Skip to main content

Main menu

  • Home
  • Articles
    • Current
    • Special Feature Articles - Most Recent
    • Special Features
    • Colloquia
    • Collected Articles
    • PNAS Classics
    • List of Issues
  • Front Matter
    • Front Matter Portal
    • Journal Club
  • News
    • For the Press
    • This Week In PNAS
    • PNAS in the News
  • Podcasts
  • Authors
    • Information for Authors
    • Editorial and Journal Policies
    • Submission Procedures
    • Fees and Licenses
  • Submit
  • Submit
  • About
    • Editorial Board
    • PNAS Staff
    • FAQ
    • Accessibility Statement
    • Rights and Permissions
    • Site Map
  • Contact
  • Journal Club
  • Subscribe
    • Subscription Rates
    • Subscriptions FAQ
    • Open Access
    • Recommend PNAS to Your Librarian

User menu

  • Log in
  • My Cart

Search

  • Advanced search
Home
Home
  • Log in
  • My Cart

Advanced Search

  • Home
  • Articles
    • Current
    • Special Feature Articles - Most Recent
    • Special Features
    • Colloquia
    • Collected Articles
    • PNAS Classics
    • List of Issues
  • Front Matter
    • Front Matter Portal
    • Journal Club
  • News
    • For the Press
    • This Week In PNAS
    • PNAS in the News
  • Podcasts
  • Authors
    • Information for Authors
    • Editorial and Journal Policies
    • Submission Procedures
    • Fees and Licenses
  • Submit
Research Article

Assessment and risk analysis of casing and cement impairment in oil and gas wells in Pennsylvania, 2000–2012

Anthony R. Ingraffea, Martin T. Wells, Renee L. Santoro, and Seth B. C. Shonkoff
  1. aSchool of Civil and Environmental Engineering and
  2. cDepartment of Statistical Sciences, Cornell University, Ithaca, NY 14853;
  3. bPhysicians, Scientists, and Engineers for Healthy Energy, Ithaca, NY 14850;
  4. dPhysicians, Scientists, and Engineers for Healthy Energy, Oakland, CA 94612; and
  5. eDepartment of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720-3114

See allHide authors and affiliations

PNAS first published June 30, 2014; https://doi.org/10.1073/pnas.1323422111
Anthony R. Ingraffea
aSchool of Civil and Environmental Engineering and
bPhysicians, Scientists, and Engineers for Healthy Energy, Ithaca, NY 14850;
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: ari1@cornell.edu
Martin T. Wells
cDepartment of Statistical Sciences, Cornell University, Ithaca, NY 14853;
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Renee L. Santoro
bPhysicians, Scientists, and Engineers for Healthy Energy, Ithaca, NY 14850;
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Seth B. C. Shonkoff
dPhysicians, Scientists, and Engineers for Healthy Energy, Oakland, CA 94612; and
eDepartment of Environmental Science, Policy, and Management, University of California, Berkeley, CA 94720-3114
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  1. Edited by William H. Schlesinger, Cary Institute of Ecosystem Studies, Millbrook, NY, and approved May 30, 2014 (received for review December 17, 2013)

  • Article
  • Figures & SI
  • Info & Metrics
  • PDF
Loading

Significance

Previous research has demonstrated that proximity to unconventional gas development is associated with elevated concentrations of methane in groundwater aquifers in Pennsylvania. To date, the mechanism of this migration is poorly understood. Our study, which looks at more than 41,000 conventional and unconventional oil and gas wells, helps to explain one possible mechanism of methane migration: compromised structural integrity of casing and cement in oil and gas wells. Additionally, methane, being the primary constituent of natural gas, is a strong greenhouse gas. The identification of mechanisms through which methane may migrate to the atmosphere as fugitive emissions is important to understand the climate dimensions of oil and gas development.

Abstract

Casing and cement impairment in oil and gas wells can lead to methane migration into the atmosphere and/or into underground sources of drinking water. An analysis of 75,505 compliance reports for 41,381 conventional and unconventional oil and gas wells in Pennsylvania drilled from January 1, 2000–December 31, 2012, was performed with the objective of determining complete and accurate statistics of casing and cement impairment. Statewide data show a sixfold higher incidence of cement and/or casing issues for shale gas wells relative to conventional wells. The Cox proportional hazards model was used to estimate risk of impairment based on existing data. The model identified both temporal and geographic differences in risk. For post-2009 drilled wells, risk of a cement/casing impairment is 1.57-fold [95% confidence interval (CI) (1.45, 1.67); P < 0.0001] higher in an unconventional gas well relative to a conventional well drilled within the same time period. Temporal differences between well types were also observed and may reflect more thorough inspections and greater emphasis on finding well leaks, more detailed note taking in the available inspection reports, or real changes in rates of structural integrity loss due to rushed development or other unknown factors. Unconventional gas wells in northeastern (NE) Pennsylvania are at a 2.7-fold higher risk relative to the conventional wells in the same area. The predicted cumulative risk for all wells (unconventional and conventional) in the NE region is 8.5-fold [95% CI (7.16, 10.18); P < 0.0001] greater than that of wells drilled in the rest of the state.

