JPH04189998A - Well pressure and temperature measuring device - Google Patents

Abstract

PURPOSE: To improve the reliability of measurement by transferring a fluid pressure to a pressure-measuring device via a single, small-diameter pipe being extended to a downhole inspection position and transferring a fluid temperature to a temperature-measuring device via an optical fiber through the inside of the small-diameter pipe for monitoring. CONSTITUTION: A single, small-diameter pipe 18 accommodating an optical fiber wire 21 is extended from the ground surface to a chamber 16 that is located at a downhole inspection position at the lower end part of a production pipe string 13 in a casing 11. Then, a valve 7 is operated for filling with a desired test fluid from a pressurization test fluid source 22 on the surface, a desired test fluid/descent fluid surface is obtained in the chamber 16 and the source 22 is broken, and the test pressure fluid between the pipes 18 is measured by a pressure-measuring device and is monitored by a pressure-reading device 27. Then, the fluid temperature in the chamber 16 is measured by making connection to a temperature-measuring device 24 of an optical fiber wire 54 that is branched from a manifold and is monitored by a temperature-reading device 25, thus improving measurement reliability.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to techniques for monitoring temperature and pressure in remote and hostile environments. More specifically, the invention provides:
The present invention is directed to the reliable measurement of downhole fluid pressure and temperature in the borehole of an oil, gas or geothermal well.

In summary of the present invention, a system is provided for measuring temperature and pressure in a well using a single small diameter tube extending from the surface to a desired downhole inspection location in the well. Downhole fluid pressure is transmitted through small diameter tubing, while sheathed thermocouples or fiber optic lines extending along the flow path of the tubing are used to communicate downhole fluid temperature information to the surface. Continuous surface readout of pressure and temperature
The temperature readout is thus possible and used to monitor downhole fluid temperature and increase the accuracy of the fluid pressure measurement system.

PRIOR ART AND ITS CHALLENGES Accurate measurement of downhole fluid pressure and temperature in wells is
It has long been recognized as important in the production of oil, gas, and/or geothermal energy.

Accurate pressure and temperature measurements generally present a number of problems in pumping bowls commonly used in oil recovery operations. Secondary hydrocarbon recovery operations and geothermal operations generally use pressure and Requires temperature information.

In secondary hydrocarbon recovery operations, accurate well pressures provide a clear indication of wellbore productivity potential and the expectation that oil or gas will be forced from the formation into the well and recovered to the surface. Allows the operator to predict the amount of fluid required to fill the formation before the formation is filled. Accurate measurements of pressure and temperature changes in the wellbore fluid from each of the various wells extending into the formation indicate the location of the injection fluid front as well as the efficiency with which the fluid front is sweeping the formation. In geothermal wells, accurate pressure and temperature information is essential due to potential failures that may occur if reinjected fluid cools the formation or changes in fluid dynamics cause plugging of the wellbore. become decisive for production.

Techniques have been devised to provide periodic measurements of downhole conditions by lowering sensors into the well at desired times; The time and expense typically required for this process make it inconvenient and expensive. Such periodic measurement techniques are limited in that they only provide an indication of valve tuning status at a particular point in time, and generally do not provide the desired information for a substantial amount of time desired by the operator. An example of this type of system is U.S. Patent No. 3.712.19
No. 2 teaches filling an open-end tube with gas until it bubbles from the bottom of the tube to provide the desired periodic pressure measurements.

Permanent installation techniques have been devised to continuously monitor pressure in wells in a way that overcomes the inherent problems associated with periodic measurements. One such prior art technique uses downhole pressure transducers and temperature sensors with electronic scanning capabilities to convert the sensed downhole pressure and temperature into electronic data that is transmitted to the surface in conductors.

The conductor is usually attached to the outside of the tube in the wellbore, and the transducer and temperature sensor are conveniently attached at the lower end of the production tube.

However, this system has not received wide acceptance in the industry, in part due to the expense and high maintenance required for electronic equipment deployed in a hostile wellbore environment for extended periods of time. I couldn't.

High temperatures, pressures and/or corrosive fluids in the wellbore
Substantially increasing expense and reducing reliability of downhole electronics. Downhole pressure transducers and temperature sensors that output electronic data for communication to the surface are generally considered precision systems and are thus not preferred in the hostile environment typically associated with downhole wellbore.

U.S. Pat. No. 3,895,527 uses a small diameter tube with one end exposed to the well pressure and the other end connected to a pressure gauge or other detector at the surface, Disclosed is a system for remotely measuring pressure in. The concept of measuring downhole pressure with a system using such small diameter tubing is also described in U.S. Patent No. 3.89.
No. 8.877, and an improved version of such a system is disclosed in US Pat. No. 4.010.642. The teaching of the latter patent is that because the lower end of the tube extends into a chamber having at least the desired volume that satisfies the relationships expressed in the °642 patent,
This technique has become particularly well suited for more reliably measuring pressure in wells.

