Abstract:
A perforator apparatus for repeated punching of holes at a multiple of selected locations in tubing of a well bore. The apparatus is activated for repeated punching operations by a fluid control valve mechanism that controls opposed directional movement of a piston connected to a punch of the perforator apparatus.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a multi-shot punch perforator for use in punching holes in tubing within a well bore, and a hydraulic control valve for use therewith. 
     In oil and gas drilling operations, it is common practice to use a wireline for raising and lowering tools into the well bore. Specifically, this is achieved by attaching a toolstring to the end of a reel of a single strand or braided wire. By reeling out the wire, the toolstring may be lowered to the desired location within the well. The toolstring consists of a plurality of individual tools connected together to form a working unit. These tools may include data-retrieving devices and devices for performing other functions with respect to the well bore tubing, including punching openings in the tubing for various purposes including accessing lateral bores extending from the vertical well bore into which the toolstring is inserted. 
     In applications wherein punching is to be performed, prior art devices used for this purpose require removal from the well bore after each punching operation to ready the punching device for the next operation thereof. This constitutes a cumbersome and time-consuming operation. 
     The present invention provides a multi-shot punch perforator mechanism, and hydraulic control valve for use in activating the same, wherein multiple punching operations may be performed without requiring removal of the punch perforator from the well bore. 
     SUMMARY OF THE INVENTION 
     A fluid control mechanism is provided in accordance with the invention that selectively controls opposed directional movement of a piston. This mechanism may be used with the punch perforator in accordance with the invention. Specifically, the piston thereof is used to activate the punch of the punch perforator. 
     The piston is adapted for linear movement in opposed directions within the housing. A first valve is provided for selectively metering fluid to a first side of the piston to move the piston linearly within the housing in a first direction, and to selectively prevent fluid flow to the first side of the piston to permit the piston to move linearly within the housing in a second direction opposed to the first direction. A second valve is provided for preventing fluid flow to a second side of the piston opposite the first side thereof during metering of fluid flow to the first side of the piston by the first valve, and for metering fluid flow to the second side of the piston when the fluid flow to the first side of the piston is prevented by the first valve to move the piston in the second direction. 
     With this fluid control valve mechanism, the fluid flow is metered in a common direction by the first valve and by the second valve selectively to the first side of the piston and to the second side of the piston, respectively. 
     The housing is tubular and the fluid flow is metered by the first valve through an annular fluid passage within this housing. The second fluid flow is metered by the second valve through a tubular fluid passage extending linearly through the annular fluid passage. 
     The first and second valves may be positioned within the housing at a location remote from the piston and opposite the first side thereof. 
     The first valve and the second valve are adapted for linear movement between open and closed positions within the housing in response to selected pressure of fluid flow within the housing. 
     The fluid flow may be of a liquid or gas. 
     The housing of the mechanism may be positioned within a well bore. 
     The mechanism, including the housing thereof, may be a component of a toolstring. 
     The perforator apparatus for punching holes in tubing within a well bore includes a punch mounted within a housing adapted for positioning within tubing of the well bore. An opening is provided in the housing that is aligned with the punch. Hydraulic control means within the housing are provided for selectively moving the punch through the opening and into punching contact with the tubing to punch a hole therein. Thereafter, the hydraulic control means returns the punch to the position within the housing. In this manner, the punch may be operated to perform repeated punching operations without requiring removal of the mechanism from the well bore and associated tubing. 
     The hydraulically controlled means of the perforator apparatus may include a movable ram connected to the punch to transfer force to the punch sufficient to punch the hole in the tubing. 
     This hydraulically controlled means may further include a hydraulic control valve for controlling movement of the ram relative to the punch. 
     The ram is mounted within the housing for selective linear movement therein toward and away from the punch by the hydraulic control valve. 
     Means are provided for preventing movement of the housing within the tubing during punching thereof by the punch. 
     The punch may be retained in a holder positioned on a tapered track connected to the ram. 
     In operation of the perforator apparatus, the ram during selective linear movement thereof away from the punch causes the tapered track to correspondingly move to thereby extend the punch through the opening into punching engagement with the tubing. Thereafter, the ram during selective linear movement thereof toward the punch causes the tapered track to correspondingly move to thereby retract the punch back through the opening and into the housing. In this manner, the punch is positioned and ready for additional punching operations. 
     The hydraulic control valve may operate at least one piston acting on the ram to impart the movement to the ram relative to the punch. 
     The means for preventing movement of the housing during the punching operation may include a plurality of hydraulically operated anchoring slips that operate to engage the tubing during punching thereof by the punch and thereafter disengage from the tubing upon completion of the punching operation. 
     In a preferred aspect of the invention, the perforator apparatus may include a punch mounted within a housing adapted for positioning within tubing of the well bore, an opening in the housing aligned with the punch, and hydraulically controlled means within the housing for selectively moving the punch through the opening and into punching contact with the tubing to punch a hole therein, and thereafter returning the punch to the position within the housing. The hydraulically controlled means may include a piston adapted for linearly movement in opposed directions within the housing. A first valve is provided for selectively metering liquid flow to a first side of the piston to move the piston linearly within the housing in a first direction, and to selectively prevent liquid flow to the first side of the piston to permit the piston to move linearly within the housing in a second direction opposed to the first direction. A second valve may be provided for preventing liquid flow to a second side of the piston opposite the first side thereof during metering of fluid flow to the first side of the piston by the first valve, and for metering liquid flow to the second side of the piston when the liquid flow to the first side of the piston is prevented by a first valve to move the piston in the second direction. 
