Abstrict A hot wire anemometer flow meter device is disclosed which is particularly
adapted to be inserted down hole in a gas or oil well line or casing
to accurately measure fluid flow through the line. The device comprises
an elongate member formed of a plurality of tubing segments or modules
interconnected in an end-to-end axial orientation. The segments
located adjacent opposite ends of the elongate member include a
plurality of arm struts, extensible radially outward to selectively
anchor and axially register the device in a desired location within
the line. Each of the arm struts mount one or more hot wire anemometers
which yield a varying current signal in response to fluid flow across
the same. A temperature gauge, pressure gauge, directional indicator,
phase gauge, and battery source are additionally provided which
enables the current signals obtained from the anemometers to be
calibrated and integrated mathematically to yield accurate flow
measurement results irrespective of laminar or turbulent flow conditions
within the line.
Claims What is claimed is:
1. An improved flow meter device for measuring flow through a conduit
comprising:
an elongate member sized to be received within a flow conduit;
plural struts pivotally mounted to said elongate member extensible
radially outward from said elongate member to contact said flow
conduit and anchor said elongate member at a desired location within
said flow conduit;
means for selectively radially extending and retracting said plural
struts from said elongate member; and
plural anemometers mounted along the length of struts for generating
a variable electrical signal in response to the amount of flow medium
passing across said anemometers.
2. The flow meter device of claim 1 wherein said plural struts
are symmetrically spaced about said elongate member to axially register
said elongate member within said flow conduit when said plural struts
are extended radially to contact said flow conduit.
3. The flow meter device of claim 2 wherein said plural struts
each comprise a pair of spaced generally parallel members pivotally
mounted at one end to said elongate member.
4. The flow meter device of claim 3 wherein said plural anemometers
are mounted to said struts to extend between said pair of spaced
generally parallel member.
5. The flow meter device of claim 4 wherein said extending means
comprises a motor mounted within the interior of said elongate member
and cooperating with linkage means attached to said plural struts.
6. The flow meter device of claim 5 further comprising a temperature
gauge positioned on said elongate member to determine the temperature
of the flow medium adjacent said anemometers.
7. The flow meter device of claim 6 further comprising a pressure
gauge positioned on said elongate member to determine the pressure
of the flow medium adjacent said anemometers.
8. The flow meter device of claim 7 further comprising means mounted
to said elongate member for determining the phase constituents within
the flow medium adjacent said anemometers.
9. The flow meter device of claim 8 wherein said plural struts
are positioned adjacent opposite ends said elongate member.
10. An improved flow meter device for accurately measuring flow
in a conduit extending from ground surface into a mineral resevoir
comprising:
an elongate tubular member sized to be received within and lowered
from ground surface to a desired elevation within said conduit;
plural struts mounted to said elongate tubular member for movement
between a retracted position wherein said struts are maintained
in a plane generally parallel to the axis of said tubular member
and an extended position wherein said struts are maintained in a
plane angularly disposed to the axis of said tubular member to contact
said conduit and anchor said elongate tubular member at said desired
elevation;
means for selectively driving said plural struts between said retracted
and extended positions;
plural hot-wire anemometers means mounted along the length of said
plural struts for generating an electrical signal representing the
amount of flow passing across said anemometer means and through
said conduit;
carried by said elongate tubular member means for measuring the
temperature of flow passing across said anemometer means; and
carried by said elongate tubular member means for measuring the
pressure of flow passing across said anemometer means.
11. The flow meter device of claim 10 wherein said elongate tubular
member is formed of a plurality of individual tubing segments connected
in an end-to-end orientation and said driving means, temperature
measuring means and said pressure measuring means are each housed
in separate ones of said individual tubing segments.
12. A method of accurately determining flow within a conduit comprising
the steps of:
positioning a plurality of hot wire anemometers at discrete radian
sections within said conduit, said anemometers adapted to generate
a variable electric signal in response to the amount of flow passing
across said anemometers;
positioning within said conduit means for detecting the direction
of flow within each of said discrete radian sections;
monitoring the electric signals generated by each of said plural
anemometers and said detecting means to obtain data representing
the flow within each of said discrete radian sections; and
mathematically integrating said data obtained from each of said
discrete radian sections to determine the total flow rate within
said conduit.
13. The method of claim 12 comprising the further step of measuring
the temperature and pressure of flow within at least one of said
discrete radian sections within said conduit.
