Wellhead System, Assembly and Method for Monitoring Landing of a Wellhead Component

Abstract

Wellhead system, assembly and method monitors landing or retrieving of wellhead component at pre-determined landed position in main bore of wellhead member of wellhead. System includes running tool, instrument spool and sensor assembly. Running tool couples to wellhead component, lands or retrieves wellhead component within main bore of wellhead member, decouples from wellhead component, and has passive triggering device disposed in or on running tool. Instrument spool is pressure-containing, connects within wellhead at location above landed position of wellhead component, forms bore to align with main bore of wellhead, provides clearance for the wellhead component and running tool to be run therethrough, and has vertical height dimension such that, in pre-determined landed position, passive triggering device is located in bore of instrument spool. Sensor assembly disposed in or on instrument spool monitors landing/retrieving of wellhead component in wellhead member located below instrument spool based on landing information detected within bore of the instrument spool, generates an output signal conveying the landing information, and transmits the output signal to a remote location.

Description

TECHNICAL FIELD

This invention relates in general to hydrocarbon wellhead equipment and method for monitoring landing or retrieving of a wellhead component in a wellhead.

BACKGROUND

Oil and gas production systems generally include a wellhead through which the oil and gas resources are extracted. The wellhead may be located at the earth's surface, termed a surface wellhead, or subsea. The wellhead is coupled to the oil and/or gas deposit through a well, which includes the wellbore extending to the oil/gas deposit. The wellhead generally includes pressure-containing wellhead members including a casing head and a tubing head, which provide access to the wellbore, a christmas tree and a blowout preventer (BOP). The tree includes multiple flow paths (bores), valves, fittings and controls for operating the well. A main bore, which may be vertical or deviated, extends through the wellhead members to communicate with the wellbore. The BOP typically includes multiple valves, fittings and controls to prevent fluid from exiting the well in the event of an unintentional release of pressure or an overpressure condition.

After drilling the wellbore, multiple wellhead components are landed at pre-determined landed positions in the wellhead. A casing hanger is landed in the casing head and is configured to support one or more casing strings suspended downhole in the wellbore. Typically a wear bushing and a packoff bushing are landed above the casing hanger. A tubing hanger is landed in the tubing head and is configured to support tubing (ex. production tubing) that is suspended in the wellbore and/or to provide a path for control lines, hydraulic control fluid, chemical injections etc. Other wellhead components may be landed in the wellhead, for example, plugs, packers, sealing assemblies, packoff bushings, and wear bushings. Running tools are used to land wellhead components at pre-determined landed positions within the confines of the wellhead. A hanger running tool is used to land the hanger (tubing hanger or casing hanger). For example, a tubing hanger running tool, or a rotatable tubing hanger running tool, is used to land the tubing hanger within the tubing head. In the case of landing a hanger, the running tool is coupled to the hanger, and is configured to be lowered (i.e., run) through the main bore of the wellhead, for example by draw works on the drilling rig or other supporting device, to align and position the hanger within a landing profile and against a landing shoulder of the casing head or the tubing head.

For ease of explanation herein, wellhead components may be described with reference to an axial axis (i.e., the longitudinal axis of the main bore of the wellhead), a radial axis (i.e., extending across the radius of the main bore), and a circumferential axis or direction, for example as a wellhead component is rotated within the main bore.

In general, landing of wellhead components such as tubing hangers, casing hangers, wear bushings, packoff bushings or sealing assemblies, into the wellhead has been conducted using manual processes to ensure proper alignment of the different components inside the wellhead.

SUMMARY

This disclosure provides a wellhead system, a wellhead assembly and a method for monitoring landing or retrieving of a wellhead component at a pre-determined landed position in a main bore of a wellhead member of a wellhead. The wellhead system includes a running tool, an instrument spool and a sensor assembly. The running tool is configured to couple to the wellhead component, to land or retrieve the wellhead component within the main bore of the wellhead member, and to decouple from the wellhead component. A passive triggering device is disposed in or on the running tool. The instrument spool is pressure-containing and is configured to connect within the wellhead at a location above the landed position of the wellhead component. The instrument spool forms a bore to align with the main bore of the wellhead and to provide clearance for the wellhead component and the running tool to be run therethrough. The instrument spool has a generally vertical height dimension such that, in the pre-determined landed position, the passive triggering device is located in the bore of the instrument spool. The sensor assembly is disposed in or on the instrument spool to monitor landing or retrieving of the wellhead component in the wellhead member located below the instrument spool based on landing information detected within the bore of the instrument spool, to generate an output signal conveying the landing information, and to transmit the output signal to a remote location.

In general, the sensor assembly includes one or more active sensors to detect the landing information, the running tool includes one or more of the passive triggering devices, and the landing information is detected by one or more of:

• • (i) conductive contact between at least one of the one or more passive triggering devices and at least one of the one or more active sensors when the wellhead component is in the pre-determined landed position;
  • (ii) a proximate position of at least one of the one or more passive triggering devices relative to at least one of the one or more active sensors when the wellhead component is in the pre-determined landed position;
  • (iii) relative movement of at least one of the one or more passive triggering devices relative to at least one of the one or more active sensors when the wellhead component is rotated in the pre-determined landed position; and
  • (iv) a change in a magnetic flux signature detected by at least one of the one or more active sensors when the running tool is coupled to the wellhead component compared to when the running tool is decoupled from the wellhead component.

The disclosure provides a wellhead assembly including the above-described wellhead system configured as a wellhead assembly with the wellhead component and the wellhead member.

The disclosure further describes a method of monitoring landing or retrieving of a wellhead component at a pre-determined landed position in a main bore of a wellhead member of a wellhead. The method includes:

• • providing a running tool adapted to couple to the wellhead component for landing at the pre-determined landed position, the running tool including a passive triggering device disposed in or on the running tool;
  • connecting a pressure-containing instrument spool into the wellhead at a location above the pre-determined landed position of the wellhead component, the instrument spool forming a bore aligned with the main bore of the wellhead and providing clearance for the wellhead component and the running tool to be run therethrough, the instrument spool having a generally vertical height dimension such that, in the predetermined landed position, the passive triggering device is located in the bore of the instrument spool, and the instrument spool including a sensor assembly disposed in or on the instrument spool;
  • for landing, coupling the running tool to the wellhead component, and running the coupled running tool and wellhead component through the bore of the instrument spool to the pre-determined landed position within the wellhead member located therebelow;
  • for retrieving, running the running tool through the bore of the instrument spool to the pre-determined landed position within the wellhead member located therebelow, and coupling the running tool to the wellhead component;
  • monitoring landing or retrieving of the wellhead component in the wellhead member located below the instrument spool by detecting landing information within the bore of the instrument spool with the sensor assembly;
  • generating an output signal conveying the landing information;
  • transmitting the output signal to a remote location;
  • for landing, decoupling the running tool from the wellhead component and removing the running tool from the wellhead; and
  • for retrieving, removing the coupled running tool and wellhead component from the wellhead.

In some embodiments, the method further includes, after landing or retrieving, removing one or more components of the sensor assembly from the instrument spool and/or removing the instrument spool from the wellhead.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is schematic, partial sectional view of one embodiment of a wellhead system, assembly and method, showing an instrument spool connected above a wellhead member, and two types of passive triggering devices (positional indicators and a conductive element) disposed on a running tool, which in turn is coupled to a wellhead component to be landed in the wellhead member. In FIG. 1A, the wellhead component is approaching the pre-determined landed position within a wellhead member (tripping in), with the running tool and the passive triggering devices located within the bore of the instrument spool. The instrument spool includes three types of active sensors, including internal proximity sensors, a resistance sensor, and external geo-magnetic sensors. The active sensors are part of a sensor assembly and are connected to a power supply, a data acquisition and data processor unit, and a telemetry unit for communicating signals to a remote location.

FIG. 1B is a schematic view similar to FIG. 1A, but showing the landed position, with the wellhead component landed on a landing shoulder of the wellhead member. The internal proximity sensors are generally vertically aligned with the positional indicators to detect relative position and relative movement, and the resistance sensor is in conductive contact with the conductive element to close an electrical circuit between the running tool, the instrument spool, the wellhead component and the wellhead member.

