The Risk Management Tool Box Blog

How Can a Fracked Well Fail?

Graham Marshall - Monday, December 08, 2014

Opponents of the drive to create energy self-sufficiency and energy-security in Britain will often call on the alleged threat to drinking water as a reason not to develop British gas resources through the process known as hydraulic fracture stimulation.

Here is a typical example of the frightening propaganda used by opponents of unconventional gas; in this case from the "Frac-free Ryedale" website: "Our drinking water would become contaminated if one of the wells leaks, as they are likely to do over time. It is estimated that one in four wells will leak within five years, and 50% of all wells will leak within 15 years."

Now before we get too far ahead of ourselves, I'd like the folks at Frac-free Ryedale answer two simple questions:

Firstly, how, does one in four wells leak within five years?

Secondly, how do 50% of all wells leak within 15-years?

You see, the problem I have with these claims, is that they are simply nonsense: let me show you how a gas well is constructed to prevent any risk of failure and you can work it out for yourself.

When the drill-rig drills the hole into the ground - anywhere up to a depth of 9,000 - 12,000 feet below the surface, and a further 9,000 - 12,000 feet "lateral" (horizontal), an outermost "conductor casing" is inserted.  This conductor casing is a steel tube which fits into the drill hole.  Surrounding the conductor casing and filling the space between the steel tube and the wall of the drill hole is a cement liner. So this provides the outermost barrier between the inside of the well-bore and the outside rock.

Inside of the conductor casing, another steel liner is then inserted into the bore-hole - called the "surface casing".  The gap between the surface casing and the conductor casing is then filled with another layer of solid cement.  So this provides a second barrier inside the well-bore to help prevent any hydrocarbons escaping from inside the well; and prevent any contaminants from migrating  from the outside rocks.

If that wasn't enough protection, there is then a third steel liner - the intermediate casing - inserted into the well-bore inside of the surface casing.  The gap between the intermediate casing and the surface casing is, once again, filled with hard-setting cement.

So, that is now three layers of steel tubing, and three layers of solid cement between the outside rocks and the inside well bore.

But we're not done with protecting the aquifers just yet; inside those three steel rings and three cement walls, the well completions folks then insert a penultimate barrier - called the Production Casing. Outside the Production Casing is another layer of cement.  Inside of the Production Casing is a gap (called the annulus) and inside the annulus is the final protective barrier inside the well.  This is the Production Tubing.

The Production Tubing is a steel pipe that allows gas to flow from the bottom of the well all the way to the surface. The gas (or oil) stays inside the Production Tubing at all times.

So, as you can see, it is practically impossible for any hydrocarbons to escape through five layers of steel tubing and four layers of reinforcing cement and contaminate groundwater aquifers.

Put quite simply, the claim that 25% of wells will fail within 5 years and 50% will fail within 15 years is nonsense.

Well done to Santos

Graham Marshall - Friday, March 14, 2014

The Greenies reaction to the news of aquifer contamination - which actually occurred several years ago - at a location recently purchased by Santos in NSW shows how these people try to create a climate of fear around low-risk and low-impact events.

In response to the leak, NSW Labor put out a press release stating that: “The O’Farrell Government’s Memorandum of Understanding with Santos to fast track the approval process for Coal Seam Gas mining in the Pilliga forest should be torn up in light of revelations of contamination of the water aquifer.”

And the Greens exclaimed that this event meant it was "game over for coal seam gas”.

Which is, of course, their ultimate aim to achieve.

Many environmental groups have also leapt on the bandwagon to justify their opposition to Coal Seam Gas (CSG).

But what actually happened - and more importantly - what is the risk?

Several years ago a retaining dam was constructed in the Pilliga Forest, near Narrabri, to hold produced water extracted from wells drilled in the search for CSG.

The dam was not lined properly and it leaked.

The leaking water then entered an aquifer.

According to the NSW EPA, the contaminated aquifer - being inside the Pilliga forest - was not used for livestock, crop irrigation or human consumption.

But the leaking water contained NORM - Naturally-occurring Radioactive Materials - and other naturally-occurring minerals found in bedrock through which the drill-string passed (e.g., lead, arsenic and barium).

Fast forward to a couple of years ago - when Santos purchased the legacy asset from the original owners.

In looking over the asset as part of its due-diligence process (a good way to identify environmental issues so they can be managed properly), Santos themselves discovered the problem with the dam.

You'll recall that the dam was constructed by the prior owner of the operation before Santos acquired it.

Being a good corporate citizen, however, Santos then reported the leaking dam to the EPA.

For whatever legal reason, the NSW EPA fined Santos $1,500 because the dam leak (which occurred prior to Santos' ownership) had contaminated the aquifer.

Maybe fair enough I guess.

But the Greenies jumped on the story and the minor fine to beef-up the talk and transform the issue of NORM into "Uranium" poisoning in drinking water and lead, arsenic, and barium toxicity.

The Greenies know that "Uranium" holds a special place of fear in the human psyche due to its association atomic bombs.

So they'll stoop to any level of fear-mongering in their desperate attempt to convince the Australian population that Santos and the search for CSG is evil.

The reality, in this case, is that a small and relatively low consequence spill, with absolutely low-risk consequence to animal or public health should not be allowed to stand in the way of a billion-dollar industry that creates tens of thousands of jobs for Australians.

And Santos should be congratulated for its environmental practices; firstly discovering the leak, secondly reporting it to the EPA, and finally, in remediating it!

Well done Santos!

Workplace Deaths for 2012 in the UK

Graham Marshall - Friday, October 25, 2013

Recent data released by the UK Health and Safety Executive (UKHSE) show an 11 per cent drop in major injuries in 2012-2013 compared to 2011.

The provisional statistics for 2012-2013 published by the UKHSE show the following results:

•  148 workers fatally injured – down from 171 the previous year.

•  19,707 major injuries such as amputations, fractures and burns, to employees were reported;

•  Workplace injuries and ill-health (excluding work related cancer) cost society an estimated £13. 8 billion.

There has also been little change in the industries in which workers are most likely to be injured by their jobs.

The waste and recycling  sector remains the most dangerous industry with 370 major injuries per 100 000 employees.

Agriculture is also dangerous with 239 major injuries per 100 000 employees.

The construction sector remains in the top three with 156 major injuries per 100 000 employees.

Speaking about the latest figures, Judith Hackitt, the Chairwoman of the UKHSE, said:

“This year’s figures demonstrate that Britain continues to be improve its health and safety performance, with important falls in the number of workers fatally injured and the number of employees suffering major injuries. But we still see too many deaths and injuries occur in the work place many of which could have been prevented through simple safety measures.  Getting this right is the key to ensuring that everyone can make it home safely at the end of their working day.  As the economy grows, new and inexperienced additions to the workforce  can increase in the risk of injuries to workers. We’re committed to helping employers understand that health and safety is about sensibly and proportionately managing risks and ensuring people understand the risks involved not creating unnecessary paperwork.”

North East England Farm Safety Event

Graham Marshall - Tuesday, October 01, 2013

Click here for information and sign-up to a free safety event aimed at farmers in the Northeast of England.



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