Abstract:
A hydraulic setting apparatus has an isolation sleeve which covers setting ports and prevents entry of hydraulic setting fluid into a pressure settable tool such as an inflatable packer or a hydraulic packer. The mandrel of the setting tool is mechanically coupled to the mandrel of the pressure settable completion tool by a guide tube which provides an enlarged counterbore chamber. The guide tube is intersected by radial setting ports which permit entry of the pressurized fluid for pressurizing a hydraulic pressure chamber in the completion tool. A shiftable isolation sleeve opens and closes the setting ports. A radially outwardly biased split C-ring is engaged against the bore of the isolation sleeve. Longitudinal travel of the split C-ring is limited by a shear collar which is releasably pinned to the isolation sleeve.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS: 
     This application is a continuation-in-part of application Ser. No. 08/001,020, filed Jan. 6, 1993, which is a continuation of U.S. application Ser. No. 07/743,792, filed Aug. 12, 1991, now U.S. Pat. No. 5,180,016. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to apparatus for completing downhole wells, and in particular to apparatus for setting hydraulic packers. 
     BACKGROUND OF THE INVENTION 
     In the course of completing an oil and/or gas well, it is common practice to run a string of protective casing into the well bore and then to run the production tubing inside the casing. At the well site, the casing is perforated across one or more production zones to allow production fluids to enter the casing bore. During production of the formation fluid, formation sand is also swept into the flow path. The formation sand is relatively fine sand that erodes production components in the flow path. 
     In some completions, however, the well bore is uncased, and an open face is established across the oil or gas bearing zone. Such open bore hole (uncased) arrangements are utilized, for example, in water wells, test wells, highly deviated and horizontal well completions. One or more sand screens are installed in the flow path between the production tubing and the open, uncased well bore face. The packer and sand screens are run in place while water is pumped under high pressure through a float shoe to wash the uncased bore and remove drill cuttings and clean well completion apparatus prior to placing the well into production. It is desirable that the wash job be performed as the completion apparatus is run into the well. After the annulus along the uncased well bore has been cleaned, the packer is customarily set to seal off the annulus in the zone where production fluids flow into the production tubing. Inflatable packers are preferred for use in sealing an uncased well bore. 
     DESCRIPTION OF THE PRIOR ART 
     The float shoe contains multiple ports through which fluids are jetted to wash drill cuttings from a well bore while a packer, screen or other set of well completion tools are run into the well bore. Because high differential pressures may be created by the jets at the end of the float shoe, it has been difficult to run hydraulically operated down hole well tools, such as hydraulic packers, in the same trip because of the potential for inadvertent set of the tools as a result of the back pressures generated in the annulus during the jet cleaning operation. Therefore, when such operations have been conducted previously, it has been necessary to first jet clean and clear the well bore, and then, in a separate trip, run the completion apparatus and production tubing into the well. 
     In the course of preparing the well for production, a well packer and screen along with a service tool and other well completion tools are run into the well on a work string, with the packer being releasably anchored against the well bore. When the well bore is cased, a hydraulically set packer having compressible seal elements and radially extendible anchor slips are utilized. When an uncased well bore is completed, an inflatable packer is utilized. Both types of packers may be set by the application of hydraulic pressure through setting ports. 
     Conventional hydraulic setting mechanisms have open ports which can allow the packer to be inadvertently set while running the packer and clearing drilling debris from the annulus with the float shoe. A build-up of hydraulic pressure might cause premature setting while pumping through the work string and circulating out through the annulus to remove debris. If the annulus or float shoe clogs up below the hydraulic setting mechanism, the pressure may build to a level which will cause the packer to set, allowing the elements to expand and engage the well bore. Some inflatable packers employ a check valve which prevents release of the pressure, and most hydraulically settable packers which include anchor slips have ratchet couplings that prevent retraction of the anchor slips. A prematurely set packer is typically required to be retrieved and then re-run. 
     OBJECTS OF THE INVENTION 
     The principal object of the present invention is to provide an improved hydraulic setting apparatus for use in combination with hydraulic settable completion equipment such as hydraulic packers which are run into a well simultaneously with the washing of the well bore without risk of causing the premature or unintentional operation of the hydraulically settable equipment. 
     A related object of the invention is to provide a hydraulic setting apparatus of the character described which maintains a hydraulic setting port in sealed condition during running operations, which may be selectively opened when it is desired to set the packer, and which automatically seals the hydraulic setting port after the tool has been set and/or the setting device is expended. 