Although the technology disclosed in the '642 patent has found acceptance in the energy recovery industry, the teachings of this patent do not allow for detection of downhole temperature and pressure at desired locations within the valve regulator. In general, the operator will determine the average temperature for the well by supplementing assumed temperature gradient data with temperature measurements taken at the surface, and/or by estimating the average temperature for the well from previously acquired drilling data. Estimate downhole fluid temperature. This estimated temperature is used to determine the test fluid correction factor that is applied to the more accurately determined downhole pressure. However, those skilled in the art will appreciate that if accurate temperature information is not obtained, and that correction of pressure readings based on such inaccurate temperature estimates is obtained by techniques that use small diameter tubing, correspondingly, It has long been recognized that pressure readings caused by

Not only is the estimated temperature inaccurate, resulting in erroneous wellbore pressure data, but the actual temperature in the wellbore is
It varies considerably as a function of wellbore depth and conditions such as evaporation, outgassing, and/or "freezing" that occur at a particular depth. The result is that operators are unable to reliably and economically measure wellbore temperature or pressure in many wells, and therefore operators are unable to maximize energy recovery from the well. It is impossible.

The disadvantages of the prior art are overcome by the present invention, and the improved method and apparatus provide a method and apparatus that can be used in a wellbore using a single small diameter tube extending from the surface of the wellbore to the desired downhole inspection location. A method for reliably detecting pressure and temperature is disclosed hereinafter.

SUMMARY OF THE INVENTION The pressure and temperature measurement system of the present invention is particularly well suited for use in oil, gas and geothermal wells. A small diameter tube extends from the surface to the desired downhole inspection location, and a sheathed thermocouple or fiber optic is inserted from the surface to the downhole location to accurately correlate downhole temperature measurements. accommodate. The housing is lowered in the wellbore to an inspection location and includes a chamber open to both the downhole fluid and the flow path in the tube. The tube and part of the chamber are filled with the selected fluid, and the well fluid pressure fluctuations are thereby transmitted to the surface through the fluid in the annular space between the inner diameter of the tube and the thermocouple or fiber optic wire. be done. Valve control temperature measurements are taken at the surface by monitoring the emf at a thermocouple that is transmitted via a wire to the surface for readout. Alternatively, the wellbore temperature profile is obtained from temperature measurements at periodic, eg 1 meter, intervals using fiber optic lines in small diameter pipes. Pressure and temperature monitoring and plotting equipment is provided at the surface and temperature sensing instruments are preferably used to determine more accurate downhole pressure readings.

Continuously providing reliable downhole temperature and pressure information at the surface of the wellbore using a single tube extending from the surface to the downhole inspection location and thermocouples or fiber optic lines inside the tube. This is the object of the present invention.

It is a further feature of the invention that the thermocouple or fiber optic wire extending from the surface to the downhole inspection location is partially protected by a test fluid in the tube, which test fluid is less hostile than the fluid in the wellbore. It is a purpose.

It is a feature of the invention that downhole fluid temperature and pressure are continuously monitored without the use of electrical connections at either the valve or wellhead.

It is a feature of the present invention that reliable wellbore temperature profiles are obtained using a single optical fiber loop in a small diameter tube extending from the surface to the downhole location.

It is an advantage of the invention that multiple lines do not need to extend from the surface to the downhole inspection location to reliably monitor both fluctuating wellbore fluid pressure and temperature.

A still further advantage of the invention is that the fiber optic surface device comprises multiple optical fibers, each protected within its own small diameter pressure tube, and preferably extending to different wellbore.
It is used to receive signals from the loop.

These further objects, features and advantages of the present invention include:
It will become clear from the following detailed description with reference to the figures in the accompanying drawings.

EXAMPLES The present invention has utility for reliably monitoring downhole fluid pressure and temperature in oil, gas or geothermal wells. For purposes of the present invention, the downhole fluid monitored is:
It is estimated to be at least 1.000 feet deep in the wellbore, and generally several thousand feet below the surface.

The fluctuating downhole fluid pressure that is monitored is generally less than the standard hydrostatic pressure, but the downhole fluid pressure is monitored in a flowing, pumping, or static wellbore, and the downhole fluid is at or above the hydrostatic pressure. .

FIG. 1 shows a typical wellbore extending into underground formations. FIG. 1 shows a production well and thus a conventional wellhead 8.
Generally shown on the surface is production equipment including. The casing 11 is positioned in the wellbore and has a perforation 12 at the lower end to allow fluid entry into the casing 11 from the formation. The production tube string 13 extends from the wellhead at the surface to a selected depth in the wellbore. The perforated portion 14 of the tube string 13 allows fluid in the casing 11 to enter the production tube and then flow to the surface. The color protector 15 is
A small diameter continuous tube 18 is provided along the tube string 13 to help secure the small diameter tube 18 to the tube string 13 and thus protect the small diameter tube in one well. Housing 1
9 is provided at the lower end of the production tube 13 and includes a chamber 16 with a port for maintaining fluid communication between the chamber and the fluid in the wellbore outside the housing 19.

The small diameter tube 18 according to the invention is connected to the housing 19 from the surface.
The test position extends to the test position where the test position is located. Tube 18 enters the lower portion of production tube 13 at entry port 17 and then continues downward into housing 19 so that the lower end of tube 18 is in fluid communication with chamber 16 . A suitable small diameter tube according to the present invention has an outside diameter of 0.250" and an inside diameter of 0.18".

The thermocouple wire is disposed within the tube, and the thermocouple wire generally has a cross-sectional area of about 25% to about 50% of the cross-sectional area of the flow path in the tube. Fiber optic lines, which will be discussed in detail subsequently, are used in place of thermocouple lines, and in this case the temperature measurement line is generally about 10% of the cross-sectional area of the flow path in the tube.
~50% cross-sectional area. Those skilled in the art will:
It is recognized that small diameter tubes in the range specified above are commonly referred to as microtubules.

