in recent years, various elastoplastic models have been proposed and employed for analyzing the stresses and deformations around the wellbore [10,[12][13][14][15][16], and borehole stability is realized by restricting either the area of the plastic region [14] or the borehole closure [10] to be less than some designated values derived from field experiences.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Wellbore Stability in Deepwater Shallow Sediments

et al. 2021

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An elaborate poro-elastoplastic numerical model has been developed in this paper to explore the stability characteristics of wellbore in shallow sediments of deepwater oil/gas wells. The combined Drucker-Prager/cap plasticity model is employed to characterize the mechanical behavior of the weakly consolidated or unconsolidated shallow sediments, by which both plastic compaction deformation and plastic shear deformation can be considered. Possible penetration of drilling fluid into the formation and its coupling to deformation have also been accounted for in the model. Using this model, deformation, stress evolution, and failure characteristics of the formation around the wellbore are analyzed in detail. Results presented in this paper demonstrate the necessity of considering the plastic compaction capability of the formation during the wellbore stability analysis of shallow sediments in deepwater. For mud pressures lower than the in situ horizontal stress, excessive wellbore shrinkage may occur if the mud pressure is too low, which, however, can be effectively mitigated through properly increasing the mud pressure even fluid penetration into the near-wellbore region may occur. It is also evidenced that, if penetration of drilling fluid into the formation is prevented, fracturing of the wellbore will not occur even the mud pressure is very high. Instead, the wellbore will expand substantially due to plastic compaction, and the deformed wellbore radius could be several times larger than the original value. However, if drilling fluid can penetrate into the formation, high pore pressure will develop within the near-wellbore region, resulting in tensile hoop stress at the wellbore and thus fracturing of the wellbore along the radial direction. The numerical results and implications in this paper are anticipated to be beneficial for the drilling operation in the shallow portion of deepwater oil/gas wells.

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“…A reliability analysis was carried out limited to a pressure range, where lower limit, compressive failure, is based on a user defined plastic region, while the upper limit is based on the rock tensile failure stress. This study was later analyzed for three-dimensional scenarios [16].…”

Section: Introductionmentioning

confidence: 99%

Stability analysis and uncertainty modeling of vertical and inclined wellbore drilling through heterogeneous field

Batalha¹,

Durán²,

Devloo³

et al. 2020

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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A stochastic two-dimensional geomechanical model developed by the authors and presented herein is used to analyze wellbore stability in heterogeneous formations. It consists of a finite element model and assumes linear elastic and isotropic material behavior under the plane strain state. The model simulates the stress state around vertical and inclined wellbore when a formation is submitted to internal drilling fluid pressure. This new state of stress may lead to rock failure, which is analyzed through a failure criteria. Since the exact variation of formation’s mechanical properties is not known, a spatially correlated field is used to evaluate the variability of a rock mechanical material property. The correlation between each pair of finite elements is determined by a covariance function. A two-dimensional spatially correlated field is used to verify the correlation between the elements of a vertical wellbore. A different approach, however, is necessary to model inclined wellbores. Once the direction and inclination of a wellbore are defined, a three-dimensional spatially correlated field becomes necessary to best simulate the formation field. Simulations using the stochastic model proposed herein and considering constant elastic modulus have been compared. It is observed that when considering the same elastic modulus along the field, the area of the plastic zone is symmetric at the borehole wall; when using the stochastic model, however, the plastic zone area surrounding the well is not symmetric; thus, the most vulnerable plastic zone may lead to premature failure. Stochastic simulations have been carried out with different heterogeneous fields for vertical and inclined wells, and distributions of the total plastic zone areas are obtained for each case. Based on the stochastic field probabilistic analysis, a distribution function is presented, which aims to define a stability framework analysis to best assist a decision making process in determining if a mud pressure is operationally acceptable or not.

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Three-dimensional analysis of boreholes considering spatial variability of properties and poroelastoplasticity

Cited by 11 publications

References 32 publications

Numerical analysis of sand/solids production in boreholes considering fluid-mechanical coupling in a Cosserat continuum

Numerical analysis of sand/solids production in boreholes considering fluid-mechanical coupling in a Cosserat continuum

Numerical Investigation of Wellbore Stability in Deepwater Shallow Sediments

Stability analysis and uncertainty modeling of vertical and inclined wellbore drilling through heterogeneous field

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