Notes from Meeting with UK Methane
On the 18th September 2012 members of Transition Keynsham met with Representatives of UK Methane. Below are notes of what was said at the meeting (without any comment on validity or acceptance of the below).
UK Methane have been granted 4 Petroleum Exploration and Development License (PEDL) by the Department of Energy for exploration in the Bristol and North Somerset area. These were granted in the 13th(14th?) round of licence bids.
Background to UK Methane Ltd
Based in Bridgend, Glamorgan run by Gerwyn Williams who previously worked in the UK coal mining industry before setting up UK Methane Ltd.
UK Methane and associated company Coastal Oil and Gas hold several PEDLs for areas in South Wales and Kent. They have three PEDLs for Bristol and Somerset (PEDL numbers 226,227,228)
In 2008 UK Methane drilled 3 exploration wells in South Wales
In 2011 they drilled a production well at Llangenior. Here they had DEC permission to drill to 600metres and later 1000metres. The well or borehole is 8” diameter steel to be screwed and cemented together. At the surface is a recessed 3 metre deep, 2 metre diameter, hole containing valve gear. There is no external visual impact from the completed well.
UK Methane say that they see the use of CBM as a bridging fuel to alleviate the potential energy shortfall after 2015.
UK Methane’s intention is rapid development of CBM sites to meet this energy shortfall.
UK Methane Plans for Keynsham
The Bristol and Somerset licences are held in a 50:50 partnership with Australian company Eden Energy. The initial introduction between the two companies was arranged by the Welsh Development Agency.
UK Methane have generated computer models of the likely locations of methane bearing coal strata in the Bristol and North Somerset area. There is a lack of historical information on the coal strata in this area. UK Methane have used data from the British Geological Survey and British Coal, but as most historical coal mining in this area took place in the upper coal measures there is little information on the lower coal levels. This is the reason why UK Methane want to drill exploratory boreholes so they can ascertain the amount of methane that may be available lower down. UK Methane think it worth exploring in this area as the coal seams of Somerset are similar to some of those in South Wales. UK Methane consider there is potential for methane in the Ashton Great Coal seams which lie at a depth of about 600-1000 metres in the Keynsham area. South of the licence areas the coal strata is very badly faulted, the implication appeared to be that methane extraction was unlikely as a result of this.
UK Methane stated that they only intend to drill within the coal measures in Keynsham.
A planning application is submitted to the council to do a test bore.
A drilling rig about 12 metres high is used to drill a 12” vertical borehole down which steel lining with a 9” outside diameter is inserted. The lining sections are 8-9 feet long and they are screwed together at the surface before being lowered into the borehole. The surrounding gap between the borehole and lining is filled with cement, the inside diameter of the steel liner is 8”
The materials used during the drilling of the borehole are identical to those used for drilling water boreholes.
Waste extracted during the drilling is put in skips and removed by a licensed waste contractor.
Any water that comes up through the borehole is initially removed off site by tanker and treated until the quality of it is established.
The test borehole is used to obtain samples of coal which are tested for methane content.
UK Methane expected the test borehole to take 2-3 months to complete.
During test boring about 15 people would be directly employed on the site.
UK Methane stated that they would be governed by the Environment Agency on noise levels created during test boring.
If there are insufficient levels of methane to make extraction economic then the borehole is filled with concrete and abandoned.
If methane extraction is considered economic then a second planning application has to be made to permit methane extraction.
A further hole at an angle of about 60 degrees is drilled into the coal, from the bottom of this borehole, holes up to 400 metres along are driven horizontally into the coal measures to collect the methane.
The gas is trapped under pressure in microfractures within the coal, lowering the pressure in the surrounding area allows the gas to flow out. The pressure is lowered by extracting water, though if the coal seam is dry, the gas can still flow out. Gas flow may be encouraged through the injection of nitrogen.
Monitoring of conditions at the wellhead is automated, 24 hour security is provided on site (unclear from notes if this is human or CCTV).
Initial use of the gas would be to produce electricity which would be fed into the national grid. This though is not the most efficient or cost effective use and is done to help UK Methane’s cash flow at the beginning of operations. Their preferred option is feeding into the local gas grid at the nearby gas pumping station owned by Wales and West Utilities. UK Methane will be able to make more money out of feeding methane to the gas grid than from producing electricity from it.
Additional methane producing boreholes would be drilled 2-3 miles apart in areas where methane production was considered economic.
Concerns Raised by TK Members
The risk of water contamination was raised.
UK Methane stated that they did not expect to come across much groundwater though there is water within the Pennant Sandstone. They were not drilling into the limestone aquifers as these are below the coal measures. If they did drill through aquifers further up these would be sealed from the borehole by the cement and steel liner. When extracting gas some water will come from the borehole. Salt water may arise from the borehole this would have to be removed and treated by a waste company before being discharged into a river. Any work involving water must meet the conditions of the groundwater directive issued by the Environment Agency.
Water extracted from the borehole must be tested for impurities, the results are supplied to the British Geological Survey and Environment Agency.
Once the initial borehole drilling is completed water will not be put down the borehole to extract the CBM.
UK Methane were challenged about the practicality of maintaining the integrity of the cement and steel borehole liners both during installation and use. The answer referenced the experiences of the North Sea Oil industry where borehole lining is used but David Sullivan who asked the question and has practical experience of site management was unconvinced that complete borehole integrity could be guaranteed.
Reference was made by Ian Wright to documentation of problems in the Australian CBM industry. UK Methane said that the UK industry was far more tightly regulated than in Australia.
Escape of Methane
The risk of methane escape was raised
CBM exists at very low pressures typically 1-2psi at the wellhead. This is in contrast to conventional gas deposits which are found in domed geological structures at high pressure. In the event of an uncontrolled leak, filling the well with water provides sufficient pressure to stop methane release. Ultimately a well can be sealed with mud and cement. UK Methane said that if the borehole lining were to fracture the ground through which they are drilling is insufficiently permeable to absorb dangerous quantities of methane gas.
UK Methane and its related companies are not involved with fracking at present.
They may at a later date consider extraction of shallow shale gas involving fracking and may use fracking in the Kent coalfield where the conditions are different from those in Somerset.
They do not consider that fracking is necessary in the next 2-3 years to extract CBM around Keynsham but cannot promise that they wouldn’t move onto fracking after this.
They have no intention of using the cavitation method for methane extraction now or in the future, instead relying on horizontal boreholes as mentioned in the production section.
UK Methane do not see themselves as at the cutting edge of technology and would be using fracking methods developed by other companies.
Posted on: September 30, 2012