|Packers » Zone Flow Tester (ZFT™)
|Baski Inc. has developed the Zone Flow Tester
(ZFT™) for the area of permeability testing.
In this type of testing, straddle packers
seal off the zone of interest and fluids are injected or withdrawn, while pressure/flow data are recorded.
Click on the image below to see the construction of a ZFT™.
Conceptually, the ZFT is a straddle packer arrangement with a specialized valve instead of a slotted
pipe between the packers. The ZFT accommodates three transducers that sense
pressure 1) below the packer, 2) in the zone between the packers, and 3) above the
zone. It also incorporates a pump shroud to house a
sample or submersible pump for taking samples or performing pumping tests.
Uphole equipment that supports the ZFT™ includes a riser pipe, transducer,
pump cable/tubes, datalogger, flow delivery panel for injection, and discharge flow meter for pumping tests. Of course, there are also
generators, inflation gas supplies, and other support equipment.
A summary of the
major equipment associated with the ZFT is listed below: including
information about packer equipment,
borehole equipment and surface equipment.
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Isolate the zone of interest by straddling it with two packers, which
are either the Baski medium-duty,
sliding-end packers or the ReFlexTM fixed-end
packers (unconfined burst rating of 500 psi).
This pressure rating is needed at the depths encountered in normal projects to
reduce the chance of failure by extrusion or blowout.
Access Port Valve
Controls the testing fluids for injection, slug and pumping tests. The Access Port Valve
(APVTM) is a pneumatically operated valve that has
pipe fittings at both ends, and
replaces the standard slotted pipe used between straddle packers. It is
excellent for pressure build-up data without casing storage effects, and a
series of APV's allows multi-level investigations.
the transducer transfer tube into the
bottom zone and protects the porous tube end of the bottom transfer tube.
leads into and out of the
main drop piping. The In-Line Adapter (ILATM) is normally constructed
of aluminum, but stainless steel is available.
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Centers the packer string in the hole and is installed at 20-foot intervals.
Pumps water from the zone of interest and can be an electric submersible or pneumatically operated bladder or
piston pump. Generally, the choice of a pump has no cost significance
on the shroud..
the pump from the fluid that surrounds the
shroud, allowing the pumped fluids to enter from the bottom of the shroud and
flow past the motor (thus cooling the motor). The pump shroud also seals transducer leads
& pneumatic tubing through the shroud and is the strength member that
supports the packers.
Porous Tube End
Allows the transfer tube to be filled
with water, and keeps the water from draining during the short trip to the
borehole static water level. It results in a more
accurate reading of formation pressures without the "offset" occurring
in air-filled transfer tubes. The use of transfer tubes also allows the transducers to be located near the top of the
packer string, avoiding the lacing of transducer cables through the
Protects the transducers on their
trip downhole. Typically, the carrier allows the leads to run outside the
drop pipe, so that the transducer is adjacent to
the drop pipe, eliminating the lacing of long lengths of transducer cable
through fittings into sealed chambers and through packers.
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Secures the transducer cables,
inflation tubing, and APV tubing (collectively called leads) to the
Connect all of the necessary equipment and can be provided in National Pipe
Taper (NPT), American Petroleum Institute (API), and British Standard Taper (BST)
thread patterns. They also include inflation equipment that consists mainly of brass tubing
and stainless steel connectors.
Inflation and APV Lines
Connect the packer string to the necessary gas or liquid sources. Inflation tubing and
APV actuation tubing
is 3/16" O.D. or
1/4" O.D. nylon tubing with a burst rating to 2,500 psi (170 bar). The typical working
pressure of 625 psi (43 bar) provides a 4:1 safety factor. Baski
Inc. stocks 5,000 ft.
reels of the nylon tubing, as well as 5,000 ft. lengths of 1/4" O.D. stainless steel
tubing [316L, 0.035" wall thickness, tested to 10,000 psi
(690 bar)]. Hydraulic hose rated from 3,000 psi (206 bar) to
10,000 psi (690 bar) working pressures is also available.
Regulates the nitrogen pressure for inflating packers. The manifold includes
a nitrogen regulator (for connection to N2 bottles) connected to a
pressure gauge (1/2%) and delivers pressures up to 2000 psi.
Rotameter Panel for Injection Testing
Allows water flow deliveries of 0.2 ml/min to 8 l/min with a maximum
pressure of 100 psi. Up to five rotameters and valving are mounted onto stainless steel
panels to provide the range of flows. A water supply is necessary that is typically a 100 to 1,000 gallon water tank with pressure
relief, valving for fill, delivery, and drain, and 20 feet of hose to the
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