Study calls for “robust monitoring” of redundant wells for methane leaks

New research into fugitive methane emissions has called for better monitoring of decommissioned onshore oil and gas wells.

Exhibit from the Methane Moment pavilion at COP26. Photo: DrillOrDrop

A study by Heriot-Watt university of six abandoned wells in the east midlands concluded that none were leaking.

But it said the wells could leak in the future and more research was needed into how decommissioned boreholes behaved to avoid the climate impact of methane leaks.

Methane is a powerful greenhouse gas and contributor to climate change. Its global warming potential is 86 times higher than carbon dioxide over 20 years.

Cutting methane leaks at oil and gas sites could be critical to achieving net zero carbon emissions.

The issue of well integrity failure resulting in fugitive gas release could also be very important if decommissioned wells were used in future as storage sites for carbon.

Most regulations do not require ongoing monitoring of decommissioned wells or specify how long seals should last.

The Heriot-Watt study, published today in the International Journal of Greenhouse Gas Control, concluded:

“These findings highlight the importance of standardisation, and the need to develop and implement fit-for-purpose and robust monitoring and detection strategies for assessing DW [decommissioned wells] integrity and fugitive gas migration in the field.”

One of the study’s authors, Dr Aaran Cahill, said:

“Decommissioned wells will be below our landscape for centuries to come. They might not be leaking now, but they could in future. In the USA and Canada, some wells have been found to be leaking.

“We need a standardised method of checking these wells for methane leaks and a plan for stewardship of this legacy infrastructure from our net positive past.

“Methane is a powerful greenhouse gas and there are more than six million oil and gas wells worldwide. We need to understand what happens to them in the long term, including how many might leak, how much and why. At the minute we simply don’t know and will need to figure this out if we are to reach net zero.”

Well findings

The Heriot-Watt study found methane concentrations and fluxes (flows per km2) at the sample wells were all within natural baseline range.

The six wells were all in the area around the Nottinghamshire-Leicestershire-Lincolnshire border.

They ranged in age from 16-77 years. Four were picked because they had previously been reported with higher than expected methane levels.

Researchers took sediment samples from all six sites and soil gas samples from two (Old Hills and Long Clawson).

Boreholes of 1-2m were monitored for methane flux at four sites. Of these, the length of monitoring was 24 hours at Old Hills, 7 hours at Long Clawson and 10 minutes each at Plungar and Bottesford. The short monitoring period was because of security concerns, the study said.

The wells were all in clay soils, which would severely limit, if not totally inhibit, any gas migration, the researchers concluded.

The findings were in contrast to a 2016 study by the Research into Fracking in Europe consortium.

This found that 31 of 102 UK decommissioned wells had enhanced methane levels, indicating well integrity failures.

The Heriot-Watt study suggested the differences between the two sets of findings may be because methane emissions vary in time and place. It was also possible, it said, to get false positives because of land use or limitations of research methods.

The low permeability clay soils surrounding wells in the Heriot-Watt study were described as “very challenging to detect integrity failure using relatively shallow or minimally intrusive methods”.

It study concluded:

“further research should view cautiously any inference on DW integrity in England from measurements taken to date, because surficial sediments in which DW are embedded may dictate that the methods employed are inadequate to accurately detect or quantify signs of leakage.

“the true integrity status of DWs [decommissioned wells] in England and elsewhere around the world remains poorly constrained and more work is needed in the coming years, as the repercussions of well integrity failure and fugitive CH4 [methane] are still unknown.”

11 replies »

  1. Or you could conclude that the wells are not leaking, integrity is sound, no need to worry going forward. Focus research on something useful…..

  2. Or, you could conclude that UK wish to follow high standards-so, whilst UK is using oil and gas much better to have it produced to such high standards. Bit like the old argument about US chlorinated chicken, which the media totally confused, but the message they tried to tap into was UK consumers like high standards, and having something produced over the horizon where the standards were not so high was bad for them and the environment.
    Another point the antis have to deny, but so what? It is the reality and reality is now upon “us”.

  3. Yes, I am, Jack.

    There are extensive gas leaks off the coast of UK where there are no wells, and never have been. Shock/horror.

    But, if you want to look at different standards then try Nigeria and Venezuela

  4. No, the headline was about on shore, Jack!

    Studied 6 wells on shore UK-none were leaking.