     Perforator apparatus may include metering of the liquid flow in a common direction by the first valve and by the second valve selectively to the first side of the piston and to the second side of the piston, respectively. 
     The housing of the perforator apparatus is tubular and the liquid flow is metered by the first valve through an annular liquid passage within the housing, and the second liquid flow is metered by the second valve through a tubular liquid passage extending linearly through the annular fluid passage. 
     The first valve and the second valve may be positioned within the housing at a location remote from the piston and opposite the first side thereof. 
     The first valve and the second valve are adapted for linear movement between opened and closed positions within the housing in response to selected pressure of liquid flow within the housing. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partial sectional view of the hydraulic anchor assembly and hydraulic control valve components of the punch perforator; and 
     FIG. 2 is a view similar to FIG. 1 of the hydraulic ram assembly and punch mechanism of the punch perforator. 
     FIG. 3 a  is a partial sectional view of the hydraulic control valve shown in FIG. 1 with designated portions thereof being in enlarged cross-section, as shown in FIGS. 3 b  and  3   c ; and 
     FIG. 4 is a perspective view, with parts broken away, of the hydraulic control valve shown in FIGS. 1 and 3. 
     These four components of the punch perforator are connected as indicated by the arrows to constitute the assembly of the perforator apparatus. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIG. 1 of the drawings, a coiled tubing anchor assembly, designated as  10 , is activated by internal liquid pressure. Specifically, within the housing  12  of this assembly there is provided a piston  14  and anchoring slips  16  having serrations  18  on the outer surface thereof. 
     By applying a selected pressure to the piston  14  within the housing  12 , the piston moves linearly to cause the slips  16  to move radially into contact with the wall of the tubing (not shown). The serrations  18  with the slip in this position anchor the device to the tubing. This permits accuracy of punching by the associated punch mechanism. Upon completion of this operation, the coiled tubing pressure is reduced and the slips are then free to retract away from the tubing wall and thus release the anchor assembly and associated toolstring components so that the toolstring components may be moved to a new location within the well bore. The operation may then be repeated to permit anchoring for an additional punching operation. 
     The hydraulic anchor assembly  10  is connected to a hydraulic control valve, designated generally as  20 . The hydraulic control valve  20  includes a housing  22  within which is provided a velocity flow valve  24  and a check valve  26 . Also, within the housing, there is provided an annular passage  27  that provides fluid flow to side  30  of a piston  32 . Likewise, a central passage  34  provides for fluid flow to the opposite side  36  of the piston  32 . 
     At a controlled flow rate/pressure differential, the velocity flow valve  24  is open and flow is directed to side  30  of the piston  32  and to the side  48   a  of piston  48 . This maintains the punch  60  in a retracted position. The check valve  26  is closed and therefore blocks flow to the central passage  34 . Therefore, no pressure is acting upon side  48   b  or  67   b  of the pistons  48  and  67 , respectively. This has the effect of generating a force on the piston  48  to move it downwardly within the housing. 
     At a higher internal flow rate/pressure differential, the velocity flow valve  24  will close and therefore block flow to the side  48   a  of the piston  48 . The check valve  26  opens and flow is directed through passage  34  to sides  48   b  and  67   b  of pistons  48  and  67 . This has the effect of generating a force on the pistons to move them upward within the housing. 
     With reference to FIG. 2, there is shown a hydraulic ram assembly designated generally as  38 . This assembly includes an upper body  40 , a middle body  44 , a lower body  46 , a first piston  48 , a second piston  67 , and a mandrel  52 . The pistons are housed in the upper and middle bodies and link through the mandrel to the punch mechanism, designated generally as  54 , at the body  56  thereof. The punch mechanism  54  includes body  56 , punch holder  58 , punch  60 , tapered track  62 , in addition to grip serration  64 , provided on the housing  66  of the punch mechanism. 
     In operation, at low flow/pressure differential, the punch mechanism remains inoperative. As flow/pressure differential is increased, the internal pressure acts on the hydraulic anchor assembly, whereby the anchoring slips  16  engage against the wall of the tubing. As flow/pressure differential is further increased, the hydraulic control valve  20  switches low/pressure to the hydraulic ram assembly pistons  48  and  67  to create a force to move them upward. In this manner, the pistons pull the punch mechanism body  56  upward thereby moving tapered track  62  in a like direction to cause the punch  60  to engage the tubing wall and punch a hole in the same. 
     This action also has the effect of maintaining an opposite force on the housing  66  of the punch mechanism  54  which assists in preventing axial movement of the toolstring during the punching operation. 
     When the punch passes through the tubing wall and perforates the same, a drop in pressure will result. This serves as an indication that the perforating operation has been completed. The internal pressure is then reduced back to low, circulating pressure. This has the effect of changing back the flow/pressure differential through the hydraulic control valve  20  to return the pistons  48  and  67  to their original position, thus causing retraction of the punch  60  and release of the slips  16 . The toolstring may then be moved to another tubing location and be ready for an additional perforating cycle as described above.