FIG. 1C is a schematic view similar to FIGS. 1A and 1B, but showing the running tool decoupled from the wellhead component and being removed from the wellhead (tripping out), as detected by the external geo-magnetic sensor, as well as by the internal proximity sensors and the resistance sensor. For retrieving of a wellhead component, the tripping in step of FIG. 1A involves only the running tool, with the wellhead member already in the landed position, the coupling of the running tool and the wellhead component takes place in the landed position in wellhead member, generally as shown in FIG. 1B, and the tripping out step of FIG. 1C involves the coupled running tool and wellhead component.

FIGS. 2A to 2E are sectional views of one embodiment of the wellhead system, assembly and method showing the steps of connecting, coupling, tripping in, landing, decoupling and tripping out for monitoring the landing of a tubing hanger in a tubing head.

FIG. 2A is sectional view of an instrument spool configured with three types of active sensors, including internal proximity sensors, a resistance sensor and external geo-magnetic sensors.

FIG. 2B is a sectional view of the instrument spool of FIG. 2A connected above the tubing head for monitoring landing of the tubing hanger in the tubing head located therebelow, based on landing information detected by the active sensors within the bore of the instrument spool.

FIG. 2C is a sectional view showing the running tool coupled to the tubing hanger, with the running tool having two types of passive triggering devices disposed on an exterior surface, including positional indicators and a conductive element. FIG. 2C shows the method prior to the tripping in step.

FIG. 2D is a sectional view showing the landed position with the tubing hanger landed on the landing shoulder in the tubing head, with the resistance sensor in conductive contact with the conductive element and closing a circuit between the running tool, the tubing hanger, the tubing head and the instrument spool, and with the internal proximity sensors generally vertically aligned with the positional indicators on the running tool.

FIG. 2E is a sectional view showing the tripping out step, with the running tool decoupled from the tubing hanger and removed from the wellhead. In this step, the geo-magnetic sensor detects a change in the magnetic flux signature for the running tool decoupled from the tubing hanger, compared to when the running tool is coupled to the tubing hanger, and thus the geo-magnetic sensor detects successful decoupling and tripping out. The resistance sensors and the internal proximity sensors are no longer in conductive contact with, or aligned with, the passive triggering devices, so also detect successful removal of the running tool from the wellhead.

FIGS. 3A-3E are sectional views of an embodiment of a wellhead system, assembly and method showing the steps of connecting, coupling, tripping in, landing, decoupling and tripping out for monitoring the landing of a packoff bushing to be landed above the tubing hanger to seal off the annulus above the tubing hanger.

FIG. 3A is a sectional view showing the instrument spool connected above a tubing head, with the tubing hanger in the landed position. The instrument spool includes two types of active sensors, including internal proximity sensors and external geo-magnetic sensors. The running tool is shown coupled to a packoff bushing to be landed above the tubing hanger. The running tool carries positional indicators as passive triggering devices for detection by the proximity sensors. FIG. 3A is just prior to the tripping in step.

FIG. 3B is a sectional view similar to FIG. 3A, but showing the landed position, with the packoff bushing landed above the tubing hanger. The proximity sensors are generally vertically aligned with the positional indicators of the running tool to detect relative position and relative movement.

FIG. 3C is a sectional view similar to FIG. 3B, but showing the landed and set position, with the retaining ring of the packoff bushing in the locked position.

FIG. 3D is a sectional view similar to FIG. 3C, but in the tripping out position, with the packoff bushing uncoupled from the running tool as the running tool is run out of the wellhead, as detected by the proximity sensors and the geo-magnetic sensors.

FIG. 3E is a sectional view similar to FIG. 3D, but showing the instrument spool disconnected from the tubing head and removed from the wellhead, for example with the removal of the drilling rig from the wellhead.

FIG. 4A is a cut-away, sectional view of the wall of the instrument spool showing a probe-type proximity sensor sealed in a radial bore extending to the bore of the instrument spool.

FIG. 4B is a cut-away, sectional view of the wall of the instrument spool showing a proximity sensor mounted in a recess in the bore of the instrument spool, with wires extending in a sealed radial bore extending from the sensor at the bore.

FIG. 4C is a cut-away, sectional view of the instrument spool showing a geo-magnetic sensor mounted on an external wall of the instrument spool to detect changes in the magnetic flux generated as the running tool connected to a wellhead component is landed, compared to a running tool uncoupled from the wellhead component.

FIG. 4D is a cut-away, sectional view of a resistance sensor sealed in a radial bore of the instrument spool, with one probe extending generally horizontally into the bore of the instrument spool to make conductive contact with a conductive element carried by the running tool, and a second probe embedded in the wall of the instrument spool.

FIG. 5 is a flowchart for the method of monitoring landing or retrieving of wellhead component in a wellhead member, with the one or more active sensors provided in an instrument spool connected above the wellhead member and with one or more passive triggering devices disposed on the running tool. The flowchart shows the steps of tripping in, angular orientation (relative movement), landing and tripping out, with one or more sensor output signals generated and processed to provide landing information for transmitting to a remote location.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Specific embodiments wellhead system, assembly and method of this disclosure are described below with respect to landing wellhead components in a wellhead member, for example landing a tubing hanger within a tubing head, followed by landing a packoff bushing above the landed tubing hanger. However, the disclosure more broadly relates to landing or retrieving wellhead components within wellhead members. All features of implementing a wellhead installation may not be described herein, but it should be appreciated that those skilled in the art are able to routinely design, fabricate, manufacture and fully implement having the benefit of this disclosure.

The present disclosure describes a wellhead system, a wellhead assembly, and a method for monitoring landing or retrieving of a wellhead component in a pre-determined landed position in a main bore of a wellhead member. The monitoring provides landing information to assist operators and workers at the wellsite to operate safely, more remotely, and with greater assurance that the landing operation at the pre-determined landed position has been properly completed and verified successfully. In some instances, the landing, setting and retrieving can be completed in a manner such that more exact and precise relative positional information can be provided to the operator, for example by providing one or more of the x, y and z azimuth positional co-ordinates of the relative position of a tubing hanger within a tubing head. In some instances, for example when the landed wellhead component is rotated during the landing, setting or securing operations, more exact and precise positional information such as relative angular orientation information relating to movement, such as rotation, can be provided to the operator. In some instances, landing information based on conductive contact signaling that the wellhead component is landed on a load shoulder can be provided to the operator to signal successful landing. In some instances, positional information relating to the coupled or decoupled state of the wellhead component and a running tool, can be provided to the operator. For example, geo-magnetic sensors are used to detect a change in the magnetic flux signature of the running tool coupled to the wellhead component compared to the magnetic flux signature of the running tool decoupled from the wellhead component in order to confirm successful landing and decoupling of the wellhead component when the running tool is removed from the wellhead.

Certain embodiments of the wellhead system, assembly and method are described herein using one or more active sensors of one or more types. In some embodiments the one or more active sensors are in the form of one or more proximity sensors, for example magnetic field sensors. In some embodiments the active sensor is in the form of a resistance sensor to detect conductive contact on landing, wherein the conductive contact is detected as opening or closing of an electrical circuit in the landed position. In some embodiments the one or more active sensors are in the form of one or more geo-magnetic sensors. Some embodiments include multiple of these types of active sensors, and/or multiple of the sensors of the same type. The active sensor(s) detects landing information relating to the landing or retrieving of the wellhead component within the wellhead member, but the landing information is detected remotely from the pre-determined landed position of the wellhead component in the wellhead member.

The output from the one or more active sensors provides landing information, that is, data in the form of one or more parameters of the sensor output signal, such as a voltage, frequency or current parameter, which is processed and transmitted to provide an operator with useful information or display about the relative position, relative orientation, and coupling status of the running tool and the wellhead component being landed or retrieved.

In general, the proximity sensor is a sensor that measures or detects the proximity of and/or the movement of, pairing component, termed herein as a passive triggering device, without making contact with the passive triggering device. Magnetic field sensors are particularly useful as the proximity sensors to detect positional information and relative movement information with a magnet as the passive triggering device. However, other types of proximity sensors may also be used to detect relative positional information and relative movement information relating to the location of a landed wellhead component, for example, acoustic sensors, ultrasonic sensors, and sensors for RFID tags.

