Coil Tube Injector System
A coil tube injector head comprising at least two gearbox units, wherein each gearbox unit drives a gripper assembly comprising a plurality of gripper assembly links. The gripper assembly links comprise a gripper surface that engages a length of coil tubing and one or more roller bearings that engage a bearing plate. The coil tube injector head further comprises a skid plate that is coupled to the bearing plate and receives pressure from one or more traction cylinders. The assembly of the claimed embodiments further allows for ease of maintenance and service of the coil tube injector by operators in the field of oil and gas production.
This application claims the benefit of U.S. Provisional Application No. 61/811,219, filed Apr. 12, 2013, which is incorporated herein by reference for all purposes.
BACKGROUNDHydrocarbons are an important resource which are often retrieved from ground by performing various subterranean operations. When performing subterranean operations, coil tube injector heads may be used to direct coil tubing (e.g., tubing which may be in a range of from approximately 1″ to approximately 3½″) into and out of a wellbore. The injectors provide a means of gripping the tubing to perform a controlled feeding operation. Injector heads are rated against the pushing/pulling force they can generate and the feedrate at which the tubing can be passed.
A complete injector head may comprise several components. For instance, the injector head may include an injector head assembly; a crash frame (providing a degree of mechanical protection during service); a service platform (allowing the operators to manage the operation of coil tube injection during service); and a gooseneck (which controls the feed of the tubing into the injector from a separate coil tube spool).
The basic premise of a coil tube injector is to simply grip the tubing with sufficient traction so that it does not slip when performing the desired subterranean operations, and then either pushing the tubing into a well or extracting it out. To achieve this goal, generally there are two sets of grippers, attached to a chain drive mechanism. The drives are generally hydraulically powered and when combined with a reduction gearbox provide sufficient torque to adequately move the loads. It is desirable to have an injector head which can operate smoothly and which can be easily maintained and serviced without disrupting ongoing subterranean operations.
A more complete and thorough understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings.
Illustrative embodiments of the present invention are described in detail herein. In the interest of clarity, not all features of an actual implementation may be described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation specific decisions must be made to achieve the specific implementation goals, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of the present disclosure.
To facilitate a better understanding of the present invention, the following examples of certain embodiments are given. In no way should the following examples be read to limit, or define, the scope of the invention. Embodiments of the present disclosure may be used with any wellhead system. Embodiments of the present disclosure may be applicable to horizontal, vertical, deviated, or otherwise nonlinear wellbores in any type of subterranean formation. Embodiments may be applicable to injection wells as well as production wells, including hydrocarbon wells.
The terms “couple” or “couples” as used herein are intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect mechanical or electrical connection via other devices and connections.
The methods and systems disclosed herein are not limited to any particular unit size. For instance, in certain implementations, the injector head unit may be an ‘80 k’ (80,000 psi) unit. However, the design concept can easily be upscaled and downscaled to suit the actual requirements. The methods and systems disclosed herein are directed to an actual operation constraint with regard to ease of operation and maintenance, making a ‘simple’ unit which is easily maintained and therefore, can be kept in production.
A coil tube injector in accordance with an illustrative embodiment of the present disclosure is generally denoted with reference numeral 100 in
Turning now to
As shown in
Each gripper/chain assembly 204A, 204B may have a plurality of chain links 400 each having one or more roller bearings 402 and one or more grippers 404 as shown in
Returning to
Specifically,
In operation, the traction cylinders 206 are pressured, moving the skid plates 208 towards the centrally located coil tubing 110 as it is passing through the gripper/chain assemblies 204A, 204B. Once the gripper/chain assemblies 204A, 204B engage with the coil tubing 110, a reaction force is applied back through the bearing plates 212 and the skid plates 208, thereby allowing a precise control of the position and load being applied to the coil tubing 110. This arrangement is replicated about the vertical centerline of the injector head assembly 102, allowing the gripper/chain assemblies 204A, 204B to encapsulate the coil tubing 110 and move the coil tubing 110 up or down as directed by the drive motors 205A, 205B. Accordingly, the traction cylinders 206 apply pressure to the skid plates 208, to bring the bearing plates 212 into contact with the gripper/chain assembly 204A, 204B so as to engage a coil tube 110.
In certain implementations, the skid plate 208, which may be manufactured from high grade aluminum, may be guided via slides which are disposed on the skid plate 208. In certain implementations, there may be four slides, one located at each corner of the skid plate 208. Composite bearings may be used to ensure that the skid plate 208 slides smoothly on the guides. The traction cylinders 206 provide the force to push and pull the skid plate 208. The skid plate 208 is of a robust design to minimize the amount of deflection it will experience under the load condition. Minimizing the distortion ensures that the bearing plate 212 provides a smooth and level surface on which the roller bearings 402 of the gripper/chain assembly 204 can run.
Returning now to
In certain implementations, the traction cylinders 206 and the tensioning cylinders 210 are located or accessible from the outside of the injector head assembly 102. For instance, as shown in
Accordingly, the use of the roller bearings 402 which run against the bearing plate 212 under the load condition reduces the friction when operating under a load. Additionally, the interaction of the bearing plates 212 with the roller bearings 402 of the gripper/chain assembly 204 provides a means of controlling the pressure applied by each gripper/chain assembly 204A, 204B as it engages the coil tubing 110. Specifically, the applied pressure by each gripper/chain assembly 204 in a load cycle may be controlled by an operator using the traction cylinders 206 which apply pressure to the roller bearings 402 through the skid plates 208 and the bearing plates 212.
