View in EDS HTML Full Text PDF Full Text

Quantitative Risk Assessment of Wellbore Collapse of Inclined Wells in Formations with Anisotropic Rock Strengths.

Saved in:
Bibliographic Details
Title: Quantitative Risk Assessment of Wellbore Collapse of Inclined Wells in Formations with Anisotropic Rock Strengths.
Authors: Ma, Tianshou1 (AUTHOR) matianshou@126.com, Liu, Keyan1,2 (AUTHOR), Qiu, Yi1 (AUTHOR), Liu, Jinhua1 (AUTHOR), Martyushev, Dmitriy A.3 (AUTHOR), Ranjith, P. G.4 (AUTHOR)
Source: Rock Mechanics & Rock Engineering. Feb2025, Vol. 58 Issue 2, p1795-1818. 24p.
Subjects: Monte Carlo method, Fick's laws of diffusion, Information dissemination, Drilling muds, Sedimentary rocks, Horizontal wells
Abstract: Shale is a typical sedimentary rock that exhibits anisotropic strength characteristics owing to the presence of planes of weakness, such as bedding planes and joints. However, conventional quantitative risk assessment (QRA) models for wellbore stability often assume that shale is isotropic, leading to inaccurate predictions of the risk of wellbore collapse. This study proposes a novel QRA model of the wellbore collapse risk in inclined wells that considers the combined effects of anisotropic rock strength and parameter uncertainty. First, the semi-analytical model of wellbore collapse was revisited using various coordinate system transformations, the classical Bradley's solution, and a single plane of the weakness criterion. Second, based on the reliability theory, a QRA method of wellbore collapse was established for inclined wells in formations with anisotropic rock strengths. Third, the K–S test and normal information diffusion (NID) method were used to determine the uncertainty of the logging interpretation results. The key parameters with significant uncertainty were obtained through sensitivity analysis. Finally, Monte Carlo simulation was conducted to quantitatively evaluate the risk of wellbore collapse. The results show that when the anisotropic rock strength is considered, the assessment of the equivalent mud weight (EMW) of the collapse pressure is more accurate. The failure of vertical wells primarily occurred within the rock matrix, whereas that of inclined and horizontal wells predominantly occurred along the planes of weakness. The pore pressure, Biot coefficient, and in-situ stress are the parameters with the greatest influence on wellbore stability. When considering the uncertainty of the weak plane occurrence, the collapse pressure EMW for inclined and horizontal wells significantly increased. The NID method yielded a more precise quantification of the parameter uncertainty compared with the normal distribution. The novel model proposed in this study incorporates the anisotropic rock strength and parameter uncertainty, resulting in more consistent predictions under actual conditions. This model and analysis provide a crucial theoretical foundation for drilling trajectory and drilling mud weight optimization to maintain wellbore stability of horizontal wells in shale formations. Highlights: A quantitative risk assessment method for wellbore collapse was proposed for inclined wells in formations with anisotropic rock strengths. The combined effects of anisotropic rock strength and parameter uncertainty were considered in this study. It is imperative to consider the impact of the uncertain properties of the plane of weakness when analyzing the stability of inclined wells. The parameters with the greatest influence on the stability of inclined wells are pore pressure, Biot coefficient, and in-situ stress. The normal information diffusion method yielded a more precise estimation of the parameter uncertainty in comparison to the normal distribution. [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.
FullText Links:
  – Type: pdflink
Text:
  Availability: 1
Header DbId: egs
DbLabel: Engineering Source
An: 183282734
AccessLevel: 6
PubType: Academic Journal
PubTypeId: academicJournal
PreciseRelevancyScore: 0
IllustrationInfo
Items – Name: Title
  Label: Title
  Group: Ti
  Data: Quantitative Risk Assessment of Wellbore Collapse of Inclined Wells in Formations with Anisotropic Rock Strengths.
– Name: Author
  Label: Authors
  Group: Au
  Data: <searchLink fieldCode="AR" term="%22Ma%2C+Tianshou%22">Ma, Tianshou</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> matianshou@126.com</i><br /><searchLink fieldCode="AR" term="%22Liu%2C+Keyan%22">Liu, Keyan</searchLink><relatesTo>1,2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Qiu%2C+Yi%22">Qiu, Yi</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Liu%2C+Jinhua%22">Liu, Jinhua</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Martyushev%2C+Dmitriy+A%2E%22">Martyushev, Dmitriy A.</searchLink><relatesTo>3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Ranjith%2C+P%2E+G%2E%22">Ranjith, P. G.</searchLink><relatesTo>4</relatesTo> (AUTHOR)
– Name: TitleSource
  Label: Source
  Group: Src
  Data: <searchLink fieldCode="JN" term="%22Rock+Mechanics+%26+Rock+Engineering%22">Rock Mechanics & Rock Engineering</searchLink>. Feb2025, Vol. 58 Issue 2, p1795-1818. 24p.
