Well fluid fallback alarms

Abstract

A well fluid fallback alarm apparatus has a wellhead assembly, a check valve that opens in response to fluid falling back through the production tubing, thereby allowing air to enter the wellhead assembly, and an air-driven alert mechanism in fluid communication with the check valve, wherein the movement of air caused by the fluid fallback is utilized to generate a notification;

Description

[0001] WELL FLUID FALLBACK ALARMS

[0002] BACKGROUND

[0003] Field of the Invention

[0004] The invention relates generally to downhole oilfield equipment and wellheads, and more particularly to systems and methods to alert personnel of falling fluid inside the production tubing.

[0005] Oil is typically produced by drilling wells into oil reservoirs in geological formations and then lifting the oil out of the reservoirs through the wells. Commonly, the oil is artificially lifted using ESPs (electrical submersible pumps), rod pumps, gas lift, or other means.

[0006] Electric power suitable for the respective ESPs is normally generated by electric drive systems that are positioned at the surface of each well, and is conveyed from the drive to the ESP via a power cable that extends from the drive system to the deployed ESP. An ESP typically includes a pump section, a seal section, and a motor section. The power from the electric drive system is provided to the motor, which drives the seal section and pump section. Frequently, the motor is a rotary motor which drives a shaft that is coupled to the shaft of a centrifugal pump. The rotating motor shaft causes the pump shaft to rotate, lifting the fluid out of the well. The pump typically contains a rotating impeller and stationary diffuser.

[0007] The motor is typically one of two types: an induction motor; or a permanent magnet motor. In the case of an induction motor, power (usually three-phase AC power) is provided to the windings of the motor's stator, causing the stator to generate rotating magnetic fields in the stator. These rotating magnetic fields induce currents and corresponding magnetic fields in a rotor, causing the rotor and the motor shaft to rotate and drive the pump. In the case of a permanent magnet motor, power (usually three- phase AC) is provided to the motor's stator windings, generating rotating magnetic fields as in the induction motor. The rotor of the permanent magnet motor, however, has a set of permanent magnets which cause the rotor to rotate in the rotating magnetic fields generated by the stator.

[0008] As explained above, in normal operation, power supplied to a conventional induction type or permanent magnet ESP motor causes the motor to rotate, which causes fluid (e.g., oil) to flow through the pump. What is less frequently considered, however, is that the reverse of this sequence may also be true. In other words, the motor can act as a generator. If fluid is caused to flow through the pump, this will cause the pump to rotate, which will in turn cause the rotor to rotate generating a voltage which is applied to the conductors of the power cable. The generated voltage is often unexpected since the motor normally consumes electrical energy, and it may be dangerous or even fatal to personnel working on the system. It would therefore be desirable to provide a means to alert personnel of the electrical potential that may be generated by an ESP motor acting as a generator.

[0009] A rod lift system comprises a traveling valve attached to the bottom of the rod string and a stationary standing valve which complement each other to produce well fluid. During the downstroke the traveling valve opens and the standing valve closes. During the upstroke the traveling valve closes, and the standing valve opens. On the surface a beam pump or nodding donkey power by motors and belts raises and lowers the rod string.

[0010] When the ESP shuts down the fluid column in the production tubing falls back through the ESP. A check valve on the wellhead allows air to enter the production tubing replacing the falling fluid. A check valve located above the ESP can support the fluid column inside the production tubing. When operating normally, the rod pump, or, more specifically, the sucker rod pump located at the bottom of the rod string will sustain the fluid column above the sucker rod pump. The integrity of the downhole components for any artificial lift system can over time be attacked by solids and corrosives allowing the fluid column in the production tubing to escape. It would therefore be desirable to provide a means to alert personnel to fluid falling back into the well.

[0011] The ESP attaches to production tubing which terminates on the surface at the wellhead. Numerous ports and valves in the wellhead direct produced fluid, control the injection of fluids, provide safety outlets, and monitor pressures and temperatures. A wellhead seals the well casing, also. The rods in a rod lift system pass through a stuffing box in the wellhead which allows oscillating movement while also sealing well fluid and gases.