FIG. 1 also shows that tube 18 extends to the surface of the wellbore and exits the side of the wellbore at pipe fitting 9.

A manifold 20 is provided to provide a seal around the tube and to allow the thermocouple or fiber optic wire to exit the manifold. A thermocouple or fiber optic line at the surface is designated as 54 and follows the temperature measurement device, the output of which is sent to the temperature readout device 25. The manifold has a fluid outlet port that effectively provides a continuation of the line to the valve 7, which is connected by one line to a source of pressurized fluid 22 and by another line to a pressure measuring device 26. and its output is sent to a pressure readout device 27. It is understood that the temperature measurement and readout device may be provided separately or as part of the pressure measurement device 26 and the readout device 27. In either case, however, the output from temperature measuring device 24 is preferably transferred to device 26, as described subsequently.
is input into a computer 23 which provides a pressure correction value for the pressure.

Referring now to FIG. 1A, the lower end of the housing 19 has an entry port 39 that establishes fluid communication between the chamber 16 and the wellbore, while the upper end of the chamber 16 has an entry port 39 that establishes fluid communication between the chamber 16 and the wellbore. In fluid communication. A thermocouple or fiber optic wire 21 is connected to the tube 1
8 into the chamber 16, and preferably
positioned in the chamber in a position below the test fluid;
In this way, it comes into contact with the Banai fluid. Filter assembly 36 is fabricated from a porous metal material or small mesh barrier and prevents solids from communicating between chamber 16 and tube 18. Pipe 18 is connected to top plug fitting 3 by assembly 28.
4, assembly 28 also provides a watertight seal between tube 18 and fitting 34. A second or backup assembly 29 similarly provides a connection between the lower end of fitting 34 and tube 18 . The thermocouple or fiber optic line 21 preferably extends downward into engagement with the wellbore fluid, while the tube 18 terminates just below the assembly 29.

If thermocouple wire is used, the thermocouple junction 38 enters directly into the downhole fluid and thus responds to changing temperatures. If fiber optic lines are used, regular spacing,
For example, temperature measurements at 1 meter intervals are taken at each test location from the surface to the pressure test housing 19. The temperature of the fluid in the tube 18 at any location is obtained and is a function of depth because the temperature acting on the fiber optic line at that location approximately corresponds to the varying temperature of the wellbore fluid in the wellbore at that location. A complete temperature profile of the wellbore is generated with a fiber optic system. Nevertheless, the lowest end of the fiber optic line preferably extends into engagement with the wellbore fluid so that a more accurate measurement of the wellbore fluid temperature within housing 19 is obtained. For this reason, the system shown in FIGS. 1 and 1A provides a semi-permanent measurement because the downhole components and tube 18 remain connected to the production tube 13 until the production tube is returned to the surface. Features a system.

FIG. 2 shows an alternative embodiment of the lower portion of the pressure and temperature monitoring system being lowered into the wellbore from a smaller diameter continuous pipe 18 than from the production pipe. In this embodiment, the downhole arrangement thus consists of a top side plate 33 for accommodating the small diameter tube 18. The side plate 33 has a top plug fitting 34 having a cylindrical internal passageway to accommodate the tube 18.
It has downward threads for engagement with. The fitting 34 is threadedly connected to the housing 19 by threads 40 and sealing engagement between these bodies is provided by suitable O-ring seals 42.

FIG. 2 shows the assembly 28 for mechanically connecting the tube 18 and the fitting 34 in detail. Member 46 is threadedly connected to fitting 34 at 44 and includes a cylindrical internal passageway aligned with the passageway in fitting 34 . Top cap 48 is screwed onto member 46 and torque rotation of 48 relative to 46 causes the cylindrical inner surface of ferrule 45 to sealingly grip tube 18 in a conventional manner.

A similar member 47 is shown for the second or backup assembly 29 and includes a corresponding cap 49 for threaded engagement with the second or back-up assembly 29, thus gripping the tube 18 as well. A side plate 33 physically protects the upper assembly 28 and a sleeve-like extension 35 protects the top plug fitting 3.
4 and likewise form a protective housing for the lower assembly 29. Filter assembly 3 above
6 is threadedly connected to the lower end of the sleeve 35 and prevents solid debris in the wellbore fluid from entering the interior of the tube 18. The thermocouple or fiber optic line 21 preferably extends downwardly through the filter 36. If thermocouple wire is used, the thermocouple measurement junction 38 is thus in fluid communication with the downhole fluid. If fiber optic lines are used, thermocouple junctions are not required;
The fiber optic line itself is then exposed to downhole fluid to create a change in the transmitted laser pulse as a function of temperature.

As shown in FIG. 2, the device is correspondingly adapted to be simply suspended in the wellbore from the tube 18. This embodiment is therefore particularly well suited for measuring downhole tube temperatures and pressures in geothermal wells where production tubes are not commonly used. However, those skilled in the art will appreciate that the downhole assembly is secured from the lower end of the production tube, as generally shown in FIG. 1A, in this case the small diameter tube 18.
recognizes that the upper part of the apparatus shown in FIG. 2 can be easily modified to pass into the interior of the production string at the appropriate ports 17 provided.