A geo-magnetic sensor is a type of proximity sensor which measures the strength and direction of the Earth's magnetic field. Geo-magnetic sensors are well known for applications in compasses and GPS devices. In this disclosure, the geo-magnetic sensor detects motion of one or more metallic objects moving within the wellhead system, so no additional passive triggering device is paired with the geo-magnetic sensor. Instead, the running tool and the wellhead component are metallic objects detected by the geo-magnetic sensor. As a metallic object moves past the geo-magnetic sensor, it causes a disturbance to the Earth's magnetic field. The measured magnetic field signature, also termed magnetic flux signature, is different depending on the surrounding magnetic objects. In this disclosure, the magnetic flux signature of the running tool coupled to the wellhead component is different from the magnetic flux signature of the running tool decoupled from the wellhead component, and thus is used to detect successful coupling and/or decoupling of the running tool and the wellhead component during tripping in and tripping out operations.

In this disclosure, magnetic field sensors are particularly useful for one or both of a proximity sensor and a geo-magnetic sensor. Examples of magnetic field sensors, their packaging and use are set out below.

Inductive sensors can be used as a proximity sensor, with a passive triggering element being any metallic feature or material added to the running tool. A coil or inductor is used to generate a high frequency magnetic field through a self-sustaining sine wave oscillation. If a metallic object crosses this magnetic field, some of the energy of the oscillation is transferred to the metallic object in the form of electrical current called eddy currents. This causes an electrical resistance in the circuit, which creates a power loss that is captured by a Schmitt Trigger.

A Hall-Effect sensor can be used as a proximity sensor or a geo-magnetic sensor, however, it is typically used as a proximity sensor. The passive triggering device is a magnetic field generator such as a permanent magnet, added to the running tool. The sensor is made of a p-type semiconductor material with a continuous current passing therethrough. If a magnetic field, such as a magnet, passes through the sensor, the magnetic flux exerts a force on the semiconductor material that deflects the charge carriers, electrons and holes, to either side of the semiconductor material. As the charges move to the sides of the material, a potential difference is created, which is measured as an output voltage, also termed a Hall voltage.

An Anisotropic Magneto-Resistive (AMR) sensor can be used as a proximity or a geo-magnetic sensor. When used as a proximity sensor, the passive triggering device is a magnetic field generator such as a permanent magnet. The sensor changes its resistance due to an applied magnetic field. It uses a ferromagnetic thin film alloy that has a property called Anisotropic Magneto-Resistive Effect (AMR-Effect). In this case, the resistance is dependent on the angle between the current direction and the magnetisation through the applied magnetic field.

A Giant Magneto-Resistive (GMR) sensor can be used as a proximity sensor or a geo-magnetic sensor. When used as a proximity sensor, the passive triggering device is a magnetic field generator such as a permanent magnet. This sensor is commonly made out of two ferromagnetic alloy layers sandwiched around an ultra thin nonmagnetic conducting layer. The magnetic fields generated in each ferromagnetic layer are in opposite directions, resulting in electron scattering in the conductive layer, causing a high resistance. Once an external magnetic field is applied, the magnetic field in the ferromagnetic layers align thus reducing the resistance in the conductive layer. This change in resistance is used to measure the external magnetic field.

Resistance sensors measure changes in resistance across a resistive load. The detection is based on opening or closing an electrical circuit with an electrical current generator, which supplies a constant electric current, and a resistance sensor acting as a voltage meter within the circuit to measure the electrical voltage between two probes (electrodes) of the sensor. The measured voltage is proportional to the electrical resistance of the electrical circuit. The probes for the sensor can constitute multiple electrodes depending on the resistance measurement circuitry, for example whether 2, 3 or 4 wire measurement. In this disclosure, one probe of the resistance sensor is positioned to make conductive contact with a conductive element on the running tool, while a second probe is embedded.

Depending on the type of proximity sensor or resistance sensor used, an appropriate passive triggering device is located in or on a running tool in a form that is detected based on being adjacent to, in close proximity to, moving relative to, or in conductive contact with, the sensor. For instance, for the proximity sensor, the passive triggering device may take the form of one or more passive positional indicators, for example a permanent magnet, a geometric feature (ex. grooves, ridges, buttons etc.), a change in a material property, a ferrous or non-ferrous metal material, component or feature, or an RFID tag. For detection by a resistance sensor, the passive triggering device is a conductive element. As noted above, the geo-magnetic sensor generally does not require the addition of the passive triggering device on the running tool.

In the wellhead system, assembly and method described herein, one or more active sensors are provided in a sensor assembly disposed in or on (i.e., coupled to and/or integral with) an instrument spool, which is connected to the wellhead, for example during installation of the drilling stack. The instrument spool is used for the landing and/or retrieving operations of the wellhead components, and generally remains in the wellhead for the duration of the drilling operation. The instrument spool may be removed from the wellhead after the landing and retrieving operations are completed, for example after the drilling operations are completed and the drilling rig is removed. One or more passive triggering devices are disposed in or on (i.e., coupled to and/or integral with) a running tool used for landing the wellhead component. In this manner, the instrument spool forms only a temporary component of the pressure-containing wellhead for the running, landing and retrieving operations while the well is being drilled. The instrument spool is connected to be integral with the wellhead for the landing/retrieving operations, but can be disconnected and removed from the wellhead after the drilling process is completed.

The sensor assembly includes one or more active sensor components and other electronic components, including the power supply components, data processing components and telemetry components. The one or more active sensors detect landing information within the bore of the instrument spool and generate output signal(s) conveying the landing information to be transmitted to a remote location. In some embodiments, the sensor assembly is configured as a sensor package including one or more of the active sensors such as the geo-magnetic sensors, together with the electronic components. The sensor package is configured to be removed from the instrument spool, for example after the landing/retrieving operations are completed, such that the components of the sensor package are exposed to fewer hazards. The sensor package components may be attached externally to the instrument spool, for example by strapping, for ease of removal. In some embodiments, one or more of the active sensors may be provided integrally with the instrument spool, for example one or more sensors such as the proximity and resistance sensors, may be configured as internal sensors in one or more radial bores in the wall the instrument spool. In such embodiments, after the running, landing and retrieval operations, the above-described sensor package may be removed, while leaving the internal sensors in place with the instrument spool. Exposed sensors and/or connectors are protected with caps to protect against fluids and damage while maintaining full rated working pressure of the instrument spool. The one or more active sensors, whether configured as internal or external sensors in or on the instrument spool, detect landing information based on activity occurring within the bore of the instrument spool, but relating to the landing operation of the wellhead component in the wellhead member located below the instrument spool.

The provision of the sensor assembly in a temporary instrument spool allows for expensive and sensitive components, such as one or more of the active sensors and the electronics to be separately packaged, for removal from the industry standard members and components of the wellhead before well completion operations begin. The industry standard members and components of the wellhead need not be modified for the monitoring operation. Furthermore, the active sensors such as the proximity and resistance sensors, being located on the instrument spool, separate from the wellhead members and the wellhead components, provide sealed access or proximate access, to the pressure of the main bore of the wellhead, while being kept out of the harsh environment of the main bore of the wellhead during the running, landing, setting and retrieving operations. This minimizes damage to the electronic sensors and limits interference with the accuracy of the detection and signal transmission. Still further, the instrument spool and running tools can be re-used on multiple wellsites, with economic advantage.

Turning to the drawings, FIGS. 1A-1C are schematic views of a wellhead system 10, a wellhead assembly 80 and a method in accordance with one embodiment of this disclosure. FIG. 1A shows a position of a “tripping in” step, FIG. 1B showing the pre-determined “landed position”, and FIG. 1C showing a position of a “tripping out” step. The wellhead system 10 includes an instrument spool 12, a running tool 14, and a sensor assembly 40. The instrument spool 12 is a pressure-containing tubular body configured for connection, top and bottom, within a pressure-containing, surface wellhead 16, above a wellhead member 18 into which a wellhead component 20 is to be landed. The instrument spool 12 is formed with a spool bore 22 extending therethrough top to bottom, which aligns with the main bore 24 of the wellhead 16 and of the wellhead member 18. The spool bore 22 provides sufficient clearance for the running tool 14 and the wellhead component 20 to be run therethrough. The running tool 14 is configured to couple, generally at a lower end 14a, to the wellhead component 20, to land the wellhead component 20 within the wellhead member 18, to set or secure the wellhead component 20 within the wellhead member 18, and to decouple from the wellhead component 20 after landing. In FIG. 1A, the running tool 14 and the wellhead component 20 are shown in the tripping in position, with the wellhead component 20 approaching a landing shoulder 26 protruding inwardly and extending circumferentially around the main bore 24 of the wellhead member 18.

