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Wednesday, December 3, 2014

The steel casing and cement sheathing in an oil and gas well are designed to last for as long as the productive life of the well. About twenty years for a conventional well. About ten for a shale well. Long before that many of them leak, and sometime after the end of their productive life, they will all leak. Because ferrous metals are not immortal.  Particularly when awash in brine. Horizontal (“deviated” in Canada) wells leak up to 10 times more than conventional vertical wells. 
A team of researchers from the University of Waterloo have concluded the obvious: all those old wells are conduits to pollution into aquifers and methane into the atmosphere. Everyone in the industry knows this, they just don’t tell the PR department, the lobbyists or the public.

Canada’s 500,000 Leaky Energy Wells: ‘Threat to Public (Planet)’

Badly sealed oil and gas wellbores leak emissions  that are barely monitored, experts find.
By Andrew Nikiforuk
A new University of Waterloo report warns that natural gas seeping from 500,000 wellbores represent “a threat to environment and public safety” due to groundwater contamination, greenhouse gas emissions and explosion risks wherever methane collects in unvented buildings and spaces.
The 69-page report on wellbore leakage cowritten by three expert UofW professors outlines a longstanding and largely invisible engineering problem for Canada’s oil and gas industry.
It also calls for dramatic reforms in monitoring and regulation including greater engineering oversight of the cementing of wellbores and “doing it right in the first place.”
The scale of the problem? Ten per cent of all active and suspended gas wells in British Columbia now leak methane.
In addition, some hydraulically fractured shale gas wells in that province have become super methane emitters that spew as much as 2,000 kilograms of methane a year.
That amount of methane would make an audible hiss at the wellbore or form a big bubble in a swamp, says report lead author Maurice Dusseault, one of nation’s top petroleum engineers.
An average wellbore may leak about 100 kilograms of methane a year, or the same as cow, but little data has been collected or accurately verified.
In Saskatchewan, about 20 per cent of all energy wells leak. In Alberta, regulators report chronic seepage from 27,000 wells.
Twenty years ago, the heavy oil fields of Lloydminster reported a leakage rate as high as 46 per cent. A 2010 industry study noted that the failure rate for steam injection wells for bitumen production approached 30 per cent...Read More