eprintid: 1717 rev_number: 15 eprint_status: archive userid: 6 dir: disk0/00/00/17/17 datestamp: 2016-07-08 08:00:27 lastmod: 2017-09-20 08:52:59 status_changed: 2016-07-08 08:00:27 type: article metadata_visibility: show creators_name: Davies, Richard J. creators_name: Almond, Sam creators_name: Ward, Robert S. creators_name: Jackson, Robert B. creators_name: Adams, Charlotte creators_name: Worrall, Fred creators_name: Herringshaw, Liam G. creators_name: Gluyas, Jon G. creators_name: Whitehead, Mark A. creators_id: richard.davies@dur.ac.uk corp_creators: Durham Energy Institute, Department of Earth Sciences, Durham University, Science Labs, Durham corp_creators: Durham Energy Institute, Department of Earth Sciences, Durham University, Science Labs, Durham corp_creators: Groundwater Science Directorate, British Geological Survey, Keyworth, Nottingham corp_creators: School of Earth Sciences, Woods Institute for the Environment, and Precourt Institute for Energy, Stanford University, Nicholas School of the Environment, Division of Earth and Ocean Sciences, Duke University corp_creators: Durham Energy Institute, Department of Earth Sciences, Durham University, Science Labs, Durham corp_creators: Durham Energy Institute, Department of Earth Sciences, Durham University, Science Labs, Durham corp_creators: Durham Energy Institute, Department of Earth Sciences, Durham University, Science Labs, Durham corp_creators: Durham Energy Institute, Department of Earth Sciences, Durham University, Science Labs, Durham corp_creators: Ward Hadaway, Sandgate House title: Oil and gas wells and their integrity: Implications for shale and unconventional resource exploitation subjects: O subjects: RU10 subjects: SHU divisions: SHEER full_text_status: none keywords: Shale; Fracking; Integrity; Barrier; Integrity; Wells abstract: Data from around the world (Australia, Austria, Bahrain, Brazil, Canada, the Netherlands, Poland, the UK and the USA) show that more than four million onshore hydrocarbon wells have been drilled globally. Here we assess all the reliable datasets (25) on well barrier and integrity failure in the published literature and online. These datasets include production, injection, idle and abandoned wells, both onshore and offshore, exploiting both conventional and unconventional reservoirs. The datasets vary considerably in terms of the number of wells examined, their age and their designs. Therefore the percentage of wells that have had some form of well barrier or integrity failure is highly variable (1.9%–75%). Of the 8030 wells targeting the Marcellus shale inspected in Pennsylvania between 2005 and 2013, 6.3% of these have been reported to the authorities for infringements related to well barrier or integrity failure. In a separate study of 3533 Pennsylvanian wells monitored between 2008 and 2011, there were 85 examples of cement or casing failures, 4 blowouts and 2 examples of gas venting. In the UK, 2152 hydrocarbon wells were drilled onshore between 1902 and 2013 mainly targeting conventional reservoirs. UK regulations, like those of other jurisdictions, include reclamation of the well site after well abandonment. As such, there is no visible evidence of 65.2% of these well sites on the land surface today and monitoring is not carried out. The ownership of up to 53% of wells in the UK is unclear; we estimate that between 50 and 100 are orphaned. Of 143 active UK wells that were producing at the end of 2000, one has evidence of a well integrity failure. date: 2014-09 date_type: published publication: Marine and Petroleum Geology volume: 56 publisher: Elsevier pagerange: 239-254 id_number: doi:10.1016/j.marpetgeo.2014.03.001 issn: 0264-8172 official_url: http://doi.org/10.1016/j.marpetgeo.2014.03.001 access_IS-EPOS: limited owner: Publisher citation: Davies, Richard J. and Almond, Sam and Ward, Robert S. and Jackson, Robert B. and Adams, Charlotte and Worrall, Fred and Herringshaw, Liam G. and Gluyas, Jon G. and Whitehead, Mark A. (2014) Oil and gas wells and their integrity: Implications for shale and unconventional resource exploitation. Marine and Petroleum Geology, 56. pp. 239-254. DOI: https://doi.org/10.1016/j.marpetgeo.2014.03.001