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Upstream -- February 17,
2006
WES employs flexible hose
to blast production laterals in US
Water jets send wells
sideways...
A patented water jetting
technology aims to blast horizontal drilling as a
quicker and cost-effective alternative for boosting oil
and gas recovery in new and existing wells, writes
Anthony Guegel.
Production can be increased as much as tenfold
from the use of water jetting, according to Well
Enhancement Services (WES), headquartered in The
Woodlands, Texas.
The company calls the technology Radial Jet
Enhancement (RJE), a method for jetting laterals from
the wellbore into the formation.
The first step is to go in the well with an
elbow or deflector shoe made up to the well tubing
string.
Next, a drillbit powered by a mud motor is
lowered into the wellbore to cut a pilot hole measuring
around one inch in diameter into the casing for the
insertion of the jetting nozzle.
Once the hole is milled, the jetting nozzle
affixed to the end of a high-pressure, flexible rubber
hose is inserted to blast water into the formation at a
pressure ranging anywhere from 3000 psi to a maximum
6000 psi.
Backward facing jets propel the nozzle,
widening the hole as it blasts a lateral out to 300 feet
from the wellbore, a limit due to the length of the
rubber hoses.
Sheathed in Kevlar for extra strength, the
hoses on WES´s coiled tubing units come in lengths of
350 feet.
“Longer laterals have been done with longer
hoses but at some point the frictional forces will
overcome the propulsion forces and you end up
stopping,”says Stephen Bowen, executive vice president
and director of marketing and administration. The
jetting process goes through four gallons a minute and
ultimately consumes around 600 gallons of water or more,
penetrating through most rock types at roughly 50 feet
per minute.
“Generally we ask the operator to budget for
about 300 gallons per lateral, and that´s mostly going
to be consumed by the mud motor to mill out the window.
The actual jetting uses a lot less,”says Bowen.
“We have also jetted with diesel fuel for
highly water-sensitive formations,”he adds.
WES has jetted laterals at a vertical depth of
some 5000 feet, a mechanical limit of its three existing
coiled tubing units.
The technology, however, has been deployed to
9000 feet of total depth outside the US, particularly in
South America and Indonesia.
“We could go deeper. We would just have to
build the equipment,”says Bowen.
A horizontal lateral can be drilled at much
greater distances, but at higher cost and increased time
than RJE, leading to WES´s claims of a cost advantage.
Bowen says Radial Jet Enhancement can jet four
laterals in two days, from rig-up to demobilisation, and
at a total cost of $25,000 to $30,000.
“That is one of the reasons why it is faster
and cheaper than a traditional horizontal drilling
job,”he explains.
“That procedure (horizontal drilling) is a lot
more expensive and takes a lot longer. But, of course,
you can drill 1000 feet in one direction with a
traditional horizontal job.”
Ideal candidates for this application are wells
that have damage near the wellbore or are simply in need
of workover to boost production.
It also does not make a difference whether the
well is an oil or gas producer, says Bowen:“Any well
where you need to improve the conductivity to the
wellbore.”
According to the company, RJE works well in a
variety of lithology types, including limestone,
sandstone and dolomite reservoirs.
WES has worked on about 25 to 30 wells so far
since it introduced its brand of technology last year.
The first well was tested in January 2005 in
the Austin Chalk near Luling, Texas. The company has
trained crews ready to go with its coiled tubing units.
It has not licensed the technology, preferring
instead to enter into joint ventures with potential
users.
“We´d be happy to talk to people, ”Bowen says.
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