Patent Abstract:
Apparatus and associated methods are provided for remotely actuating a plug apparatus in a subterranean well. In a described embodiment, a plug apparatus has a plug member blocking fluid flow through one of two flow passages of the plug apparatus. A predetermined fluid pressure applied to one of the flow passages permits the plug member to be expended from the plug apparatus.

Full Description:
This is a division, of application Ser. No. 09,184,521, filed Nov. 2, 1998, now the U.S. Pat. No. 6,161,622, such prior application being incorporated by reference herein in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to operations performed in subterranean wells and, in an embodiment described herein, more particularly provides a remotely actuatable plug apparatus. 
     It is common practice for plugs in subterranean wells to be serviced via intervention into the wells. For example, a plugging device may be latched in an internal profile of a tubular string using a slickline, wireline, coiled tubing, etc. The plugging device may then be retrieved also using a slickline, wireline, coiled tubing, etc. 
     However, it would be more convenient, and at times less expensive, to be able to remotely actuate a plugging device. For example, instead of mobilizing a slickline, wireline or coiled tubing rig, ceasing production if necessary, and entering the tubing string with equipment for retrieving a plugging device, it would be far more convenient and economical to merely apply fluid pressure to open a plug apparatus and thereby permit fluid flow through a portion of the tubing string. It would, therefore, be desirable to provide a plug apparatus which is remotely actuated. 
     SUMMARY OF THE INVENTION 
     In carrying out the principles of the present invention, in accordance with an embodiment thereof, a remotely actuated plug apparatus is provided which permits actuation of the apparatus by application of fluid pressure thereto. Methods of using a remotely actuated plug apparatus are also provided. 
     In broad terms, a plug apparatus is provided which includes an expendable plug member. The plug member initially blocks fluid flow through one of two flow passages of the plug apparatus. The plug member may be expended by applying a predetermined fluid pressure to one of the two flow passages. 
     In one aspect of the present invention, a flow passage is isolated from fluid communication with a portion of the plug member by a fluid barrier or a flow blocking member. Application of the predetermined fluid pressure to the flow passage, or another flow passage, ruptures the fluid barrier or displaces the flow blocking member, thereby permitting fluid communication between one or both of the flow passages and the plug member portion. In various representative embodiments of the invention, the flow passages may or may not be placed in fluid communication with each other, and either of the flow passages may by placed in fluid communication with the plug member portion. 
     In another aspect of the present invention, fluid may be delivered to the plug member portion by a fluid source located within the well, or at the earth&#39;s surface. The fluid source may be interconnected to the plug apparatus by a line extending externally to the tubing string in which the plug apparatus is connected. The line may also extend through a well tool interconnected in the tubing string between the fluid source and the plug apparatus. 
     These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative embodiments of the invention hereinbelow and the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1A&amp;1B are cross-sectional views of successive axial portions of a first plug apparatus embodying principles of the present invention; 
     FIGS. 2A&amp;2B are cross-sectional views of successive axial portions of a second plug apparatus embodying principles of the present invention; 
     FIGS. 3A&amp;3B are cross-sectional views of successive axial portions of a third plug apparatus embodying principles of the present invention; 
     FIG. 4 is a schematicized view of a first method of using a remote actuated plug apparatus, the method embodying principles of the present invention; and 
     FIG. 5 is a schematicized view of a second method of using a remote actuated plug apparatus, the method embodying principles of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Representatively illustrated in FIGS. 1A&amp;1B is a plug apparatus  10  which embodies principles of the present invention. In the following description of the plug apparatus  10  and other apparatus and methods described herein, directional terms, such as “above”, “below”, “upper”, “lower”, etc., are used for convenience in referring to the accompanying drawings. Additionally, it is to be understood that the various embodiments of the present invention described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., without departing from the principles of the present invention. 
