Coil tubing injector

Some embodiments may include a coil tubing injector, which may include: a cylinder-rod assembly including at least one cylinder rod operably coupled to a first load beam and a second load beam, the at least one cylinder rod to change a separation distance between the first load beam and the second load beam; opposing grippers; and at least one additional beam, at least one link, a set of gears, or control valves to maintain a parallel orientation of the load beams relative to each other during operation of the at least one cylinder rod, the at least one additional beam, the at least one link, or the set of gears operably coupled to at least one of the load beams or the control valves coupled to hydraulic piping to hydraulically operate the cylinder-rod assemblies independently. Other embodiments may be disclosed and/or claimed.

FIELD OF THE INVENTION

This disclosure relates generally to drilling, and more particularly to a coil tubing injector to insert coil tubing drill pipe into well bores.

BACKGROUND

Coiled tubing pipe is a continuous length of pipe, often 10,000 feet or longer. It is used in the oil drilling industry because it can be inserted into and removed from a well bore without making and breaking connections which is the more common method.

The coil tubing is gripped by two opposing chain assemblies which provide vertical forces to push the pipe into a well overcoming fluid pressures. The push force can be as high as 50,000 pounds. When the long length of coil tubing is in the well, the upward pull force can be as high as 100,000 pounds, especially if the pipe becomes stuck in the well. The gripping friction forces between the chain and the coil tubing must be sufficient to prevent the coil tubing from slipping with respect to the chains. The usual method of providing the gripping or traction force is with hydraulic cylinders. The hydraulic cylinders provide a mechanism to adjust the gripping force and allow the chains to move apart for coil tubing insertion. The force on a single chain can be higher than 400,000 pounds.

U.S. Pat. No. 9,091,129 describes a common method of configuring the chains, and cylinder assemblies.

DETAILED DESCRIPTION

A known apparatus for coil tubing injectors100is shown inFIGS.1A-B. Coil tubing130is gripped by opposing grippers110(e.g., gripper blocks), which are attached to chains111. The chains are tensioned by sprockets116and powered by motors (not shown) attached to sprockets115that are supported by bearings114. The chains,111, have rollers112which bear against load beams120. The load beams have one or more sets of crossmembers125and126which transfer force from load beams120to one or more sets of cylinders122and124. Oil is pressurized in piping135as shown by pressure gauge132which causes the cylinder rods123to retract, making the cylinder-rod assembly shorter, gripping the coil130. Oil in piping134is at a lower pressure as shown by gauge133. The chains111, rollers112, motors (now shown), and grippers110are supported by an inner frame105. In frame105is supported by outer frame101and by brackets140and141.

FIG.2shows the grippers110moved apart for coil tubing insertion or removal.

Referring toFIG.3, one limitation to this arrangement is that the coil tubing130, grippers110, and rollers112can move laterally with respect to load beam120as shown on dimension350. Some lateral movement is desired to allow the coil tubing130to align itself to the well bore. Too much movement and too much cylinder force can cause the crossmembers125and126, and hence load beams120, to rotate as shown inFIG.4, causing an eccentricity450. This can cause misalignment on chains111, and wear on grippers110. Cylinder rods123can bend as a result of these forces. In extreme cases, the coil tubing130can be pinched and broken, falling into the well.

FIGS.5A-Cshow an improved injector to prevent the rotation of load beams120. An additional beam512is attached to cylinders122and124by pivot brackets516. Links505and506are connected to an additional beam510with brackets508. Links505and506are connected to additional beam512by pivot brackets514. Additional beam512is connected to additional beam510by links505and506. A additional beam510is connected to crossmember125with brackets503and504. The additional beam512is allowed to rotate at pivot brackets516in the directions shown as520which allows the cylinders122and124to extend or retract equally (the additional beams510and512may synchronize contraction or extension of cylinder rods123), keeping the crossmembers125and126parallel.

FIGS.6A-Cshows another embodiment that prevents the rotation shown inFIG.4. InFIGS.6A-C, additional beam618is connected to links616by pivot brackets617. Links616are connected to cylinders122and124. Additional beam618is attached to the frame (e.g., outer frame101in this embodiment or the inner frame105(FIG.1A) in other embodiments) by pivot brackets614. This allows pivot brackets617to move to the right or left in unison, keeping rods616and thereby crossmember126moving parallel to members of the outer frame101. Similarly, additional beam619is connected to outer frame101with pivot brackets615. Additional beam619is operably connected to crossmember125with rods606and with brackets604which move together keeping crossmember125parallel to the members of the other frame101. Since the crossmembers125and126are parallel to the members of the outer frame101, they are parallel to each other.

FIGS.7A-Cshow a similar mechanism to keep crossmembers125and126parallel with each other. A beam assembly including individual additional beams717is pivoted on the frame (e.g., outer frame101in this embodiment or the inner frame105(FIG.1A) in other embodiments) by pivot brackets714. At the centerline of the injector, link718connects each individual additional beam717. The link718can translate right or left, providing equal displacement of links716and722. Links716and722are attached to cylinder rods123by brackets702and704. Thus crossmember125moves parallel to members of the outer frame101. In a similar manner, links724and726are attached to cylinders122and124. The cylinders are attached to crossmember126by brackets732and730. Thus crossmembers125and126move parallel to the members of the outer frame101and with respect to each other.

FIGS.8A-Cshow the same basic mechanism asFIGS.7A-C. Instead of the links being attached to the cylinders, links816and822are attached to a beam assembly including individual beams817and attached directly to crossmember126with brackets802. Likewise, links824and826are attached to individual beams817and directly to crossmember125with brackets702and704.