One or more passive triggering devices 28a, 28b are disposed in or on the running tool 14, for example in or on an external circumferential surface 30 of the running tool 14. The passive triggering devices can be strapped, fastened, mounted as a circumferential ring such as an O-ring, or otherwise adhered to the running tool 14. For example, the passive triggering devices may be fastened with adhesives, bolted, dovetailed, or fastened by magnetic properties. Apart from the added passive triggering devices 28a, 28b, the running tool 14 is otherwise unmodified for landing of the particular wellhead component 20.

The sensor assembly 40 of the instrument spool 12 includes one or more active sensors 32, 34, 35 disposed in or on the wall 36 of the instrument spool 12. In the Figures, sensors 32 and 35 are mounted and sealed in radial bores 38, 39 (shown in FIGS. 4A and 4B) in the wall 36 of the instrument spool 12, and are thus termed “internal sensors”, while sensor 34 is mounted on the exterior of wall 36 of the instrument spool 12, and is thus termed an “external sensor”. While sensors 32, 34 are termed “internal sensors”, it will be understood that they are mounted in the spool wall 36 and not within the internal spool bore 22. Mounting the sensors 32, 34 within the spool wall allows for sealed access and proximity to the spool bore 22, without placing the sensors directly within the harsh environment of the wellhead bore 24 once the instrument spool is connected into the wellhead 16. Examples of active sensors 32, 34, 35 are provided in greater detail below, with reference to FIGS. 4A-4D. In FIG. 1B, the wellhead component 20 is shown in the pre-determined landed position, i.e., with the wellhead component 20 successfully landed against the landing shoulder 26, and aligned within a landing profile 26a formed in the wellhead member 18. The instrument spool 12 has a generally vertical height dimension such that, in the landed position, the running tool 14 positions the passive triggering devices 28a, 28b within the spool bore 22, and in a position to align with, or make contact with, one or more of the sensors 32, 34, 35 for active sensing, as will be described more fully below.

In some embodiments, the sensor 32 is a proximity sensor 32 located as an internal sensor, sealed in a radial bore 38 (shown in FIG. 4A) formed in the wall 36 of the instrument spool 12, and extending to the spool bore 22. The proximity sensor 32 and the passive triggering device 28a are positioned on the instrument spool 12 and the running tool 14 respectively so as to be generally horizontally aligned one with another when the wellhead component is in the landed position against the landing shoulder 26. While the horizontal alignment in the landed position may not be critical for all types of proximity sensors 32, it is preferred for accuracy and strength of the signals produced before, during and after landing. For pairing with the proximity sensor 32, the passive triggering device 28b on the running tool 14 is a positional indicator 28a operative to generate a signal in the particular type of proximity sensor 32. The proximity sensor/passive positional indicator pairing 32, 28a detects landing information within the spool bore 22 of relative position and/or relative movement between the sensor 32 and the positional indicator 28a. The landing information provides data relating to the landing status, as the sensor 32 and positional indicator 28a move into vertically aligned proximity during landing, and as they move relative to one another during rotation to set, secure and decouple the wellhead component 20 from the running tool 14. In this disclosure, the landing information provided by the proximity sensor 32 during landing is termed the primary confirmation of landing.

In some embodiments, the sensor 34 is a geo-magnetic sensor located as an external sensor mounted on an external surface of the instrument spool wall 36, such as by clamping, strapping or fastening. In other embodiments, the sensor 34 may be mounted as an internal sensor within the wall 36 of the instrument spool 12. The geo-magnetic sensor 34 is located to detect movement of the running tool 14, whether coupled or decoupled from the wellhead component 20, as the running tool 14 is run within the spool bore 22. Since the geo-magnetic sensor 34 does not generally rely on pairing with the passive triggering devices to detect a change in the coupling status of the running tool 14, the sensor 34 can be located at any position between the top and bottom of the instrument spool 12. The geo-magnetic sensor 35 detects landing information within the spool bore 22 by detecting a change in the magnetic flux signature when the running tool 14 is coupled to the wellhead component 20 during tripping in and landing, compared to when the running tool 14 is decoupled from the wellhead component during tripping out. Based on the output from the geo-magnetic sensor 34, the location of the running tool 14 is determined by comparing the output to a known pre-determined value providing the operator with the exact positional information.

In some embodiments, the sensor 35 is a resistance sensor 35, located as an internal sensor, sealed in a radial bore 39 formed in the wall 36 of the instrument spool. The resistance sensor 35 has an internal probe component (electrode) 35a extending generally horizontally inwardly in the spool bore 22, and an embedded probe 35b embedded in the wall 36 of the instrument spool 12. The resistance sensor 35 and the passive triggering device 28b are positioned on the instrument spool 12 and the running tool 14 respectively, such that the probe 35a makes conductive contact with the passive triggering device 28b, in this case a conductive element 28b, when the wellhead component 20 is in the landed position. Since each of the components 12, 14, 18 and 20 are metallic, and thus electrically conductive, the conductive contact between the resistance sensor 35 and the conductive element 28b occurs as the wellhead component 20 lands aligned within the landing profile 26a of the wellhead member 18, and against the landing shoulder 26 of the wellhead member 18, thus closing an electrical circuit between the running tool 14, the instrument spool 12, the wellhead component 20 and the wellhead member 18. This conductive contact changes the voltage of the output of the resistance sensor 35 to provide useful landing information. Thus, the resistance sensor 35 detects landing information within the spool bore 22 by detecting conductive contact between the resistance sensor 35 and the conductive element 28b when the wellhead component 20 lands in the wellhead member 18. In this disclosure, this landing information is termed secondary landing information, with the proximity sensor 32 providing primary landing information. However, it will be understood that the sensors 32, 34 may be provided independently of one another in other embodiments of the disclosure.

The active sensors 32, 34, 35 form part of a sensor assembly 40 on the instrument spool 12. As shown in FIGS. 1A-1C, the sensor assembly 40 further includes additional electronic components, shown schematically as a combined power source, data acquisition and data processing unit 42 (microprocessor) to process sensor output signals generated from the active sensors 32, 34, 35 and to transmit the processed output signals to a telemetry unit 44 for transmission to a remote monitoring location 46, such as the rig floor or a more remote office location. The sensors 32, 34, 35 are shown as wired sensors, but may be wireless in some embodiments. The telemetry unit 44 generally transmits wirelessly to the remote location 46, although wired transmission may be used in some embodiments. The microprocessor generally includes a micro-controller, memory and power supply. The micro-controller reads data from the sensor output signal through a master/slave communication interface and an analog-to-digital (ADS) converter. A processing logic through an executed software loaded on the microprocessor memory converts the read sensor data into a relative wellhead component position and saves the results to the microprocessor memory. The microprocessor output signal generally includes a data set of date, time, part numbers of the wellhead system 10, and current proximity of the wellhead component from the landed position. The output signal further includes a landing status of either landed or not landed. The micro-controller then sends the output signal for transmission through wired or wireless telemetry (for example, ethernet, WiFi, Bluetooth, or cellular) to a remote computer at the remote monitoring location 46 to be viewed by the operator.

The wellhead system 10 is calibrated based on the known dimensions of the relevant wellhead member 18, wellhead component 20 and running tool 14 in the coupled, decoupled and landed positions, the relative positions of the passive triggering device 28 on the running tool 14 and the one or more active sensors 32, 34, on the instrument spool 12, and the known measurements between the landing shoulder 26 and the triggering device/sensors when the wellhead component 20 is in the pre-determined landed position within the wellhead member 18. In this manner, a database of part numbers for specific wellhead members 18, wellhead components 20 and running tools 14 is developed, such that landing information detected in the spool bore 22 during the running and landing operations is compared to stored data in the database to provide the operator with current landing information including the vertical position, the rotational position, the coupling/decoupling status, and the conductive coupling as the running tool and the wellhead component move through the instrument spool into the landed position.

FIGS. 2A-2E show an embodiment of a wellhead system 10, in the steps of landing a tubing hanger 20A in a tubing head 18A of a wellhead (other components of the wellhead above and below 18A, 20A are not shown, but are industry standard and well understood in the art). The instrument spool 12 is shown in the form of a flanged, steel, pressure-containing, tubular body 13 with a inner spool bore 22, and optional side outlets 52 to the spool bore 22.