14. The method of claim 12 further comprising the step of storing
said data representing flow within each of said discrete radian
sections.
Description BACKGROUND OF THE PRESENT INVENTION
The present invention relates to flow measuring devices and, more
particularly, to a hot wire anemometer flow meter adapted to measure
fluid flow within a conduit such as that utilized in downhole gas,
oil well, or geothermal applications.
As is well known in the oil and gas industry, it is usually advantageous
and often necessary to measure the flow in an oil or gas line to
determine or forecast well production. Heretofore, the most common
practice in the industry was to insert a turbine flow meter down
hole which upon rotational movement of the turbine rotor, generated
an electrical signal representing the flow through the well. Although
such prior art turbine flow meters have proven generally effective
in their intended application, they possess inherent deficiencies
which have detracted from their overall effectiveness in the trade.
Foremost of these deficiencies has been the inability of the prior
art turbine flow meter devices to provide accurate flow measurements
in turbulent flow or combination laminar/turbulent flow conditions.
Further, the prior art turbine flow meters have typically yielded
inaccurate measurement results in two phase (i.e. water and soil)
or three phase (i.e. water or oil and gas) flow conditions. In addition,
the operation of the turbine flow meters is dependent upon a generally
vertical or axial orientation within the line which has rendered
their use inappropriate for many of the more modern well applications,
which utilize angularly extending well drilling techniques. Additionally,
the prior art turbine flow meter devices have typically been incapable
of being disposed down hole for extended periods of time to record
long term changes in the flow within the well.
Hence, there exists a substantial need in the art for an improved
down hole measuring device which provides both flow speed and direction
measurements, is accurate in both turbulent and/or laminar flow
conditions, can be utilized in singular, double, or triple phase
flow applications, and is not dependent upon orientation within
the flow line.
SUMMARY OF THE PRESENT INVENTION
The present invention specifically addresses and alleviates the
above-referenced deficiencies associated in the prior art by providing
a hot wire anemometer flow meter device which is particularly adapted
to be inserted down hole in a gas or oil well line to accurately
measure the flow through the line in both laminar and turbulent
flow applications with either single, dual, or triple phase flow
conditions.
More particularly, the present invention comprises an elongate
member formed of a plurality of tubing segments interconnected in
an end-to-end orientation. The tubing segments located adjacent
opposite ends of the elongate member include a plurality of arm
struts which are adapted to pivot or extend radially outward from
the member to selectively anchor the device at a desired location
within the line. Each of the arm struts are provided with a plurality
of hot wire anemometers located at pre-determined positions along
the length of the struts which yield a varying current signal in
relation to the cooling rate of the anemometer in response to flow
across the same. The arm struts are operated by an electric or hydraulic
motor servo-mechanism which selectively extends the struts radially
outward between a fully extended and fully contracted orientation.
As such, the measuring device of the present invention may be lowered
downward into the line, with the arm struts collapsed radially inward
and once positioned at a desired location within the line, the arm
struts may be extended radially outward to maintain the elongate
member at a selected location within the line. Additionally, due
to the anemometers being mounted to the struts at pre-determined
locations, when maintained within the line, the anemometers provide
signal data representing flow conditions at discrete regions or
segments within the line. By monitoring the electric output from
each of the anemometers, the flow within the line may be mathematically
integrated and, thus determined.
The medial tubing segments of the flow meter device of the present
invention house additional measuring instruments such as a temperature
gauge, pressure gauge, and phase monitor which permit the output
signals of the hot wire anemometers to be corrected or adjusted
in response to other flow characteristics to insure accuracy in
flow measurement results. Further, the medial tubing segments may
house a battery source and data storage system which permits the
hot wire anemometer flow meter device of the present invention to
be maintained in a down hole application for extended periods of
time to record and store the long term changes in flow characteristics
within the well.