According to the invention, the volume of chamber 16 must be large enough to accommodate the minimum and maximum pressures expected in the wellbore. The required volume of this chamber is based, in part, on the volume of the flow path in the tube, thus taking into account the internal cross-sectional area of tube 18, the length of tube 18, and the cross-sectional area of conduit 21.

The downhole chamber 16 is thus constructed as described in U.S. Patent No. 4.010.6.
42, having at least a preselected volume. This minimum chamber volume is based on the volume of test fluid in the tube, and the chamber volume is
is considerably reduced by the inclusion of Therefore, the minimum chamber volume according to the invention is based on the cross-sectional area of the annulus between the inner diameter of the tube and the outer diameter of the thermocouple or fiber optic wire in the tube, rather than the internal cross-sectional area of the tube itself. Further details regarding the minimum volume of chamber 16 are disclosed in US Pat. No. 4.010.642, incorporated herein by reference.

In operation, a small diameter tube 18 containing a thermocouple or fiber optic wire is secured to a housing 19, as shown in FIGS. 1A or 2. Then housing 19
The tube 18 is lowered to the desired test location in the wellbore and the valve 7 is operated such that the tube 18 is filled with the desired test fluid from the source 22 at the surface. Once the desired test fluid/downhole fluid interface in chamber 16 has been obtained, valve 7 is operated to shut off test fluid source 22 while simultaneously applying pressure to the test fluid pressure at the surface of tube 18. The measuring device 26 is made to respond. Fluid temperature and pressure are
Either maintained continuously by a downhole system that remains at the same depth of a semi-permanent installation, as shown in Figure 1 or 1A, or a downhole system, as shown in Figure 2. The time period during which the wafer is raised or lowered through the well is monitored at various depths.

Various types of test fluids can be used to fill the interior of tube 18 and portions of chamber 16, provided the thermocompressive properties of the fluid are known. Both nitrogen and helium are highly compressible, in part because the compressibility factor, sometimes referred to as the "Z-factor" for each of these fluids, is very well known over the range of commonly found downhole fluid pressures and temperatures. , was found to be particularly suitable as a test fluid.

Those skilled in the art will appreciate that the thermocouple wires are placed within tube 18;
And once the tube has been used as described above, the temperature of the wellbore fluid at the desired test location in the wellbore can be easily and reliably monitored by a surface device that measures the emf generated by the thermocouple junction. Recognize that it will happen. The thermocouple wire is thus exposed to the thermocouple junction 38 in contact with the wellbore fluid.
to a measuring device 24 at the surface. If desired, these temperature readings are conveniently output at 25 and maintained on any number of suitable recording means.

Alternatively, fiber optic lines are placed within tube 18 and the tube is used. In this case, the temperature of the fluid in the pipe,
The approximate temperature of the wellbore fluid outside the tube is thus measured at regular intervals such that a complete wellbore temperature profile is obtained.

Fiber optic systems rely on the concept that the local light scattering power of the fiber core depends on the fiber temperature, and this relationship is well understood by those skilled in the art of fiber optic temperature measurement systems. A suitable fiber optic system for the present invention is located in California;
Burbank's York V, S, U, P, 5a
DTS System distributed by les
It is I+. A laser pulse is fired into the sensor fiber and travels along the fiber at a constant speed. As it travels along the fiber, the pulse interacts with the silica and dopant matrix, scattering energy in all directions. Some of the light is effectively reflected and returned to the source at the surface, where it is bypassed by a fiber optic coupler to the detector. Because the distance from the source to the reflection location along the fiber is a direct function of the speed and time of a constant laser pulse, the amount of power to the detector at a particular time determines the temperature of the fiber at a particular depth. to be measured. In this case, the temperature measurement device 24 at the surface includes an optical front end, a timer, an A/D
Y including converter, amplifier and microprocessor
The sensor system is commercially available from Ork.

An optical system that measures temperature every 1 meter and can extend to a depth of 1000 meters is 1°C
allows for precision smaller than .

If desired, optical system surface fittings [24 and 25] may be used for multiple optical paths, each extending into different fluid conduits located in nearby wells. The easily obtained temperature profile can be used not only to obtain more accurate wellbore pressure measurements, but also to indicate critical temperature-related wellbore conditions, as will be fully explained hereinafter. For example, in geothermal, the light system temperature profile dictates the depth to which superheated water will evaporate, thereby providing an initial indication at which scale is formed that changes the well.In an oil well, the temperature profile produced is , indicating the location where gases exit the solution that affect the performance of the well.

In natural gas wells, this temperature profile is called “freezing”.
Indicates the depth to which problems are likely to occur and will halt production if not corrected.