FIGS. 2A-2E show the operation of a connecting the instrument spool 12 into the wellhead, tripping in, landing, and tripping out. FIG. 2A shows the instrument spool before connecting into the wellhead 16, as described above. FIG. 2B shows the instrument spool 12 connected and sealed to the tubing head 18A, with the spool bore 22 of the instrument spool 12 aligned with the main bore 24 of the tubing head 18A. For ease of explanation, other members of the wellhead 16 are not shown in the Figures, but the full implementation with these wellhead members will be apparent to one skilled in the art based on this disclosure. For the tripping in step of FIG. 2C, the running tool 14A is coupled to the tubing hanger 20A, for example by a threaded coupling. The sensor bore 22 provides sufficient clearance for the coupled running tool and tubing hanger to pass therethrough. The tubing head 18A forms a hanger profile 60 within the main bore 24, and a landing shoulder 62 for landing of the tubing hanger 20A.

Active sensors 32, 34, 35 are shown schematically as a plurality of internal proximity sensors 32, a plurality of external geo-magnetic sensors 34, and an internal resistance sensor 35. The sensors 32, 3435 are shown in greater detail in FIGS. 4A-4D. Two internal proximity sensors 32 are shown in FIG. 2, circumferentially, and diametrically spaced apart with access to the spool bore 22. A single internal proximity sensor 32 may be provided in some embodiments, to provide relative positional information, that is, relative to the positional indicator(s) 28a on the running tool 14A, from which measurements can be obtained for one or more of the x, y and z azimuth co-ordinates of the position of the wellhead component 20 being landed. The plurality of internal proximity sensors 32 may be included to provide relative movement information, such as angular orientation information during rotational movement, including the direction and angular orientation of the rotation, of the running tool 14A as the tubing hanger 20A is set and locked in the landed position. Two external geo-magnetic sensors 34 are shown in FIGS. 2A-2E, circumferentially, and diametrically spaced apart. In some embodiments, a single external sensor 34 may be provided or additional external sensors may be provided. A resistance sensor 35 is shown, located as an internal sensor, sealed in a radial bore 39 in the wall of the instrument spool 12, and with one probe (electrode) 35a extending generally horizontally inwardly into the spool bore 22, to make conductive contact on landing, as described above. A second probe 35b is embedded to make conductive contact within the wall 36 of the instrument tool 12.

In some embodiments, a plurality of passive positional indicators 28a or a single passive positional indicator 28a may be provided in or on the running tool 14. In FIGS. 2C-D, a pair of passive positional indicators 28a are shown circumferentially spaced apart (diametrically opposed) on the running tool 14 to align with a plurality of proximity sensors 32 during landing and/or rotation of the running tool 14. In other embodiments, additional positional indicators may be used. When detected by proximity sensor(s) 32, this provides vertical relative positional landing information and relative movement (angular orientation) landing information. Alternatively, or in addition, the active proximity sensors 32 and/or the positional indicators 28a may be vertically spaced apart in an array, to provided additional relative vertical positional information between the sensors 32 and the indicators 28a during the tripping in, landing and tripping out steps of the running tool 14.

For example, providing a single active proximity sensor 32 on the instrument spool 12 and two passive positional indicators 28a diametrically spaced apart on the running tool 14, provides 180 degree relative positional and relative movement information during rotation of the running tool 14. Increasing the number of proximity sensors 32 and/or the number of the positional indicators 28a improves relative rotational measurement capability during landing, setting, locking and decoupling steps. Providing the proximity sensors 32 and/or the positional indicators 28a in a vertical array provides improved relative vertical position information during the tripping in, landing and tripping out steps.

As shown in FIGS. 2A-2E, the instrument spool 12 includes top and bottom connectors 48, 50 to connection within the wellhead 16, and above the tubing head 18A into which the tubing hanger 20A is being landed. In some applications, the instrument spool 12 may be connected directly above the tubing head 18A, or above a tubing head adapter or other wellhead member, if present. While the top and bottom connectors 48, 50 are shown as flange connections, other connections such as threaded connectors, quick connectors, studded up/down connectors, and hub connectors might be provided. Side access outlets/inlets 52 on the instrument spool may be optionally provided.

FIGS. 4A-4D show multiple embodiments of the internal and external active sensors 32, 34, 35. In FIG. 4A, the internal sensor is a probe proximity sensor 32A sealed in the radial bore 38 of the spool wall 36 with pressure seal 54. The probe head 32B is mounted flush with the inner wall of the spool bore 22 for accurate positional sensing of positional indicator(s) 28a on the running tool 14. Sensor wires 32C extend from the probe base 32D for connecting to the power supply, data acquisition and data processing unit 42. In FIG. 4B, the internal proximity sensor 32E is mounted in an internal recess 56 formed in the inner wall of the spool bore 22 such that the sensor 32E is flush with the inner wall of the spool bore 22. Sensor wires 32F extend though a radial bore 38B in the spool wall 36 to the probe base 32G, which is mounted in an external recess 57 formed in the external wall of the spool wall 36. The radial bore 38B is sealed with pressure seal 54B. In FIG. 4C, the external geo-magnetic sensor 34 is fastened to an external surface of the spool wall 36, for example by clamping, strapping, adhesives or with fasteners, and sensor wires 34A extend from the sensor 34 to the power supply, data acquisition and data processing unit 42. In FIG. 4D, the resistance sensor 35 is shown sealed in a radial bore 39 formed through the wall 36 of the instrument spool 12, with wires 35c extending to the power supply, data acquisition and data processing unity 42. One probe 35a of the resistance sensor 35 extends generally vertically into the spool bore 22 to make conductive contact with the conductive element 28b when the on the running tool 14A, when the tubing hanger 20A is in the landed position against the landing shoulder 62. A second probe 35b is embedded to provide conductive contact with the wall 36 of the instrument spool. While FIGS. 4A-4D show wired sensors, wireless sensor may be used in some embodiments. As indicated above, the sensor assembly 40 may be configured with one or more of the sensor components and the electronic components, configured as a sensor package which can be removed from the instrument spool 12. For example the geo-magnetic sensor 34, the power supply, data acquisition and data processing unit 42 and the telemetry unit 44 can be packaged as a removable sensor package, so that these sensor and electronic components can be removed from the instrument spool 12 after the running, landing and retrieving operations are completed. In such embodiments, the sensor package components may be fastened to the external wall of the instrument spool 12, for example by removable straps, and any sensor components remaining on the spool 12, for example sensors 32, 35 may be configured with plugs in the wire connectors for ease of removal. After removing the sensor package components 34, 42, 44, the radial bores 38, 39 may be capped to protect the sensors 32, 35 and their respective connectors.

The internal proximity sensors 32A and 32E, are shown to be positioned with sensing components at or flush with the spool bore 22, such that the sensing components have sealed access and proximity to the spool bore 22 for maximum accuracy and signal strength. As noted above, the sensors 32A, 32E are also positioned to generally horizontally align with a positional indicator(s) 28a on the running tool 14A when the wellhead component 20 is at the pre-determined landed position. When generally aligned with the positional indicator(s) 28a on the running tool 14A, the sensor 32A or 32E provides positional information on the relative position of the positional indicator(s) 28a, and thus the wellhead component 20 being landed. As above, providing multiple active proximity sensors 32 and/or multiple positional indicators 28a, provides positional information on the relative movement of the positional indicators 28a, and thus relative rotational information of the running tool 14A and/or the tubing hanger 20A.

In some embodiments, the active proximity sensor(s) 32 are magnetic sensors, as described above. Depending on the type of proximity sensor(s), the positional indicators 28a on the running tool 14A are ferrous or non-ferrous metal materials such as iron, steel or other magnetic metals or alloys. In some embodiments, the positional indicators 28a are geometric features of such ferrous or non-ferrous metal materials. The geometric features may be in the form of grooves, ribs, buttons and/or thickened areas. In some embodiments, the positional indicators 28a on the running tool 14A are permanent magnets, such as rare earth magnets.