DESCRIPTION OF THE DRAWINGS
These as well as other features of the present invention will become
more apparent upon reference to the drawings, wherein:
FIG. 1 is a cross-sectional view of a well line or casing extending
through the overburden and into a mineral formation with the hot
wire anemometer flow meter device of the present invention;
FIG. 2 is an enlarged partial cross-sectional view of the well
line of FIG. 1 depicting the modular construction of the hot wire
anemometer flow meter device of the present invention and illustrating
the manner in which the same is anchored within the well line;
FIG. 3 is an enlarged partial perspective view illustrating the
detailed construction of the plural arm struts and servo-mechanism
utilized to extend and retract the arm struts from the hot wire
anemometer flow meter device of the present invention;
FIG. 4 is a plan view of the upper arm struts of the hot wire anemometer
flow meter device of the present invention depicting the position
of the hot wire anemometers mounted thereon; and
FIG. 5 is a plan view of the lower arm struts of the hot wire anemometer
flow meter device of the present invention depicting the position
of the hot wire anemometers mounted thereon.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1 there is shown the hot wire anemometer flow
meter device 10 of the present invention disposed within a flow
conduit casing or line 12. As by way of example only, the line 12
comprises an oil or gas well line or casing which extends through
the overburden 14 and into a mineral formation 16 such as an oil
reservoir, gas reservoir or geothermally active area. However, those
skilled in the art will recognize that the flow meter device 10
of the present invention may additionally be utilized in other flow
measuring applications.
Referring more particularly to FIG. 2 it may be seen that the
flow measuring device 10 of the present invention is preferably
formed as an elongate tubular member composed of a plurality of
tubing segments 20 through 34 which are interconnected as by way
of intermeshing threads or aligned flanges (not shown) in a coaxial
end-to-end orientation. In the preferred embodiment, the flow meter
device 10 is formed having an overall length of approximately six
feet and a maximum outside diameter of approximately one and eleven
sixteenths inch which is suitable for typical small sized oil and
gas line applications. However, the variations in these sizes may
be easily made to accommodate the particular flow measurement application.
The uppermost end of the device 10 is provided with a suitable
end coupling 41 which receives suspension cable or wire 42 extending
upward to ground surface. As will be recognized, the cable 42 may
additionally provide an electrical power source connection for the
measuring device 10 as well as a conduit for relaying electrical
signals obtained from the flow meter device 10 to ground surface.
The lowermost end of the device 10 includes an end cap 44 which
preferably includes a bullnose 46 to prevent damage to the device
10 and/or well line 12 during insertion of the device 10 within
the well line 12.
The coupling 40 and end cap 44 are rigidly mounted to the tubing
segments 20 and 34 respectively, both of which are provided with
a plurality of arms or struts 50 adapted to extend radially outward
from the tubing segments 20 and 34. Referring to FIGS. 3 4 and
5 it will be seen that both the upper and lower tubing segments
20 and 34 respectively preferably include three arm struts 50 which
are symmetrically spaced about the center line of the segments 20
and 34 but rotated 60 degrees with respect to one another such that
the struts 50 of the upper tubing segment 20 do not circumferentially
coincide with the struts 50 of the lower tubing segment 34. Each
of the struts 50 are formed by a pair of spaced parallel elongate
members 52 which are interconnected at opposite ends by a pair of
cross-members 54. The uppermost cross-members 54 are pivotally mounted
to the tubing segments 20 and 34 by suitable pins or bearing 56
and the struts 50 are each sized to be received within a respective
complimentary shaped elongate aperture 60 formed in the tubing segments
20 and 34.
Each of the arm struts 50 includes a linkage 62 which is pivotally
mounted at one end to the medial portion of the arm members 50 and
at the opposite end to a common sleeve or transmission disk 64 disposed
within the interior of the tubing segments 20 and 34. As best shown
in FIG. 3 the sleeve 64 threadingly communicates with a lead screw
66 which is driven by a suitable hydraulic or electrical motor 68
mounted within the interior of the tubing segments 20 and 34.
By such a structure, it will be recognized that rotation of the
motor 68 causes a corresponding rotation of lead screws 66 which
is effective in transporting the sleeves 64 vertically along the
length of the lead screws 66. Due to the interaction of the linkages
62 with the sleeves 64 and each of the struts 50 during this axial
transport of the sleeves 64 the arm struts 50 pivotally extend
radially outward from their fully retracted position (i.e. disposed
within the elongate apertures 60) to a fully extended position (i.e.
indicated by the phantom lines in FIGS. 2 and 3).
