Not applicable.
Not applicable.
1. Field of the Invention
The subject invention relates generally to drilling and/or servicing subterranean wells for recovery of hydrocarbon-bearing fluids and more specifically to a method and apparatus for drilling and/or servicing subterranean wells with rotating coiled tubing.
2. Description of the Related Art
Historically, subterranean wells have been drilled by rotating a bit attached to the end of jointed pipe or tubing sections. The jointed pipe string is rotated from the surface, which rotation is transferred to the bit. As the rotating bit drills into the earth, additional sections or joints of pipe must be added to drill deeper. A significant amount of time and energy is consumed in adding and removing new sections of pipe to the drill string.
Coiled tubing, such as described in U.S. Pat. No. 4,863,091, is available in virtually unlimited lengths and has been used for a variety of purposes in the exploration and production of hydrocarbons from subterranean wells. Coiled tubing has not, to date, supplanted jointed pipe for drilling operations.
It is believed that the most common use of coiled tubing in drilling operations involves the use a motor or other energy source located at the end of tubing adjacent the drill bit. One type of motor is a mud motor that converts pressurized drilling mud flowing through the coiled tubing into rotational energy for the drill bit. In this type of system, the coiled tubing itself does not rotate. For example, U.S. Pat. No. 5,360,075 is entitled “Steering Drill Bit While Drilling A Bore Hole” and discloses, among other things, a motor powered drill bit at the end of coiled tubing that can be steered by torsioning the tubing. The article Introduction to Coiled Tubing Drilling by Leading Edge Advantage International Ltd. is believed to provide an overview of the state of the art of drilling using non-rotating coiled tubing, a copy of which may be found at www.lealtd.com. The substance of that article is incorporated by reference herein for all purposes.
Another approach for drilling with coiled tubing is taught in U.S. Pat. No. 4,515,220, which is entitled “Apparatus and Method for Rotating Coil Tubing in a Well” and discloses, among other things, cutting the coiled tubing away from the spool before the tubing can be rotated for drilling operations.
U.S. Pat. No. 6,315,052 is entitled “Method and a Device for Use in Coiled Tubing Operations” and appears to disclose an apparatus that physically rotates a spool of coiled tubing about a is to thereby drill the well bore. U.S. Pat. No. 5,660,235 is similarly entitled “Method and a Device for Use in Coil Pipe Operations” and discloses, among other things, maintaining the coiled tubing in substantial alignment with the injector head as the tubing is spooled and unspooled by rotating the reel about a pivot point and/or translating the reel relative to the injector head.
The present invention builds on the prior art and is directed to an improved method and apparatus for drilling and/or servicing subterranean wells with rotating coiled tubing.
In one aspect of the present invention, a system for drilling or servicing a well with coiled tubing is provided that comprises a rotatable base or turntable comprising a bearing system rotatably fixing to the base to a floor, and a reel assembly comprising a support structure adapted to support a reel of coiled tubing. The support structure comprises an alignment system to align the coiled tubing with the well as the coiled tubing is payed off the reel. The reel assembly is located near a periphery of the base and a coil tubing injector head is aligned with the well. A counterbalance assembly is located on the base opposite the reel assembly and is moveable toward and away from the reel assembly to maintain balance of the system, as coiled tubing is payed off the reel. A motive system is also provided for turning the base and thereby transmitting torque to the coiled tubing in the well.
In another aspect of the present invention, system may be disposed as part of a mobile or permanent rig that may be moved from location to location.
The foregoing summary is not intended to summarize each potential embodiment of the present invention, but merely summarizes the illustrative embodiments disclosed below.
The foregoing summary, detailed description of preferred embodiments, and other aspects of this disclosure will be best understood when read in conjunction with the accompanying drawings, in which:
a and 10b illustrate a collapsible mast raised and attached to a mobile rig.
a and 12b illustrate raising the upper floor of a mobile rig.
The figures above and detailed description below are not intended to limit in any manner the breadth or scope of the invention conceived by applicants. Rather, the figures and detailed written description are provided to illustrate the invention to a person of ordinary skill in the art by reference to the particular, detailed embodiments disclosed.
Illustrative embodiments of the invention are described below. In the interest of clarity and disclosure of what Applicants regard as their invention, not all features of an actual implementation are 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 developers' specific goals, such as compliance with system-related, business-related, and government-related constraints, 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 this disclosure.