[0012] Wellhead systems are used for the surface containment of hydrocarbons from subterranean deposits. Wellhead assemblies also provide support for tubing and casing inserted into the wellbore. The casing lines the wellbore, thereby isolating the wellbore from the surrounding formation. The tubing typically lies concentric within the casing and provides a conduit for producing the hydrocarbons entrained within the formation. Wellhead assemblies include a wellhead and, optionally mounted thereto, various production tree equipment (for example, casing and tubing head spools, mandrels, hangers, connectors, and fittings). The production tree controls and distributes the fluids produced from the wellbore. Valves assemblies are typically provided within wellhead production trees for controlling the flow of oil or gas from a wellhead and / or for controlling circulating fluid flow in and out of a wellhead. Gate valves and other sliding stem type valves have a valve member or disc and operate by selectively moving the stem to insert / remove the valve member into / from the flow of fluid to stop / allow the flow when desired. This object of the present invention is to alert personnel around the wellhead and other users to falling fluid levels and / or to the ESP acting as a generator.

[0013] According to the present invention, there is provided a wellhead system according to the independent claims.

[0014] By utilizing apparatus which interact with the air entering the wellhead caused by well fluid fallback, personnel shall be alerted to the fluid falling state. The moving air creates a sound through a wind instrument or a rotating hammer striking a bell. Alternatively, the moving air creates a visual alarm with a raised flag or energized lamp. A further alternative method uses the moving air to energize a light bulb or sends an instrument signal through wires or the air to computers, phones or other computational devices.

[0015] Numerous other embodiments may also be possible.

[0016] BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Other objects and advantages of the invention may become apparent upon reading the following detailed description and upon reference to the accompanying drawings.

[0018] Figure 1 is a diagram illustrating a typical ESP system and wellhead.

[0019] Figure 2 is a cross section diagram of a typical wellhead during normal well production.

[0020] Figure 3 is a cross section diagram of a typical wellhead with fluid fallback.

[0021] Figure 4 is a cross sectional diagram of an external air actuated audible alarm apparatus.

[0022] Figure 4.1 is a cross sectional diagram of an alternative external air actuated audible alarm apparatus.

[0023] Figure 4.2 is a cross sectional diagram of a reed instrument audible alarm apparatus.

[0024] Figure 4.3 is a cross sectional diagram of a rotating disc siren audible alarm apparatus.

[0025] Figure 4.4 is a diagram illustrating components in a rotating disc type siren alarm apparatus.

[0026] Figure 4.5 is a cross sectional diagram of a two-chamber air actuated audible alarm apparatus.

[0027] Figure 5 is a cross sectional diagram of an air actuated flag alarm apparatus.

[0028] Figure 6 is a cross sectional diagram of an air actuated alarm bell apparatus.

[0029] Figure 7 is a cross sectional diagram of an air actuated lamp apparatus.

[0030] Figure 8 is a cross sectional diagram of an alternative air actuated lamp apparatus.

[0031] Figure 9 is a cross sectional diagram of a wireless air monitoring apparatus.

[0032] Figure 10 is a cross sectional diagram of a wired air monitoring apparatus.

[0033] Figure 11 is a cross sectional diagram of an electrically powered audible alarm.

[0034] Figure 12 is a cross sectional diagram of an air movement alarm test apparatus. DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0035] One or more embodiments of the invention are described below. It should be noted that these and any other embodiments described below are exemplary and are intended to be illustrative of the invention rather than limiting.

[0036] Referring to figure 1, there is shown a typical ESP system in a subterranean well. The downhole ESP system 140 consists of electric motor 142, seal section 144, and multistage centrifugal pump 146 installed above well perforations 130. Power cable 150 conveys power provided by variable speed drive 160. Power cable 150 connects to motor 142. Motor 142 rotates seal section 144 and multistage centrifugal pump 146. Pump 146 pushes the fluid up the production tubing 120. Atop well casing 110 resides the well head 170 with multiple outlets, inlets, and valves 175.

[0037] Referring to figure 2, there is shown a cross sectional view of a typical wellhead during normal well fluid production mode. Wellhead 230 resides on top of well casing 210 and suspends production tubing 220. Fluids 270 entering and exiting wellhead 230 through various outlet and inlet piping 245 are controlled with gate valving 240. Wellhead 230 receives produced well fluid 270. Gate valves 240 direct the produced well fluid 270 to the appropriate piping 245. Well fluid 270 upon exiting wellhead 230 passes through check valve 260. Another check valve 250 controls atmospheric air entering the wellhead 230 and production tubing 220. Produced fluid 270 closes air check valve 250 and opens check valve 260.

