FIELD OF THE INVENTION

The invention relates to a tool for running and retrieving a wear bushing or a bore protector. The invention also relates to a process for running and retrieving a wear bushing or a bore protector using this tool incorporated in the drill string.

STATE OF THE ART

In an offshore well for oil and gas extraction, it is known to use wear bushings (also known as wear sleeves) or bore protectors to protect the sealing profiles of the wellhead while drilling. In particular, a wellhead typically has sealing polished bores which are used for well barriers purposes during the well construction and the production phases. These sealing surfaces need to be protected during drilling operations to prevent any damage of the sealing interfaces that could jeopardize the well integrity.

To this end, it is known to position a wear bushing or a bore protector within the wellhead prior to a drilling operation, and to remove said wear bushing or bore protector once the drilling operation is completed.

A conventional way to position and retrieve a wear bushing or a bore protector is to use a dedicated tool, which is specifically run into the well for the sole purpose of installing, and then of retrieving, the wear bushing or bore protector.

With reference to figure 1 a, such a tool 9 is schematically represented. This tool comprises a generally tubular body having an external surface comprising at least two annular portions 90, 91 of different diameters, one of the diameters being adapted to run or retrieve wear bushings, and one of the diameters being adapted to run or retrieve a bore protector.

On each annular portion are provided shear pins 92 as well as gripping members 93 which can adopt either one position in which the gripping members are retracted, or a position in which the gripping members are extended under the effect of a spring. Switching between the positions is done mechanically when the tool is pulled out of hole.

As also visible on figure 1 a, a wear bushing or bore protector B also has, on its outer surface, shear pins 95 which are adapted to be received in a corresponding internal groove 96 of the wellhead W. For the installation of the wear bushing or bore protector, the tool holding the wear bushing or bore protector B is run down the hole until reaching the well head W, in which position the shear pins 95 of the wear bushing or bore protector engage in the groove 96 of the wellhead.

Upon pulling of the tool, with reference to figure 1 b, the shear pins of the tool

92 engage in a recessed profile 97 of the wear bushing or bore protector and abut against a wall of the recessed profile. Those shear pins 92 are configured to break upon application of a lower shear than those 95 of the wear bushing or bore protector. Thus, by pulling upon the tool, the shear pins of the latter break and the tool is removed, leaving the wear bushing or bore protector in place.

Once the drilling section has been completed, the wear bushing or bore protector is retrieved by running the wear bushing/bore protector pulling tool. The gripping members are run in extended position, until they engage in corresponding grooves of the wear bushing or bore protector. By pulling upon the tool, the shear pins of the wear bushing/bore protector break and the two can be pulled out of hole.

Given the very expensive rigs' daily rates, these round trips of running or pulling the tool are time consuming and thus very expensive. It is thus desirable to combine the operations of running and retrieving the wear bushing or bore protector with those of running and retrieving the drilling bottom hole assembly from the well.

As schematically shown on figure 2, another type of tool 9 is known, which comprises a tubular member which is adapted to be threaded on drill pipes. The tool is thus run down the well at the same time that the drilling bit.

The tool moreover comprises shear pins 91 allowing engagement with the wear bushing or bore protector B, so that an assembly comprising the drilling bit, drilling strings, the tool and the wear bushing can be simultaneously run down the well.

A shoulder 92 provided on the internal wall of the wellhead W forms a stop for the wear bushing or bore protector, abutting against said shoulder. Further running down the drill bit causes the shear pins to break and leave the wear bushing or bore protector in place.

For retrieval of the wear bushing or bore protector, the tool further comprises a section 93 protruding from the tubular member, this section abutting against a complementary profile 94 of the wear bushing or bore protector. Upon further retraction of the tool the shear pins engaging the wear bushing or bore protector with the wellhead break and the assembly comprising the drill string, the tool and the wear bushing or bore protector can be pulled out of hole.

This solution has the advantage of reducing the number of run in hole and pull-out of hole operations for running and retrieving the wear bushing or bore protector.

However, it has the drawbacks that the protruding section of the tool partially obstructs the section of the hole and impedes good evacuation of the cuttings from the drilled section.

Another drawback of this tool is that if it is needed or desired to pull the bit string out of the hole, it cannot be done without also removing the wear bushing or bore protector.

PRESENTATION OF THE INVENTION

In view of the above, one aim of the invention is to at least partially alleviate the inconvenience of the prior art.