     The plug apparatus  10  is similar in some respects to plug apparatus described in U.S. Pat. Nos. 5,479,986 and 5,765,641, the disclosures of which are incorporated herein by this reference. Specifically, the plug apparatus  10  includes a generally tubular housing assembly  12  configured for interconnection in a tubing string, a flow passage  14  extending generally axially through the housing assembly, and a plug member  16  which blocks fluid flow through the flow passage, but which is expendable upon contact between a fluid and a portion  18  of the plug member. As used herein, the term “expend” means to dispense with or to make no longer functional. For example, the plug member portion  18 , or a portion thereof, may be dissolvable in the fluid, may otherwise react with the fluid, etc., so that the plug member portion is no longer able to block fluid flow through the flow passage  14 . In the embodiment representatively illustrated in FIGS. 1A&amp;1B, the plug member portion  18  is a compressed mixture of salt and sand which is isolated from contact with fluid in the flow passage  14  by elastomeric end closures  20 , but it is to be clearly understood that the plug member portion may be made of any other material and may be otherwise configured without departing from the principles of the present invention. 
     A fluid passage  22  is formed in the housing assembly  12  for providing fluid communication between a port  24  positioned externally on the housing assembly and the plug member portion  18 . When fluid is delivered through the fluid passage  22  to the plug member portion  18 , in a manner described more fully below, the plug member portion becomes weakened, so that the plug member  16  is no longer able to block fluid flow through the flow passage  14 . A conventional rupture disk  26  or other fluid barrier may be installed between the port  24  and the fluid passage  22 , so that a predetermined fluid pressure must be applied to the port  24  to rupture the rupture disk and permit fluid communication between the port and the plug member portion  18  through the fluid passage  22 . 
     Note that the port  24  is formed in a conventional tubing connector  28  which also retains the rupture disk  26  and is threadedly installed externally in the housing assembly  12 . It is to be clearly understood that the connector  28  is not necessary in a plug apparatus constructed in accordance with the principles of the present invention, for example, the port  24  could be formed directly on the housing assembly  12  and the rupture disk  26  could be eliminated or otherwise retained relative to the housing assembly. 
     The connector  28  is configured for connection of an external flow passage or line thereto for application of a predetermined fluid pressure to the rupture disk  26  to rupture it and deliver fluid to the plug member portion  18 , as described more fully below. However, the flow passage or line could also extend internally within the housing assembly  12 , or be placed in fluid communication with the fluid passage  22  via an appropriately designed connection between the plug apparatus  10  and an external fluid source. Thus, it may be readily appreciated that it is not necessary for the fluid passage  22  to be in fluid communication with a line or flow passage external to the housing assembly  12 . 
     When the plug member  16  is expended, permitting fluid flow through the flow passage  14 , note that the flow passage  14  will be placed in fluid communication with the fluid passage  22 . This may be desirable in some instances, such as when it is desired to inject fluid into the flow passage  14  via the fluid passage  22  after the plug member  16  has been expended. A check valve (not shown) could be installed to prevent fluid flow from the flow passage  14  into the line or other flow passage connected to the port  24 . However, it is not necessary for the flow passage  14  and fluid passage  22  to be placed in fluid communication after the plug member  16  is expended, in keeping with the principles of the present invention. Representatively illustrated in FIGS. 2A&amp;2B is another plug apparatus  30  embodying principles of the present invention. Elements of the plug apparatus  30  which are similar to elements previously described are indicated in FIGS. 2A&amp;2B using the same reference numbers, with an added suffix “a”. 
     In the plug apparatus  30 , the port  24   a  is formed directly externally in the outer housing assembly  12   a , and no rupture disk  26  is utilized to block fluid communication between the port  24   a  and the fluid passage  22   a . However, a tubing connector  28  could be installed in the outer housing assembly  12   a , and a rupture disk  26  or other fluid barrier could be utilized, without departing from the principles of the present invention. 
     Instead of the rupture disk  26 , the plug apparatus  30  utilizes a sleeve  32  sealingly and reciprocably disposed within the housing assembly  12   a  to isolate the fluid passage  22   a  from fluid delivery thereto. As viewed in FIG. 2A, the sleeve  32  is in an upwardly disposed position relative to the housing assembly  12   a , in which the sleeve prevents fluid flow between the fluid passage  22   a  and the port  24   a , and between the fluid passage  22   a  and the flow passage  14   a . The sleeve  32  is releasably secured in this position by shear pins  34 . 