[0038] Referring to figure 3, there is shown a cross sectional view of a typical wellhead 330 during fluid fallback mode. When the normal production of well fluid ceases well fluid 375 in production tubing 320 falls back into the well. The vacuum created closes fluid check valve 360 and opens air check valve 350. Air 370 enters wellhead 330 and production tubing 320 through check valve 350.

[0039] Referring to figure 4, there is shown a cross sectional diagram of an air actuated audible alarm apparatus. View 4.1 shows the audible alarm apparatus 430 attached to the ball check valve 420 which attaches to wellhead 410. Fluid 445 falling into the well unseats check valve 420 and pulls air 440 into the apparatus 430. Wind musical device 450 attaches to the apparatus 430 creating audible alarm 460. View 4.2 shows an enlarged view of wind musical device 450. Air 440 enters orifice 442. Moving air 440 creates vortex 444. Exiting air 440 makes audible sound 460 exiting through angled port 446.

[0040] Referring to figure 4.1, there is shown a cross sectional diagram of an alternative air actuated audible alarm apparatus. View 4.3 shows the audible alarm apparatus 430 attached to the ball check valve 420 which attaches to wellhead 410. Fluid 445 falling into the well unseats check valve 420 and pulls air 440 into the apparatus 430. Wind musical device 450 attaches to the apparatus 430 creating audible alarm 460. Echo chamber 470 amplifies the alarm 460 which passes through membrane 480. View 4.4 shows an enlarged view of wind musical device 450. Air 440 enters orifice 442. Moving air 440 creates vortex 444. Exiting air 440 makes audible sound 460 exiting through angled port 446.

[0041] Referring to figure 4.2, there is shown a cross sectional diagram of reed type instrument audible alarm apparatus. View 4.5 shows the audible alarm apparatus 430 attached to the ball check valve 420 which attaches to wellhead 410. Fluid 445 falling into the well unseats check valve 420 and pulls air 440 into the apparatus 430. Reed audible instrument 450 attaches to the apparatus 430 creating audible alarm 460. View 4.6 shows an enlarged view of reed type audible alarm device 450. Air 440 enters orifice 475 causing reed 470 to vibrate audibly.

[0042] Referring to figure 4.3, there is shown a cross sectional diagram of rotating disc siren audible alarm apparatus. View 4.7 shows the audible alarm apparatus 430 attached to the ball check valve 420 which attaches to wellhead 410. Fluid 445 falling into the well unseats check valve 420 and pulls air 440 into the apparatus 430. Rotating disc audible instrument 450 attaches to the apparatus 430 creating audible alarm 460. View 4.8 shows an enlarged view of rotating disc audible alarm device 450. Device 450 contains a stationary disc 452 and a disc 454 which rotates on shaft 456. Air 440 enters the device 450 rotating disc 454. Air 440 passing from rotating disc 454 to stationary disc 452 creates alarm sound 460.

[0043] Referring to figure 4.4, there are shown detailed depictions of the components in a typical rotating disc siren. View 4.9 shows the siren assembly 450 with housing 405, stationary disc 415, rotating disc 425, and shaft 435. View 4.10 shows the stationary disc 415 with communication holes 416 and a central hole 417 to hold the shaft 435. View 4.11 shows the rotating disc 425 with communication holes 426 and a central hole 427 to accommodate the shaft 435. The angle of communication holes 426 induces the disc to rotate.

[0044] Referring to figure 4.5, there is shown a cross sectional diagram of two chamber air actuated audible alarm apparatus. View 4.12 shows the audible alarm apparatus 430 attached to the ball check valve 420 which attaches to wellhead 410. Fluid 445 falling into the well unseats check valve 420 and pulls air 440 into the apparatus 430. Air 440 entering device 450 energizes fan 476 which transfers rotation 474 to shaft 478. Rotating shaft 478 energizes fan 472 in second chamber 480. Rotating fan 472 pulls air 442 into the second chamber 480. Air 442 exits the second chamber 480 through audible alarm instrument 450. View 4.13 shows an enlarged depiction of the audible alarm instrument 450. Air 442 enters instrument 450 creating a vortex 453. Air 456 exits the instrument through labium 458 creating an audible alarm 460. Further air 442 exits device 450 past labium 458.