The above temperature readings are also used to more reliably determine the exact downhole fluid pressure. Those skilled in the art will recognize that the actual downhole fluid pressure is a function of the pressure measured at the surface and the hydrostatic pressure of the test fluid flowing from the surface to the downhole test location. The hydrostatic head of the test fluid is a function of the vertical depth from the surface to the downhole test location and the gas gradient of the test fluid. The true vertical depth for determining the hydrostatic pressure of the test fluid is generally known and
or easily determined by conventional methods. The gas gradient of the test fluid is determined by the following formula:

The above formula thus requires that the average temperature of the test fluid be known, and the technique of the present invention is readily used to monitor the downhole temperature of the test fluid, thereby allowing the average temperature of the test fluid to be known. Determine the temperature more accurately and determine the correct gas gradient. The specific gravity of the test fluid, along with the Z-factor, is determined with sufficient accuracy from uncorrected or approximate test fluid pressure readings and test fluid temperature readings. The addition of thermocouple wire in the small diameter tube allows accurate temperature measurement of the downhole fluid and thus more accurate average test fluid temperature determination. The use of fiber optic lines in small diameter tubing allows accurate temperature measurements of both the downhole fluid at the location of the housing 19 and the wellbore fluid at each incremental depth of the wellbore. A significant advantage of fiber optic temperature measurement systems is that a single small diameter tube of fiber optic line is used to generate a complete wellbore temperature profile. This temperature profile provides a highly accurate average test fluid temperature determination, which results in more accurate downhole pressure measurements.

Significantly, more accurate and continuous pressure measurements of wellbore fluids are thus determined in real time by the present invention.

FIG. 3 shows a convenient (
Indicates the appropriate manifold to be located. The T-shaped body has an input port for accommodating a tube 18 and a thermocouple or fiber optic line, an output port in fluid communication with the tube for transmitting pressure readings to a measurement device 26, and a test fluid within the body 56. Three identical end caps 58 are provided on each of the boats, with an output port for transmitting a thermocouple or fiber optic line to the temperature measurement device 24 while sealing the temperature measurement device 24 . End cap 58 is threaded onto body 56 at the input port to force ferrule 60 into gripping and sealing engagement with outer cylindrical surface 52 of tube 18 .

Similarly, an end cap 58 is provided at the pressure output boat of manifold 20 to communicate test fluid to the outside of manifold 20 and to measurement device 26 . A tube fitting 64 having a sleeve-shaped portion 66 structurally similar to tube 18 is connected to body 56 by an end cap 58 . The outer end of the fitting 64 of the body 56 has a cylindrical passageway that closely approximates the outer diameter of the thermocouple or fiber optic line 54 extending to the temperature measurement device 24 . The line 54 is
Another end cap 62 and ferrule 68 seal to the fitting 64 . Although the design and construction of the manifold 20 is not critical to the invention, the fact that the manifold is located at surface in a location separate from the wellhead 8 is a critical feature of the invention.

The small diameter tube 18 according to the invention preferably has a diameter of about 0.21
It has an inner diameter smaller than an inch. To accommodate the thermocouple wire, this inner diameter is greater than about 0.10 inches.

The effective volume and thus the cross-sectional area of the tube are described in U.S. Pat.
．． 010,642. If used, the thermocouple wires are connected to the tube 1 that surrounds the thermocouple wires.
The combination of the protection afforded by the non-hostile environment created by the test fluid in FIG. 8 and the physical protection provided by the structure shown in FIG. including.

This physical construction is relatively inexpensive compared to thermocouple wires extending to the valve due to the non-hostile environment in which the thermocouple wires are placed according to the present invention. Two dissimilar metal conductors are
A thermocouple junction located within the chamber of the housing 19 is used to measure downhole fluid temperature by being engaged with the downhole fluid or by being positioned in the test fluid directly above the downhole fluid. combined to form. The latter situation thus results in slow response times to detect varying downhole fluid temperatures.

In the fiber optic line embodiment, the two optical fibers in the line are halves of a single optical fiber loop, with both ends of the loop at the surface and the central portion of the loop within the housing 19. Again, high reliability and reduced coating costs for the optical fiber loop are obtained as a result of the non-hostile environment created by the test fluid in the tube 18 surrounding the optical fiber line.

Although multiple temperature points are measured, the cost per foot of a fiber optic system is approximately equal to the cost of a thermocouple system. Tube 18 not only reduces the cost of coatings applied on the fiber optic line, but also allows the fiber optic line itself to
Overcomes the significant limitations of fiber optic temperature measurement systems in the wellbore if not protected by such tubes, in that they are generally too light and flexible to withstand the flow velocities in dynamic wellbore do. Fiber optic lines are likely calibrated to minimize this difficulty, but the increased weight exceeds the recommended strength of fiber optic lines if used in deep wells. By closing the fiber optic line in tube 18, the line is protected in a non-hostile and essentially static environment sacrificing the wellbore pressure measurement concept of this invention.

The downhole fluid measured by the present invention is 1 below the surface.
．． 000 feet or less, it is difficult, if not impossible, to insert thermocouples or optical fibers into small diameter tubes after the tubes are manufactured. Although such insertion is possible for large diameter tubes, the small diameter of tube 18 and the associated low cost and volume are important features of the invention. Accordingly, thermocouple or fiber optic wire 21 is preferably inserted into tube 18 when the tube is manufactured. FIG. 4 shows flat sheet metal stock 17 used to form a tube, bent by a suitable extrusion die (not shown) to form a tubular member. The tube is completed by sealing the adjacent end faces with continuous welds 72. Thermocouple or fiber optic wire 21 is preferably placed against sheet metal 70 and kept away from weld 72 during the welding process so that tube 18
The heat from the weld 17 effectively formed around the wire is
Do not damage the wire 21. FIG. 4 shows wire 21 with a relatively low cost outer stainless steel sheath 74. For thermocouple wires, conductors 76 and 78 are positioned within the sheath and electrically isolated from each other and from the sheath by an insulating material 80.