FIGS.9A-Cshow another mechanism similar toFIGS.7A-CandFIGS.8A-C. Instead of unequal rods and offset beams, a beam assembly including individual beams917is arranged with gear teeth meshing near the centerline of the injector. Additional beams917are connected to links920, which are connected to cylinders122and124. On the opposite side, additional beams917are connected to links921, which are connected to brackets702and704.

In this embodiment, the gear teeth are located on individual beams917of a beam assembly. In other embodiments, the gear teeth may be located on a gear assembly including a set of gears. The set of gears may be operably coupled to at least one of the load beams120in a similar arrangement as the individual beams917are operably coupled to at least one of the load beams. The set of gears may be attached to any part of the injectors frame, also.

FIGS.10A-Bshow another mechanism to maintain the orientation of the grippers. Additional beams1002are connected to crossmember1025. Additional beams1002are inserted into sleeve1001, which is connected to crossmember1026. As the cylinder rods123extend and retract, the tight fitment of the beams1002into sleeves1001maintain the crossmembers1025and1026parallel to each other. Grippers110are maintained in an orthogonal relationship to each other.

FIG.11shows an additional alternate mechanism to maintain the orientation of the grippers110. InFIG.1hydraulic piping is used to pressurize the oil in both cylinders from a single pressure source (not shown). InFIG.11, the piping1135and1136, and1137and1138are connected to more than one control valves (not shown) so that cylinders1122and1124may be controlled independently. In some embodiments, multiple cylinders1122and1124of multiple cylinder-rod assemblies may be controlled by a single control valve1140. In various embodiments, multiple cylinders122(FIG.1A) of a same cylinder-rod assembly may be controlled by a single control valve1140. Position sensors1110and1111may report the length of extension of each cylinder rod1123, pressure sensors1101,1102,1103,1104may be used to indicate pressures in the cylinders1122and1124. A control system (not shown) uses the data from the sensors (e.g., from position sensors1110and1111, or from pressure sensors1101,1102,1103, and1104to actuate the separate control valves (now shown) to ensure that the grippers110are maintained in an orthogonal orientation with respect to each other.

The control system may be implemented using application specific hardware (now known or later developed) or general purpose hardware (now known or later developed). Embodiments implemented using general purpose hardware may include hardware and associated software. For example, in some embodiments, a control system may one or more processors and software executable on those processors to carry out the operations described. We use the term software herein in its commonly understood sense to refer to programs or routines (subroutines, objects, plug-ins, etc.), as well as data, usable by a machine or processor. As is well known, computer programs generally comprise instructions that are stored in machine-readable or computer-readable storage media. Some embodiments of the present invention may include executable programs or instructions that are stored in machine-readable or computer-readable storage media, such as a digital memory. We do not imply that a “computer” in the conventional sense is required in any particular embodiment. For example, various processors, embedded or otherwise, may be used in equipment such as the components described herein.

Memory for storing software again is well known. In some embodiments, memory associated with a given processor may be stored in the same physical device as the processor (“on-board” memory); for example, RAM or FLASH memory disposed within an integrated circuit microprocessor or the like. In other examples, the memory comprises an independent device, such as an external disk drive, storage array, or portable FLASH key fob. In such cases, the memory becomes “associated” with the digital processor when the two are operatively coupled together, or in communication with each other, for example by an I/O port, network connection, etc. such that the processor can read a file stored on the memory. Associated memory may be “read only” by design (ROM) or by virtue of permission settings, or not. Other examples include but are not limited to WORM, EPROM, EEPROM, FLASH, etc. Those technologies often are implemented in solid state semiconductor devices. Other memories may comprise moving parts, such as a conventional rotating disk drive. All such memories are “machine readable” or “computer-readable” and may be used to store executable instructions for implementing the functions described herein.

A “software product” refers to a memory device in which a series of executable instructions are stored in a machine-readable form so that a suitable machine or processor, with appropriate access to the software product, can execute the instructions to carry out a process implemented by the instructions. Software products are sometimes used to distribute software. Any type of machine-readable memory, including without limitation those summarized above, may be used to make a software product. That said, it is also known that software can be distributed via electronic transmission (“download”), in which case there typically will be a corresponding software product at the transmitting end of the transmission, or the receiving end, or both.

Although illustrated embodiments show a cylinder-rod assembly located on either side of a center line of the injector, it should be appreciated that any of the principles described herein may be applied to an injector including a single cylinder-rod assembly. In such an embodiment, a cylinder rod of the single cylinder-rod assembly may be located on the center line of the injector. In this arrangement of an injector, the injector may not include any crossmembers (the cylinder-rod assembly may be operatively coupled to the load beams using a bracket, fastener, or the like, or combinations thereof).

Also, crossmember(s) are not required in embodiments with more than one cylinder-rod assembly. The cylinder-rod assemblies may be operably coupled to at least one load beam of load beams of the injector using a bracket, fastener, or the like, or combinations thereof.

Various embodiments of an improved injector may include at least one additional beam, at least one link, a set of gears, or some other mechanism to maintain parallel orientation of the load beams relative to each other during operation of the at least one cylinder rod. The at least one additional beam, at least one link, a set of gears, or other mechanism may be operably connected to at least one load beams of load beams of the injector (e.g., using crossmembers or some other coupling mechanism such as a bracket, a fastener, or the like, or combinations thereof). The at least one link may be a rigid link, a flexible link (e.g., a cable), or a semi-flexible link.

References above have been made in detail to preferred embodiment. Examples of the preferred embodiments were illustrated in the referenced drawings. While preferred embodiments where described, it should be understood that this is not intended to limit the invention to one preferred embodiment. To the contrary, it is intended to cover alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.

Having described and illustrated the principles of the invention in a preferred embodiment thereof, it should be apparent that the invention may be modified in arrangement and detail without departing from such principles. Claim is made to all modifications and variation coming within the spirit and scope of the following claims.