OBTAINING DATA FROM A WELL

Abstract

The invention relates to gathering data about a hydrocarbon well by dropping a ball or dart (1) through the well (21) that emits an acoustic signature and/or senses information about the wellbore, such as deformation or bending. The dart signature and/or sensed data is communicated to the surface via a DAS cable (25) running down the tubing (20). The dart (1) may be made in two detachable modules, the first module (4) containing an acoustic emitter and the second module (6) having a certain drift diameter and being one of a set of interchangeable modules of different drift diameter that may be selected and assembled to the first module (4). The second module or both modules may be dissolvable. The dart (51) may store data as it descends through the tubing (60) and then dock with a docking station (65) that is connected with a TEC line (66) running up the outside of the tubing (60) and download the data via the TEC line (66) up to the surface.

Claims

1. A process for obtaining data from a wellbore, where the process comprises: a) dropping or pumping a ball or dart into the well, wherein the dart is equipped with one or more sensors to detect restrictions in the tubing, casing or liner in the well, b) or to detect geometry of the tubing, casing or liner in the well, or to detect leaks in the tubing, casing or liner; b) storing detected data in the dart; c) processing data in the ball or dart; and d) communicating the data from the dart to the surface via a DAS cable or TEC line or by transmitting signals through well fluid.

2. The process according to claim 1, wherein the said one or more sensors include an acoustic caliper, impulse radar sensor, ultra sound sensor or multi finger caliper (MFC) for gathering data about wellbore geometry, e.g. detecting restrictions in the well or tubing.

3. The process according to claim 1, wherein the said one or more sensors include a flex sensor, e.g. an optical fibre within the dart oriented along the length of the dart or arranged in a coil, able to detect bending of the dart and thus of the well or tubing.

4. The process according to claim 1, wherein the said one or more sensors include a gyro that can gather information about shape of the wellbore.

5. The process according to claim 1, wherein the said one or more sensors include an acoustic sensor in the dart/ball to detect leaks in tubing casing or liner, or behind tubing, casing or liner.

6. The process according to claim 1, wherein the said one or more sensors include a casing collar locator (CCL) for identifying measured depth location in the well by detecting features, e.g. collars, on tubing, casing or liner.

7. The process according to claim 1, wherein the said one or more sensors include a temperature sensor and/or a pressure sensor.

8. The process according to claim 1, wherein the dart or ball docks in a docking station in the well, where data stored in the dart or ball is transferred to the docking station and transmitted up a pre-installed TEC line to the surface.

9. The process according to claim 1, wherein the dart or ball transmits data to a pre-installed DAS line.

10. The process according to claim 1, wherein the dart or ball is not retrieved, is dissolvable, or degrades.

11. The process according to claim 1, wherein the dart or ball comprises a first module comprising a data sensor and/or transmitter and a second module having a drift diameter greater than that of the first module, the first and second modules being detachable, and wherein a plurality of second modules having different drift diameters are provided.

12. The process according to claim 1, wherein a plurality of balls or darts are provided, each comprising a data sensor and/or transmitter and each having a different drift diameter and/or length.

13. A ball or dart for dropping or pumping through well tubing, the ball or dart comprising: (a) one or more sensors for detecting a condition of the well as the ball or dart passes along the tubing; (b) a data storage facility for storing sensed data; (c) a data processing facility for processing data before or after storage; (d) a communication facility for transferring data to the surface via well fluids or through casing or liner, a DAS line or a TEC line.

14. The ball or dart according to claim 13, wherein the said one or more sensors are selected from an acoustic caliper, a multi finger caliper (MFC), an impulse radar sensor, an ultra-sound sensor, an acoustic sensor, an optical fibre within the dart, an optical fibre oriented along the length of the dart, an optical fibre arranged in a coil, a flex sensor able to detect bending of the dart, a gyro, a casing collar locator (CCL), a temperature sensor, a pressure sensor, a flow meter, a magnetometer, and a camera.