[0045] Referring to figure 5, there is shown a cross sectional diagram of an air actuated flag alarm apparatus. View 5.1 shows the apparatus 530 attached to ball check valve 520 which attaches to wellhead 510. Fluid 545 falling into the well unseats ball check valve 520 and pulls air 540 into the apparatus 530. Paddle 550 swings open when air is entering and closes when air is not moving. View 5.2 is an enlarged view of paddle 550 function. View 5.3 is an external view the apparatus 530 and flag 560 shown attached to the shaft in paddle 550. When air 540 enters the apparatus flag 560 is raised. When the air 540 is not moving flag 560 falls.

[0046] Referring to figure 6, there is shown a cross sectional diagram of an air actuated alarm bell apparatus. View 6.1 shows apparatus 630 attached to ball check valve 620 which attaches to wellhead 610. Fluid 645 falling into the well unseats check valve 620 and pulls air 640 into the apparatus 630. Air 640 entering the apparatus 630 rotates fan 650 which rotates external hammer 660 striking bell 670. View 6.2 shows an external top view with air 640 entering the apparatus 630. The rotating hammer 660 strikes bell 670.

[0047] Referring to figure 7, there is shown a cross sectional diagram of an air actuated lamp apparatus. The apparatus 730 connects to ball check valve 720 which attaches to wellhead 710. Fluid 745 falling into the well unseats check valve 720 and pulls air 740 into the apparatus 730. Air 740 entering the apparatus 730 rotates fan 750 connected to generator 760 which energizes lamp 770.

[0048] Referring to figure 8, there is shown a cross sectional diagram of an alternative air actuated lamp apparatus. View 8.1 shows the apparatus 830 attached to ball check valve 820 which attaches to wellhead 810. Fluid 845 falling into the well unseats check valve 820 and pulls air 840 into the apparatus 830. Air 840 entering the apparatus 830 rotates a switch 850 closing the circuit. Power supply 860 energizes lamp 870. View 8.2 shows an enlarged view of the switch 850 arrangement.

[0049] Referring to figure 9, there is shown a cross sectional diagram of a wireless air monitoring apparatus. The apparatus 930 is attached to ball check valve 920 which attaches to wellhead 910. Fluid 945 falling into the well unseats check valve 920 and pulls air 940 into the apparatus 930. Air 940 entering the apparatus 930 rotates fan 950 which energizes generator 960 sending a variable electrical data signal to computer processing device 970 which sends the data wirelessly with antenna 980.

[0050] Referring to figure 10, there is shown a cross sectional diagram of a wireless air monitoring apparatus. The apparatus 1030 is attached to ball check valve 1020 which attaches to wellhead 1010. Fluid 1045 falling into the well unseats check valve 1020 and pulls air 1040 into the apparatus 1030. Air 1040 entering the apparatus 1030 rotates fan 1050 which energizes generator 1060 sending a variable electrical data signal to computer 1070.

[0051] Referring to figure 11, there is shown a cross sectional diagram of an air-driven, electrically powered audible alarming apparatus. The apparatus 1130 connects to ball check valve 1120 which attaches to wellhead 1110. Fluid 1145 falling into the well unseats check valve 1120 and pulls air 1140 into the apparatus 1130. Air 1140 enters the apparatus 1130 and rotates fan 1150. Fan 1150 connects to generator 1160 which sends a variable electrical data signal boosted by power supply 1180 to electrically powered audible alarm 1190.

[0052] Referring to figure 12 is shown a cross sectional diagram of a test method for an air movement alarm apparatus. The apparatus 1230 connects to ball check valve 1220 which attaches to wellhead 1210. Vacuum pump 1250 connects to piping between air movement alarm apparatus 1230 and check valve 1220. Removed air 1240 enters apparatus 1230.

[0053] All the embodiments shown and described here use a ball check valve, however flapper valves, poppet valves, or similar other valves could be used instead. The alert mechanism is shown in the embodiments as being upstream of the check valve, but of course this order could be reversed, and one or both of these could be integrally formed with the wellhead. The embodiments also show the check valves directly attached to or incorporated within the well head, though of course the check valves can be external and merely in fluid communication.

Claims

CLAIMS1: A well fluid fallback alarm apparatus comprising: a wellhead assembly; a check valve that opens in response to fluid falling back through the production tubing, thereby allowing air to enter the wellhead assembly; an air-driven alert mechanism in fluid communication with the check valve, wherein the movement of air caused by the fluid fallback is utilized to generate a notification;2. A well fluid fallback alarm apparatus according to claim 1 wherein the air-driven alert mechanism comprises: an audible device configured to convert the airflow into sound via mechanical means; or a visual device configured to convert the airflow into a visual signal; or an electrical generation device including a generator to convert the airflow to electrical energy.