Moreover, the bearing plates 212 are sacrificial items given the arduous nature of coil tubing. The bearing plates 212 may be accessed from the front and rear of the injector head assembly 102 and they may be easily removed to the sides of the injector head assembly. Accordingly, the bearing plates 212 may be easily replaced and/or repaired in situ.
Additionally, the gripper/chain assemblies 204A, 204B (including the grippers 404 and the roller bearings 402) are highly loaded during service. Accordingly, in certain implementations, the vertical space may be maximized to allow additional gripper assemblies to be in the load path, thus reducing the load to individual grippers 404, which in turn extends the life of the injector head assembly 102. Further, the grippers 404 are an integral part of the gripper/chain assembly 204. Accordingly, in certain implementations, a gripper carrier allows individual replacement of grippers 404. In another embodiment, the whole gripper/chain assembly 204 may be replaced in one operation. This results in a quick service period to change gripper size (e.g., going from 1½″ to 2″) and ensures that all grippers operate in a similar condition, i.e., a singular worn item does not get maintained with the system. When the gripper/chain assembly 204 or the grippers 404 do become worn out, an effective replacement can be made in a short time period which may be in a matter of minutes. Operational time is typically of great importance when performing subterranean operations. Accordingly, the longer the machine can operate and maintain performance the better.
In certain embodiments, different components may be manufactured from high grade aluminum which is sufficiently strong while giving a reduced weight compared to steel (steel being roughly 2½ times the weight of aluminum). The benefit of reduced weight is the ease of handling during installation, making the operator's job easier and therefore more productive.
Therefore, the present disclosure is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified, and all such variations are considered within the scope and spirit of the present invention. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee.
Claims
1. An injector head assembly comprising:
- a first gripper assembly and a second gripper assembly, wherein each of the first and second gripper assemblies comprises one or more grippers and one or more roller bearings;
- a first gearbox unit and a second gearbox unit, wherein the first gearbox unit drives the first gripper assembly and wherein the second gearbox unit drives the second gearbox assembly;
- a traction cylinder;
- a skid plate coupled to the traction cylinder, wherein the traction cylinder applies pressure to the skid plate;
- a bearing plate coupled to the skid plate, wherein the bearing plate is in contact with the one or more roller bearings.
2. The injector head assembly of claim 1, wherein the pressure applied by the traction cylinder moves the skid plate and the bearing plate between a first position and a second position.
3. The injector head assembly of claim 1, wherein the skid plate is made from high grade aluminum.
4. The injector head assembly of claim 1, wherein the bearing plate is made from steel.
5. The injector head assembly of claim 1, further comprising a tensioning cylinder, wherein the tensioning cylinder is operable to apply a force in a direction that is substantially perpendicular to direction of a force applied by the traction cylinder.
6. The injector head assembly of claim 1, wherein the skid plate is guided via a plurality of slides, wherein the slides are disposed on the skid plate.
7. The injector head assembly of claim 1, wherein the skid plate is coupled to a plurality of traction cylinders.
8. The injector head assembly of claim 1, wherein the first gearbox unit drives the first gripper assembly in a first direction and wherein the second gearbox unit drives the second gearbox assembly in a second direction.
9. The injector head assembly of claim 8, wherein a side of the first gripper assembly faces a side of the second gripper assembly and wherein the facing sides of the first gripper assembly and the second gripper assembly move in same vertical direction.
10. A injector head assembly comprising:
- a coil tube injector head, wherein the coil tube injector head comprises: a first gripper assembly and a second gripper assembly, wherein each of the first and second gripper assemblies comprise one or more grippers and one or more roller bearings; a first gearbox unit and a second gearbox unit, wherein the first gearbox unit drives the first gripper assembly and wherein the second gearbox unit drives the second gearbox assembly; a traction cylinder; a skid plate, wherein the traction cylinder provides pressure to the skid plate; a bearing plate, wherein the skid plate is coupled to the bearing plate and wherein the bearing plate is coupled to the one or more roller bearings; and
- wherein the coil tube injector head controls the feedrate of a length of coil tubing into or out of a well hole.
11. The injector head assembly of claim 10, wherein the pressure applied by the traction cylinder moves the skid plate and the bearing plate between a first position and a second position.
12. The injector head assembly of claim 10, wherein the skid plate is made from high grade aluminum.
13. The injector head assembly of claim 10, wherein the bearing plate is made from steel.
14. The injector head assembly of claim 10, further comprising a tensioning cylinder, wherein the tensioning cylinder is operable to apply a force in a direction that is substantially perpendicular to direction of a force applied by the traction cylinder.
15. The injector head assembly of claim 10, wherein the skid plate is guided via a plurality of slides, wherein the slides are disposed on the skid plate.
16. The injector head assembly of claim 10, wherein the skid plate is coupled to a plurality of traction cylinders.
17. The injector head assembly of claim 10, wherein the first gearbox unit drives the first gripper assembly in a first direction and wherein the second gearbox unit drives the second gearbox assembly in a second direction.
18. The injector head assembly of claim 17, wherein a side of the first gripper assembly faces a side of the second gripper assembly and wherein the facing sides of the first gripper assembly and the second gripper assembly move in same vertical direction.
Type: Application
Filed: Apr 10, 2014
Publication Date: Oct 16, 2014
Inventor: Gary Pendleton (Spring, TX)
Application Number: 14/250,156
International Classification: E21B 19/08 (20060101);