The present invention relates to the drilling and completion of well bores in the field of oil and gas recovery. More particularly, this invention relates to an apparatus to provide selective communication of control fluid through a downhole tool, such as a safety valve. A method of using the communication tool apparatus is also described.
In the oil and gas industry, a production tubing string is typically run thousands of feet into a well bore. Generally, when running a tubing string downhole, it is desirable—and in some cases required—to include a safety valve on the tubing string. The safety valve typically has a fail safe design whereby the valve will automatically close to prevent production fluid from flowing through the tubing, should, for example, the surface production equipment be damaged or malfunction.
Should the safety valve become inoperable, the safety valve may be retrieved to surface by removing the tubing string, as described hereinafter. The tubing retrievable subsurface safety valve (“TRSSSV”) may be a flapper-type safety valve, a ball-seat type of valve, or other types of valves known in the art. The TRSSSV is attachable to production tubing string and generally comprises a flapper pivotally mountable on the lower end of the safety valve assembly by a flapper pin, for example. A torsion spring is typically provided to bias the flapper in the closed position to prevent fluid flow through the tubing string. When fully closed the flapper seals off the inner diameter of the safety valve assembly preventing fluid flow therethrough.
A flow tube is typically provided above the flapper to open and close the flapper. The flow tube is adapted to be movable axially within the safety valve assembly. When the flapper is closed, the flow tube is in its uppermost position; when the flow tube is in its lowermost position, the lower end of the flow tube operates to extend through and pivotally open the flapper. When the flow tube is in its lowermost position and the flapper is open, fluid communication through the safety valve assembly is allowed.
A rod piston contacts the flow tube to move the flow tube. The rod piston is typically located in a hydraulic piston chamber within the TRSSSV. The upper end of the chamber is in fluid communication, via a control line, with a hydraulic fluid source and pump at the surface. Seals are provided such that when sufficient control fluid (e.g. hydraulic fluid) pressure is supplied from surface, the rod piston moves downwardly in the chamber, thus forcing the flow tube downwardly through the flapper to open the valve. When the control fluid pressure is removed, the rod piston and flow tube move upwardly allowing the biasing spring to move the flapper, and thus the valve, to the closed position.
On relatively rare occasions, the safety valve assembly may become inoperable or malfunction due to the buildup of materials such as paraffin, fines, and the like on the components downhole, e.g., such that the flapper may not fully close or may not fully open. Regardless, it is known to replace the TRSSSV by retrieving the safety valve assembly to surface by pulling the entire tubing string from the well and replacing the safety valve assembly with a new assembly, and then rerunning the safety valve and the tubing string back into the well.
Because of the length of time and expense required for such a procedure, it is known to run a replacement safety valve downhole within the tubing retrievable safety valve as described hereinafter. These replacement safety valves typically are run downhole via a wireline. Thus, these replacement safety valves are often referred to as wireline retrievable sub-surface safety valves (“WRSSSV”). Before inserting the wireline safety valve into the TRSSSV assembly, however, two operations are performed. First, the TRSSSV is locked in its open position (i.e., the flapper must be maintained in the open position); and second, fluid communication is established from the existing control fluid line to the interior of the TRSSSV, thus providing control fluid (e.g. hydraulic fluid) to the replacement wireline safety valve. Lockout tools perform the former function; communication tools perform the latter.
Various lockout tools are commercially available, and will not be further discussed herein. When it is desired to lock the safety valve assembly in its open position, the lockout tool is lowered through the tubing string and into the safety valve. The lockout tool is then actuated to lock the valve mechanism (e.g. the flapper) of the TRSSSV in the open position.
Before inserting the replacement safety valve or WRSSSV, communication is established between the hydraulic chamber of the TRSSSV and the internal diameter of the TRSSSV. The communication tool disclosed herein may be utilized to provide fluid communication between the inner diameter of the safety valve and the hydraulic chamber, so that the hydraulic control line from surface can be utilized to operate the replacement wireline safety valve.
Once communication has been established with the hydraulic line, the WRSSSV may be run downhole. The WRSSSV may resemble a miniature version of the TRSSSV assembly described above. The WRSSSV is adapted to be run downhole and placed within the inner diameter of the TRSSSV assembly described above. The WRSSSV typically includes an upper and lower set of seals that will straddle the communication flow passageway established by the communication tool so that the control line to the TRSSSV may be used to actuate the valve mechanism of the WRSSSV.
More specifically, the seal assemblies allow control fluid from the control line to communicate with the hydraulic chamber and piston of the WRSSSV in order to actuate the valve of the WRSSSV between the open and closed positions. Once the WRSSSV is in place, the wireline may be removed and the tubing string placed on production.
There are various methods of establishing communication used today. One such method involves inserting a communication tool downhole which must be radially aligned just right in order for the cutter to cut the required communication point. Some of these tools require special sleeves which precisely position the communication tool in exact alignment.
