GB2130727A

GB2130727A - High percentage water content monitor

Info

Publication number: GB2130727A
Application number: GB08232840A
Authority: GB
Inventors: Roy Pasqual Mazzagatti
Original assignee: Texaco Development Corp
Current assignee: Texaco Development Corp
Priority date: 1982-11-17
Filing date: 1982-11-17
Publication date: 1984-06-06
Also published as: FR2536538A1; FR2536538B1; GB2130727B

Abstract

The monitor 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. A housing (3) is adapted to be connected in a pipe through which the oil and brine mixture is flowing, and a sensor (50) is mounted within the housing so that the sensor is suspended in the flowing mixture. The sensor is a resistivity sensor having a transmitter coil (55) and a receiver coil (56) and provides a signal corresponding to the percent by volume of water in the mixture, even when percent by volume of water is 80% or more, in response to an excitation voltage from a source. Indicating apparatus (63) 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. <IMAGE>

Description

SPECIFICATION High percentage water content monitor The presentsnvention relates to monitors in general and, more particularly, to oil-in-brine and crude oil-in-brine monitors.

The present invention provides an oil-in-brine monitor which is capable of measuring percent by volume of water in an oil-in-brine mixture in which the water content is 80% or more and includes a housing which houses a sensor. The sensor receives an excitation voltage from a source and provides a signal in accordance with the water content of the oil-in-brine mixture. Apparatus provides an indication of the percent water in the mixture in accordance with the signal from the sensor.

Objects and 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.

The single Figure of the accompanying drawing is a mechanical drawing of an oil-in-brine monitor constructed in accordance with the present invention.

The determination of water content in oil-inbrine 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-inoil emulsions are monitored. This effectively limits the application to a water cut of O to 70 percent by volume of water in oil.

For oil production water flood 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 where the water content of the mixture 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 a 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 the single Figure of the drawing, there is shown a monitor which for resistivity determination of water cuts in the 80% to 100% range includes a tee 3 having concentric reducers 6 welded to opposite ends. Concentric reducers 6 reduce the measuring cell size down to the pipe diameter. Victaulic-Bdaptors 10 are welded to the narrow ends of reducers 6. A flange extension 1 5 is welded to the remaining 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 at 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) electromagnetic energy into the flowing oil-inbrine mixture and one for receiving (coil 56) the electromagnetic energy from the mixture. Head 50 may be of the type manufactured by Great Lakes Instruments, Inc. as their part number 32014 electrodeless sensor. The wires (not shown) for 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 accordance 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.

1. An oil-in-brine monitor comprising a housing adapted for connection in an oil and brine mixture flow pipe so that in use the mixture flows through the housing, sensor means mounted within said housing and exposed to said flowing mixture, 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, 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 from the sensor means.

2. A monitor as claimed in claim 1 wherein the housing includes a pair of adaptors having approximately the same diameter as that of the pipe, a chamber affixed between the adaptors and increasing in diameter from the adaptor diameter to a large diameter of sufficient dimension to house the sensor means and having an opening with sufficient clearance of said sensor means to pass through it, and sealing means for sealing said sensor means within said housing while permitting the passage of electrical conductors from the sensor means to the excitation means and to the indicating means.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION High percentage water content monitor The presentsnvention relates to monitors in general and, more particularly, to oil-in-brine and crude oil-in-brine monitors. The present invention provides an oil-in-brine monitor which is capable of measuring percent by volume of water in an oil-in-brine mixture in which the water content is 80% or more and includes a housing which houses a sensor. The sensor receives an excitation voltage from a source and provides a signal in accordance with the water content of the oil-in-brine mixture. Apparatus provides an indication of the percent water in the mixture in accordance with the signal from the sensor. Objects and 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. The single Figure of the accompanying drawing is a mechanical drawing of an oil-in-brine monitor constructed in accordance with the present invention. The determination of water content in oil-inbrine 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-inoil emulsions are monitored. This effectively limits the application to a water cut of O to 70 percent by volume of water in oil. For oil production water flood 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 where the water content of the mixture 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 a 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 the single Figure of the drawing, there is shown a monitor which for resistivity determination of water cuts in the 80% to 100% range includes a tee 3 having concentric reducers 6 welded to opposite ends. Concentric reducers 6 reduce the measuring cell size down to the pipe diameter. Victaulic-Bdaptors 10 are welded to the narrow ends of reducers 6. A flange extension 1 5 is welded to the remaining 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 at 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) electromagnetic energy into the flowing oil-inbrine mixture and one for receiving (coil 56) the electromagnetic energy from the mixture. Head 50 may be of the type manufactured by Great Lakes Instruments, Inc. as their part number 32014 electrodeless sensor. The wires (not shown) for 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 accordance 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. CLAIMS

3. A monitor as claimed in claim 1 or claim 2 wherein the sensor means also includes temperature sensing means which senses the temperature of the oil and brine mixture and provides a representative temperature signal.

4. A monitor as claimed in claim 3 wherein the temperature sensing means is a thermistor.

5. A monitor as claimed in claim 3 or claim 4 wherein the indicating means provides the water content indication in accordance with the sensed water signal and the temperature signal.

6. A monitor as claimed in any one of claims 1 to 5 wherein the sensor means includes a head having a channel through which in use the mixture 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 sealing means of the housing and has threaded ends and a channel for the passage of electrical conductors, 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 the sensor head channel, and electrical conductors for connecting the one coil to the excitation means and the other coil to the indicating means.

7. A monitor as claimed in claim 6 wherein 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.

8. An oil-in-brine monitor substantially as described herein with reference to the accompanying drawing.