|There is a lot of confusion regarding the terms Shale Gas and Coal Bed Methane, along with an array of other terms.
Here, I attempt to clear up some of the confusion regarding the terms and associated issues.
Shale Gas is defined as a natural gas produced from shale. Shale has low permeability, so gas production in commercial quantities requires fractures to provide permeability. Shale gas has been produced for years from shales with natural fractures; the shale gas boom seen in the USA in recent years has been due to new technology in hydraulic fracturing (especially directional drilling and frack fluids) to create extensive artificial fractures around well bores. It is sometimes referred to as tight gas. Shale is by far the most common rock associated with tight gas, but others include certain sandstones.
Tight gasis natural gas held in rocks with pores up to 20,000 times narrower than a human hair, such that the gas will not flow freely into a well without fracturing.
Coal Bed Methane (CBM), also sometimes known as sweet gas, coalbed gas, or coal mine methane (CMM), is a form of natural gas extracted from coal beds. To extract the gas, a steel-encased hole is drilled into the coal seam (100 to1500 meters below ground). Often, pressure within the coal seams brings water and gas to the surface readily enough. As the pressure within the coal seam declines, due to natural production or the pumping of water from the coalbed, stimulation by hydraulic fracturing is used . Unlike shale, coal is frequently very porous and permeable, and therefore often has a high water content. It generally needs to be de-watered before any gas can be extracted and collected. The ‘produced water’ is either re-injected into isolated formations, released into streams, used for irrigation, or sent to evaporation ponds. It is often contaminated with all manner of dissolved ingredients from the coal beds and associated rocks.
All the above types of gas extraction fall under the category of Unconventional Gas. One way of defining unconventional gas is that can only be produced economically by using hydraulic fracturing, horizontal drilling, or other techniques to expose more of the reservoir to a borehole in order to gain access to the gas.
HYDRAULIC FRACTURING (FRACKING)
I hope this is helpful.
If you want to know anything else, please ask via the reply facility (Leave a Comment) or the Facebook page. If I don’t know, I will do my best to find out.
|I can report that, as anticipated, Pippa Bartolotti has been elected as Wales Green Party’s new leader. Pippa is known by her local community as a hard-working campaigner against the Newport Incinerator and a member of the flotilla offering aid to Gaza.
“I am proud and indeed humbled to be leading Wales Green Party at a time when our message of solving economic and environmental challenges together is desperately needed. Our membership has nearly doubled in the last 2 years, and our voice is getting stronger. The people of Wales deserve to be represented by a party which is prepared to stand strong in action and principle, and present sturdy policies to bring Wales successfully through the difficult years to come.””All over this country we face threats from an unrepentant banking sector which the rest of us have been forced to pay for, and a Government refusing to protect our health and our future by safeguarding the environment. The Green Party will push for policies which create decent jobs and tangible stability. Our strength is in our unwavering commitment to a philosophy which has been proved right time and again. I will work hard to forward our Green agenda for small businesses, for green jobs, for clean industries, better health and a more stable economy.”
“I would like to thank all the members of the Green Party who have voted for me, and thank them for their honesty and commitment which has become the hallmark of a party I am proud to serve.”
Bridgend members will have the chance to meet Pippa at an event Keith is hosting in Swansea, early in the New Year. Details soon.
|Firstly, DECC blog, published today asks the right questions – so let us hope ministers read it and act on it:
Secondly, our fight against the frackers get acknowledged in the BBC Wales Review of the Year:
(although I am not happy that they chose to highlight a misleading quote from Gerwyn Williams!)
|The moral bankruptcy of the the Coalition Government is laid bare by this analysis of the forthcoming
tax changes. The Government’s flagship policy of raising income-tax thresholds has been trumpeted
by the Liberal Democrats as their main achievement since the Coalition was formed last year and
a major boost for the low-paid. But they are now shown to be either utterly inept at checking over the
small print produced by their Tory partners, or aware that it is no more than yet another ‘con’ trick to
rob the poor to give to the rich.
To quote the Resolution Foundation’s findings:
regressive in the lower half of the distribution… Not only is the change huge overall; it is not widely
understood or known about being made up of a number of small changes to both the child tax
credit and working tax credits.” The study concluded: “Low to middle-income households receive
56 per cent of all tax credits in cash terms and so will be hit disproportionately.”