For fiber optic lines, the optical fibers are located within a sheath, ie, isolated from each other or from the sheath 74 or not. In fiber optic systems,
Sheath 74 may be replaced with a suitable covering or wrapping. Although a wide variety of thermocouple wires and thermocouple junctions may be used in accordance with the present invention, suitable thermocouple wires are made of magnesium oxide insulating material to protect the junction and minimize stray emf signals. Use an ungrounded measurement joint that is electrically isolated from the sheath end. Suitable fiber optic lines are preferably sheathed or coated before being placed within tube 18 in the manner shown in FIG. A suitable covering is
Due to the expected temperature in the tube 18 and the coating, especially since the wire is protected by a non-hostile fluid, the temperature ranges from -100'''C to
It can be used to withstand conditions of +6009C or higher. If desired, the last few meters of the wire in assembly 29 and housing 19 are not protected by tube 18.
A new and expensive coating is applied to the central portion of the fiber optic loop (the lowermost portion of the installed fiber optic line).

FIG. 5 shows a fiber optic pressure and temperature system according to the present invention. The downhole components in assembly 29 are similar to those described above, except that the multiple temperature point measurement nature of the optical system allows for more flexibility. In the embodiment shown in FIG. 5, the fiber optic line 82 is housed within the tube 18 and connected to the tube fitting 34 to terminate within the test housing 19 at a point W in engagement with the wellbore fluid 16. It extends through. However, fiber optic systems allow multiple temperature measurements, thereby providing a reliable wellbore temperature profile and accurate wellbore pressure compensation signal even though the fiber optic line 82 does not engage the wellbore fluid. is generated. For reasonable accuracy of the correction signal for compensation, the fiber optic line extends reasonably close to the assembly 29 and preferably extends from the top of the housing 19 to the length of the test housing 19.
Extends to a double depth. Therefore, the optical fiber line 82
is located entirely within tube 18 directly above assembly 29 (
In this case no special coating is required for the lower part of the line), extending into engagement with the wellbore fluid, or terminating at some point.

FIG. 5 shows the pipe 18 exiting the wellhead 8 via the pipe fitting 9 described above. Manifold 20. Valve 7, test fluid source 22, pressure measuring device 26 and pressure readout device 27 are each located on the surface and have been described above. Fiber optic line 82 exits manifold 20 unprotected by tube 18 and comprises optical fibers 84 and 86 structurally wrapped or covered by a suitable layer 88, although the optical fibers need not be isolated from each other. is shown. FIG. 5 also shows additional fiber optic lines 82A and 82B extending to the temperature measurement device 24, and each of these lines is connected to a line in a similar tube 18 extending into an adjacent wellbore. corresponds to In one embodiment, device 24 includes an optical front end device 90, a laser pulser 91, a timer 92, an electronics package 93, a microprocessor 94 and a detector 95. The timer 92 is
A pulser 91 is controlled to intermittently generate laser bursts that pass through an optical front end device 90 . At each inspection point, a portion of this laser pulse is reflected from the surface and measured by detector 95. Timer 92, electronics 93 and microprocessor 94 cooperate to receive output from the detector and determine the temperature at each of the test points, as described above. Although it is preferred to have a fiber optic loop including fibers 84 and 86 in line 82 for increased accuracy, a single optical fiber is used in line 82 extending from device 24 to a downhole location adjacent assembly 29. be done. In addition, tubes other than thermocouple wires or optical fiber wires 18
The temperature sensing line within is possibly used to measure the downhole temperature according to the present invention.

One of the advantages of the present invention is that - although lines need to be installed in the wellbore, temperature and pressure readings of the downhole fluid are easily obtained at the surface. A fiber optic system allows multiple valve temperature measurements to be
The diameter of 8 is obtained without having to be increased to accommodate multiple thermocouple wires, thereby increasing the flexibility and accuracy of the system without significantly increasing cost. The use of one wire rather than two wires increases the reliability of the system according to the invention since the twisting problems normally associated with long lengths of two or more wires when lowered into the well are avoided. substantially increase. along with the delays and costs associated with repairing the system.
The reliability problems of systems using multiple wires are avoided by the present invention since a single wire is used to reliably measure pressure and temperature.

It is a further advantage of the present invention that the thermocouple or fiber optic line is substantially protected by the inert test fluid in the small diameter tube. Thermocouple or fiber optic wire
Preferably, the entire length of the wire or fiber optic is sheathed so that it is not exposed to the test fluid, but the thermocouple or fiber optic line itself is not exposed to the hostile and generally corrosive valving environment. The test fluid is sealed at the manifold location outside the wellhead, so that no electrical connections are required at either the wellhead or the valve control. Because the thermocouple or fiber optic wire is substantially protected by the selected test fluid, the metal sheath of the wire 21 is a novelty needed to protect the thermocouple wire or fiber optic from corrosive and hostile valve control fluids. Manufactured from stainless steel or other materials that are substantially cheaper.

While particular embodiments of the invention have been shown and described, it will be obvious that further changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended that the following claims cover such changes and modifications.

Main features and aspects of the present invention are as follows.