In general terms, the present inventions provide an improved method, system and/or drilling/service rig that can rotate continuous lengths of coiled tubing down hole for drilling and other exploration and/or production operations. A system is disclosed in which at least one reel of coiled tubing is located on a rotatable platform oriented about the well bore. The reel of tubing is adapted to adjust its position relative to the well bore centerline, as tubing is payed on and off. A dynamic counterbalance system may also be provided to offset the dynamically changing weight of coiled tubing and may be adapted to translate toward and away from the well bore as may be needed to maintain rotational balance. A coil tubing injector head may be disposed adjacent the well bore for injecting and retracting coiled tubing from the well. The present invention allows the use of conventional or third party tubing reels or proprietary reels and conventional or proprietary coiled tubing handling equipment, such as coiled tubing injector heads. The present invention may be incorporated on a trailer or other mobile structure for fast rig-up and rig-down, and ease of transportation from well site to well site. Such mobile structure may incorporate trailer axles and wheels designed with adequate spacing to clear the external walls of the well cellar or other well structures.
The present invention, at least one embodiment of which is described in more detail below, greatly improves the efficiency at which both over balanced and under balanced wells can be drilled and completed; improves the safety associated with re-entering, side-tracking and working over live or depleted wells; and greatly reduces the time spent in the reservoir and during rig-up and rig-down, as compared to conventional drilling operations. As compared to conventional drilling operations, the present invention allows for smaller crew numbers, reduced rotational friction, increased rate-of-penetration, reach, and the ability to safely and simultaneously drill, produce, and log the well bore.
Turning now to
The reel 28 preferably has a capacity of at least about 13,000 feet (4,000 meters) of 3¼ inch (8.255 cm) outside diameter by 14 inch (0.635 cm) wall thickness coiled tubing 14. Although 3¼″ tubing is not widely available, it has been found that such tubing has an optimum balance of fatigue and torsional strengths. Precision Tube Technology of Houston, Tex. offers 3¼″ coiled tubing. Of course, the present invention has application with all types and sizes of coiled tubing. The reel assembly 12 further comprises a hydraulic cylinder 30 (
The reel assembly 12 also comprises a reel drive and tensioning system 15 that is capable of spooling tubing 14 at about 2,500 psi or less. The drive system 15 may comprise one or more hydraulic motors located adjacent the periphery of the reel 28 and engaging a chain or other gear on the outer periphery of the reel 28. Alternatively, a hydraulic motor may be located adjacent the center axis of this reel 28 for driving and tensioning the tubing. It will be appreciated that because the preferred embodiment of the present invention is a mobile rig, attention must be given to traveling weights and orientation of components. For example, a cantilevered hydraulic motor adjacent the reel 28 axis may be prone to fatigue failures. The presently preferred embodiment for the drive system 15 comprises a single hydraulic motor and chain as shown in
Mounted above or on the top of the injector head 22 is a transducer system 34 that senses the orientation or alignment of the coiled tubing with respect to the injector head 22. As shown in
In an alternate embodiment, a PLC or other logic device, rather than the transducer system may directly control the alignment of the tubing described above. For example, as tubing is spooled on or off, the footage spooled can be sent to a logic device by an appropriate transducer (such as an odometer). A simple logic program can convert the amount of tubing spooled into the correct orientation of the reel assembly and send the appropriate control signals to the alignment system, such as the hydraulic cylinders. The transducer system 34 shown in
Returning to
In a presently preferred embodiment, the tubing injector 22 is a Hydra-Rig model HR-5100, 100,000 lb. capacity injector head assembly. The HR 5100 is designed to handle coiled tubing sizes from 1¾-inch OD through 3 1/2-inch OD. It is designed for operation with both open loop and closed loop hydraulic systems. As illustrated in
When there are little or no reactive forces downhole working on the coiled tubing, the injector 22 and the main turntable 10 will rotate substantially together. However, as reactive forces, such as frictional drag, increase down hole, rotation of the injector 22 may lag behind the rotation of the main turntable 10 with the amount of lag being indicative of the reactive forces being experienced down hole. These reactive forces may be quantified in several different ways. For example, an instrumented torque arm 64 may be disposed between the injector turntable 60 and the main turntable 10. As the down hole reactive forces increase, the strain, for example, on the torque arm 64 would increase, thereby providing a measure of the reactive forces downhole. Alternately, a motor 66 could separately power the injector turntable 60. A control system, such as the PLC mentioned above, may be used to drive the injector table 60 in synch with the main turntable 10. As the downhole reactive forces increase, it will be appreciated that more power will have to be supplied to the injector turntable motor 66 to keep the injector in synch with the reel 20 and main turntable 10. Of course, it is also contemplated that the injector 22 can be coupled to the main turntable 10 so that there can be no relative rotation there between.