     SUMMARY OF THE INVENTION 
     The foregoing objects are achieved according to the present invention in which a hydraulic setting apparatus has an isolation sleeve which covers setting ports and prevents entry of hydraulic setting pressure into a pressure settable tool such as an inflatable packer or a hydraulic packer. The setting apparatus has a production mandrel adapted for coupling and flow registration with the flow bore of the pressure settable completion tool. The setting apparatus mandrel is mechanically coupled to the mandrel of the pressure settable completion tool by a guide tube member which provides an enlarged counterbore chamber. The guide tube is intersected by radial setting ports which permit the entry of pressurized fluid for pressurizing a hydraulic pressure chamber in the completion tool. 
     In one embodiment, the hydraulic pressure chamber provides driving pressure for a piston actuated, hydraulically set packer. In an alternative embodiment, the pressure chamber is coupled in fluid communication with the pressure chamber of an inflatable packer. In both embodiments, a shiftable isolation sleeve opens the setting ports. A radially outwardly biased split C-ring is engaged against the bore of the isolation sleeve. Longitudinal travel of the split C-ring is limited by a shear collar which is releasably pinned to the isolation sleeve. 
     In one embodiment, the isolation sleeve is pinned to the guide tube by hollow shear pins. The packer is set by flowing a drop ball down the work string until it engages the seating surface provided by the C-ring. The hydraulic pressure is increased until the hollow shear pins shear and separate, and the isolation sleeve is shifted longitudinally through the bore to the open port position. After the packer has been set, the drop ball is still engaged against the C-ring seat. The hydraulic pressure is increased until the shear pins on the shear collar shear and separate, permitting the shear collar to shift toward an extended open position, with the outwardly biased split C-ring being shifted into the counterbore of the isolation sleeve. As this occurs, the isolation sleeve expands radially outwardly, thus permitting the drop ball to be shifted through the flow production bore to the next packer. At this point, the bore of the setting apparatus is no longer restricted which will allow passage of a tool string. 
     Consequently, it will be appreciated that the setting ports remained sealed by the isolation sleeve while running the packer and completion apparatus into the well bore, while circulating debris by high pressure jet flow from the annulus to the surface. Since the setting ports are sealed until the drop ball is flowed into place, the jet washing may proceed and there is no risk of prematurely setting the packer, even though the annulus may become blocked by debris. 
     Operational features and advantages of the invention will be understood by those skilled in the art upon reading the detailed description which follows with reference to the attached drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a simplified, sectional view which illustrates installation of the setting apparatus of the present invention, as part of an expandable packer and well screens in a horizontal, uncased well bore; 
     FIG. 2 is a view similar to FIG. 1 in which the inflatable packer is inflated; 
     FIG. 3 is a longitudinal sectional view, partially broken away, of an hydraulic setting sleeve showing its components in the closed port, run position; 
     FIG. 4 is a view similar to FIG. 3 with the components of the hydraulic setting apparatus being shown in the open port, fill position; 
     FIG. 5 is a view similar to FIG. 4 with the components of the hydraulic setting apparatus being shown in the open port, fully inflated position; 
     FIG. 6 is a view similar to FIG. 5 with the components of the hydraulic setting apparatus being shown in the closed port, set position; 
     FIG. 7 is an elevational view, partially in section, showing the components of an alternative embodiment of a hydraulic setting apparatus in the run-in, sealed port position; and 
     FIG. 8 is a view similar to FIG. 5 in which the components of the hydraulic setting apparatus are in the open port, set position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In the description which follows, like parts are indicated throughout the specification and drawings with the same reference numerals, respectively. The drawings are not necessarily to scale and the proportions of certain parts have been exaggerated to better illustrate details of the invention. 
     Referring now to FIG. 1 and FIG. 2, multiple sand screens 10 are shown installed in an uncased well bore 12 which penetrates horizontally through an unconsolidated formation 14. Multiple screen sections 10 are assembled together, with the screen assembly being terminated by a float shoe 16. 
