GB2582889A

GB2582889A - Ultrasonic reflectometry sensor arrangement

Info

Publication number: GB2582889A
Application number: GB1819457.1A
Authority: GB
Inventors: Costello Laurie; P Brunskill Henry; Hunter Andrew
Original assignee: Creid 7 Ltd
Current assignee: Creid 7 Ltd
Priority date: 2018-11-29
Filing date: 2018-11-29
Publication date: 2020-10-14
Also published as: WO2020109803A1; GB201819457D0

Abstract

A device 10 may have multiple sensors 12 circumferentially spaced around a mating zone 112 of two conduits 110,120. Alternatively, a single sensor 12 may be rotated around the circumference of the conduits (Fig. 4). The device 10 senses the contact pressure at the mating surfaces of the two conduits via ultrasonic reflectometry. The greater the contact pressure, the better that ultrasonic waves may be transmitted. Processor 14 may compare the readings from sensors 12 to determine whether the pipes are correctly mated along their entire circumference. The sensor arrangement may be used in the oil and gas industry to check the connections of nested casings in a wellhead.

Description

Ultrasonic Reflectometry Sensor Arrangement The present invention relates to sensor arrangements. In particular, but not exclusively, the present invention relates to using ultrasonic reflectometry sensor arrangements to measure a contact pressure for use in oil and gas equipment for drilling, extracting, inspection and the like.

In ultrasonic reflectometry (UR), a transducer generates ultrasonic waves which propagate through a material until they reach an interface in the material. The wave is partially reflected at the interface and partially transmitted onwards. The reflected waves travel back to the transducer, then the impedance of the material is determined by measuring the amplitude and/or the time of flight of the reflected waves. There are many practical applications of this technology and the most common engineering application is nondestructive testing (NDT). In NDT, the interface being investigated is a potential crack, region of corrosion etc in a material.

However, UR can also be employed to investigate the contact between two surfaces. The greater the contact, the better that ultrasonic waves are transmitted from one surface to the other. Indeed, the degree of wave transmission can even be used to determine the contact pressure at the interface of the two surfaces.

In the oil and gas industry, a wellhead is the component at the surface of an oil or gas well that provides the structural and pressure-containing interface for the drilling and production equipment. It provides the suspension point and pressure seals for the casing and production tubing strings that run from the bottom of the hole sections to the surface pressure control equipment. Hereinafter, the term "casings" will be used for the casings, production tubing strings, pack off seals, spool pieces and the wellhead itself.

Casings (of successively smaller diameter) are inserted within other casings until lip and shoulder features on the casings mate with each other. However, if a casing is not inserted correctly, there can be non-uniform pressure at two contacting surfaces. Also, a pack-off seal is used to provide pressure containment. This is a separate component which is installed sequentially. If the casing is incorrectly installed, it can prevent the seal reaching the correct location or prevent subsequent strings reaching the correct location. Similarly, if dirt or debris is located between the two contacting surfaces, there can again be non-uniform pressure and poor sealing. Because the wellhead is a load bearing, pressure containing system, it is difficult to inspect the wellhead to ascertain if there has been correct mating.

It is desirable to utilise UR to inspect two mating surfaces within a wellhead. It is desirable to utilise UR to determine the contact pressure, in particular the uniformity of the contact pressure, at two mating surfaces within a wellhead.

Frequently, a seal is provided between the mating surfaces of two conduits. Within this specification, the term "mating surfaces of two conduits" and similar terms are intended to cover two surfaces physically separated by a seal.

Within the cylindrical wellhead, there can be multiple mating surfaces at different vertical heights of the wellhead. For a given vertical height, a region of poor mating/sealing could occur at any circumferential point.

It is desirable to provide a sensor arrangement which can inspect the full circumference of a wellhead or other cylindrical conduit. It is desirable to provide a sensor arrangement which can inspect a plurality of vertical heights of a wellhead or other cylindrical conduit.

According to a first aspect of the present invention there is provided an ultrasonic reflectometry sensor device adapted to circumferentially sense the contact pressure at the mating surfaces of two conduits.

Optionally, the sensor device comprises a plurality of ultrasonic reflectometry sensors arranged or arrangeable circumferentially around an interface of the conduits.

Optionally, each sensor of the plurality of sensors is circumferentially equispaced around the interface.

