HIGH PERCENTAGE WATER CONTENT MONITOR

DISPOSITIF POUR LA DETERMINATION DU POURCENTAGE D'EAU DANS UN MELANGE

English Abstract

HIGH PERCENTAGE WATER CONTENT MONITOR
(D#77,089-F)
ABSTRACT OF THE DISCLOSURE
A monitor which is capable of measuring accurately
the water content in percent by volume of an oil and brine
mixture, where the water content is 80% or more, includes a
housing which is adapted to be connected to a pipe through
which the oil and brine mixture is flowing so that the oil
and brine mixture flows through a portion of the housing. A
sensor is mounted within the housing so that the sensor is
suspended in the flowing oil and brine mixture. The sensor
provides a signal corresponding to the percent by volume of
water in the oil and brine mixture, even when percent by
volume of water is 80% or more, in response to an excitation
voltage from a source. Indicating aparatus provides an
indication of the percent by volume of the water in the oil
and brine mixture in accordance with the signal from the
sensor.
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Claims

The embodiments of the invention in which an
exclusive property or privilege is claimed are defined as
follows:
1. An oil-in-brine monitor comprising
housing means connected to a pipe having an
oil and brine mixture flowing through the pipe in a manner
so that the oil and brine mixture flows through a portion of
the housing means;
sensor means mounted within said housing
means in a manner so that the sensor means will be suspended
in the flowing mixture, said sensor means includes water
sensing means for detecting the water content of oil and
brine mixtures having a water content of 80% or more by
volume and providing a sensed water signal representative
thereof, and temperature sensing means for sensing the
temperature of the oil and brine mixture and provides a
representative temperature signal;
means electrically connected to said sensor
means for providing an excitation voltage to said sensor
means; and
means for providing an indication of the
percent by volume of the water in the oil and brine mixture
in accordance with the sensed water signal and the
temperature signal from the sensor means.
2. A monitor as described in Claim 1 in which the
housing means includes
a pair of adaptor means having approximately
the same diameter as that of the pipe,
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chamber means affixed between the adaptor
means and increasing in diameter from the adaptor means
diameter to a larger diameter of sufficient dimension to
house the sensor means and having an opening with sufficient
clearance for said sensor means to pass through it, and
sealing means for sealing said sensor means
within said housing means while permitting the passage of
electrical conductors from the sensor means to the
excitation means and to the indicating means.
3. A monitor as described in Claim 2 in which the
temperature sensing means is a thermistor.
4. A monitor as described in Claim 3 in which the
sensing means includes
a head having a channel through which the oil
flows,
a pair of toroidal coils mounted in the channel of
the mounting head, one coil receiving the excitation
voltage, the other coil providing the sensed water signal in
accordance with an electromagnetic field developed in the
oil and brine mixture by the one coil in response to the
excitation voltage,
sensor arm means which passes through the
sealing means of the housing means having threaded ends and
a channel for the passage of wires,
connector means for connecting said head
means to said sensor arm means so that when said sensor head
means is positioned the oil-in-brine mixture flows through
it,
the thermistor, and
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wire means for connecting the one coil to the
excitation means and the other coil to the indicating means.
5. A monitor as described in Claim 6 in which the
sealing means includes
flange means in which the sensor arm means is
affixed and permanently sealed,
O-ring sealing means arranged with said
flange means so that when said flange means is mated with
said chamber means, the O-ring means provides sealing, and
means for fastening the flange means to said
chamber means in a manner so that the head means when
connected to the sensor arm by the connector passes through
the opening of said chamber means and is positioned in said
chamber means.
6. A method of monitoring oil-in-brine comprising
the steps of
arranging a housing with a pipe having an oil
and brine mixture flowing through the pipe in a manner so
that the oil and brine mixture flows through a portion of
the housing,
detecting the water content of oil and brine
mixtures having a water content of 80% or more by volume
with a water sensing device mounted within said housing
means in a manner so that the sensing device will be
suspended in the flowing mixture,
providing a sensed water signal
representative of the detected water content,
sensing the temperature of the oil and brine
mixture with a temperature sensor mounted within said
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housing means in a manner so that the temperature sensor
will be suspended in the flowing mixture,
providing a representative temperature signal
in accordance with the sensed temperature,
providing an excitation voltage to said water
sensing device, and
providing an indication of the percent by
volume of the water in the oil and brine mixture in
accordance with the sensed water signal and the sensed
temperature signal.
7. A method as described in Claim 6 in which the
detecting step includes transmitting electromagnetic energy
into the flowing oil and brine mixture in response to the
excitation voltage,
receiving the electromagnetic energy at
another location in the flowing mixture within said housing,
and
providing the sensed water signal in
accordance with the received electromagnetic energy.
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Description