     The screens 10 are coupled to a work string 18 by a running tool 20 and an inflatable packer 22. As the completion equipment is run through the horizontal bore 12, water is pumped through the work string 18 and the production mandrels of the setting tool 20, the inflatable packer 22 and screens 10, where it is discharged through the float shoe 16 for washing the bore and circulating drill cuttings, filter cake and lost circulation material from the annulus 24 upwardly for recovery at the surface as indicated by the arrows. While the wash and circulation are proceeding, the packer 20 is in its deflated condition as shown in FIG. 1. It will be appreciated that the annulus 24 may become blocked by an accumulation of debris, particularly in the elbow transition region of the horizontal well bore. If that should occur, the packer 22 may inadvertently be set and seized against the uncased well bore, if the setting ports of the packer are exposed to the high pressure hydraulic fluctuations produced by operation of the float shoe 16. 
     Inadvertent set of the inflatable packer 22 is prevented, according to the present invention, by an isolation sleeve 26 which is shiftable from a sealing position, as shown in FIG. 3, in which a hydraulic setting port 28 is sealed, to a set position in which the setting port 28 is uncovered, as shown in FIG. 4. 
     The setting apparatus 20 has a tubular mandrel 30 with a longitudinal flow bore 32. The setting tool mandrel 30 is coupled to the mandrel 34 of the inflatable packer 22 by a guide tube 36. The guide tube 36 has a smooth bore 38 which is radially offset with respect to the setting tool flow bore 32. 
     The inflatable packer 22 includes an expandable bladder 40 which is secured and sealed by a coupling collar 42 and set screws 44, which secure the end of the bladder 40 onto a shoulder 46 formed on the guide tube 36. The guide tube 36 is intersected by the radially setting ports 28, which provide flow communication with the pressure chamber 48 defined in the annulus between the packer mandrel 34 and the bladder 40. 
     Referring now to FIG. 5, the isolation sleeve 26 is shiftable longitudinally along the smooth bore surface 38 of the guide tube 36. During run-in, the isolation sleeve 26 is biased to the covered, closed port position as shown in FIG. 3 by a coil compression spring 50. 
     Referring again to FIG. 3, a releasable seat is provided for a drop ball by an outwardly biased split C-ring 52. The C-ring 52 is received within the flow bore 54 of the isolation sleeve 26. Longitudinal displacement of the C-ring 52 is blocked by a shear collar 56. The shear collar 56 is received within a smooth counterbore 58 which intersects the isolation sleeve 26. The shear collar 56 is pinned to the isolation sleeve 26 by shear pins 60. The entrance to the setting port 28 is sealed by annular O-ring seals 62 and 64 so that the hydraulic expansion chamber 48 is sealed with respect to the flow bore 32 during run-in. The O-ring seals 62 and 64 are longitudinally spaced in slidable, sealing engagement between the isolation sleeve 26 and the smooth bore 38 of the guide tube. The C-ring seals 62 and 64 thus seal the flow bore 32 with respect to the inflation chamber 48 when the isolation sleeve is in the covered (RUN) position as shown in FIG. 3. 
     When it is desired to inflate the bladder 40, a drop ball 66 is dropped into the bore of the work string, and is flowed into sealing engagement against the C-ring 52. The internal C-ring 52, which is compressed within the smooth bore 54 of the isolation sleeve, has a sloped shoulder 68 which is coated with a polymeric coating 70. The coated shoulder 68 defines a valve seat for receiving and sealing against the drop ball 66. 
     When it is desired to expand the bladder 40 and set the packer 22, hydraulic pressure is applied sufficient to compress the spring 50 and move the isolation sleeve 26 from the covered position as shown in FIG. 3 to the uncovered position as shown in FIG. 4, thereby exposing the setting port 28. Hydraulic fluid is injected into the inflatable packer through the exposed setting port until the bladder 40 is fully expanded, as shown in FIG. 5. The hydraulic pressure is then increased to cause shearing separation of the shear pins 60. 
     When separation occurs, the shear collar 56 and the C-ring 52 are shifted longitudinally into the isolation sleeve counterbore 58, as shown in FIG. 5. When the C-ring 52 enters the counterbore 58, it expands radially into engagement with the counterbore surface, thereby releasing the drop ball 66 and permitting it to be flowed through the setting tool bore 32 into the packer mandrel bore 35. Simultaneously, the coil spring 50 will drive the isolation sleeve 26 back to the covered position so that the setting ports 28 are once again sealed and isolated. This will hold the hydraulic setting fluid in the packer expansion chamber 48 at the injection pressure. The packer mandrel bore 35 is also unrestricted since the C-ring ball seat has expanded radially into the isolation sleeve counterbore 58. 