In some embodiments, the internal proximity sensor 32 is one or more Hall-Effect magnetic sensors, and the positional indicator(s) 28a is one or m ore permanent magnets circumferentially spaced on the external surface of the running tool 14A. In general, the Hall-Effect sensor(s) 32 provide a voltage output corresponding to the magnetic surrounding environment. When the magnets 28a on the running tool 14A pass by the Hall-Effect sensor 32 during tripping-in, the surrounding magnetic field changes, causing a change in the output voltage of the Hall-Effect sensor(s) 32. This is indicative of the position of the running tool 14 and therefore the position of the tubing hanger 20A coupled to the running tool 14A, based on the known dimensions/measures of the running tool 14A and the tubing hanger 20A. Relative rotational position detection may be generated using a circumferential spaced plurality of magnets 28a on the running tool 14A, and a single Hall-Effect sensor 32 on the instrument spool 12, from which the angular rotation of the tubing hanger 20A can be detected and measured in the wellhead 16. Alternatively, a plurality of Hall-Effect sensors 32 may be used on the instrument spool 12 to detect a single or a plurality of magnets 28a on the running tool 14A to detect and measure the relative rotational position of the running tool 14 and thus the tubing hanger 20A. Once landing occurs, the voltage output from the Hall-effect sensor reaches zero, to provide a primary confirmation of the landing.

In some embodiments the external sensor 34 on the instrument spool 12 is one or more geo-magnetic sensors 34 from which the magnetic flux measured by the sensor 34 represents the strength of earth's magnetic field. When the running tool 14A is coupled to the tubing hanger 20A and is tripped into the wellhead 16, the magnetic flux measurement of the geo-magnetic sensor 34 has a specific signature, which is unaltered if the running tool 14A and tubing hanger 20A remain coupled during the tripping out. However, if the running tool 14A trips out without the tubing hanger 20A, this signature sensed by the geo-magnetic sensor 34 is different. Thus, the signals from the geo-magnetic sensor 34 are used to confirm that the running tool 14 is tripping out free of the tubing hanger 20A as an indication of a successful landing, setting, securing and/or decoupling operation. In some embodiments the geo-magnetic sensor 34 also provides landing information relating to the vertical position of the running tool/hanger 14A/20A in the spool bore 22 as this vertical movement within the bore 22 is detected by the sensor 34. In some embodiments, the geo-magnetic sensor 34 can be positioned along the inner bore 22 of the instrument spool 12, but since it can detect the geomagnetic flux without access to the inner bore, it can be positioned as an external sensor, away from the pressure and the environment of the bore 22. Depending on the surrounding environment and possible metallic interference, magnetic shielding can be used to maximize signal-to-noise ratio. Also, shielding can be used to focus the geo-magnetic sensor's field of sensing.

The use of magnetic sensors and magnets with a separate instrument spool 12 in the wellhead system 10 is advantageous, in that the components of the wellhead system 10 do not need to be formed from non-magnetic materials, and complex equipment to generate magnetic fields are not needed. Similarly, the wellhead components 20 and the other members of the wellhead 16, which are typically industry standard, do not need to be modified from the industry standard, and do not need to be formed from non-magnetic materials, in order to operate with the wellhead system 10.

In the embodiment of FIGS. 2A-2E, the instrument spool 12 is shown with a pair of diametrically opposed, circumferentially spaced internal Hall-Effect sensors 32, and a pair of diametrically opposed, circumferentially spaced external geo-magnetic sensors 34, as described above, although additional sensors 32, 34 may be used. The running tool 14A has a pair of diametrically opposed, circumferentially spaced permanent magnets 28a, disposed on its external surface, positioned to generally horizontally align with the sensors 32 when the tubing hanger 20A is landed on the landing shoulder 62 of the tubing head 18A. As noted above, additional permanent magnets 28a may be used. The landed position, with aligned sensors 32 and magnets 28a is shown in FIG. 2D. If the sensors 32 and magnets are mis-aligned, this is detected, providing the operator with positional information to correct the landed position, for example by raising the running tool 14A and re-landing. FIG. 2E shows the tripping out operation, after the running tool 14A is decoupled from the tubing hanger 20A, for example by rotating to decouple the threaded connection, which can be detected by the sensors 32. In the tripping out step, the geo-magnetic sensors 34 detect a change in the geo-magnetic flux signature of the running tool decoupled from the tubing hanger, compared to the coupled signature, to provide information to confirm successful landing and decoupling of the tubing hanger 20A from the running tool 14.

In some embodiments, the instrument spool includes a resistance sensor 35, which may be provided with or without the proximity sensors 32 and the geo-magnetic sensors 34. In the embodiment of FIGS. 2A-2E, all three types of sensors 32, 34 and are provided, with the proximity sensors 32 providing primary landing information of proximate position and/or relative movement in the pre-determined landed position, the geo-magnetic sensors 34 providing successful decoupling information, and the resistance sensor 35 providing additional, or secondary, landing information using conductive contact to signal successful landing of the tubing hanger 20A aligned in the landing profile 60 on the landing shoulder 62. The use of a resistance sensor 35 is based on electrical conduction principle, where the metallic, and thus electrically conductive, properties of the wellhead assembly components 12, 14A, 20A and 18A provide an electrical circuit continuity once conductive contact on landing. One probe 35b of the resistance sensor 35 is embedded inside the wall 36 of the instrument spool 12, in contact with its metallic structure, while the other probe 35a of the resistance sensor 35 is insulated from the instrument spool 12 and extends into the spool bore 22 of the instrument spool 12 to made conductive contact on landing. The running tool 14A carries a passive conductive element 28b with a flexible deformable structure relative to the other components of the wellhead system 10. The conductive element 28b may formed from a rubber material with conductive particles, known as metal/conductive rubber or from a softer conductive metal such as brass or copper that permanently deforms upon contact. The conductive element 28b may be provided in the form of an O-ring to protrude from the exterior surface of the running tool 14A. The conductive element 28b and the resistance sensor are positioned to make conductive contact with each other when the tubing hanger 20A lands, aligned within the landing profile 60 and against the landing shoulder 62 of the tubing head 18A. Once conductive contact is made, a sudden drop in measured electrical resistance by the resistance sensor 35 occurs. An electrical circuit continuity occurs between the tubing hanger 20A, running tool 14A, instrument spool 12, and tubing head 18A, causing a significant reduction in electrical resistance.

FIGS. 3A-3E show the operation of tripping in, landing and tripping out, when the wellhead component 20 is a packoff bushing 20B. The packoff bushing 20B carries circumferential seals 64 to seal the annulus A above the landed tubing hanger 20A of FIG. 2D, and a retaining ring 66 to lock the packoff bushing 20B in place in the tubing head 18A. The instrument spool 12, with sensors 32, 34 of FIGS. 2A-2E remains in place above the tubing head 18A. While not shown in FIGS. 3A-3E, the resistance sensor 35, as above, with conductive element on the running tool, may also be present. For the tripping in step of FIG. 3A, the running tool 14B is coupled to the packoff bushing 20B, for example by a threaded coupling. The main bore 24 of tubing head 18A forms a smooth sealing surface 65 above the tubing hanger profile 60, and grooves 68 above the sealing surface 65 to lock the retaining ring 66 in place after landing. The running tool 14B has a pair of diametrically opposed, circumferentially spaced magnets 28c, disposed on its external surface, positioned to generally vertically align with the active internal proximity sensors 32 when the packoff bushing 20B is landed on a landing shoulder 70 of the tubing hanger 20A. This landed position is shown in FIG. 3B, and is detected by the sensors 32, 34. FIG. 3C shows the setting of the packoff bushing 20B with the retaining ring 66 in the grooves 68 of the tubing head 18A. During the setting, the running tool 14B is rotated a certain number of turns to drive the retaining ring 66 outwardly as the running tool 14B moves downwardly. If the resistance sensor 35 is used, sensor 35 detects the retaining ring 66 being driven outwardly, for example by detecting a break in the conductive contact. The proximity sensors 32 detect the number of rotations. Proper landing and placement is confirmed with an over pull with the draw works on the rig, and a pressure test confirms the packoff bushing seals 64 are intact. To remove and decouple, the running tool 14B is rotated in the opposite direction, which decouples the running tool 14B from the packoff bushing 20B, and raises the running tool 14B with each turn. If the resistance sensor 35 is included, the resistance sensor 35 detects when the running tool 14B reaches the initial position, by detecting conductive contact, while the geo-magnetic sensor 34 determines the vertical position of the running tool 14B, confirming that it is decoupled from the packoff bushing 20B. FIG. 3D shows the tripping out step, as the running tool 14B is decoupled from the packoff bushing 20B and is raised in (i.e., run out) of the wellhead. As above, the geo-magnetic sensors 34 on the instrument spool 12 detect a change in the geomagnetic flux signature during the tripping out to confirm the running tool 14B is successfully decoupled from the packoff bushing 20B. FIG. 3E shows the instrument spool 12 disconnected from the tubing head 18A and removed from the wellhead. In the above description, the Hall-Effect proximity sensors 32 also detect the rotations and vertical position of the running tool 14B, however the number of turns does not necessarily determine proper setting and decoupling of the packoff bushing 20B, so the use of the geo-magnetic sensor 34, and the resistance sensor 35 can provide more exact positional and coupling status information.