15. The ball or dart according to claim 13, wherein the dart or ball is dissolvable.

16. The ball or dart according to claim 13, wherein the dart or ball comprises a first module comprising a data sensor and/or transmitter and a second module having a drift diameter greater than that of the first module, the first and second modules being detachable, and wherein a plurality of second modules having different drift diameters are provided.

17. A set comprising a plurality of balls or darts each according to claim 13, each ball or dart comprising a data sensor and/or transmitter and each having a different drift diameter.

18. A ball or dart according to claim 13, said ball or dart comprising one or more wiper darts with integrated sensors to detect flexing of the dart fins said fins composed of rubber, nitrile, polymer, or gel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] A more complete understanding of the present invention and benefits thereof may be acquired by referring to the follow description taken in conjunction with the accompanying drawings in which:

[0031] FIG. 1 is a schematic view showing a dart passing along a cased well with a DAS line, illustrating a method in accordance with the invention;

[0032] FIG. 2 is a schematic view of a set of modular darts according to the invention;

[0033] FIGS. 3A and 3B are schematic views of a further embodiment of the invention, employing an optical fibre to detect bending; and

[0034] FIGS. 4A, 4B and 4C are schematic views of a further embodiment of the invention, that employs a dart docking station and TEC line.

DETAILED DESCRIPTION

[0035] Turning now to the detailed description of the preferred arrangement or arrangements of the present invention, it should be understood that the inventive features and concepts may be manifested in other arrangements and that the scope of the invention is not limited to the embodiments described or illustrated. The scope of the invention is intended only to be limited by the scope of the claims that follow.

[0036] As shown in FIG. 1, a dart 1 is passing down production tubing 20 of a hydrocarbon well 21. The well includes casing/liner 22 of different diameters and a production liner 23. The production tubing 20 terminates in the region of a production packer 24. Running down the outside of the production tubing 20 is a distributed acoustic sensing (DAS) line 25, comprising optical fibre cable. All of these components are in themselves conventional and will not be described in detail. In a first embodiment of the invention, the dart 1 comprises two parts: a proximal part 4 equipped with a signal generator 7 and loudspeaker or other device 2 for transmitting an acoustic signal together with a battery 3 for powering the signal generator 7 and loudspeaker 2. The proximal part 4 has a male threaded portion 5 by means of which it is connected to a distal part 6 of the dart that has a larger outer diameter than that of the proximal part 4. The distal part 6 includes a complementary female thread by means of which the distal part 6 is attached to the proximal part 4.

[0037] Some or all of the dart is dissolvable. In particular the distal part 6 would normally be dissolvable. The distal part 6 is a component designed to have a certain drift diameter so that the fact that the dart has reached a certain point in the tubing indicates that there is at least that drift diameter of tubing above the dart. For clarity, drift or drift diameter refers to the largest diameter part; for example, the profile may include slots running along the length of the dart to allow bypass. The term drift thus includes fluted drift. Different drift diameters for testing can be selected by selecting from a range of different distal parts 6 that can be fitted interchangeably to the proximal part 4. The distal part plays no part in the generation or transmission of acoustic signals and so can be made entirely or at least mostly of a material that will dissolve in a well after time, or can be dissolved intentionally, e.g. by passing acid down the well. In the latter case, the distal part 6 may be made, e.g., of aluminium or some other material that will be attacked by acid. The proximal part 4 may also be dissolvable or it may have a dissolvable housing, e.g. of aluminium.

[0038] As the dart passes along the tubing 20, it emits a distinctive acoustic signal. The acoustic signal interacts with the DAS cable as the dart descends, causing microstrain in the cable. Light transmitted from the surface down the DAS cable is subjected to scattering and returned/backscattered light will be modulated in some way that is representative of the acoustic signal and also at what location along the acoustic signal has interacted with the cable. Using known techniques, the returning light can be analysed to indicate the position of the dart in the tubing.

[0039] In this way, a dart with selected drift diameter can be dropped or pumped down tubing and the progress of the dart monitored via DAS cabling. When the dart has served its purpose, it can either be allowed to dissolve in well fluid or a liquid, such as acid, passed down the tubing to dissolve the dart. Any small, undissolved parts can simply be allowed to be lost downhole or produced back to surface.