Optionally, the sensor device comprises at least three sensors. Optionally, the sensor device comprises at least sixteen sensors. Optionally, the array comprises at least twenty-four sensors.

Optionally, the sensor device comprises at least one array of ultrasonic reflectometry sensors. Optionally, the sensor device comprises a plurality of arrays of ultrasonic reflectometry sensors.

Optionally, the array or the plurality of arrays of sensors are arranged or arrangeable circumferentially around an interface of the conduits.

Optionally, the array is a horizontal array. Alternatively, the array is a vertical array.

Alternatively, the array is a matrix array comprising a plurality of rows and columns.

Alternatively, the sensor device comprises a sensor or array which is movable in a circumferential direction around the interface of the conduits. Optionally, the sensor or array is adapted to successively sense the contact pressure at a plurality of circumferential regions.

Optionally, the sensor device comprises a rig positioned around the conduits. Optionally, the sensor or array is movably coupled to the rig to allow movement of the sensor around the interface of the conduits.

Alternatively, the sensor device comprises a portable unit, such as a handheld unit, which may be operated by an operator.

Optionally, the sensor device is movable in a vertical direction to allow sensing of the contact pressure at a plurality of mating surfaces of two conduits.

When the sensor device comprises a plurality of sensors or arrays, optionally, the plurality of sensors or arrays are movable in a vertical direction.

When the sensor device comprises a movable sensor or array, optionally, the plurality of sensors or arrays are movable in a vertical direction. Optionally, the rig of the sensor device is height adjustable.

Optionally, the sensor device includes a processing unit. Optionally, the processing unit is adapted to compare the readings taken at a plurality of circumferential regions with each 10 other.

Optionally, the sensor device includes a display. Optionally, the display is adapted to indicate whether the reading taken at each of the plurality of circumferential regions is relatively high or low.

Optionally, the sensor device comprises a sensor which is attached or attachable to an engaging member for coupling two conduits. Optionally, the engaging member is a lock down screw.

Optionally, the sensor device comprises a sensor which is located or locatable at a flanged connection of two conduits. Optionally, the sensor is located or locatable between the flange of a first conduit and the abutting flange of a second conduit.

Optionally, at least one sensor of the sensor device is fixed to the interface of the two conduits. Optionally, a plurality of sensors are provided, each sensor being fixed to a different circumferential region of the interface of the two conduits.

Optionally, the or each sensor is a passive sensor. Optionally, the sensor device includes an interrogating device. Optionally, the interrogating device is adapted to electromagnetically excite the sensor such that the sensor takes a measurement. Optionally, the interrogating device includes a receiver for wirelessly receiving the measurement of the sensor.

According to a second aspect of the present invention there is provided a method of sensing within an enclosed pressure vessel, wherein the method comprises circumferentially sensing, using an ultrasonic reflectometry sensor device, the contact pressure at mating surfaces of two conduits.

Optionally, the sensor device comprises a plurality of ultrasonic reflectometry sensors. Optionally, the method includes arranging the plurality of sensors circumferentially around an interface of the conduits.

Alternatively, the method includes moving the sensor device in a circumferential direction around the interface of the conduits. Optionally, the method includes successively sensing the contact pressure at a plurality of circumferential regions.

Alternatively, the sensor device comprises a portable unit, such as a handheld unit, which may be operated by an operator. Optionally, the method includes encircling the conduits by the operator and simultaneously taking a plurality of readings.

Optionally, the method includes moving the sensor device in a vertical direction to allow sensing of the contact pressure at a plurality of mating surfaces of two conduits.

Optionally, the method includes comparing the readings taken at a plurality of circumferential regions with each other.

Optionally, the method includes displaying an indication of whether the reading taken at each of the plurality of circumferential regions is relatively high or low.

Optionally, the method includes attaching a sensor to an engaging member for coupling two conduits. Optionally, the engaging member is a lock down screw.

Optionally, the method includes locating a sensor at a flanged connection of two conduits.

Optionally, the method includes locating the sensor between the flange of a first conduit and the abutting flange of a second conduit.

Optionally, the method includes fixing at least one sensor to the interface of the two conduits. Optionally, the method includes fixing a plurality of sensors to the interface, each sensor being fixed to a different circumferential region of the interface.

