Shale Gas: The Meeting.
At the end of this article we give details of a meeting no-one with an interest in shale gas will want to
But first, we present a very technical update, and for which we are grateful to a reader wheo seems to us to have some experience of the process.
Back in Shale Gas Update, we noted that public opinion was hardening against the drilling exploration, and we outlined the final results of the FBC Task and Finish Group as they reported their
findings to their parent Scrutiny Committee.
We also expressed our own - growing - concern about the volume of liquid involved and how that
might be 'cleaned' for subsequent re-use, and how it's transport might be a bigger problem than had at first been thought.
After publication we were contacted by a reader who clearly had some significant knowledge of this process - and we have included most of their views in this article with our gratitude.
The reader thought our calculations regarding volume were probably
"overly scary" but was complimentary about our spotting the potential for fast-track development scenarios when the FBC report had missed this aspect.
With regard to the fluids issue, our reader prefaced their own comments by saying they had "used UK gallons and m3 throughout, whilst most oil-field figures use US Barrels and US gallons:-"
And with that caveat, they continued....
"Cuadrilla's figures estimate 12,000m3/frac = 2.6 million (UK) gallons.
However I believe this is to be for one frac only and I would estimate that in a 1,000m horizontal drain (typical development well) that up to 10 fracs could easily be required thus a total of some 120,000m3 = 26 million (UK) gallons would be pumped.
However not more than 30% (say 40,000 m3 = 9 million gallons) will be initially produced back during initial well clean up, say over 60 days. The remainder will be produced over life of the well + 20 years. Therefore I would estimate flow back water
production during well clean up/production test would be circa 40,000m3 = 9 million gallons divided by 60 days = 660m3 = 145,000 gallons/day to be handled on-site.
These are probably worst case figures as one would expect that some flow back would occur/be-allowed after each frac, this flow back would be retained/re-used for inclusion with next frac operation.
Due to constituency of flow back water open pit storage would not be allowed, thus all flow-back fluid and water taken from the test separator during well clean up/production testing would have to be routed to on-site storage/buffer tanks and to
accommodate such volumes one would estimate a requirement of circa 1,000m3 for contingency = 10 x 100m3 = 1,000m3 = 220,000 gallon vertical storage tanks (Vertical Tank 12'8" dia x 28'7" height = 100m3 =22,000gal).
Transport from site to waste water disposal facility could peak at 660m3/day over the initial 60 days, thus with the on-site buffer tank storage and using 30m3 transport tankers could require circa 20 tanker loads/day. Note as I already said I
estimate these would be absolute maximum figures."
They continued "I don't have much idea about waste water disposal routes, however I don't believe it can be diluted and then re-used for other water usage and
certainly not from the site, so my thoughts on dilution would be to dump at sea if permission/approval could be gained. In the longer term of full scale development the concept of a central fluids handling and piped to site storage facility might
prove to be economic along with the provision of a dedicated water disposal well, which would inject the water into deeper horizons. I understand that the flow back water from the initial well fraccng is still stored on the drill site as Cuadrilla
have not yet been able to establish a licenced waste disposal facility that can handle this fluid. So in my humble opinion this is the main issue to date.
One other issue you should bear in mind is the disposal of drilling fluids, up to now on their vertical well Cuadrilla have used a simple Bentonite based drilling mud and apparently have recognised disposal routes for this application, however as and
when they drill horizontal wells, particularly in Shales, they may well require a much more complex mud formula to prevent hole problems, enlargements/washouts/stuck-pipe etc., etc. Avoidance of these is critical in the desire to drill an in-gauge
hole and provide the very best chance for a good cement job and thus ensure well-bore integrity.
Most operators would prefer to use Oil Base Muds but these are a nightmare from an environmental perspective, therefore complex synthetic fluids are used, these fluids will also require dedicated and specialised waste disposal routes and/or the more
desirable option of setting up a dedicated off-site fluids facility for storage and re-use of the drilling fluid."
Turning to the wider issues away from fluids, our reader was also mostly complimentary about the Mike Hill report for FBC, and believed the central plank of the Task and Finish Group's Report conclusion (the possible Gas Tsar), demonstrated a lack of understanding as to how
the UK Oil & Gas Industry is managed and regulated.
In contrast, they said the HSE response to the points raised was factually correct and quite implicitly made the point that HSE approach is of a goal setting rather than a prescriptive approach, thus
the onus is on the Operator to demonstrate compliance and prior approval of all steps in the Well Construction process based upon a lifecycle well integrity approach.
Those of us less well-informed in such matters find this approach less credible (or at least less creditable), but it appears to be the model in use by HSE elsewhere.
Our correspondent also believed that Cuadrilla are a fledgling small operator, and they would need to do a lot more work to demonstrate that they have in place a fully compliant HSE Management System and controlled Well Construction Documentation.
In another section our correspondent writes "Within the report there is much talk about well integrity issues without actually coming to grips with the main problems and reading the report one might conclude that running some Cement Bond Logs will
solve/identify the problem. Oh one wishes it was so simple, this is an evaluation tool who’s interpretation is a very grey area, it generally identifies no cement, but degrees of effectiveness of bond and channelling, as such
remedial activities such as perforating and squeezing cement are not taken lightly and must be taken in full consideration of overall success, its called a poor boy cement job for obvious reasons. In these scenarios other possibilities of isolation
may well be considered, i.e. open annulus monitoring during squeezing/fraccing and/or use of isolation packers and tie-back strings based on the fact and a competent well design would allow and cater for such eventualities. So far no one has mentioned
typical horizontal development wells and the problems associated with cement placement and well bore integrity are now very much compounded"
Referring to an earlier email to counterbalance they went on to say "remember the previous comments about maintaining an in-gauge hole and the possibilities of requiring exotic drilling fluids in my earlier e-mail. In this context any use of special
drilling fluid would challenge the Cuadrilla response under Item 8 that all other water including drilling mud, will not require a permit under new regulations."
Another point which our correspondent believes was missed was also relating to fluid transport/consumption in that the issue of a central fluids handling/treating facility was not raised.
In summary they thought it was "Overall a fair report and I do concede that it should prompt the regulatory authorities (HSE OSD) to review it against their current legislation and guidelines to confirm that all issues relating to on-shore activities
are covered. "
We're grateful to our knowledgeable reader for sharing their opinion and views both with us, and with our other readers.
Despite the increasing technical complexity needed of us to understand what is proposed, we're also going along to what promises to be potentially one of the best balanced presentations about the shale gas exploration processes so far.
It's on the evening of Wednesday next (25th July) at the United Reformed Church Hall in St Annes, starting at 7:00pm. The meeting is being chaired by our MP Mark Menzies. We understand Cuadrilla and
RAFF (and possibly others with expert knowledge)*
See update at end.
will be available to inform the public. We think this will be a definitive meeting, and is not to be missed so we're going to be there early just in case it gets full. (It's limited to residents of Fylde Borough and the hall has a max capacity of 200).
We hope to bring readers a report after the meeting.
Dated: 22 July 2012
UPDATE 23 July 2012
At the time of writing the above article, we did not have definitive information about who would be on the platform, nor what the format of the meeting would be. As previously expected, Mark Menzies MP will chair the
meeting, but we have now heard the format will not be a series of presentations followed by questions, it will be an introduction by Mr Menzies, then straight into a question and answer session, with members of the public in Fylde having the opportunity to put questions
to the following people who have been invited to share the platform:
A representative from the Department of Energy and Climate Change
A representative from the Health and Safety Executive
A representative from the Environment Agency
A representative from Cuadrilla
A representative from Friends of the Earth
Mike Hill (who produced the technical report for FBC)