– Name: Subject
  Label: Subjects
  Group: Su
  Data: <searchLink fieldCode="DE" term="%22Monte+Carlo+method%22">Monte Carlo method</searchLink><br /><searchLink fieldCode="DE" term="%22Fick's+laws+of+diffusion%22">Fick's laws of diffusion</searchLink><br /><searchLink fieldCode="DE" term="%22Information+dissemination%22">Information dissemination</searchLink><br /><searchLink fieldCode="DE" term="%22Drilling+muds%22">Drilling muds</searchLink><br /><searchLink fieldCode="DE" term="%22Sedimentary+rocks%22">Sedimentary rocks</searchLink><br /><searchLink fieldCode="DE" term="%22Horizontal+wells%22">Horizontal wells</searchLink>
– Name: Abstract
  Label: Abstract
  Group: Ab
  Data: Shale is a typical sedimentary rock that exhibits anisotropic strength characteristics owing to the presence of planes of weakness, such as bedding planes and joints. However, conventional quantitative risk assessment (QRA) models for wellbore stability often assume that shale is isotropic, leading to inaccurate predictions of the risk of wellbore collapse. This study proposes a novel QRA model of the wellbore collapse risk in inclined wells that considers the combined effects of anisotropic rock strength and parameter uncertainty. First, the semi-analytical model of wellbore collapse was revisited using various coordinate system transformations, the classical Bradley's solution, and a single plane of the weakness criterion. Second, based on the reliability theory, a QRA method of wellbore collapse was established for inclined wells in formations with anisotropic rock strengths. Third, the K–S test and normal information diffusion (NID) method were used to determine the uncertainty of the logging interpretation results. The key parameters with significant uncertainty were obtained through sensitivity analysis. Finally, Monte Carlo simulation was conducted to quantitatively evaluate the risk of wellbore collapse. The results show that when the anisotropic rock strength is considered, the assessment of the equivalent mud weight (EMW) of the collapse pressure is more accurate. The failure of vertical wells primarily occurred within the rock matrix, whereas that of inclined and horizontal wells predominantly occurred along the planes of weakness. The pore pressure, Biot coefficient, and in-situ stress are the parameters with the greatest influence on wellbore stability. When considering the uncertainty of the weak plane occurrence, the collapse pressure EMW for inclined and horizontal wells significantly increased. The NID method yielded a more precise quantification of the parameter uncertainty compared with the normal distribution. The novel model proposed in this study incorporates the anisotropic rock strength and parameter uncertainty, resulting in more consistent predictions under actual conditions. This model and analysis provide a crucial theoretical foundation for drilling trajectory and drilling mud weight optimization to maintain wellbore stability of horizontal wells in shale formations. Highlights: A quantitative risk assessment method for wellbore collapse was proposed for inclined wells in formations with anisotropic rock strengths. The combined effects of anisotropic rock strength and parameter uncertainty were considered in this study. It is imperative to consider the impact of the uncertain properties of the plane of weakness when analyzing the stability of inclined wells. The parameters with the greatest influence on the stability of inclined wells are pore pressure, Biot coefficient, and in-situ stress. The normal information diffusion method yielded a more precise estimation of the parameter uncertainty in comparison to the normal distribution. [ABSTRACT FROM AUTHOR]
– Name: AbstractSuppliedCopyright
  Label:
  Group: Ab
  Data: <i>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.</i> (Copyright applies to all Abstracts.)
PLink https://search.ebscohost.com/login.aspx?direct=true&site=eds-live&db=egs&AN=183282734
RecordInfo BibRecord:
  BibEntity:
    Identifiers:
      – Type: doi
        Value: 10.1007/s00603-024-04206-9
    Languages:
      – Code: eng
        Text: English
    PhysicalDescription:
      Pagination:
        PageCount: 24
        StartPage: 1795
    Subjects:
      – SubjectFull: Monte Carlo method
        Type: general
      – SubjectFull: Fick's laws of diffusion
        Type: general
      – SubjectFull: Information dissemination
        Type: general
      – SubjectFull: Drilling muds
        Type: general
      – SubjectFull: Sedimentary rocks
        Type: general
      – SubjectFull: Horizontal wells
        Type: general
    Titles:
      – TitleFull: Quantitative Risk Assessment of Wellbore Collapse of Inclined Wells in Formations with Anisotropic Rock Strengths.
        Type: main
  BibRelationships:
    HasContributorRelationships:
      – PersonEntity:
          Name:
            NameFull: Ma, Tianshou
      – PersonEntity:
          Name:
            NameFull: Liu, Keyan
      – PersonEntity:
          Name:
            NameFull: Qiu, Yi
      – PersonEntity:
          Name:
            NameFull: Liu, Jinhua
      – PersonEntity:
          Name:
            NameFull: Martyushev, Dmitriy A.
      – PersonEntity:
          Name:
            NameFull: Ranjith, P. G.
    IsPartOfRelationships:
      – BibEntity:
          Dates:
            – D: 01
              M: 02
              Text: Feb2025
              Type: published
              Y: 2025
          Identifiers:
            – Type: issn-print
              Value: 07232632
          Numbering:
            – Type: volume
              Value: 58
            – Type: issue
              Value: 2
          Titles:
            – TitleFull: Rock Mechanics & Rock Engineering
              Type: main
ResultId 1