Three-dimensional finite element modelling of stress relaxation tests in anisotropic clayey medium: direct problem and back analysis

Giot, Richard; Giraud, Albert; Homand, Françoise

doi:10.1007/s10706-005-7723-x

Cited by 6 publications

(2 citation statements)

References 17 publications

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“…A review of these methods can be found in [29][30][31]. Gradient-based methods have commonly been used in the field of geomechanics to identify parameters for elastic geomaterials [32,33], elastoplastic [16,23,[34][35][36][37][38][39] and elastoviscoplastic [40,41] media, as well as for poromechanical problems [42][43][44]. Giraud et al [45,46] used this kind of method for the interpretation of drying tests in argillites with the aim of assessing the relative permeability and retention curve of partially saturated porous media.…”

Section: The Pulse Test As a Parameter Identification Problemmentioning

confidence: 99%

Fully coupled poromechanical back analysis of the pulse test by inverse method

Giot¹,

Giraud²,

Auvray³

et al. 2011

Num Anal Meth Geomechanics

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SUMMARYIn this paper, we investigate the pulse test, which is usually considered as efficient for measuring the permeability of weakly permeable porous media. The pulse is first analyzed and we show that it is a fully poromechanical coupled problem. Owing to those couplings, the problem is 2D-axisymmetrical, rather than 1D as is usually considered to be the case. As a consequence, the 1D solutions, for example under constant mean stress hypothesis, although giving good approximates of permeability and storage coefficient, are not rigorous and an enhanced back analysis of the test requires 2D solutions. Therefore, no analytical solution exists, and the problem has to be solved using 2D-axisymmetrical numerical modelings of the pulse test. The finite element method is considered in this paper. We then proceed to formulate the pulse test back analysis as a parameter identification problem, and we focus on intrinsic permeability, Biot coefficient, drained Young's modulus and reservoir compressibility levels. This parameter identification problem is solved by an inverse method consisting of the minimization of a cost-functional, through a gradient-based algorithm. This new method of interpretation of the pulse test is finally applied to laboratory tests on Meuse/Haute-Marne argillite and is shown to give encouraging results.

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Section: The Pulse Test As a Parameter Identification Problemmentioning

confidence: 99%

Fully coupled poromechanical back analysis of the pulse test by inverse method

Giot¹,

Giraud²,

Auvray³

et al. 2011

Num Anal Meth Geomechanics

Self Cite

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“…Such an inverse problem may have a non-unique solution. Nevertheless, the developed inversion procedure has proven to be efficient in the field of geomechanics, for example, on the axial pulse test (Giot et al [9,13]) or overcoring (Giot et al [14]), particularly concerning the issues of local minima and the consideration of uncertainties on measurements.…”

Section: Introductionmentioning

confidence: 99%

Assessing the Permeability in Anisotropic and Weakly Permeable Porous Rocks Using Radial Pulse Tests

Giot

Giraud

Auvray

2013

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

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Re´sume´-Estimation de la perme´abilite´d'une roche anisotrope tre`s faiblement perme´able par pulse tests radiaux -Le pulse test est ge´ne´ralement conside´re´comme un essai adapte´pour la mesure de la perme´abilite´des roches poreuses tre`s faiblement perme´ables. Classiquement, l'essai consiste aì mposer un saut de pression a`la base d'un e´chantillon cylindrique et a`mesurer les variations de pression dans les re´servoirs amont et aval. Dans les pre´sents travaux, nous proposons un nouveau dispositif et une nouvelle proce´dure sur e´chantillon de type cylindre creux : le saut de pression est impose´dans un trou axial et la pression mesure´e dans le trou et a`la circonfe´rence de l'e´chantillon. Cette configuration ge´ne`re un e´coulement a`la fois axial et transversal, et non seulement axial comme dans le cas de l'essai classique. Pour les roches isotropes transverses, cela permet la de´termination de la perme´abilite´dans les directions paralle`le et perpendiculaire aux plans d'isotropie, a`partir d'un seul e´chantillon, judicieusement oriente´. L'essai est couple´hydro-me´caniquement, et en conse´quence aucune solution analytique ne peut eˆtre conside´re´e. L'essai est alors interpre´te´en ayant recours a`des mode´lisations nume´riques couple´es HM 3D, prenant en compte l'anisotropie des e´chantillons. Dans les travaux pre´ce´dents, une loi poro-e´lastique isotrope transverse, ainsi qu'une me´thode inverse couple´e aux mode´lisations nume´riques pour identifier des parame`tres, ont e´te´de´veloppe´es et implante´es dans le code aux e´le´ments finis Code_Aster (Edf). La me´thode est adapte´e pour l'interpre´tation de l'essai de pulse radial et applique´e a`des e´chantillons cylindriques creux d'argilites de Meuse/Haute-Marne, avec axe soit perpendiculaire soit paralle`le aux plans d'isotropie. Alors que pour l'essai de pulse axial classique, la me´thode requiert deux e´chantillons pour de´terminer les perme´abilite´s intrinse`ques dans les directions paralle`le et perpendiculaire aux plans d'isotropie, la me´thode applique´e al 'essai de pulse radial permet la de´termination des perme´abilite´s intrinse`ques dans ces deux directions sur un seul e´chantillon. Ceci permet de s'affranchir d'effets d'he´te´roge´ne´ite´s des e´chantillons.Abstract -Assessing the Permeability in Anisotropic and Weakly Permeable Porous Rocks Using Radial Pulse Tests -The pulse test is usually considered to be an efficient method for measuring the permeability of weakly permeable porous rocks. Classically, the test consists of imposing a pressure drop on the base of a cylindrical sample and measuring the pressure variations in the upstream and downstream reservoirs. In the present work, we propose a new apparatus and procedure for hollow Oil & Gas Science and Technology -Rev. IFP Energies nouvelles, Vol. 69 (2014), No. 7, pp. 1171-1189 Copyright Ó 2013, IFP Energies nouvelles DOI: 10.2516 cylindrical samples in which the pressure drop is imposed in an axial hole and the pressure is measured both in the hole and on the circumferen...

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