    So, based upon the actual headline it looks as if UK on shore is the way to go. Paul put the point another way, so no excuse for missing it.

    (There can’t be much of your feet left, Jack. Helpful hint: In the UK there is a saying about “shooting yourself in the foot” that refers to someone who is not capable of handling a firearm. Now seen regularly on anti social media.)

    Frack on, would seem to be your direction of travel.

    • Noooooo MARTIN,

      In your above statement, y ou said , quote, ” UK wish to follow high standards-so, whilst UK is using oil and gas much better to have it produced to such high standards. ”

      You talk of high UK standards in the UK Oil and Gas industry..

      When in fact the ” standards ” are far from high.

      Would you trust some of these smaller two bit oil/gas companies to safely extract shale gas in your area ????????? NOOOOOO , I think not .

      I understand the need for energy , but not at any cost ….

      Oil and Gas companies have a golden opportunity to use their financial might to invest in green energy production .. Some of the larger players are doing so , they are the energy companies I support.

  5. Good for you Jack, but don’t assume you know what I would support.

    An energy source under my feet, developed by someone at their cost, supplying me energy at a discounted price, washing up jobs at $60k/year, money supplied to the local community for community projects, and increased sexual activity! Sounds pretty attractive to me. Goodness, I could see the estate agents having to beat away prospective property buyers.

    So, Ineos ARE investing in green energy, yet you do not support them. So are many of the oil and gas companies that are also fracking in the USA, yet you don’t support them either.

    The only consistency is your inconsistency, and contradictions. Good job Heriot-Watt are there to show the reality. Good job there weren’t any rice paddies for them to research.

    • MARTIN ,

      The ” experts ” are clear with what they are saying.

      Fracking is a toxic, dangerous to human and animal health, environmentally damaging, climate changing process, that blights local communities and devalues house prices…

      Unless you MARTIN are a computer BOT , I would “ASSUME ” that you don’t want to be exposed to any of the above …

      OR do you ??????????

      Oh yes MARTIN , all these high paying Fracking jobs … YES I remember, Toilet cleaners were flying to work in chartered private jets , HAHA.

      Caudrillas big Fracking site in Lancashire , when fully operational was going to employ ( drum roll please )

      11 , yes 11 full time staff and how many of the 11 would of been , minimum rates of pay security staff ?????????

      For the odd one or two at the site drawing a reasonable rate of pay , how many of them would of been British ?????????

      I wonder how many UK Oil/Gas engineers would have the right skills needed to conduct this type of process .

    • MARTIN ,

      Who said I don’t support INEOS in their Green Projects ??????

      BUT on the other hand , I won’t support them on Fracking the Hell out of the UK.

      I hope public opinion would help guide/sway Jim Ratcliffe in a more Green direction.

  6. What do you think pays for INEOS in their Green Projects, Jack?????????????

    It is their involvement with petrochemicals! You know, the involvement that is protested about, and reported on DoD. Yet they are the building blocks for modern society including helping people like yourself relieve your pent up emotions.

    I believe public opinion is a bit more informed in UK than you accept, Jack.

    By the way Jack, I am exposed to all sorts of things in all sorts of parts of the UK. If I live near a row of pylons that could be a problem, many do in UK. If I live near a nuclear power station, or Sellafield, that could be a problem. If I had loads of money and the right connections I could apply to live in New Zealand and risk their seismic activities, that they live with every day of every year. As do the inhabitants of UK, but less so. Currently, those living near a major UK base for the armed forces could have a problem. I have to cut a hedge later today with a hedge trimmer powered by electricity. If I do it incorrectly-shock/horror and end of Martin!

    The human race is not living in a vacuum Jack. They take risks every day. Goodness, today I may even cross the road. The decision always is, why does one want to cross the road? (Hopefully not to avoid someone glued to the pavement.) Maybe to get to a $60k/year job having dropped out of high school and help provide energy for those living across the other side of the “pond” who would be in a dire situation without?

    At this very moment my son is making me a bacon sandwich. The risks involved with the production of the bread, the bacon and the control of the gas to fry it, are too many to contemplate, and of course the process must then be described as a giant Ponzi scheme. However, my bacon sandwich will be worth all those risks Jack.

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