A plurality of hot wire anemometers 70 are mounted to each of the
struts 50 and extend in a generally normal direction to the parallel
arm members 52 of the struts 50. Such hot wire anemometers are well
known in the art and generate a varying electrical output signal
in response to the cooling rate of the same caused by fluid flowing
across the anemometers. In the preferred embodiment, two anemometers
70 are mounted on each of the respective arm struts 50; however,
additional anemometers may be mounted thereon at predetermined locational
intervals along the length of the struts 50 to provide suitable
data collection locations. In addition to the plural anemometers
70 the struts 50 each mount a flow direction indicator 71 (shown
in FIG. 3) which in the preferred embodiment, comprises a simple
weather vane-like or paddle wheel-like mechanism adapted to rotate
in either a clockwise, counterclockwise direction, or remain stationary
dependent upon the flow direction across the struts 50. However,
those skilled in the art will recognize that alternative direction
indicators can be utilized for indicating flow direction.
Referring again to FIG. 2 it may be seen that the tubing segments
20 and 34 are rigidly mounted to the tubing segments 22 and 32
respectively, which in the preferred embodiment comprise a battery
source adapted to provide power to the electric or hydraulic motors
68 in the tubing segments 20 and 34. In those instances, however,
where electrical power is supplied through the cable or wire 42
the battery sections 22 and 32 may, of course, be eliminated from
the composite flow meter device 10. The sections 24 26 28 and
30 are disposed between the battery sections 22 and 32 and, hence,
form the medial portion of the flow meter device 10. The tubing
segments 26 and 28 comprise conventional pressure and temperature
gauges respectively, while the tubing segment 30 houses a phase
monitor adapted to determine the proportionate amount of water,
oil and gas within the well line 12. Such phase monitors are well
known in the art and typically comprise the capacitance measuring
device which electrically analyzes a test sample of fluid from the
line 12.
In the preferred embodiment, the tubing segment 24 comprises a
common connecting section wherein the various electrical connections
from the separate tubing segments 20 22 26 28 30 32 and 34
may be facilitated. In addition, the section preferably includes
a suitable microprocessor (not shown) and data storage means (not
shown) which permits the numerical tabulation of and/or storage
of data received from the separate tubing segments 20 through 34.
With the structure defined, the operation of the hot wire anemometer
flow meter device 10 of the present invention may be described.
Initially, the plural struts 50 must be positioned in their fully
retracted position (i.e. wherein they reside within the respective
elongate apertures 60 formed in the tubing segments 20 and 34) and
the entire measuring device 10 may be lowered downward into the
line 12. When lowered to a desired location, the motors 68 mounted
within the interior of the tubing segments 20 and 34 may be activated
causing the plural struts 50 to extend from their retracted position
radially outward to their fully extended position to contact the
line wall 12 as indicated by the phantom lines in FIG. 2. As will
be recognized, in their extended position, the struts 50 anchor
the device 10 in a desired location within the line 12 and additionally
self-axially register the device 10 in a coaxial orientation within
the line 12. In addition, it will be noted that the plural anemometers
70 and direction indicators 71 positioned upon the struts 50 are
disposed at differing radial locations within the casing 12 and,
hence, provide data representing the flow through the line 12 at
predetermined axial spacing from the center line of the flow line
12 as well as in discrete radian sections corresponding to localized
cross-sectional flow regions within the conduit or line 12.
By monitoring the electrical output signal from each of the anemometers
70 and obtaining the flow direction by way of the directional indicators
71 flow data at multiple or discrete radian sections within the
line 12 may be obtained. Further, by knowing the temperature pressure,
and water, gas and oil ratio or percentage of the fluid from the
data received from the pressure gauge 26 temperature gauge 28
and phase monitor 30 the total flow rate within the line 12 may
be numerically calculated by mathematical integration of flow data
obtained in each of the discrete radian sections within the line;
which in the preferred embodiment, is accomplished as by way of
a microprocessor (not shown) disposed within the tubing segment
24. In those instances where flow within the line 12 is desired
to be constantly determined, the various data signals may be communicated
to ground surface via the cable 42 while in those instances where
long term flow characteristics are desired, the data may be stored
within the electronic storage apparatus in the tubing segment 24
for later review.
Thus, in summary, the present invention provides a significant
improvement in the art by providing a flow meter device which yields
accurate data in both laminar and turbulent flow conditions, as
well as in both single, dual and triple phase flow applications.
Although in the preferred embodiment, specific materials and/or
sizes are specified, variations in the same may be readily made
without departing from the spirit of the present invention and such
variations are contemplated herein. |