     The drop ball 66 is then pumped into the next inflatable packer which is fitted with identical setting tool 20, and the setting process is repeated for setting the next packer. 
     It will be appreciated that the spring 50 may not be required for use in combination with inflatable packers which are inflated through a check valve. 
     The guide tube 36 is secured and sealed to the setting tool mandrel by a threaded union T, and its opposite end is secured and sealed to the packer mandrel 34 by a threaded union T. 
     For hydraulic packers which utilize anchor slips and expandable seal elements and for those inflatable packers which include check valve means coupled to the setting ports, the coil spring 50 is not needed. A packer setting tool with the hydraulic setting apparatus 72 constructed without a coil spring is illustrated in FIG. 7 and FIG. 8. 
     The construction of the setting apparatus 72 as shown in FIGS. 7 and 8 is similar to that shown in FIGS. 3 and 4, except that a bias spring is not needed. In that embodiment, the setting port 28 is releasably sealed by a shearable cup-like member or shear screw 74 which isolates pressure chamber 76 from bore 32 and pins the isolation sleeve 26 to the guide tube 36. The shear screw 74 is intersected by a longitudinally blind bore or pocket which serves as an open flow passage through the body of the screw when the screw has been separated by a shearing force. Otherwise, the construction is essentially the same as that shown in FIGS. 3 and 4. 
     Operation of the alternative setting tool embodiment 72 is different in that the setting port 28 is not resealed after it has been opened. This is not necessary when the setting tool 72 is used in combination with inflatable packers which are fitted with check valves, or when used in combination with hydraulically set packers which include ratchet couplings for preventing retraction of the anchor slips. 
     In the alternative embodiment shown in FIG. 7, the setting port 28 provides flow communication between the flow bore 32 and a hydraulic pressure chamber 76. The hydraulic chamber 76 is formed in the annulus between the guide tube 36 and a pressure cylinder 78. Pressurization of the chamber 76 causes a piston 80 to be driven longitudinally along the setting tool mandrel 84 for simultaneously applying a setting force to anchor slips and seal elements, for example as disclosed in U.S. Pat. No. 4,834,175 and U.S. Pat. No. 5,103,902, which are incorporated by reference. When it is desired to set the packer, the drop ball 66 is released and flowed into sealing engagement with the C-ring 52. The hydraulic pressure is increased until the hollow shear screws 74 separate, thus opening the setting port 74 and permitting the isolation sleeve 26 to be shifted along the smooth bore of the guide tube 36 to the uncovered position as shown in FIG. 8. 
     When the setting port 28 is opened, hydraulic fluid is pumped into the pressure chamber 76, thus causing the piston 80 to be driven longitudinally along the setting tool mandrel 84 for applying a setting force against the seal elements and anchor slips. After the seal elements and anchor slips have been set, the drop ball is still on the C-ring seat 70 and the shear collar 56 remains pinned to the isolation sleeve 26. The hydraulic pressure is increased until the shear pins 81 separate, thus permitting the C-ring 52 and the shear collar 56 to be shifted into the isolation sleeve counterbore 58. Upon entry into the counterbore, the C-ring 52 expands radially outwardly, thus releasing the drop ball 66 and permitting it to be flowed through the setting tool mandrel bore 85 to the next seat. 
     It will be appreciated that high pressure jet washing operations may be carried out while the setting tool, packer and screens are being run into the well bore, without causing premature set of the packer. Moreover, since the C-ring seat remains coupled to the isolation sleeve, it eliminates the need for an additional ball seat to set the packer. 
     Although the invention has been described with reference to a horizontal completion, and with reference to particular preferred embodiments for setting packers, the foregoing description is not intended to be construed in a limiting sense. For example, the hydraulic setting apparatus of the present invention may also be used for injecting completion chemicals through the exposed port into the annulus surrounding the tubing string. This arrangement permits the corrosive well treatment fluids to be pumped into the formation while isolating and protecting the interior of the hydraulically settable well completion apparatus. The hydraulic setting apparatus of the present invention may also be used to good advantage in alternative applications, for example, in oil wells, gas wells, environmental wells, including monitoring wells, recovery wells and disposal wells, and in combination with expandable packers as well as hydraulically set packers having anchor slips and other hydraulically operated tools which would benefit from selective hydraulic isolation. It is therefore contemplated that the appended claims will cover any such applications which incorporate the hydraulic setting apparatus of the present invention.