In particular, one aim of the invention is to provide a tool for running or retrieving a wear bushing or bore protector, which can be run or pulled into/from the well head while running/pulling the drilling string.

Another aim of the invention is to provide a tool which does not obstruct the evacuation of the cuttings from the drilled section, and also allows removing the drilling bottom hole assembly from the hole while maintaining the wear bushing or bore protector in place, if desired.

To this end, a tool for running or retrieving a wear bushing or bore protector is disclosed, comprising:

- a tubular body, having an external diameter smaller than an internal diameter of the wear bushing or bore protector, the tubular body comprising threaded ends adapted to engage with drill pipes, and

- a plurality of gripping members adapted to engage on an interior portion of a wear bushing or bore protector, the gripping members being extendable and retractable relative to the tubular body,

the tool being characterized in that it further comprises a remotely controlled positioning system adapted to selectively retract or extend the gripping members. In a preferred embodiment, the remotely controlled positioning system comprises an RFID tag reader. The RFID tag reader may be of the active type and the remotely controlled positioning system then further comprises a battery.

In embodiments, the remotely controlled positioning system further comprises a battery, an electric motor driven by the battery, and an actuator of the gripping members driven by the electric motor.

In a particular embodiment, the actuator comprises a spring urging each gripping member in retracted position, and a movable wedge which motion is driven by the motor, such that the wedge can switch between a first position in which it urges the gripping member against the spring in extended position, and a second position in which it allows retraction of the gripping member under the effect of the spring.

Preferably, each gripping member is removable from the tubular body.

A process for running a wear busing or bore protector in a well, comprising the following steps:

running down the well a wear bushing or bore protector mounted on a tool according to the preceding description, wherein the gripping members of the tool are extended to engage the wear bushing or bore protector on the tool, - when the wear bushing or bore protector is in position in a wellhead positioned in the well, remotely actuating the gripping members of the tool in order to retract the gripping members.

In embodiments, the tool is integrated to a drill string, and the process further comprises running down the drill string and the tool for further operation.

In a preferred embodiment, the tool comprises an RFID reader, and the step of actuating the gripping members comprises circulating, in the drill mud flowing through the tool, a plurality of RFID tags, wherein the RFID tags are configured such that their reading by the RFID reader drives the retraction of the gripping members. A process for retrieving a wear bushing or a bore protector positioned in a well head is also disclosed, comprising the steps of:

positioning a tool according to the preceding description such that the gripping members of the tool face an interior surface of the wear bushing or bore protector, remotely actuating the gripping members of the tool in order to extend the gripping members until they engage the interior surface of the wear bushing or bore protector, and

pulling out of hole the tool and the wear bushing or bore protector.

In embodiments, the tool is integrated to a drill string, and the retrieval of the wear bushing or bore protector is performed following an open hole or cased-hole operation during which the gripping members are retracted,

and wherein the positioning step comprises pulling back the drill string until the tool is inside the wear bushing or bore protector.

In a preferred embodiment, the tool comprises an RFID reader, and the step of actuating the gripping members comprises circulating, in the drill mud flowing through the tool, a plurality of RFID tags, wherein the RFID tags are configured such that their reading by the RFID reader drives the extension of the gripping members. The tool according to the invention comprises gripping members for engaging a wear bushing or bore protector, wherein said gripping members can be selectively extended or retracted thanks to a remote control. Therefore, it is possible to retract the gripping members once the wear bushing or bore protector has been positioned in the well-head to allow running the drill string further down the hole without obstructing the cross-section of the hole.

As the gripping members are retracted, it is also possible to pull the drilling bottom hole assembly out of hole without removing the wear bushing or bore protector. However, when it is desired to remove the wear bushing or bore protector, this is easily performed by commanding the gripping members of the tool to engage the groove of the wear bushing or the bore protector.

The actuation of the gripping members can be performed in a cheap and easy manner by circulating RFID tags in the drilling mud, the RFID tags being programmed either to instruct the gripping members to extend or retract when passing through the tool. RFID tags are small enough to prevent any obstruction of the drill string or bottom hole assembly.

Last, the gripping members are removable from the tubular members. This allows gripping members to be custom-shaped and particularly adapted for running and retrieving either a wear bushing or a bore protector of various diameters and/or suppliers.

DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will be apparent from the following detailed description given by way of non-limiting example, with reference to the accompanying drawings, in which:

- Figures 1 a and 1 b, already described, represents the use of a tool according to the prior art for installing and retrieving a wear bushing.

