PSI - Issue 48

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ScienceDirect Structural Integrity Procedia 00 (2023) 000–000 Structural Integrity Procedia 00 (2023) 000–000

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 48 (2023) 207–214

Second International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023) The Structural Limit of Wellbore Tubulars Subjected to Tension-Collapse Second International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023) The Structural Limit of Wellbore Tubulars Subjected to Tension-Collapse

Udaya B Sathuvalli a *, P V (Suri) Suryanarayana a a Blade Energy Partners, 2600 Network Boulevard, Suite 550, Frisco, TX 75034, USA Udaya B Sathuvalli a *, P V (Suri) Suryanarayana a a Blade Energy Partners, 2600 Network Boulevard, Suite 550, Frisco, TX 75034, USA

© 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IRAS 2023 organizers © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IRAS 2023 organizers Keywords: Wellbores; Tension-Collapse Load; Thin-walled casings; Thick-walled casings; Constrained plasticity; Inextensional deformation 1. Introduction An understanding of the mechanical response of casings (hollow steel cylinders) to pressure, tension and bending loads is a crucial step in executing operations in the O&G industry. In a number of these operations, the external pressure on the cylinder is greater than the internal pressure, so that the loading is characterized by a “collapse differential” on the tubular wall. In many reservoirs, the lower section of the wellbore contains a production casing or liner (Fig. 1a). The production casing (a thick walled cylinder, d o / t ~ 8 to 14) provides structural support and presents a barrier to hydrocarbons flowing inside the production tubing. When hydrocarbons are extracted from the reservoir, the pore pressure within the reservoir matrix decreases. Because of the weight of overlying rock strata, the depleted reservoir undergoes compaction while the overburden above the caprock experiences tension (Geertsma, 1973). Abstract We examine the mechanical response of well casings subjected to combined tension and collapse loads in two special situations. In the first situation, a thick-walled casing is exposed to reduced reservoir pressure and geomechanically transferred axial strain. In the second situation, a thin-walled casing experiences thermal strain during heating and cooling cycles in a steam (or geothermal) well. Importantly, both situations involve displacement controlled axial loading of the pipe, and the applied axial strain approaches or exceeds the uniaxial yield strain of the casing material. The magnitudes of the tensile strain and allowable differential pressures on the casings in both cases exceed the elastic limits, enough to rule out the possibility of working stress design. Further, the guidelines stipulated by the American Petroleum Institute (API) are of limited use in these scenarios. Though collapse of hollow cylinders has been studied extensively, the design and analysis of the casings in the loading conditions described above is performed with finite element analyses and/or physical testing. In this context, our paper presents a numerical method to determine the structural limits of pipes in such tension-collapse conditions. © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IRAS 2023 organizers Keywords: Wellbores; Tension-Collapse Load; Thin-walled casings; Thick-walled casings; Constrained plasticity; Inextensional deformation 1. Introduction An understanding of the mechanical response of casings (hollow steel cylinders) to pressure, tension and bending loads is a crucial step in executing operations in the O&G industry. In a number of these operations, the external pressure on the cylinder is greater than the internal pressure, so that the loading is characterized by a “collapse differential” on the tubular wall. In many reservoirs, the lower section of the wellbore contains a production casing or liner (Fig. 1a). The production casing (a thick walled cylinder, d o / t ~ 8 to 14) provides structural support and presents a barrier to hydrocarbons flowing inside the production tubing. When hydrocarbons are extracted from the reservoir, the pore pressure within the reservoir matrix decreases. Because of the weight of overlying rock strata, the depleted reservoir undergoes compaction while the overburden above the caprock experiences tension (Geertsma, 1973). Abstract We examine the mechanical response of well casings subjected to combined tension and collapse loads in two special situations. In the first situation, a thick-walled casing is exposed to reduced reservoir pressure and geomechanically transferred axial strain. In the second situation, a thin-walled casing experiences thermal strain during heating and cooling cycles in a steam (or geothermal) well. Importantly, both situations involve displacement controlled axial loading of the pipe, and the applied axial strain approaches or exceeds the uniaxial yield strain of the casing material. The magnitudes of the tensile strain and allowable differential pressures on the casings in both cases exceed the elastic limits, enough to rule out the possibility of working stress design. Further, the guidelines stipulated by the American Petroleum Institute (API) are of limited use in these scenarios. Though collapse of hollow cylinders has been studied extensively, the design and analysis of the casings in the loading conditions described above is performed with finite element analyses and/or physical testing. In this context, our paper presents a numerical method to determine the structural limits of pipes in such tension-collapse conditions.

* Corresponding author. Tel.: +1972-712-8407; fax: +1-972-712-8408. E-mail address: ubsathuvalli@blade-energy.com * Corresponding author. Tel.: +1972-712-8407; fax: +1-972-712-8408. E-mail address: ubsathuvalli@blade-energy.com

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IRAS 2023 organizers 2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IRAS 2023 organizers

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IRAS 2023 organizers 10.1016/j.prostr.2023.07.150