Links that describe integrity issues such associated with casing failures and cement failures.
- - 1619 - [June 5, 2014] - Geofirma Engineering, Ltd, NA - "Research – Wellbore Integrity and Leakage"
- "Wells that slowly seep gas upwards outside the casing because of inadequate primary cementation, and because there is a source of gas (generally a thin, undepleted and non-commercial gassy formation at intermediate depth), are commonplace. Slow seepage can develop many years after a successful well abandonment procedure. The seepage gas is usually close to 100% – methane...."
- - 1773 - [June 2013] - EnergyInDepth, Steve Everley - "60 Percent of Statistics are Made Up"
- "Writing in The New York Times on Christmas Day 2012, none other than Yoko Ono declared that 60 percent of wells producing natural gas from shale will fail – perhaps surprising those who weren’t previously familiar with Ms. Ono’s background and experience as a petroleum engineer. Expertise (or lack thereof) aside, could it really be the case that more than half of all wells will be “poisoning drinking water” sometime in the not too distant future?"
- - 1776 - [April 27, 2015] - Marine and Petroleum Technology, Richard J. Davies, Sam Almond, Robert S. Ward, Robert B. Jackson, Charlotte Adams, Fred Worrall, Liam G. Herringshaw, Jon G. Gluyas and - "Oil and gas wells and their integrity: Implications for shale and unconventional resource exploitation"
- "Data from around the world (Australia, Austria, Bahrain, Brazil, Canada, the Netherlands, Poland, the UK. Here we assess all the reliable datasets (25) on well barrier and integrity failure in the published literature and online."
- - 1778 - [November 2013] - SHIP - Shale Gas Information Platform, Water Protection, Operations - "New numbers on well integrity failures"
- "The biggest environmental concern with shale gas exploration and production is water contamination. Whether or not hydraulic fracturing causes methane contamination of drinking water remains to be proved (Davies, 2011), although the possibility cannot be totally ruled out. Well integrity failure is a far more likely cause of elevated thermogenic methane concentrations in shallow groundwater and water supplies than pathways induced solely by hydraulic fracturing (Davies et al 2014 and references therein). "