After landing and retrieval operations are completed, components of the sensor assembly 40 may be removed, such as the geo-magnetic sensor 34 and the electronic components 42, 44. As described above, in some embodiments, these removable components 34, 42 and 44 are packaged as a sensor package for ease of removal. The internal sensors 32, 35 may be disconnected from the power components of unit 42, and the radial bores 38, 39 are capped. In other embodiments, all sensors may be removed, and the bores 38, 39 are sealed and capped. Once drilling and/or well completion operations are completed, the instrument spool 12 can be removed from the drill stack with the rig, and re-used on another well.

In other embodiments, a wellhead system is used to land other wellhead components, for example one or more casing hangers, a plug, a packer, a sealing assembly, or a wear bushing. In landing operations of a casing hanger, the wellhead member is a casing head, and the instrument spool 12 is connected, as shown above for the tubing hanger landing of FIGS. 2A-2E, i.e, above the tubing head and above the casing head. The instrument spool 12 includes one or more of the three types of sensors 32, 34, 35. The casing hanger is coupled to a running tool configured to run the casing hanger through the wellhead and the instrument spool 12 to land on a landing shoulder of the casing head. The operation is similar to the above description for landing a tubing hanger. The passive triggering devices are located on the running tool for the casing hanger, and are disposed to generally vertically align with the sensors 32 and/or 35 when the casing hanger is landed on the landing shoulder of the casing head. After landing a casing hanger, the instrument spool 12 is again used for the landing and latching of a wear bushing, and for the landing and setting of a packoff bushing, similarly to the above-description for FIGS. 3A-3E.

While the above description details embodiments of landing a tubing hanger and a packoff bushing, it should be understood that the disclosure extends to landing of other wellhead components, and including retrieval of landed wellhead components. In some applications, a wellhead component may be removed due to a failed landing, operation or pressure test. For example, a packoff bushing may be removed after a failed pressure test. In drilling operations, one or more casing hangers are landed. In addition, a wear bushing and a packoff bushing are landed and engaged in the wellhead to retain the casing string and casing hanger in position. The wellhead system 10 of this disclosure can be used to monitor the successful landing of each of the casing hangers, wear bushings and the packoff bushings. A pressure test from the exterior of the wellhead is performed to ensure integrity of the sealing elements of the packoff bushing. However, after a failed pressure test, the packoff bushing may be retrieved by connecting the instrument spool above the casing head and running the running tool through a BOP stack and tree above the instrument spool to engage with the packoff bushing. The running tool is rotated in a reverse direction to relax a latching mechanism so that the packoff bushing can be retrieved with the running tool for inspection at the rig floor. The one or more active sensors provide landing information during the retrieval operations, much as described above for the landing operation, but including reverse order for some steps such as coupling and decoupling. Tripping in is with only the running tool, and tripping out is with the coupled running tool and wellhead component.

In some embodiments, the wellhead system 10 forms part of a wellhead assembly 80, including the wellhead system 10, the wellhead component 20 and the wellhead member 18, as indicated schematically in FIG. 1A. After landing, and removal of the running tool 14 and the instrument spool 12, the wellhead component 20 remains in place during the production phase of the well. The instrument spool 12 and the running tool 14 are used only during the well intervention phase for landing/installing/retrieving the wellhead component 20. After removing the running tool 14 and instrument spool 12, the wellhead system 10 can be used on the next well. The geometries of the components of the wellhead assembly 80 are used to define the relative positions of the instrument spool 12 to the wellhead 16, and the wellhead component 20 to the running tool 14. The active proximity sensor 32 detects the proximity of the passive positional indicator 28a once the indicator 28a is adjacent or in close proximity to the sensor 32. The resistance sensor 35 makes conductive contact with the conductive contact with the conductive element 28b on the running tool in the landed position of the wellhead component 20. Consequently, this proximity sensing and the conductive contact identifies the position of the wellhead component 20 within the wellhead member 18, based on the known dimensions of all of the components, and the relative position of the running tool 14 within the instrument spool 12 in the landed position.

Based on the above description, and with reference to the flowchart of FIG. 5, it will be understood that the wellhead system 10, and wellhead assembly 80, including the three types of sensors 32, 34, 35, detects landing information within the spool bore 22 of the instrument spool during the steps set out below. The data processing unit 42 is calibrated with the known geometric configuration and measurements of the components (instrument spool 12, running tool 14, wellhead member 18 and wellhead component 20), and the position of the sensors 32, 35 relative to the passive triggering devices 28a, 28b, for the pre-determined landed position.

• • A. Axial tripping-in: In this operation the wellhead component 20 is being run into and landed within the wellhead member 18. A single active proximity sensor 32 or a plurality of proximity sensors 32 on the instrument spool 12 detect the running tool arriving, remaining, passing by along the axial travel direction, based on the proximate position of the passive triggering devices 28a on the running tool 14. The sensors 32 also detect the landed position based on the sensors 32 aligning with the passive triggering devices 28a. The resistance sensors 35 detect and confirms the landed position by conductive contact within the bore 22 of the instrument spool 12, confirming that landing of the wellhead component 20 is in contact with the landing shoulder 62 and aligned in the landing profile 60. The geo-magnetic sensor 34 may also detect vertical movement of the running tool 14 and/or wellhead component 20 within the spool bore 22.
  • B. Rotational positioning/Angular Orientation: In some landing applications, rotation of the running tool 14 and/or the wellhead component 20 is required to properly orient the wellhead component 20, to set or secure it in the landed position, and/or to decouple the running tool 14 from the landed wellhead component 20. A plurality of the proximity sensors 32 and/or a plurality of the passive triggering devices 28a detect this relative rotational movement. The geo-magnetic sensor 34 detects vertical movement, for example as the wellhead component 20 moves vertically within threaded connections.
  • C. Axial tripping-out: Once the wellhead component 20 is landed in the wellhead member 18, the running tool 14 is removed from the wellhead. In this step, it is important to ensure that the running tool 14 is tripping-out without the wellhead component 20 to confirm successful wellhead component landing. One or more of the external, geo-magnetic sensor(s) 34 detect a change in the geomagnetic flux signature to confirm that the running tool 14 is decoupled during the tripping out.

As used herein and in the claims, the word “comprising” is used in its non-limiting sense to mean that items following the word in the sentence are included and that items not specifically mentioned are not excluded. The use of the indefinite article “a” in the claims before an element means that one of the elements is specified, but does not specifically exclude others of the elements being present, unless the context clearly requires that there be one and only one of the elements.

As used herein and in the claims, the terms “inner” and “outer”, “up” and “down”, “upper” and “lower”, “upward” and “downward”, “above” and “below”, “inward” and “outward”, and other like terms refer to relative positions to one another and are not intended to denote a particular direction or spatial orientation. The terms “coupled”, “coupled”, “coupling”, “connect”, “connection”, “connected”, “in connection with”, and “connecting” refer to “in direct connection with” or “in connection with via one or more intermediate elements or members”.

All references mentioned in this specification are indicative of the level of skill in the art of this invention. All references are herein incorporated by reference in their entirety to the same extent as if each reference was specifically and individually indicated to be incorporated by reference. However, if any inconsistency arises between a cited reference and the present disclosure, the present disclosure takes precedence. Some references provided herein are incorporated by reference herein to provide details concerning the state of the art prior to the filing of this application, other references may be cited to provide additional or alternative device elements, additional or alternative materials, additional or alternative methods of analysis or application of the invention.

The terms and expressions used are, unless otherwise defined herein, used as terms of description and not limitation. There is no intention, in using such terms and expressions, of excluding equivalents of the features illustrated and described, it being recognized that the scope of the invention is defined and limited only by the claims which follow. Although the description herein contains many specifics, these should not be construed as limiting the scope of the invention, but as merely providing illustrations of some of the embodiments of the invention.