- Figure 2, also already described, represents another prior art tool for running and retrieving a wear bushing.

Figure 3 schematically represents a tool according to an embodiment of the invention.

Figures 4a-4d schematically represent a wear bushing installation using a tool according to an embodiment of the invention.

Figure 4e represents the main steps of an installation process according to an embodiment of the invention.

Figures 5a-5d schematically represent a wear bushing retrieval using a tool according to an embodiment of the invention

- Figure 5e represents the main steps of a retrieval process according to an embodiment of the invention.

DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION

With reference to figure 3 is schematically shown an example of a tool 1 for running and retrieving a wear bushing or bore protector according to one embodiment of the invention.

The tool 1 comprises a tubular body 10, adapted to be inserted in a wear bushing or bore protector. To this end, the tubular body has an external diameter (or maximum external diameter, if the external diameter of the tubular body is variable) which is smaller than the internal diameter of a wear bushing or bore protector.

The tubular body 10 is generally cylindrical around a main axis X-X, and is hollow, i.e. it comprises an inner cylindrical through hole 1 1 extending along an axis which coincides with the main axis X-X. The tool is preferably adapted to be integrated to a drill string, in order to be put in an oil or gas well simultaneously with the drilling bottom hole assembly, during the drilling operations. To this end, the longitudinal ends of the tubular body 10, along the main axis X-X, are threaded so that they can be engaged by screwing on threaded ends of drilling pipes.

Preferably, one of the ends 12 may form a female cooperation member with a drilling pipe, and the other end 13 may form a male cooperation member with another drilling pipe.

The tool 1 further comprises gripping members 20 which are adapted to engage on an interior portion of a wear bushing or a bore protector, such as a groove arranged on an interior surface of a wear bushing or bore protector. To this end, the gripping members 20 are extendable and retractable relative to the tubular body 10. In extended position, the gripping members 20 protrude from the tubular body 10 and can engage in a corresponding recess or groove of a wear bushing or bore protector to make the latter cooperate with the tool.

In retracted position, the gripping members 20 are received in corresponding cavities 14 of the tubular body 10 so as not to protrude from the tubular body.

A well completion comprises a multitude of different diameters, and each shoulder between two diameters must be protected by a wear bushing or bore protector. In order for the gripping members 20 to be able to engage a wear bushing or a bore protector of various diameters, the gripping members 20 are removably attached to the tubular body 10. Therefore, a collection of various gripping members 20 can be designed, wherein gripping members 20 are custom-shaped according to various types and diameters of the part (wear bushing or bore protector) that they have to engage. One can therefore select specific gripping members according to their intended use, and install them on the tubular body 10.

Moreover, the tool further comprises a positioning system 30 of the gripping members, which is adapted to selectively retract of extend the gripping members relative to the tubular body. The positioning system 30 is remotely controllable, so that it is not necessary to pull the tool 1 out of the well to switch the gripping members 20 between their extended and retracted positions.

Moreover, as explained in more details below, the remote control of the actuator enables selectively extending the gripping members for installing or retrieving a wear bushing or bore protector, and retracting the gripping members when they are not used, in order to prevent the gripping members from obstructing the open hole cuttings removal.

According to a preferred embodiment, the positioning system 30 comprises a radio-identification (RFID) tag reader 31 . The tag reader is adapted to read RFID tags 2 dropped into the drilling string from the surface and flowing in the inner through hole 1 1 with drilling mud. The tags 2 are programmed with different information whether it is needed to retract or extend the gripping members. According to tag flowing through the tool, and thus to the information read by the tag reader 31 , the positioning system 30 is therefore controlled to selectively retract or extend the gripping members.

According to a preferred embodiment, the tags 2 that are flowing in the mud are passive tags, which are less expensive than active tags, as they are very likely to be destroyed by the drill bit after flowing through the tool. In that case, the tag reader 31 is preferably an active tag reader. The positioning system further comprises a battery 32 for feeding the tag reader with electrical current.

Alternatively, the gripping members could be activated by the tag reader 31 and tag 2 operating by Near Field Communication (NFC).

According to still another embodiment, a non-contact transmitter comprising an electric cable can be inserted down the hole, inside the tool, to transmit instruction to a receiver embedded in the tool by inductive coupling.