Optionally, the or each sensor is a passive sensor. Optionally, the method includes using an interrogating device to electromagnetically excite the sensor such that the sensor takes a measurement. Optionally, the interrogating device includes a receiver for wirelessly receiving the measurement of the sensor.

The invention will be described below, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a (a) sectional side view of a first casing inserted within a second casing and (b) sectional plan view of the first casing inserted within the second casing and showing a representation of sensor readings according to a first embodiment of the invention; Figure 2 is another (a) sectional side view of a first casing partially inserted within a second casing and (b) sectional plan view of the first casing fully inserted within the second casing and showing a representation of sensor readings according to the first embodiment; Figure 3 is another (a) sectional side view of a first casing inserted within a second casing and (b) sectional plan view of the first casing inserted within the second casing and showing a representation of sensor readings according to the first embodiment; Figure 4 is another (a) sectional side view of a first casing inserted within a second casing and (b) sectional plan view of the first casing inserted within the second casing and showing a second embodiment of a sensor device; Figure 5 is another (a) sectional side view of a first casing inserted within a second casing and (b) sectional plan view of the first casing inserted within the second casing and showing a different representation of sensor readings according to a third embodiment of the invention; Figure 6 is a (a) sectional side view of a wellhead and (b) sectional side view of nested casings within the wellhead and showing a representation of sensor readings according to a fourth embodiment of the invention; Figure 7 is a sectional side view of a casing inserted within a spool piece (a) prior to and (b) subsequent to engaging the lock down screws; and Figure 8 is a (a) sectional side view of flanged conduits within a wellhead and (b) plan view of a flange and showing a representation of sensor readings.

Figure 1 shows a first casing 110 of a wellhead 100 which has been inserted within a second casing 120. The second casing 120 has a shoulder 122 which a lip 112 of the first casing 110 contacts and abuts when the first casing 110 is fully inserted.

Arranged circumferentially around the two casings, at a vertical height which corresponds to the interface of the shoulder 122 and lip 112, is an ultrasonic reflectometry (UR) sensor device 10. The device 10 comprises a number of individual sensors 12 which are equispaced around the circumference of the casings. Each sensor 12 senses the contact pressure at a particular circumferential region of the mating surfaces of the shoulder 122 and lip 112. In the figures, for clarity, only three sensors 12 are shown. However, the device 10 could comprise many more. The greater the number of sensors 12, the greater the resolution of the pressure measurement.

In this embodiment, the sensors are point sensors which output a single measurement value. The output signals from each sensor 12 are passed to a processing unit 14 which could be the likes of a dedicated circuit or a processor or the like. The values are compared to each other by the processing unit 14. A display, which may take many forms, indicates whether the reading at each sensor 12 is relatively high or low.

In the example of Figure 1, the first casing 110 has been inserted in an axial direction which is truly parallel to the axial direction of the second casing 120 (in this example, the second casing is the wellhead itself but will be more generically referred to as a second casing). This results in true alignment of the two casings. Subsequently, the contact pressure at the mating surfaces is high and also highly uniform. Therefore, the measurement at each sensor 12 is substantially the same. This is the ideal situation and is represented by the tick 130 at each sensor 12 in the figures.

In the example of Figure 2, the first casing 110 has again been inserted in a true axial direction parallel to the axial direction of the second casing 120. However, there is a piece of debris 140 lodged at a specific circumferential region of the shoulder 122 of the second casing 120. This region corresponds to the location of one of the sensors 12.

This results in a contact pressure at the mating surfaces which is non-uniform. There is high contact pressure in the region of the debris 140. The lip 112 of the first casing 110 exerts a pressure on the debris 140 which in turn exerts a pressure on the shoulder 122 of the second casing 120 in this region. Therefore, the measurement at the sensor 12 is this region is high. However, at other regions, the lip 112 does not make good contact and the measurement at other sensors is low, which is represented by a cross 132 at these sensors in the figures.

It should be noted that, as in this example, a single relatively high measurement at a particular region does not indicate that there is good overall contact between two mating surfaces. Indeed, relying on a single measurement would provide a false positive reading if the reading is taken in the region of the debris. Rather, it is the relative relationship between all the sensor readings that indicates whether there is good contact.