[0040] FIG. 2 shows a proximal component 4, separately from any distal component 6. Loudspeaker 2, signal generator 7 and power supply 3 are shown schematically. The male threaded portion is shown at 5. Three distal parts 6 are shown, each having a different drift diameter. A female thread is shown at 8, which in the assembled dart receives the male thread 5 of the proximal part 4. Assembled darts are also shown at 1. Having a modular system allows great flexibility in how the dart is used.

[0041] Obtaining information in this way is considerably less expensive than the normal method of wireline logging, and allows for more frequent, regular logging of wells, in particular to gain early information about deformation of tubing.

[0042] The drift information can be important to be able to confirm the integrity of the well (whether it is a production well or an injector well) potentially planning plug and abandonment in a better timed and more prudent way, keeping well in production for a longer time, ensuring no Out Of Zone injection, etc. Gaining early knowledge of evolving tubing deformations might trigger rush intervention jobs while there is still access through the restriction(s), e.g. to secure/improve production, plug the well deep, etc.

[0043] Having a DAS (Distributed Acoustic Sensing) line clamped along the tubing is becoming increasingly common when installing production tubing, so the DAS cable and associated surface equipment is likely already to be present, thus limiting the equipment cost to just the dart.

[0044] In an alternative arrangement, the acoustic signal emitting system (power source, signal generator and loudspeaker) or one or more parts of it can also be integrated to the drift part, i.e. the distal part 6. The drift part 6 can also be manufactured on location using a 3D printer for quick and flexible adjustments. Although the terms proximal part and distal part have been used to refer to the two components of the dart in this embodiment, the drift part 6 may equally be at the proximal end of the dart and the acoustic signal emitting part at the distal end. It may be preferable in some cases to provide the dart as a single integrated structure rather than as a modular system. In this event, a range of darts having different drift diameters may be provided.

[0045] In another embodiment, the dart may be equipped with one or more sensors to detect restrictions in the tubing, casing or liner in the well, or to detect geometry of the tubing, casing or liner in the well, or to detect leaks in the tubing, casing or liner in the well. In this event, the dart also includes some means to store and process the data and to transmit it to a DAS line or alternatively a TEC line in order to get the information to the surface. FIGS. 3A and 3B show a dart 31 passing along a well 45, through tubing 46. The well is cased with casing 47. The dart 31 is in two parts, as described above with reference to FIGS. 1 and 2. The description above of the elements, or optional elements, of the dart with respect to FIGS. 1 and 2 also applies to the embodiment shown in FIG. 3; thus, the dart may or may not be made in two parts and may comprise a modular system where a set of components of different drift diameter are provided. In the embodiment described in relation to FIG. 3, the length of one component of the dart may be varied, e.g. by providing different length components as part of a set.

[0046] In this embodiment, the signal emitting system of the proximal part 34 (which may alternatively be distally located, as discussed above) comprises a pulse transmitter 32, signal generator 37 and power source (e.g. battery) 33. In addition, it comprises a receiver and processor 38 for receiving and processing signals from an optical fibre bend detector, which will be described further below.

[0047] Within the distal part 36 of the dart (which may also be proximally located), is an optical fibre 41. An emitter of light such as a laser, together with transceiver, shown at 40, are located at one end of the fibre. The laser and transceiver transmit pulses of light through the fibre and received returned light signals and transform them to electrical signals that are passed through a pair of contacts 39 and line 42 to the receiver and processor 38.

[0048] The distal part 36 is relatively long and somewhat flexible, such that when passed down tubing that has a bend it is distorted, as shown in FIG. 3B. The optical fibre 41 is embedded in the material of the distal part 36 and is also distorted. The optical fibre 41 acts like a small scale DAS or DTS cable in that the properties of returned/scattered light are indicative of the degree of bending (and hence strain) of the fibre. The dart outer diameter should ideally be close to, but smaller than the tubing inner diameter, then the bending measurements will give a good representation of local bending of the tubing. As with the embodiment described in relation to FIGS. 1 and 2, the dart (or the distal part of it) can be customized on location using a 3D printer.