1. A device for continuously measuring the fluctuating pressure and temperature of downhole fluid in a valve control at a desired depth, the device being placed within the well and extending continuously from the surface to the desired depth. a tube having a flow path, a housing suspended in a valve at a desired depth from the tube and defining a chamber in fluid communication with the downhole fluid and the flow path in the tube; A pressurized test fluid source at the surface of the tube and the pressurized test fluid source to initially pressurize the channel in the tube and the chamber portion in the housing with a selected fluid to form a downhole fluid interface for the test. a valve for selectively isolating fluid communication between the fluid source and a valve disposed within the flow path of the tube and adjacent the housing in the downhole from the surface for sensing downhole fluid temperature adjacent the housing; an input port for sealingly accommodating the tube and the fiber optic line, and a manifold at the surface for sealing the selected fluid in the flow path; a manifold having a fiber optic exit port for directing a thermocouple wire from the manifold and a fluid exit port for directing a pressurized selected fluid from the manifold while enclosing the fluid contained therein; and a drop at a desired depth. To determine the pore fluid pressure,
a pressure measuring device at a surface in fluid communication with the fluid outlet port of the manifold and a fiber optic line extending from the manifold and descending at a desired depth to measure the fluid pressure of the selected fluid; and a temperature measuring device at the surface for measuring the temperature of the pore fluid.

2. The apparatus of claim 1 further comprising first and second axially spaced connectors each in physical sealing engagement with the tube for interconnecting the tube and the housing.

3. The method according to claim 1, further comprising calculation means on the surface for receiving the temperature signal from the temperature measuring device and for outputting a correction value for determining the fluid pressure as a function of the value of the measured temperature of the downhole fluid. Device.

4. The apparatus of claim 1, wherein the fiber optic line is positioned within the chamber and engaged with the downhole fluid.

5. The device of 1 above, wherein the selected fluid is selected from the group consisting of nitrogen and helium.

6. a filter positioned within the housing to prevent solids in the downhole fluid from passing into the tube;
2. The apparatus of claim 1, further comprising a filter having a passage for receiving a fiber optic line and an exit port for passing the fiber optic line outside the filter and into engagement with downhole fluid.

7. The apparatus of claim 1, further comprising a temperature readout device for outputting an indication of downhole fluid temperature in response to the temperature measurement device.

8. A device for monitoring the fluctuating pressure and temperature of a downhole fluid in a well at a desired depth, the device being disposed within the valve well and extending continuously from the surface to the desired depth in the valve well; a housing defining a chamber suspended in the valve and in fluid communication with the downhole fluid and the flow path in the tube; and forming an interface between the selected fluid and the downhole fluid in the chamber. a source of pressurized test fluid at the surface for initially pressurizing the flow path in the tube and the chamber portion in the housing with a selected fluid; A temperature sensing line extending toward the housing in the valve, a manifold at the surface for sealing the selected fluid within the flow path, and an input port for sealingly accommodating the tube and temperature sensing line. , a manifold having a temperature sensing wire exit boat for directing a temperature sensing wire from the manifold while sealing a selected fluid within the manifold, and a fluid exit boat for directing a pressurized selected fluid from the manifold; , a pressure monitoring device at the surface and in fluid communication with the fluid outlet port of the manifold for monitoring the fluid pressure of the selected fluid to determine the downhole fluid pressure at a desired depth; and a temperature monitoring device at a surface for accommodating a temperature sensing line extending from the manifold and monitoring the temperature of the downhole fluid.

9. The temperature sensing line is a fiber optic line having a fiber optic loop at its end on the surface, the fiber optic line extending into the downhole in the tube at least to a depth adjacent to the housing in the well. equipment.

10. A temperature sensing line which is a fiber optic line, a laser pulser at the surface for intermittently generating and transmitting light pulses to the downhole by the fiber optic line, and a laser pulse reflected from the downhole at the surface. and a detector at the surface for receiving and outputting a signal indicative of downhole fluid temperature.

11. The apparatus of claim 8, wherein the housing is suspended in the well from a production pipe extending to a desired depth from the surface and having a flow path for communicating fluid between the surface and the well.

12. The apparatus of claim 8, further comprising calculation means at the surface for receiving the temperature signal from the temperature monitoring device and for outputting a correction value for determining fluid pressure as a function of the monitored temperature of the downhole fluid. .

13. The device according to item 12, further comprising a pressure reading device for outputting an indication of the downhole fluid pressure and a correction value from the calculation means in response to the pressure monitoring device.

14. In a method of monitoring the fluctuating pressure and temperature of downhole fluid in a regulating valve at a desired depth, lowering a tube with temperature sensing into the well, the tube being continuously lowered from the surface to the desired depth. lowering the housing to the desired depth in the well, and lowering the housing to the desired depth in the well, and lowering the housing to the desired depth in the well; in the tube with a selected fluid to define a chamber in fluid communication with the bore fluid and a flow path in the tube and to form an interface between the selected fluid and the downhole fluid in the chamber in the housing. pressurizing the channel and a portion of the chamber in the housing; sealing the selected fluid in the channel while outputting a temperature sensing line from the tube at the surface; and depositing the downhole fluid at a desired depth. monitoring the pressure of the selected fluid in the tube at the surface to determine the fluid pressure; and monitoring a temperature sensing line at the surface to determine the temperature of the downhole fluid at the desired depth. method including.

15. Suspending the housing at the desired depth in the valve adjustment from the production pipe extending from the surface to the desired depth, positioning the outside of the production pipe, and from the outside of the production pipe into the chamber in the opening. 15. The method of claim 14, further comprising forming a port through the production tube for passage of the tube.