In the example of Figure 3, the first casing 110 has not been inserted in a true axial direction parallel to the axial direction of the second casing 120. Rather, it has been inserted at an angle. This can occur if the derrick is not positioned directly above the well. Consequently, the contact pressure at the mating surfaces is non-uniform. There is high contact pressure in one circumferential region but lower contact pressure at others. This is again detected at the sensors 12 in terms of a high measurement at one (or some) of the sensors 12 and low measurements at others.

In the second embodiment of Figure 4, the first casing 110 has again been inserted in a true axial direction parallel to the axial direction of the second casing 120. The contact pressure at the mating surfaces is highly uniform and the measurement at each sensor 12 is substantially the same.

However, in this embodiment, a single sensor 12 is provided. The sensor 12 is coupled to a rig 16 which surrounds the casings so that the sensor 12 can be moved circumferentially in a clockwise or anticlockwise direction around the casings. Readings are taken at various circumferential positions of the sensor 12. Subsequently, the readings are compared with each other. The rig 16 could also be adapted to move the sensor 12 in a vertical direction.

In the third embodiment of Figure 5, the first casing 110 has again been inserted in a true axial direction. The contact pressure at the mating surfaces is highly uniform and the measurement at each sensor 12 is substantially the same.

However, in this embodiment, each sensor is itself an array 20 of sensors. Together, the sensors of each array 20 provide a visual indication 134 of the pressure distribution at a circumferential region, similar to the pixels of a display. In the embodiment of Figure 4, each array 20 has six rows and four columns of sensors, or a total of 24 sensors.

Figure 6 shows a wellhead and a number of nested casings within the wellhead 100. The casings either abut a shoulder 102 of the wellhead 100 or a shoulder of another casing.

Also, pack-off seals isolate the annular spaces. The various shoulders are vertically staggered. A sensor device according to a third embodiment of the invention is also shown. In this embodiment, arrays 20 of sensors are again circumferentially provided around the wellhead 100. However, arrays 20 are provided at a number of different vertical heights of the wellhead 100. These vertical heights correspond to the known location of where a casing contacts another casing. Therefore, multiple interfaces of casings, as well as multiple circumferential regions can be simultaneously monitored. The increase in contact pressure /load from subsequent casing strings should be observed on the lower sensors. The upper sensors can monitor the location and effectiveness of the seals.

Older types of wellheads, still much in use, often use lock down screws and casing spools for coupling two casings. Each casing is fitted with a spool and upper and lower spools are coupled using flanged connections.

A single casing 150 and spool piece 160 is shown in Figure 7. The casing 150 includes recesses 152 for receiving a lock down screw 154. The casing 150 is inserted into the spool piece 160 until a lip 156 of the casing 150 abuts a shoulder 162 of the spool piece 160. A lock down screw 164 is then screwed into a threaded aperture in the spool piece 160 and, if the casing has been correctly inserted, it will engage with a recess 152. However, if the casing has not been correctly inserted, it will abut an outer surface of the casing 150. Not only has the casing 150 not been locked down but there is potential damage to the casing 150.

Similar to previous embodiments, sensors 12 can be arranged circumferentially around the spool piece 160 at a vertical height corresponding to the interface of the shoulder 162 and lip 156. However, a sensor 12 is also provided at an end of one or more of the lock down screws 154. If the lock down screw 154 has correctly engaged, there will be little or no contact pressure on the conical tip of the lock down screw 154. However, if the lock down screw 154 is abutting the outer surface of the casing 150, the contact pressure will be relatively high. Also, If the lock down screw 154 has correctly and fully engaged, contact will be distributed across the conical profile of the lock down screw 154. However, if the lock down screw 154 has not correctly engaged, the contact area will be confined to just the tip of the lock down screw 154. Both of these situations can be detected by the sensor 12 at the end of the lock down screw 154.

Figure 8 shows a number of conduits with flanged connections 170. In this embodiment, arrays 20 of sensors are circumferentially provided at the flanged connection 170, such as between the flange 172 and gasket. Seals can move over time which can cause wear and degradation of the sealing surface leading to poor sealing. This can be detected as a change in the contact pressure at the flanged connection 170. This is shown at one circumferential position in Figure 8(b).

In another embodiment (not shown), the sensors are permanently fixed to the interface of the two conduits. The sensor device includes an interrogating device which is adapted to electromagnetically excite the passive sensor and cause the sensor to take a measurement. The interrogating device also includes a receiver for wirelessly receiving the measurement of each sensor.

