This disclosure relates to wellbore interventions.
When drilling a wellbore, drilling operators can come across high-loss zones. A high-loss zone within a wellbore results in a loss of drilling fluid and a reduction of static head that can be used to keep a wellbore under control during drilling operations. High-loss zones are often treated with loss control material to reduce or stop the loss rate of drilling fluid. In other instances, the high-loss zone is plugged with cement, and then the cement plug is drilled through. Both mitigations seal the wellbore from fluid losses into the high-loss zone so that drilling can continue without the risks associated with lost drilling fluid. Cement plugs can be used for other operations as well, for example, plugging and abandoning a well.
This disclosure describes technologies relating to cementing high-loss zones within a wellbore.
An example implementation of the subject matter described herein is a wellbore tool with the following features. A non-metallic tubular defines a central flow passage. Actuable rollers are actuable between an extended position and a retracted position. The actuable rollers are pivotally attached to the non-metallic tubular. The actuable rollers centralize the non-metallic tubular when in the extended position. The actuable rollers extend between the non-metallic tubular to an inner surface of the wellbore when in the extended position. A connector is attached to an uphole end of the non-metallic tubular. The connector is configured to attach to a downhole end of a work string.
Aspects of the example wellbore tool, which can be combined with the example wellbore tool alone or in combination, include the following. The non-metallic tubular comprises a plastic.
Aspects of the example wellbore tool, which can be combined with the example wellbore tool alone or in combination, include the following. The wellbore tool further includes an actuator to actuate the actuable rollers between the extended position and the retracted position.
Aspects of the example wellbore tool, which can be combined with the example wellbore tool alone or in combination, include the following. The actuator comprises a ball seat trigger.
Aspects of the example wellbore tool, which can be combined with the example wellbore tool alone or in combination, include the following. The connector or the non-metallic tubular have a lower yield strength than the work string.
An example implementation of the subject matter described herein is a method with the following features. A non-metallic tubular is received by a wellbore. Cement is received by central flow passage of the non-metallic tubular. The cement is emitted from a downhole end of the non-metallic tubular. A cement plug is formed from the emitted cement to plug a high loss zone by the cement or to spot a conventional cement plug.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The cement plug flash-sets. The non-metallic tubular is retained within the cement plug.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. A metallic work string uphole of and attached to the non-metallic tubular is rotated. The non-metallic tubular, or a connector retaining the non-metallic tubular to the work string, is sheared responsive to rotating the metallic work string. The metallic work string is retracted from the wellbore. The non-metallic tubular is left within the wellbore.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The cement plug is drilled through and the non-metallic tubular that remains within the wellbore.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The non-metallic tubular is removed from the wellbore.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The non-metallic tubular is received by a second wellbore different from the wellbore.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. The non-metallic tubular is centralized by actuable rollers.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. Centralizing the non-metallic tubular includes actuating the actuable rollers by circulating a ball within the non-metallic tubular.
Aspects of the example method, which can be combined with the example method alone or in combination, include the following. Actuating the actuable rollers includes actuating between an extended position and a retracted position, the actuable rollers centralizing the non-metallic tubular when in the extended position.
An example implementation of the subject matter described herein is a well system with the following features. A non-metallic tubular defines a central flow passage. Actuable rollers are actuable between an extended position and a retracted position. The actuable roller is pivotally attached to the non-metallic tubular. The actuable rollers extend between the non-metallic tubular to an inner surface of the wellbore when in the extended position. A connector is attached to an uphole end of the non-metallic tubular. The connector is configured to attach to a downhole end of a metallic work string.
Aspects of the example well system, which can be combined with the example well system alone or in combination, include the following. The non-metallic tubular includes a plastic.
Aspects of the example well system, which can be combined with the example well system alone or in combination, include the following. An actuator actuates the actuable rollers between the extended position and the retracted position.
Aspects of the example well system, which can be combined with the example well system alone or in combination, include the following. The actuator comprises a ball seat trigger.
Aspects of the example well system, which can be combined with the example well system alone or in combination, include the following. The non-metallic tubular is configured to be removed from the metallic work string by torsional shearing.