3. A well fluid fallback alarm apparatus according to claim 1 wherein the air-driven alert mechanism passively converts the kinetic energy of the entering air into a mechanical, visual, or electrical notification without requiring an external power source.

4. A well fluid fallback alarm apparatus according to claim 2 wherein the audible device is selected from the group consisting of wind instruments, reed instruments, rotating disc sirens, or bells activated by rotating hammers.

5. A well fluid fallback alarm apparatus according to claim 2 wherein the visual device is selected from the group consisting of raised flags or illuminated lamps.

6. A well fluid fallback alarm apparatus according to claim 2 wherein the electrical generation device comprises a fan driven by the airflow, connected to a generator that produces electrical energy, which energizes either an audible alarm, a visual lamp, or a data transmission system.

7. A well fluid fallback alarm apparatus according to claim 6 whereby air entering the wellhead actuates a switch and power supply which energizes a lamp.

8. A well fluid fallback alarm apparatus according to claim 6 wherein data generated by air entering the wellhead is captured and transmitted wirelessly.

9. A well fluid fallback alarm apparatus according to claim 6 wherein data generated by air entering the wellhead is captured and transmitted by wire.

10. A well fluid fallback alarm apparatus according to any previous claim whereby air entering a wellhead generates an electrically powered audible alarm.

11. A well fluid fallback alarm apparatus according to any previous claim further comprising a testing apparatus for verifying the functionality of the air-driven alert mechanism, the testing apparatus comprising: a means for generating controlled airflow connected to the air-driven alert mechanism, configured to simulate air movement corresponding to fluid fallback by drawing or pushing air through the check valve into the air-driven alert mechanism; wherein the testing apparatus allows activation of the air-driven alert mechanism by generating a controlled airflow, enabling verification of the operational status of the notification system under simulated conditions.12: The well fluid fallback alarm apparatus of claim 11, wherein the testing apparatus verifies the functionality of audible alarms.13: The well fluid fallback alarm apparatus of claim 11, wherein the testing apparatus verifies the functionality of visual alarms.14: The well fluid fallback alarm apparatus of claim 11, wherein the testing apparatus verifies the functionality of data transmission.15: The well fluid fallback alarm apparatus according to any of claims 2 to 14, further comprising a plurality of audible alarms.16: The well fluid fallback alarm apparatus of claim 15, wherein some or all of the audible alarms have an air flow control valve.17: The well fluid fallback alarm apparatus according to any of claims 2 to 16, further comprising multiple alarms arranged in series.18: The well fluid fallback alarm apparatus according to any of claims 2 to 17, further comprising multiple alarms arranged in parallel.19: The well fluid fallback alarm apparatus according to any of claims 2 to 18, further comprising a rotating shaft energized by air entering the wellhead.20: The well fluid fallback alarm apparatus of claim 19, wherein the rotating shaft energizes an air movement device in a second chamber.21: The well fluid fallback alarm apparatus of claim 20, wherein the moving air in the second chamber creates an audible alarm.22: The well fluid fallback alarm apparatus of claim 21, wherein the audible alarm selected from the group consisting of a wind instrument, a reed-type instrument or a rotating disc siren.23: The well fluid fallback alarm apparatus according to any previous claim, further comprising a first chamber controlling air entering the wellhead, and a second chamber wherein external air is pulled in.24: The well fluid fallback alarm apparatus of claim 23, further comprising a shaft and fan arrangement which transforms the kinetic energy of air into rotational energy.25: The well fluid fallback alarm apparatus of claim 23, wherein the shaft and fan arrangement extends into a separate chamber which induces air movement through an audible alarm device.26: The well fluid fallback alarm apparatus of claim 24, further comprising a plurality of chambers being energized by the rotating shaft.27: The well fluid fallback alarm apparatus of claim 23, further comprising a plurality of external air conditioning chambers.28: The well fluid fallback alarm apparatus of claim 23, wherein the data is transmitted to one or a plurality of other chambers.29: The well fluid fallback alarm apparatus of any previous claim wherein the check valve is incorporated in the wellhead assembly.

Images