The present invention relates to monitors in general
and, more particularly, to crude-in-brine monitors.
STATEMENT OF THE INVENTION
~ he invention provides an oil-in-brine monitor com-
prising housing means connected to a pipe having an oil and
brine mixture flowing through the pipe in a manner so that the
oil and brine mi~ture flows through a por-tion of the housing
means; sensor means mounted within said housing means in a
manner so that the sensor means will be suspended in the flowing
mi~ture, said sensor means includes water sensing means for
detecting the water content of oil and brine mixtures having a
water content of 80% or more by volume and providing a sensed
water signal representative thereof, and temperature sensing
means for sensing the temperature of the oil and brine mixture
and provides a representative -temperature signal; means electri-
cally connected to said sensor means for providing an excitation
voltage to said sensor means; and means for providing an indi-
cation of the percent by volume of the water in the oil and
brine mixture in accordance with the sensed water signal and
the temperature signal rom the sensor means.
From another aspect, the invention provides a method
of monitoring oil-in-brine comprising the steps of arranging a
housing with a pipe having an oil and brine mixture flowing
through the pipe in a manner so that the oil and brine mixture
flows through a portion of the housing, detecting the water con-
tent of oil and brine mixtures having a water content of 80~ or
more by volume with a water sensing device mounted within said
housing means in a manner so that the sensing device will be
suspended in the flowing mixture, providing a sensed water
siqnal representative of the detected water content, sensing
the temperature of the oil and brine mixture with a temperature
sensor mounted within said housing means in a manner so that the
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temperature sensor will be suspended in the flowing mixture,
providing a representative temperature signal in accordance with
the sensed temperature, providing an excitation voltage to said
water sensing device, and providing an indication of the per-
cent by volume of the water in the oil and brine mixture in
accordance with the sensed water signal and -the sensed temper-
ature signal.
The advantages of the invention will appear more
fully hereinafter, from a consideration of the detailed
description which follows, taken together with the accompanying
drawing wherein one embodiment is illustrated by way of
example. It is to be expressly understood, however, that the
drawing is for illustration purposes only and is not to be con-
strued as defining the limits of the invention.
The drawing is a mechanical drawing of an oil-in-
brine monitor constructed in accordance with the present inven-
tion.
DESCRIPTION OF THE INVENTION
The determination of water content in oil-in-brine
mixtures is of utmost importance to the petroleum industry.
In the conventional use of commercial capacitance type sensors,
the devices are usually limited to applications where brine-in-
oil emulsions are monitored. This effectively
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:~75~;7~
limits the application to a water cut of 0 to 70 percent by
volume of water in oil.
For oil production water f~ood projects, water cut
values of 80% to 100% are common~ In this water cut range,
where free brine is present, the capacitance type probes are
not applicable. The present invention utilizes a resistivity
measuring technique for determining the water content in an
oil-in-brine mixture where there is a water cut range of 80%
to 100%.
It should be noted ~here the water content of the
mi~ture is in the vicinity of 74% to 76%, the water becomes
the continuous phase which contains the oil. This type of
mixture is unstable and will separate into water and oil in
relatively short time period. A water-in-oil mixture,
i.e. where oil is the continuous phase, is highly stable and
does not separate readily.
Referring now to Figure 1, there is shown a
monitor which for resistivity determination of water cuts in
the 80% to 100% range includes a tee 3 having concentric
~educers 6 welded to opposite ends. Concentric reducers 6
reduce ~he measuring cell size down to the pipe diameter.
Victaulic adaptors 10 are welded to the narrow ends of
reducers 6. A flange extension 15 is welded to the re-
maining open end of tee 3.
A probe assembly includes an outlet box 21 having
an internal threaded end for being connected to a sensor
extension arm 24. Sensor extension arm 24 also has internal
threads a-t the end that is connected to outlet box 21 and
external threads at the opposite end. A plug 28 is threaded
into sensor extension arm 24 and has a passageway for the

passage of wires. A probe flange 30 is welded to sensor
extension arm 24 and has holes for mounting bolts 83 which
are used to affix probe flange 30 to flange extension 15. A
wiper 36 of neoprene rubber is held in place by a plastic
retainer 38 which is affixed to probe flange 30 by screws
44. A thermistor 54 is mounted in a connector 52 which is
connected to extension arm 24.
Sensor head 50 containing two toroidal coils 55
and 56, one for transmitting (coil 55) ~lectromagnetic
energy into the flowing oil~in-brine mixture and one for re~
ceiving (coil 56) the electromagnetic energy from the mix-
ture. Head 50 may be of the type manufactured by Great
Lakes Instruments, Inc. as their part number 32014 elec-
trodeless sensor. The wires (not shown) from thermistor 54
and coils 55, 56 pass through extension arm 24 to outlet box
21 and are connected to analyzer means 63 by way of a cable
in a conduit 60. Analyzer means 63, which may be of the
type also manufactured by Great Lakes Instruments, Inc. as
their model 75 conductivity analyzer, also provides an
excitation voltage to coil 55. Analyzer means 63 provides
an indication of the water content of the mixture in accor-
dance with the signals from coil 56 and from thermistor 54.
The present invention as hereinbefore described is
an oil-in-brine monitor which measures the water cut of a
mixture wherein the water cut lies within the range of 80 to
100 percent.
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