  • shale oil and gas
  • casing integrity
  • cement integrity
  • onshore wells
  • wellbore integrity

Footnotes

  • ↵1To whom correspondence should be addressed. E-mail: ari1{at}cornell.edu.
  • Author contributions: A.R.I. designed research; R.L.S. performed research; M.T.W. and R.L.S. analyzed data; and A.R.I., M.T.W., R.L.S., and S.B.C.S. wrote the paper.

  • The authors declare no conflict of interest.

  • This article is a PNAS Direct Submission.

  • This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1323422111/-/DCSupplemental.

Freely available online through the PNAS open access option.

Next
Back to top
Article Alerts
Email Article

Thank you for your interest in spreading the word on PNAS.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Assessment and risk analysis of casing and cement impairment in oil and gas wells in Pennsylvania, 2000–2012
(Your Name) has sent you a message from PNAS
(Your Name) thought you would like to see the PNAS web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Casing and cement impairment in oil and gas wells
Anthony R. Ingraffea, Martin T. Wells, Renee L. Santoro, Seth B. C. Shonkoff
Proceedings of the National Academy of Sciences Jun 2014, 201323422; DOI: 10.1073/pnas.1323422111

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Request Permissions
Share
Casing and cement impairment in oil and gas wells
Anthony R. Ingraffea, Martin T. Wells, Renee L. Santoro, Seth B. C. Shonkoff
Proceedings of the National Academy of Sciences Jun 2014, 201323422; DOI: 10.1073/pnas.1323422111
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Mendeley logo Mendeley

See related content:

  • The integrity of oil and gas wells
    - Jul 09, 2014
Proceedings of the National Academy of Sciences: 118 (15)
Current Issue

Submit

Sign up for Article Alerts

Jump to section

  • Article
  • Figures & SI
  • Info & Metrics
  • PDF

You May Also be Interested in

Water from a faucet fills a glass.
News Feature: How “forever chemicals” might impair the immune system
Researchers are exploring whether these ubiquitous fluorinated molecules might worsen infections or hamper vaccine effectiveness.
Image credit: Shutterstock/Dmitry Naumov.
Reflection of clouds in the still waters of Mono Lake in California.
Inner Workings: Making headway with the mysteries of life’s origins
Recent experiments and simulations are starting to answer some fundamental questions about how life came to be.
Image credit: Shutterstock/Radoslaw Lecyk.
Cave in coastal Kenya with tree growing in the middle.
Journal Club: Small, sharp blades mark shift from Middle to Later Stone Age in coastal Kenya
Archaeologists have long tried to define the transition between the two time periods.
Image credit: Ceri Shipton.
Illustration of groups of people chatting
Exploring the length of human conversations
Adam Mastroianni and Daniel Gilbert explore why conversations almost never end when people want them to.
Listen
Past PodcastsSubscribe
Panda bear hanging in a tree
How horse manure helps giant pandas tolerate cold
A study finds that giant pandas roll in horse manure to increase their cold tolerance.
Image credit: Fuwen Wei.

Similar Articles

Site Logo
Powered by HighWire
  • Submit Manuscript
  • Twitter
  • Facebook
  • RSS Feeds
  • Email Alerts

Articles

  • Current Issue
  • Special Feature Articles – Most Recent
  • List of Issues

PNAS Portals

  • Anthropology
  • Chemistry
  • Classics
  • Front Matter
  • Physics
  • Sustainability Science
  • Teaching Resources

Information

  • Authors
  • Editorial Board
  • Reviewers
  • Subscribers
  • Librarians
  • Press
  • Cozzarelli Prize
  • Site Map
  • PNAS Updates
  • FAQs
  • Accessibility Statement
  • Rights & Permissions
  • About
  • Contact

Feedback    Privacy/Legal

Copyright © 2021 National Academy of Sciences. Online ISSN 1091-6490