Depending upon the injector 22 system chosen it may be beneficial to mount the injector 22 on a sliding base that allows it to be moved out of the way for clear access to the well. When fully retracted the injector 22 may stored within the support structure 16. When the system is being moved (e.g., to a different well), the injector may be stored within the support structure 16.
Returning to
Turning now to
In
a illustrates that the upper floor (102, 106 & 116) is pivotally connected to the lower floor by a plurality of legs 122. The upper floor is pivoted into position, such as by winching, and locked with pins. For example, the mast 118 may be used to winch the upper floor into position. Additional bracing may be used as needed to support the upper floor. Preferably, the legs 122 provide about 27 feet of vertical clearance from the ground or lower rig floor. The upper floor has a footprint of approximately 39 feet long by 39 feet wide.
In
A conventional snubbing unit may be used to make the improved systems substantially self-sufficient and capable of preparing and completing both underbalanced and overbalanced wells. It is anticipated that embodiment of the present invention may be rigged up and operational within about six hours of arrival upon location. Because the coiled tubing is rotated, the improved system is less likely to be limited by frictional lock up, hole cleaning issues and weight to bit transfer. In addition, existing or conventional bottom hole assembly (BHA) technology may be used to great advantage with the present system. For example, it is expected that the improved system will be able to trip four times faster than a conventional jointed pipe rig while utilizing the same crews sizes as traditional coil tubing drilling operations. The improved system can be used with existing or conventional underbalanced separation units and perhaps most effectively with a fully integrated, mobile under balanced drilling (UBD) system.
In underbalanced applications, the BHA can be deployed using a conventional lubricator. A number of BHA options are available from standard positive displacement motor applications through turbine to rotary steerable systems using either mud pulse technology or electromagnetic while drilling (EMWD) options for a variety of drilling applications.
In practice, it is contemplated that the connection of the BHA to the coiled tubing is made and pressure tested. The BHA will then be run into the well to begin drilling. When tubing rotation is required, the reel of coiled tubing and, therefore, the coil tubing in the well can be rotated up to about 20 RPM or higher, if desired. If reactive torque is an issue then the reel can also be rotated in the opposite direction. While directional drilling, the rotation of the reel can be halted to facilitate the necessary change in well trajectory and once the necessary correction has been achieved the tangent section can then be drilled. All of the tripping and drilling may be performed without having to make jointed connections, thus maintaining steady state downhole pressure conditions and preventing down hole pressure transients from potentially damaging the reservoir and negating the benefits of underbalanced drilling.
While tripping out of the well, the system may back ream continuously without making or breaking connections back to the shoe to assist in well cleaning and to reduce the potential for stuck pipe. Once the bit is at the shoe, the rotation of the tubing may be halted if desired to prevent bit damage and the coiled tubing tripped to the surface while maintaining under balanced conditions. The BHA may be recovered and the system can either begin the rig down process or re-complete the well as the rig program dictates.
As mentioned, the present invention may be used with conventional bottom hole assemblies and mud motors in addition to conventional coiled tubing and rotary steerable assemblies. The ability to use a variety of BHA or options gives the present invention the capacity to reduce sinusoidal oscillation that are currently found with existing wells drilled with coiled tubing BHAs. The present invention may also be used with all manner of downhole drilling, logging, fishing, abandonment, production, and other tools or processes. In addition, the coiled tubing may be rotated in a direction opposite to the rotation of drill bit/motor to reduce the mount of drilling torque reacted by the tubing and may beneficially reduce the sinusoidal oscillations of tubing in the well.
The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof.
This application claims the benefit of U.S. Provisional Application No. 60/584,616.
Number | Date | Country | |
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60584616 | Jul 2004 | US |