Although 1.1 million people will be taken out of tax by April, the analysis concluded that family incomes
have dropped “dramatically” since the Coalition was formed when inflation and earnings are taken into
account. A couple with two children and an income of £40,000 a year will see it fall by 8.9 per cent between
2010-11 and 2012-13, and by 14.5 per cent by 2013-14. “The scale of that obviously puts in context the
very small impact of the personal-allowance increase,” said the think tank. It defines low to middle earners
as having incomes ranging from £12,000 for a couple with no children to £42,500 a year for a couple with
Full Independent article here: http://www.independent.co.uk/news/uk/politics/britains-poorest-hit-by-25bn-stealth-tax-6281832.html?fb_action_ids=782901269654&fb_action_types=news.reads&fb_source=other_multiline#access_token=AAADWQ6323IoBAP66jCpcCoEZCMaJT2ZBsaWYD4lGGVoGzkTO4h5m2BpQL6myscsxiojWclJ0FCZBpLmHsmFX42RzYlOxSHuXGC3qxt1ZAoRgzefF3cul&expires_in=6876
We have to get our Citizen’s Income proposals out there so people can see that there is a genuine, honest
|From: Andy & Natalie ChybaDate: 26/12/2011 21:06:40
To: GreenParty Blog Post
Subject:SOME SIMPLE NEW YEAR’S RESOLUTIONS THAT WILL MAKE THE WORLD A BETTER PLACE TO LIVE IN
A HAPPY NEW YEAR TO ALL OUR SUPPORTERS
|I have been making most of these points about the problems of well case integrity from the outset of the campaign based on my own knowledge of first principles and the evidence of experts like Prof Tony Ingraffea. Here we have Karlis Muehlenbachs, a geochemist and a leading authority on identifying the unique carbon fingerprint or isotopes of shale and conventional gases, at the University of Alberta, expanding on these points based his own research and U.S. Federal studies:
The findings, which clearly contradict industry assurances, didn’t surprise Muehlenbachs, who has studied leaking wells in Alberta’s heavy oil fields for decades.
“The shale gas boom combined with hydraulic fracking will cause wellbores to leak more often than run-of-the-mill conventional wells,” says Muehlenbachs. “The problem is going to get worse, not better.”
Muehlenbachs, who has been fingerprinting leaking gases since 1994, says that hydraulic fracking, which as we know, injects water, chemicals and sand into rock formations at high pressures, may create more leaks in wellbores overtime. (As industry searches for deeper and more extreme hydrocarbons, it must blast open tight rocks with more brute force over larger land bases than conventional operations.)
According to Schlumberger, the world’s largest oilfield company, there are problems galore. In 2003, the company reported that 43 per cent of 6,692 offshore wells tested in the Gulf of Mexico by U.S. Regulators were found to be leaking. In fact, by the time a well gets 15 years old, there is a 50/50 probability it will leak significantly and therefore contaminate other zones, wells, or groundwater.
“That’s amazing. It’s not Greenpeace reporting this but Schlumberger in the Oilfield Review,” says Muehlenbachs. (Reliable data on well integrity – see below – is hard to find, but a University of Calgary study found that in Alberta approximately five per cent of all wells leak, while leakage rates in Norway range from 13 to 19 per cent from producing wells.)
The University of Calgary study on ‘Well Design and Well Integrity’ can be found here: http://www.ucalgary.ca/wasp/Well%20Integrity%20Analysis.pdf
Muehlenbachs also recognises the industry’s propensity to tell blatant lies.
Although petroleum engineers now admit that companies routinely blast fluids and gas into other industry wells hundreds of metres away (B.C., Texas and North Dakota have all documented such cases), they still claim that “fracture communication incidents” can’t happen with groundwater.
Muehlenbachs, who has documented numerous cases of groundwater contamination, calls such denials dishonest. “Such claims do more harm than good to industry. Don’t they realize that social license matters to industry?”
Whenever methane leaks from one well into a neighboring wellsite, “industry says let’s fix the leaks,” says Muehlenbachs. “But as soon as the leaks enter groundwater, everyone abandons the same logic and technology and says it can’t happen and the denials come out. In Alberta, it’s almost a religious belief that gas leaks can’t contaminate groundwater.”
Yet it happens routinely. At a conference in Washington D.C. last month sponsored by ‘Resources for the Future’, Muehlenbachs showed evidence that shale gas drilling activity in Quebec and Pennsylvania had in several cases resulted in surface contamination.
The debate about whether leaking shale methane comes from heavily fracked zones creating faults into groundwater or along poorly cemented wellbores is immaterial to landowners, says Muehlenbachs. “You don’t care if it comes from fracking or a bad cement job, you suffer the consequences all the same, and lose your well water.”
Given these findings and a Duke University study that found extensive methane contamination of domestic water wells in a heavily fracked area, Muehlenbachs recommends that regulators do rigorous gas and water testing. In addition to baseline isotope testing of methane for all water wells and groundwater sources, Muehlenbachs says regulators must also test for ethane and propane (the shale gas fingerprint) as well as gas from abandoned wells and natural seeps and gases from well casings.
This is certainly is not part of our Environment Agencies regime of testing at present.
FOOTNOTE – Courtesy of Will Cottrell:
For the record, the audio for the event you mention is at http://video.rff.org:8000/~rff/111411.mp3, while Muehlenbachs’ slides are here – http://www.rff.org/Documents/Events/Seminars/111114_Managing_the_Risks_of_Shale_Gas/Muehlenbachs%20Nov%2014%20FINAL.pdf
|This is a brilliant presentation of what, I trust, we all know to be true. Share it far and wide, especially with anyone you suspect has not got the message yet.|