Aspects of the example well system, which can be combined with the example well system alone or in combination, include the following. The non-metallic tubular and the actuable rollers are configured to be drilled out of a wellbore when the non-metallic tubular becomes stuck in a wellbore.
Aspects of the example well system, which can be combined with the example well system alone or in combination, include the following. The metallic work string comprises coiled tubing.
Particular implementations of the subject matter described in this disclosure can be implemented so as to realize one or more of the following advantages. The tool described herein can be re-used multiple times. In the event that the tool becomes stuck, it is constructed of easily drillable materials.
The details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.
Like reference numbers and designations in the various drawings indicate like elements.
In instances where it is advantageous to use a cement plug to mitigate a high-loss zone during drilling, a work string is inserted into the wellbore to a depth proximal to the high-loss zone. In some instances, the work string is retained within the cement, such as when the cement “flash sets”. That is, when the cement cures faster than expected, securing and retaining a portion of the work string within the wellbore. In such situations, the work string must be slowly milled out of the wellbore before the plug can be drilled through. Such an operation requires specialized equipment and adds substantially more time to drilling operations. Instances where the high-loss zone is within a horizontal or deviated wellbore, can increase the likelihood of the work string becoming stuck as the downhole end of the work string is more likely to impact the walls of the wellbore in such situations.
This disclosure relates to a non-metallic tubular at the downhole end of a work string. The tubular includes actuable rollers to centralize and at least partially protect the non-metallic tubular from breakage. The tubular is used to form drillable cement plugs to block lost circulation zones or to spot a conventional cement plug. The tubular, rollers, and actuation mechanisms are made of drillable materials. In operation, a cement plug is formed using the non-metallic tubular. In some instances, the non-metallic tubular becomes stuck within the cement plug due to flash settings. In such instances, the non-metallic tubular is then sheared from the work string by over pull or rotation of the work string. The non-metallic tubular is then left within the cement plug to be drilled out at a later time in case of lost in hole due to stuck pipe event, such as a flash-set.
A connector 206 is attached to an uphole end of the non-metallic tubular 204. The connector 206 is configured to attach to a downhole end of the metallic work string 108. That is, when in use, the connector 206 is between the non-metallic tubular 204 and the metallic work string 108. The connector 206 can connect to the metallic work string 108 and the non-metallic tubular 204 in a variety of ways, for example, a threaded connection, a keyed friction connection, or any other connection that is appropriate for the service. In general, through material properties, geometry, or both, the connector 206, the non-metallic tubular 204, or both, have a lower yield strength than the metallic work string 108. In other words, the non-metallic tubular 204 or the connector 206 will shear away from the metallic work string 108 if sufficient torsional shear (twisting) or tension (pulling) is applied in the event that the non-metallic tubular 204 becomes stuck.
The wellbore tool also includes actuable rollers 202. The actuable rollers 202 are actuable between an extended position (shown in
The wellbore tool 200 includes an actuator to actuate the actuable rollers 202 between the extended position and the retracted position. Components of an example actuator are described later within this disclosure.
At 504, cement is received by the central flow passage of the non-metallic tubular. At 506, the cement is emitted from a downhole end of the non-metallic tubular. At 508, a cement plug is formed from the emitted cement to plug a high-loss zone by the cement or to spot a conventional cement plug for any other reason. In some instances, the non-metallic tubular is then removed from the wellbore to allow the cement to cure and form a cement plug. The non-metallic tubular can then be re-used in a different, second wellbore. That is, the non-metallic tubular can be received by the second wellbore. In other words, the non-metallic tubular can be re-used multiple times in multiple different wellbores.
In some instances, during operation, the cement plug flash-sets. That is, the cement sets faster than intended. In such an instance, the non-metallic tubular is retained within the set cement plug.
While this disclosure contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular implementations. Certain features that are described in this disclosure in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Moreover, the separation of various system components in the implementations described herein should not be understood as requiring such separation in all implementations, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products.
Thus, particular implementations of the subject matter have been described. Other implementations are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results.