Stability of Infill Wellbores in Dissimilar Layers of Depleted and Confining Rock.
Saved in:
| Title: | Stability of Infill Wellbores in Dissimilar Layers of Depleted and Confining Rock. |
|---|---|
| Authors: | Su, Xing1 (AUTHOR), Li, Diyuan1 (AUTHOR), Li, Sanbai1 (AUTHOR), Mehrabian, Amin2 (AUTHOR) amin.mehrabian@psu.edu |
| Source: | Rock Mechanics & Rock Engineering. May2025, Vol. 58 Issue 5, p5455-5473. 19p. |
| Subjects: | Strains & stresses (Mechanics), Pore fluids, Fluid pressure, Poroelasticity, Stress concentration |
| Abstract: | This paper presents the stability analysis of infill wellbores when drilled toward and through a depleted rock layer confined in between two mechanically dissimilar formations. The analysis is based on an analytical solution for the nonuniform distribution of the in-situ stress change within each rock formation due to an axisymmetric volume of pore fluid pressure change within the middle layer. The solution is derived using the Hankel transform of the stress equilibrium equations and by adopting poroelastic constitutive relations to describe the mechanical behavior of fluid-saturated rock. The obtained expressions for change in the in-situ stress tensor are next applied as boundary conditions of the infill wellbore stability problem to find the wellbore wall stress, and subsequently, the post-depletion values of the wellbore shear and tensile failure gradients. Results indicate that aside from the contrast in mechanical properties between the depleted and confining rock layers, the distance from the center point of depleted volume, as well as the geographical azimuth of the point of interest along the well trajectory, are among the key factors that determine the wellbore mud weight window. Highlights: The largest variability in the mud weight window occurs when an infill wellbore is drilled close to the reservoir flanks. Dissimilarity of the depleted and surrounding rock layers strongly affects the depletion-induced change in the in-situ stress. The wellbore shear and tensile failure gradients may decrease or increase depending on the relative stiffnesses of depleted and confining rock layers. Wellbore tensile failure may start in the overburden layer before it enters the depleted layer, if the former layer is stiffer than the latter. [ABSTRACT FROM AUTHOR] |
| Copyright of Rock Mechanics & Rock Engineering is the property of Springer Nature and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
|
Full text is not displayed to guests.
Login for full access.
|
|
| Abstract: | This paper presents the stability analysis of infill wellbores when drilled toward and through a depleted rock layer confined in between two mechanically dissimilar formations. The analysis is based on an analytical solution for the nonuniform distribution of the in-situ stress change within each rock formation due to an axisymmetric volume of pore fluid pressure change within the middle layer. The solution is derived using the Hankel transform of the stress equilibrium equations and by adopting poroelastic constitutive relations to describe the mechanical behavior of fluid-saturated rock. The obtained expressions for change in the in-situ stress tensor are next applied as boundary conditions of the infill wellbore stability problem to find the wellbore wall stress, and subsequently, the post-depletion values of the wellbore shear and tensile failure gradients. Results indicate that aside from the contrast in mechanical properties between the depleted and confining rock layers, the distance from the center point of depleted volume, as well as the geographical azimuth of the point of interest along the well trajectory, are among the key factors that determine the wellbore mud weight window. Highlights: The largest variability in the mud weight window occurs when an infill wellbore is drilled close to the reservoir flanks. Dissimilarity of the depleted and surrounding rock layers strongly affects the depletion-induced change in the in-situ stress. The wellbore shear and tensile failure gradients may decrease or increase depending on the relative stiffnesses of depleted and confining rock layers. Wellbore tensile failure may start in the overburden layer before it enters the depleted layer, if the former layer is stiffer than the latter. [ABSTRACT FROM AUTHOR] |
|---|---|
| ISSN: | 07232632 |
| DOI: | 10.1007/s00603-024-04341-3 |