[0049] A signal indicative of the degree of bending of the tubing and/or the direction of bending is thereby created and transmitted to the components in the proximal part of the dart. The signal is encoded and the loudspeaker 32 energized to transmit encoded pulses through the fluid in the tubing and up to the surface. Alternatively, the encoded signal may be acoustically transmitted to a DAS cable running along the tubing, as with the embodiment described in relation to FIGS. 1 and 2. The dart/ball can send data to surface using MWD (Measure While Drilling) or similar techniques.

[0050] In this way, a continuous reading of the shape of the wellbore may be transmitted to the surface.

[0051] Other known types of sensor may be used in the dart in addition to or alternatively to the optical fibre bend detector described above. These include, for example, a high frequency gyro that is able to gather information about shape of the wellbore. Since the distal-proximal orientation of the dart in the wellbore is defined, information about angle/azimuth of the dart at any given time may be obtained from the gyro. Other examples include multi-finger calipers to determine the drift/interior profile of the tubing, acoustic calipers to sense the same thing, multi-beam sensor(s) or (impulse) radar sensors. Casing collar locators could also be included in the dart; these known devices detect when a casing collar or other features are passed by sensing, e.g., the increased mass of metal. Acoustic sensors may be included to detect leaks in tubing, behind tubing or casing throughout the wellbore.

[0052] The above techniques/sensors/tools can be combined into a multi-functional dart. The dart/ball can have internal memory to store, at least temporarily, gathered data. This would allow data to be condensed and transmitted as a summary signal. This would reduce the amount of data required to be transferred. The dart could convert raw data into simple, functional messages, e.g. dart landed, max deflection: 2 degrees, minimum ID: 3.75 inches, etc.

[0053] Another embodiment is shown in FIGS. 4A, 4B and 4C. FIG. 4A illustrates a wellbore 61 with casing/liner 62 and tubing 60. At the end of the casing is a production or injection packer 64 and, a small distance above the packer 64, a docking station 65 for a dart. Connected to the docking station 65 and running along the outside of the tubing to the surface is so-called tubing encapsulated cable 66, commonly referred to as a TEC line 66. A TEC line is able to transmit power and data from and to the surface. Although still highly schematic, FIG. 4B shows the docking station 65 and TEC line 66 in slightly more detail. The docking station comprises a joint of tubing that can be added into the tubing string as it is run into the well; connections with the normal tubing joints are shown at 67. Recesses 68 into which corresponding sprung projections on the dart can engage (see FIG. 4C) are provided in the internal surface of the docking station 65. These are shown in highly schematic form, but arrangements such as this for capturing a ball or dart are well known and can take a number of different forms.

[0054] FIG. 4C shows a dart 51 in place in the docking station 65. The dart is fitted with sprung lugs or projections 52 that engage in the recesses 68 of the docking station when the dart 51 arrives at the docking station 65. The dart 51 is thereby retained, allowing data stored in the dart to be transmitted from the dart to the TEC line and then up to the surface.

[0055] The docking station includes a radio receiver unit 69 connected to the TEC line and able to receive radio signals transmitted from the docked dart 51 and convert them to electrical signals and pass them into the TEC line 66. The receiver may be powered by a battery 70, but would normally be powered via the TEC line.

[0056] The dart 51 includes a short range radio transmitter 53, a data storage unit 54 and power supply (battery) 55. Data gathered by the dart as it travels down the tubing 60 is stored in the data storage unit 54. When the dart is docked, this can trigger a signal to the docking station that the dart has arrived, which is transmitted through the TEC line. Data stored in the dart is then transmitted by the transmitter 53 though the tubing 60 and received by the docking station receiver 69. The data transfer can be accomplished through well-known wireless technologies. The transmitter and data storage unit are powered by battery 55. The acquired data may be processed prior to transmission by a processing unit 56. Processing may include condensing the data into a simpler form, as discussed above.

