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New technology clears
blocked boreholes in less than 2 hours, so that it becomes unnecessary to drill
new wells or treat old ones with chemicals or explosives
·
Following treatment
with AirBurst® the specific
capacity is significantly increased
·
Licenses to use the
technology are available world-wide
Background
More
than 3 billion people die every year from avoidable water related diseases, and
with the World’s population growing at 200,000 every day the pressure on water,
as a finite resource, is growing rapidly. Consequently, a heavy responsibility
lies with those responsible for the management of this precious resource.
Groundwater is the primary source of water for drinking and irrigation. Its
reliable supply, uniform quality, minimal evaporation losses, and low cost of
development are attributes making groundwater more attractive when compared to
other sources. However, the World Bank warns: ‘population and economic growth
have led to ever more demands on the world's groundwater resources and in many
countries there are already significant impacts due to inadequately-regulated
groundwater pumping and/or from pollution due to inadequate management’
Groundwater – the problem
The
deposition of silt, minerals and bacteria gradually blocks both screened and
unscreened wells. This results in lower production (specific capacity) and
increased pumping costs due to wasted energy and maintenance costs. As a
result, water authorities have to either rehabilitate the well or drill
replacements.
The drilling of new wells simply exacerbates the problems outlined above by the
World Bank, whereas rehabilitation enables managers to grasp a clearer
understanding of the groundwater status so that its management can be more
effective. For example, lowering well
production may not be a result of well blockage – it may be an indication of a
lowering water table with potentially serious results.
Rehabilitation
History
A variety of methods have existed for many years to help rejuvenate a well. The
success of these methods has been variable and the time taken to implement them
is frequently extensive with very variable results. For example, a rotating brush, a string of explosive charges, or
high pressure jets may be utilised
inside the well. Alternatively, chemicals can be used to react with
encrustation. However, this method involves an element of environmental risk
and renders the well unusable for a period of time.
New
Technology
The new technique (AirBurst®) uses air as the “explosive” in the form of an exploding
bubble repeatedly fired along the well screen or producing area.
The
AirBurst® tool
configuration and operation are tailored to the well dimensions and
construction, by controlling pressures up to 3000 psi and tool size allows
energy equivalents of a few grams of dynamite to over half a kilo!
The tool action releases an expanding air bubble of 1 meter or more in less than a millisecond. This action extends
beyond the well diameter, and ensures that the gravel pack is treated as well
as the borehole liner. The bubble then contracts, implodes, and as a result
silt is drawn into the body of the well.
Typically,
a well would be video-surveyed before treatment, and the tool would be ‘fired’
regularly within the screen or producing area, at intervals of 4 to 10 seconds.
The whole operation usually takes around 1-2 hours.
Initially developed in the US, AirBurst® is now available worldwide through Cirrus International and Frazier Industries. Patents have been granted in the EU, Australia and USA and other worldwide Patents are currently under application.
Abu Dhabi Trials
High temperatures and low annual rainfall in Middle East countries make water
management a vitally important issue, and the UAE is no exception. The Emirate of Abu Dhabi employs some 70,000
wells and Cirrus’ local partner, Specialised Technical Services Est (STS) was
invited to test the AirBurst® technology by Abu Dhabi Municipality on some of its
“problem” wells. Other techniques had previously been utilised with little or
no success. However, AirBurst® improved the specific
capacity of these wells considerably - Craig Somerville from Cirrus
International who oversaw the Abu Dhabi trial, commented that “ the results
were tremendous; much better than we had hoped for. To make such a difference
from zero flow to almost full operation was very rewarding. This came as a
considerable surprise to the Municipality staff who had observed the other remediation
techniques fail. The success of the
initial work has prompted further trials with similar results - even on one
well that had been abandoned as unproductive!”
The Benefits
·
Boreholes can be back
in service within 2 hours
·
Once the well is
clear, valuable information can be gleaned on the local hydrology
·
AirBurst® has a variable, controllable output so that treatment can
be matched to precisely meet the needs of the borehole.
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AirBurst® treats the gravel and surrounding rock in addition to the
borehole itself
·
Specific capacity is
increased in nearly every case
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AirBurst® can be used to settle the gravel pack in new drills
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AirBurst® can be used to remove drilling mud from the screen and
gravel pack
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When used in
conjunction with chemical treatment, AirBurst® can ensure that treatment extends into the gravel pack.
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Explosive and
compressive action ensures that scale, silt and bacteria are removed
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No damage to well
casing
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No chemicals
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It is often not
necessary to remove the pump, which saves time and effort
Anyone responsible for the management of groundwater
resources will be interested in the AirBurst® method, and licenses are available to water authorities,
land owners and drilling organisations for the AirBurst® technology from Craig Somerville at Cirrus International,
Email csomerv@cirrusuk.com Tel. +44
(0) 1242 604 895.
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