16. The temperature detection line is a fiber optic line, intermittently transmits light pulses to the downhole through the fiber optic line, and detects and responds to the light pulses reflected from the downhole on the surface. 15. The method of claim 14, further comprising outputting a signal indicative of downhole fluid temperature.

17. 14 above, further comprising calculating a fluid pressure of the downhole fluid as a function of the determined temperature of the downhole fluid.
The method described in.

18. The method of claim 14, further comprising suspending the housing from the tube and simultaneously lowering the tube and housing to the desired depth in the well.

19. The method of claim 18, wherein downhole fluid pressure is monitored at various selected depths in the valve as the tube and the suspended housing are lowered within the valve.

20. 19. The method of claim 18, further comprising selecting tubes having different material strengths and different cross-sectional areas as a function of the weight of the tube extending to the desired depth and the weight of the housing.

[Brief explanation of the drawing]

FIG. 1 is a partially cross-sectional pictorial diagram of a pressure and temperature monitoring system according to the present invention in a production hydrocarbon recovery valve wellbore. FIG. 1A is a simplified pictorial diagram, partially in cross-section, of a portion of the pressure and temperature monitoring system shown in FIG. 1; FIG. 2 is a detailed cross-sectional view of a suitable downhole section of a pressure and temperature monitoring system suspended in the wellbore from small diameter tubing. FIG. 3 is a detailed cross-sectional view of a suitable surface manifold for separating a pressurized test fluid and a thermocouple or fiber optic line such that pressure and temperature are monitored by suitable surface devices. FIG. 4 is a simplified pictorial diagram of a suitable technique for installing thermocouples or fiber optic lines in a test tube according to the present invention. FIG. 5 is a simplified pictorial and block diagram of the surface components of a fiber optic system according to the present invention for accurately determining downhole pressure and temperature. 7 Valve 11 Casing 13 String 16 Chamber 18 Continuous pipe 19 Housing 20 Manifold 21 Fiber line 26 Pressure measuring device 27...Pressure reading device 39...Enter port

Claims (1)

[Claims] 1. An apparatus for continuously measuring the fluctuating pressure and temperature of a downhole fluid in a well at a desired depth, comprising: a tube having a continuously extending flow path; a housing suspended in the well at a desired depth from the tube and defining a chamber in fluid communication with the downhole fluid and the flow path in the tube; a source of pressurized test fluid at the surface for initially pressurizing the passageway in the tubing and the portion of the chamber in the housing with a selected fluid to form an interface between the selected fluid and the downhole fluid in the chamber; , a valve for selectively isolating fluid communication between the tube and the source of pressurized test fluid; a fiber optic line extending adjacent to the housing in the downhole and a manifold at the surface for sealing the selected fluid in the flow path and an input port for sealingly receiving the tube and the fiber optic line; and a manifold having a fiber optic exit port for directing a thermocouple wire from the manifold while sealing a selected fluid within the manifold, and a fluid exit port for directing a pressurized selected fluid from the manifold; To determine the downhole fluid pressure at the desired depth,
a pressure measuring device at a surface in fluid communication with the fluid outlet port of the manifold and a fiber optic line extending from the manifold and descending at a desired depth to measure the fluid pressure of the selected fluid; and a temperature measuring device at the surface for measuring the temperature of the pore fluid. 2. A device for monitoring the fluctuating pressure and temperature of a downhole fluid in a well at a desired depth, the device being disposed within the well and extending continuously from the surface to the desired depth in the well. a tube having a flow path; a housing defining a chamber suspended in the well and in fluid communication with the downhole fluid and the flow path in the tube; and a housing defining an interface between the selected fluid and the downhole fluid in the chamber; a pressurized test fluid source at the surface for initially pressurizing the flow path in the tube and the chamber portion in the housing with a selected fluid; a temperature sensing wire extending toward the housing at the surface; a manifold at the surface for sealing the selected fluid within the flow path; an input port for sealingly accommodating the tube and the temperature sensing wire; a manifold having a temperature sensing wire exit port for directing a temperature sensing wire from the manifold and a fluid exit port for directing a pressurized selected fluid from the manifold while sealing a selected fluid within the manifold; a pressure monitoring device at the surface and in fluid communication with the fluid outlet port of the manifold for monitoring the fluid pressure of the selected fluid to determine the downhole fluid pressure at a desired depth; , a temperature sensing line extending from the manifold and a temperature monitoring device at the surface for monitoring the temperature of the downhole fluid. 3. In a method of monitoring the fluctuating pressure and temperature of downhole fluid in a board well at a desired depth, lowering a tube with temperature sensing into the board well, the tube is continuously lowered from the surface to the desired depth. has an extending flow path, and the temperature detection line is
extending from the surface to an adjacent desired depth; and lowering the housing to the desired depth in the well, the housing defining a chamber in fluid communication with the downhole fluid in the well and the flow path in the pipe. pressurizing the flow path in the tube and the portion of the chamber in the housing with the selected fluid to form an interface between the selected fluid and the downhole fluid in the chamber in the housing; Selected fluids in the tubes at the surface to seal the selected fluids in the flow path while outputting temperature sensing lines from the tubes at the surface and determine the fluid pressure of the downhole fluid at the desired depth. A method comprising: monitoring the pressure of the fluid; and monitoring a temperature sensing line at the surface to determine the temperature of the downhole fluid at a desired depth.