Last, the positioning system 30 further comprises an actuator 33 of the gripping members, which is controlled by a controller 34. The controller is connected to the tag reader 31 and the battery 32. It may be for instance a printed circuit board, an ASIC or a FPGA.

The actuator 33 of the gripping members can be achieved in different manners. According to a non-limiting example, the actuator 33 may comprise an electric motor 330 connected to the battery, and for each gripping member 20, a spring 331 urging the gripping member in retracted position, and a wedge 332 which is driven in translation by the electric motor.

The wedge 332 can translate between two extreme positions. In a first position, the wedge urges the gripping member 20 in extended position, against the effort of the spring on the gripping member 20. In a second position, the wedge does not oppose the effort of the spring so that the gripping member is in retracted position thanks to the spring. As the tool 1 is part of the drill string located either at the bottom hole assembly level or upward in the string, it has to be compliant with downhole fluids and resist to hydrocarbons. To this end, the tubular body 10 and gripping members are preferably made of steel suitable to resist the downhole damaging conditions and conventionally used by the industry.

With reference to figures 4a-4e, a process 100 for running a wear bushing or bore protector 3 in a wellhead 4 will now be disclosed. This process is preferably performed simultaneously with the running of a drill string down the well for a drilling operation.

During an installation step 1 10, the tool 1 is screwed to drill pipes 50 to be part of a drill string 5. A wear bushing or a bore protector 3 is mounted on the tool 1 by inserting the tool in the wear bushing / bore protector while the gripping members 20 are in retracted position, and then controlling the gripping members 20 to switch to the extended position.

Then the drill string 5 comprising the tool 1 and wear bushing or bore protector 3 is run down the well during a step 120 (fig. 4a and 4b), until reaching a position where the wear bushing or bore protector is inside the wellhead 4. In this position, shear pins (not shown) of the wear bushing or bore protector may engage in a corresponding recessed profile of the wellhead to prevent any relative motion between them.

During a step 130 (fig. 4c), the wear bushing or bore protector is released by remotely controlling the tool in order to retract the gripping members 20. As shown in figure 4, this step is preferably performed by circulating, in the drilling mud that is injected through the tool 1 , at least one RFID tag 2. This RFID tag is programmed such that its reading by the RFID reader 31 launches retraction of the gripping members 20 by the actuator33. Preferably, in order to ensure that the RFID reader 31 will read at least one tag, a plurality of tags 2 may be injected in the drilling mud, for instance at least ten tags.

During a step 140 (fig. 4d), the drilling string can be run further down the well and drilling operations can be continued deeper. The RFID tags 2 flow with the drilling mud until reaching the drill bit, and then being evacuated with the mud and cuttings. One can notice that as the gripping members 20 are retracted, they do not obstruct the space between the drill string and the casing or the open hole, and therefore do not prevent evacuation of the mud and cuttings. Therefore the tool 1 can be part of the drilling string and do not prevent open hole or cased hole operations such as drilling, formation logging, downhole interventions etc.

Moreover, as the gripping members 20 are retracted, the drill string can also be pulled out of the well without removing the wear bushing or bore protector.

With reference to figures 5a-5e, a process 200 for retrieving a bore protector or well bushing from a wellhead will now be described.

This process is preferably performed upon pulling the drill string out of the well at the end of an open hole or cased hole operation such as drilling, formation logging, downhole interventions etc.

During a step 210 (figures 5a and 5b), the drill string is pulled from the bottom of the well until the tool 1 reaches a position where it is inserted in the wear bushing or bore protector, with the gripping members opposite an interior surface of the latter. The gripping members are in the retracted position during this step.

During a step 220 (fig. 5c), the tool is remotely control to switch the gripping members to the extended position, so that they engage with the interior surface of the wear bushing or bore protector. The gripping members may engage in a dedicated recessed portion of the interior surface.

This remote control is preferably performed by injecting RFID tags inside the tool by circulating the tags in the drilling mud. The tags are programmed such that their reading by the RFID reader 1 triggers extension of the gripping members.

The assembly comprising the drill string comprising the tool 1 and the wear bushing or bore protector is then pulled out of the well during a step 130 (fig. 5d). In the event that the wear bushing or bore protector was engaged with the wellhead through shear pins, the pulling on the wear bushing or bore protector causes those pins to break.

Once the tool 1 and the wear bushing or bore protector are pulled out of thole, they can be disconnected from the drill string and stored for a next use.