The interrogating device can be a handheld device and an operator can sequentially position the interrogating device near to each sensor to take a reading.

Various modifications and improvements can be made to the above without departing from the scope of the invention.

Claims

CLAIMS1. An ultrasonic reflectometry sensor device adapted to circumferentially sense the contact pressure at the mating surfaces of two conduits.
2. A sensor device as claimed in claim 1, comprising a plurality of ultrasonic reflectometry sensors arranged or arrangeable circumferentially around an interface of the conduits.
3. A sensor device as claimed in claim 2, wherein each sensor of the plurality of sensors is circumferentially equispaced around the interface.
4. A sensor device as claimed in any preceding claim, wherein the sensor device comprises at least one array of ultrasonic reflectometry sensors.
5. A sensor device as claimed in claim 4, wherein the array or the plurality of arrays of sensors are arranged or arrangeable circumferentially around an interface of the conduits.
6. A sensor device as claimed in claim 4 or 5, wherein the array is a horizontal array.
7. A sensor device as claimed in claim 4 or 5, wherein the array is a vertical array.
8. A sensor device as claimed in claim 4 or 5, wherein the array is a matrix array comprising a plurality of rows and columns.
9. A sensor device as claimed in claim 1, wherein the sensor device comprises a sensor or array which is movable in a circumferential direction around the interface of the conduits.
10. A sensor device as claimed in claim 9, wherein the sensor or array is adapted to successively sense the contact pressure at a plurality of circumferential regions.
11. A sensor device as claimed in claim 9 or 10, wherein the sensor device comprises a rig positioned around the conduits, and wherein the sensor or array is movably coupled to the rig to allow movement of the sensor around the interface of the conduits.
12. A sensor device as claimed in claim 9 or 10, wherein the sensor device comprises a portable unit which may be operated by an operator.
13. A sensor device as claimed in any preceding claim, wherein the sensor device is movable in a vertical direction to allow sensing of the contact pressure at a plurality of mating surfaces of two conduits.
14. A sensor device as claimed in claim 13 when dependent on claim 11, wherein the rig of the sensor device is height adjustable.
15. A sensor device as claimed in any preceding claim, wherein the sensor device includes a processing unit adapted to compare the readings taken at a plurality of circumferential regions with each other.
16. A sensor device as claimed in any preceding claim, wherein the sensor device includes a display adapted to indicate whether the reading taken at each of the plurality of circumferential regions is relatively high or low.
17. A sensor device as claimed in any preceding claim, wherein the sensor device comprises a sensor which is at least one of: attached or attachable to an engaging member for coupling two conduits; or located or locatable at a flanged connection of two conduits; or fixed to the interface of the two conduits.
18. A sensor device as claimed in claim 17, wherein the or each sensor is a passive sensor, and wherein the sensor device includes an interrogating device adapted to electromagnetically excite the sensor such that the sensor takes a measurement.
19. A sensor device as claimed in claim 18, wherein the interrogating device includes a receiver for wirelessly receiving the measurement of the sensor.
20. A method of sensing within an enclosed pressure vessel, wherein the method comprises circumferentially sensing, using an ultrasonic reflectometry sensor device, the contact pressure at mating surfaces of two conduits.
21. A method as claimed in claim 20, wherein the sensor device comprises a plurality of ultrasonic reflectometry sensors, and wherein the method includes arranging the plurality of sensors circumferentially around an interface of the conduits.
22. A method as claimed in claim 20, including moving the sensor device in a circumferential direction around the interface of the conduits and successively sensing the contact pressure at a plurality of circumferential regions.
23. A method as claimed in any of claims 20 to 22, including moving the sensor device in a vertical direction to allow sensing of the contact pressure at a plurality of mating surfaces of two conduits.
24. A method as claimed in any of claims 20 to 23, including at least one of: attaching a sensor to an engaging member for coupling two conduits; or locating a sensor at a flanged connection of two conduits; or fixing at least one sensor to the interface of the two conduits.
25. A method as claimed in claim 24, wherein the or each sensor is a passive sensor, and wherein the method includes using an interrogating device to electromagnetically excite the sensor such that the sensor takes a measurement.