There are disadvantages to these designs. If the alignment is off, the cutter will miss the intended communication point and communication will not be established. This may also lead to costly damage to the interior of the tool. Also, designing and installing the sleeves used to align the tools is costly and may introduce unnecessary leak paths in the tubing.
In view of the foregoing, there is a need in the art for, among others, a cost effective communication tool which establishes fluid communication without the need for alignment of the tool or the costly components associated therewith.
According to one embodiment, the invention relates to an apparatus for establishing communication between a control fluid line from surface to the inner diameter of a downhole tool such as a safety valve. In a preferred embodiment, a communication device is provided to establish fluid communication between the control line and the inner diameter of a safety valve. Should a need arise where it is necessary to establish fluid communication between the control line and the interior of the safety valve (e.g., if the TRSSSV is no longer operable), an embodiment of a communication tool may be run into the safety valve. At a predetermined point, a cutter extends from the tool and will ultimately penetrate through a communication component in the TRSSSV. The communication component is installed in, and extends from, the non-annular hydraulic piston chamber of the TRSSSV. When the cutter is above the communication component, application of a downward force causes the cutter to axially penetrate the communication component, thereby establishing communication between the control line and the inner diameter of the safety valve. A wireline replacement valve may then be run downhole, and operated utilizing the control line to surface.
According to a preferred embodiment, the cutter of the communication tool does not have to be axially aligned with the communication component of the TRSSSV prior to actuating the communication tool. The cutter is extended from the communication tool once the tool has been locked into position inside the TRSSSV. The cutter extends into an internal recess on the inner diameter of the TRSSSV. With the cutter in the extended position, downward jarring on the central prong of the tool causes downward displacement of the cutter. A return spring and indexing spring combine to cause the cutter to rotate a pre-selected amount when the jarring weight is removed from the central prong. Following rotation, jarring is commenced again. The cutter will rotate through 360 degrees with continued jarring and rotating steps. The cutter will contact the communication component at least once per complete revolution.
While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the intention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims.
Illustrative embodiments and related methods of the invention are described below as they might be employed in the oil and gas well. In the interest of clarity, 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, 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. Further aspects and advantages of the various embodiments and methods of the invention will become apparent from consideration of the following description and drawings.
Embodiments of the invention will now be described with reference to the accompanying figures. Like numbers refer to like elements throughout.
Prior to jarring, the return spring 70 holds a preload that is, for example, two times greater than the weight of the cutter 55, cutter housing 50, nose 60, central prong 15 and the jar weight. The preloaded return spring 70 is illustrated in
As illustrated in
The ratchet springs 75, as shown in
Communication tool 10 is run inside of the production tubing and into the top of TRSSSV 100 until the lock dogs 40 are positioned adjacent to a mating profile in the safety valve hydraulic chamber housing 105. In this position, cutter 55 is in the retracted position as illustrated in
Hydraulic piston 125 is mounted inside non-annular piston bore 120 and connects to flow tube 135. Flow tube 135 may be shifted via hydraulic pressure acting on piston 125 to extend through flapper 145 to open TRSSSV 100. If hydraulic pressure is lost, power spring 140 will force flow tube 135 upwardly above flapper 145, thereby allowing flapper 145 to pivot to the closed position and to prevent flow of well bore fluids up through the safety valve. Although not shown in detail, it is understood that flow tube 135 is locked in the open position prior to the insertion of communication tool 10. Various methods of locking open the TRSSSV 100 are known.
To set lock dogs 40, weight is applied to central prong 15 causing shear pins 42 to be severed thereby allowing the central prong 15 to move downwardly until an enlarged section of the central prong moves behind locking dogs 40 causing the dogs to radially extend into the mating profile in the hydraulic chamber housing 105. In this position, locking dogs 40 are set thereby locking the communication tool to the TRSSSV 100. The downward movement of a central prong 15 also causes an internal profile in the central prong 15 to move downwardly relative to cutter extension pin 57. As shown in
The downward movement of the central prong 15 during the jarring mode, causes return spring 70 to be compressed. More particularly, extension mandrel 71 (shown in FIG. 7B) connected about the lower end of prong 15 compresses spring 70. The downward movement of prong 15 also causes the indexing springs 65 to snap over the index profile ramps 80 as shown in
Although various embodiments have been shown and described, the invention is not so limited and will be understood to include all such modifications and variations as would be apparent to one skilled in the art. For example, the communication tool could be used to establish communication with other types of downhole devices (i.e., devices other than a TRSSSV). Such tools may, or may not, include a communication component through which fluid communication is established with the communication tool. Thus, the present invention is not limited to establishing communication with a TRSSSV but may be used to establish communication with other types of downhole devices. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.
This application claims the benefit of U.S. Provisional Application No. 60/901,187, filed on Feb. 13, 2007, entitled “COMMUNICATION TOOL FOR SUBSURFACE SAFETY VALVE WITH COMMUNICATION DEVICE,” which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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60901187 | Feb 2007 | US |