One of ordinary skill in the art will appreciate that elements and materials other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such elements and materials are intended to be included in this invention. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

Claims

1. A wellhead system for monitoring landing or retrieving of a wellhead component at a pre-determined landed position in a main bore of a wellhead member of a wellhead, comprising: a running tool configured to couple to the wellhead component, to land or retrieve the wellhead component within the main bore of the wellhead member, and to decouple from the wellhead component;a passive triggering device disposed in or on the running tool;a pressure-containing instrument spool configured to connect within the wellhead at a location above the landed position of the wellhead component, the instrument spool forming a bore to align with the main bore of the wellhead and to provide clearance for the wellhead component and the running tool to be run therethrough, the instrument spool having a generally vertical height dimension such that, in the pre-determined landed position, the passive triggering device is located in the bore of the instrument spool; anda sensor assembly disposed in or on the instrument spool to monitor landing or retrieving of the wellhead component in the wellhead member located below the instrument spool based on landing information detected within the bore of the instrument spool, to generate an output signal conveying the landing information, and to transmit the output signal to a remote location.

2. The wellhead system of claim 1, wherein: the sensor assembly comprises one or more active sensors to detect the landing information;the running tool includes one or more of the passive triggering devices; andthe landing information is detected by one or more of:(i) conductive contact between at least one of the one or more passive triggering devices and at least one of the one or more active sensors when the wellhead component is in the pre-determined landed position;(ii) a proximate position of at least one of the one or more passive triggering devices relative to at least one of the one or more active sensors when the wellhead component is in the pre-determined landed position;(iii) relative movement of at least one of the one or more passive triggering devices relative to at least one of the one or more active sensors when the wellhead component is rotated in the pre-determined landed position; and(iv) a change in a magnetic flux signature detected by at least one of the one or more active sensors when the running tool is coupled to the wellhead component compared to when the running tool is decoupled from the wellhead component.

3. The wellhead system of claim 1 wherein the landing information is detected by: one or more of (i), (ii), and (iii), with or without (iv);(ii) and (iii), with or without (iv); or(i), (ii) and (iii), with or without (iv).

4. The wellhead system of claim 2 or 3, wherein at least one of the one or more active sensors is a proximity sensor disposed in the instrument spool, and at least one of the one or more passive triggering devices is a positional indicator disposed in or on the running tool such that the proximity sensor and the positional indicator are generally horizontally aligned, one with another, when the wellhead component is in the pre-determined landed position.

5. The wellhead system of claim 4, wherein the proximity sensor is sealed in a radial bore extending from the bore of the instrument spool such that the proximity sensor is positioned at the bore.

6. The wellhead system of claim 5, comprising a plurality of the proximity sensors circumferentially spaced in the instrument spool to detect relative rotational movement of the positional indicator relative to the plurality of proximity sensors.

7. The wellhead system of claim 5, comprising a plurality of the passive positional indicators circumferentially spaced in or on the running tool such that the proximity sensor detects relative rotational movement of the plurality of positional indicators relative to the proximity sensor.

8. The wellhead system of claim 5, comprising a plurality of the proximity sensors circumferentially spaced in the instrument spool and a plurality of the passive positional indicators circumferentially spaced in or on the running tool such that the plurality of proximity sensors detects relative rotational movement of the plurality of positional indicators relative to the plurality of proximity sensors.

9. The wellhead system of any one of claims 4-8, wherein the passive positional indicator is selected from a permanent magnet disposed on an exterior surface of the running tool, a ferrous or non-ferrous metal material provided on or formed on an exterior surface of the running tool, and a ferrous or non-ferrous geometric metal feature provided on or formed on an exterior surface of the running tool.

10. The wellhead system of any one of claims 4-9, wherein the proximity sensor is a magnetic field sensor such as a Hall-Effect sensor, and the passive positional indicator is a permanent magnet.

11. The wellhead system of any one of claims 2-10, wherein at least one of the one or more active sensors is a resistance sensor disposed in or at the bore of the instrument spool, and the one or more passive triggering devices is a conductive element disposed on an exterior surface of the running tool such that the conductive element makes conductive contact with the resistance sensor when the wellhead component is in the pre-determined landed position.

12. The wellhead system of claim 11, wherein the running tool, the instrument spool, the wellhead component and the wellhead member are electrically conductive such that the conductive contact between the conductive element and the resistance sensor closes an electrical circuit between the running tool, the instrument spool, the wellhead component and the wellhead member when the wellhead component is in the pre-determined landed position aligned within a landing profile of the wellhead member.

13. The wellhead system of claim 12, wherein the pre-determined landed position includes the wellhead component landed against a landing shoulder in the wellhead member.

14. The wellhead system of claim 13, wherein the conductive element is a conductive O-ring or other element made of a conductive material disposed on the running tool.

15. The wellhead system of any one of claims 2-14, wherein at least one of the one or more active sensors is a geo-magnetic sensor disposed in or on the instrument spool to detect a change in the magnetic flux signature of the running tool coupled to the wellhead component compared to the magnetic flux signature of the running tool decoupled from the wellhead component in order to confirm successful landing and decoupling of the wellhead component when the running tool is removed from the wellhead.

16. The wellhead system of claim 15, wherein the geo-magnetic sensor is mounted on an exterior surface of the instrument spool.

17. The wellhead system of claim 15 or 16, wherein the geo-magnetic sensor is an anisotropic magneto-resistive (AMR) sensor.

18. The wellhead system any one of claims 1-17, wherein the wellhead component is selected from a casing hanger, a tubing hanger, a plug, a packer, a sealing assembly, a packoff bushing, and a wear bushing.

19. The wellhead system of any one of claims 1-17, wherein the wellhead component is a tubing hanger.

20. The wellhead system of any one of claims 1-19, wherein the sensor assembly includes a data acquisition and data processing unit to process sensor output and a transmitter to transmit the processed output signal to a telemetry unit for transmission to the remote location.

21. The wellhead system of any one of claims 1-20, configured as a wellhead assembly and further comprising the wellhead component and the wellhead member.

22. A method of monitoring landing or retrieving of a wellhead component at a pre-determined landed position in a main bore of a wellhead member of a wellhead, the method comprising: providing a running tool adapted to couple to the wellhead component for landing at the pre-determined landed position, the running tool including a passive triggering device disposed in or on the running tool;connecting a pressure-containing instrument spool into the wellhead at a location above the pre-determined landed position of the wellhead component, the instrument spool forming a bore aligned with the main bore of the wellhead and providing clearance for the wellhead component and the running tool to be run therethrough, the instrument spool having a generally vertical height dimension such that, in the predetermined landed position, the passive triggering device is located in the bore of the instrument spool, and the instrument spool including a sensor assembly disposed in or on the instrument spool;for landing, coupling the running tool to the wellhead component, and running the coupled running tool and wellhead component through the bore of the instrument spool to the pre-determined landed position within the wellhead member located therebelow;for retrieving, running the running tool through the bore of the instrument spool to the pre-determined landed position within the wellhead member located therebelow, and coupling the running tool to the wellhead component;monitoring landing or retrieving of the wellhead component in the wellhead member located below the instrument spool by detecting landing information within the bore of the instrument spool with the sensor assembly;generating an output signal conveying the landing information;transmitting the output signal to a remote location;for landing, decoupling the running tool from the wellhead component and removing the running tool from the wellhead; andfor retrieving, removing the coupled running tool and wellhead component from the wellhead.

23. The method of claim 22, wherein the wellhead is a surface wellhead, and wherein the method further comprised, after landing or retrieving, removing one or more components of the sensor assembly from the instrument spool and/or removing the instrument spool from the wellhead.

24. The method of claim 22 or 23, wherein; the sensor assembly comprises one or more active sensors to detect the landing information;the running tool includes one or more of the passive triggering devices, andthe landing information is detected by one or more of:(i) detecting conductive contact between at least one of the one or more passive triggering devices and at least one of the one or more active sensors when the wellhead component is in the pre-determined landed position;(ii) detecting a proximate position of at least one of the one or more passive triggering devices relative to at least one of the one or more active sensors when the wellhead component is in the pre-determined landed position;(iii) detecting relative movement of at least one of the one or more passive triggering devices relative to at least one of the one or more active sensors when the wellhead component is rotated in the pre-determined landed position; and(iv) detecting a change in a magnetic flux signature with at least one of the one or more active sensors when the running tool is coupled to the wellhead component compared to when the running tool is decoupled from the wellhead component.