[0057] The dart 51 may gather data by means of any of the different systems described above, including optical fibre bend detector, calipers, etc. These are not shown in FIG. 4C but have been described or illustrated in connection with previous embodiments and it can easily be seen how any of these techniques can be applied to this embodiment. However, in this embodiment it may not be possible for data to be transferred continuously to the surface as the dart descends, therefore data storage in the dart may be a requirement. Also, it would not be appropriate in this embodiment for the dart to be designed to have its descent arrested when it encounters an obstruction or deformation of the tubing (thereby detecting the obstruction or deformation) since, of course, in this scenario the dart would not reach the docking station.

[0058] In an alternative arrangement, when docked, the dart can be powered by electromagnetic induction from the TEC line such that it gets the required power to compute, transmit, etc.

[0059] As an alternative to the recess 68, the docking station can include a variety of profiles that the dart lands/engages in, which are common in the oil industry, especially within well intervention. The profile can be an ID restriction (e.g. dissolvable, or easy-millable cast iron), a recessed profile (which mates e.g. with a selective, spring loaded profile on the dart) which doesn't create an ID restriction, etc.

[0060] In some scenarios it is important to confirm that the dart passes the injection/production packer 64 (e.g. to avoid compression above packer if pressurized above a sealing dart, or just to confirm drift related to well plugging depths). However, it is more challenging/expensive to have the TEC line protrude the packer (requires feedthrough packer). For such a scenario it can be placed an engagement profile right below the packer and a TEC line docking station right above the packer. The drift will need to be long enough to land in the engagement profile and at the same time communicate with the docking station-achieved by having a slimmer, possibly flexible tail which includes the internal communication device.

[0061] In an alternative arrangement the docking station and dart may be equipped with electrical contacts that make contact when the dart is docked and via which data and power may be transferred from dart to docking station.

[0062] For all these ideas the ball/dart can be dissolvable. There might be electronics etc. inside the ball/dart that will not dissolve, but might cause no harm due to the small size.

[0063] In closing, it should be noted that the discussion of any reference is not an admission that it is prior art to the present invention, especially any reference that may have a publication date after the priority date of this application. At the same time, each and every claim below is hereby incorporated into this detailed description or specification as a additional embodiments of the present invention.

[0064] Although the systems and processes described herein have been described in detail, it should be understood that various changes, substitutions, and alterations can be made without departing from the spirit and scope of the invention as defined by the following claims. Those skilled in the art may be able to study the preferred embodiments and identify other ways to practice the invention that are not exactly as described herein. It is the intent of the inventors that variations and equivalents of the invention are within the scope of the claims while the description, abstract and drawings are not to be used to limit the scope of the invention. The invention is specifically intended to be as broad as the claims below and their equivalents.

REFERENCES

[0065] All of the references cited herein are expressly incorporated by reference. The discussion of any reference is not an admission that it is prior art to the present invention, especially any reference that may have a publication date after the priority date of this application. Incorporated references are listed again here for convenience: [0066] 1. U.S. Pat. No. 4,676,310, Scherbatskoy & Neufeld, Apparatus for transporting measuring and/or logging equipment in a borehole. [0067] 2. U.S. Pat. No. 8,887,799, EP3361041, Robichaux, et al., Tattle-tale apparatus. [0068] 3. U.S. Pat. No. 9,476,274, Edmonstone, et al., Apparatus and System and Method of Measuring Data in a Well Extending Below Surface. [0069] 4. U.S. Pat. No. 10,392,910, Walton, et al., Multi-zone actuation system using wellbore darts. [0070] 5. U.S. Pat. No. 10,443,354, Murphree, et al., Self-Propelled Device for Use in a Subterranean Well. [0071] 6. U.S. Pat. No. 10,718,175, Cabot & Cramer, Light and Buoyant Retrievable Assembly-Wellbore Tool and Method. [0072] 7. U.S. Pat. No. 11,466,525, US20200024915 (Wessel & Duckering) Propulsion Unit for Wellbore Tractor Tool. [0073] 8. U.S. Pat. No. 11,933,142, WO2022250664, Kazanci, et al., Traceability of cementing plug using smart dart. [0074] 9. US20210277771, Pawar, et al., Distributed Acoustic Sensing for Coiled Tubing Characteristics.