     When a predetermined fluid pressure is applied to the port  24   a , the shear pins  34  will shear, and the fluid pressure will downwardly displace the sleeve  32  relative to the housing assembly  12   a . Such downward displacement of the sleeve  32  places openings  36  formed through the sleeve in fluid communication with openings  38  formed in the housing assembly  12   a , thereby permitting fluid communication between the flow passage  14   a  and the fluid passage  22   a . Fluid in the flow passage  14   a  may then flow through the openings  36 ,  38  and through the fluid passage  22   a  to the plug member portion  18   a.    
     Note that, in the plug apparatus  30 , the fluid passage  22   a  is placed in fluid communication with the flow passage  14   a  when fluid is delivered to the plug member portion  18   a . Additionally, the port  24   a  is not placed in fluid communication with the fluid passage  22   a . Thus, although the predetermined fluid pressure is applied to the port  24   a  to expend the plug member  16 , it is the flow passage  14   a  which is placed in fluid communication with the plug member portion  18   a . However, the port  24   a  could be placed in fluid communication with the flow passage  14   a  and/or fluid passage  22   a  without departing from the principles of the present invention. For example, one or more seals providing sealing engagement between the sleeve  32  and the housing assembly  12   a  could be disengaged from sealing engagement with the sleeve and/or the housing assembly when the sleeve  32  is displaced downwardly. 
     Referring additionally now to FIGS. 3A&amp;3B, a plug apparatus  40  embodying principles of the present invention is representatively illustrated. Elements of the plug apparatus  40  which are similar to elements previously described are indicated in FIGS. 3A&amp;3B using the same reference numbers, with an added suffix “b”. 
     The plug apparatus  40  is similar in many respects to the plug apparatus  30  described above, in that a predetermined fluid pressure may be applied to the port  24   b  to shear the shear pins  34   b  and thereby downwardly displace a sleeve  42  within the housing assembly  12   b , permitting fluid communication between the flow passage  14   b  and the fluid passage  22   b . However, in the plug apparatus  40 , a predetermined fluid pressure may also be applied to the flow passage  14   b  to shear the shear pins  34   b  and downwardly displace the sleeve  42 . 
     Note that the sleeve  42  of the plug apparatus  40 , unlike the sleeve  32  of the plug apparatus  30 , presents an upwardly facing piston area  44  in fluid communication with the openings  38   b . Thus, when fluid pressure is applied to the flow passage  14   b , that fluid pressure also biases the sleeve  42  downward. The predetermined fluid pressure which may be applied to the flow passage  14   b  to shear the shear pins  34   b  may be the same as, or different from, the predetermined fluid pressure which may be applied to the port  24   b  to shear the shear pins, depending upon the respective piston areas on the sleeve  42 . 
     When a predetermined fluid pressure is applied to the port  24   b  or flow passage  14   b , the shear pins  34   b  will shear, and the fluid pressure will downwardly displace the sleeve  42  relative to the housing assembly  12   b . Such downward displacement of the sleeve  42  places the openings formed through the sleeve in which the shear pins  34   b  are installed in fluid communication with the openings  38   b , thereby permitting fluid communication between the flow passage  14   b  and the fluid passage  22   b . Fluid in the flow passage  14   b  may then flow through the openings  38   b  and through the fluid passage  22   b  to the plug member portion  18   b.    
     Note that, in the plug apparatus  40 , the fluid passage  22   b  is placed in fluid communication with the flow passage  14   b  after fluid is delivered to the plug member portion  18   b . Additionally, the port  24   b  is not placed in fluid communication with the fluid passage  22   b . Thus, although a predetermined fluid pressure is applied to the port  24   b  or the flow passage  14   b  to expend the plug member  16   b , it is the flow passage  14   b  which is placed in fluid communication with the plug member portion  18   b . However, the port  24   b  could be placed in fluid communication with the flow passage  14   b  and/or fluid passage  22   b  without departing from the principles of the present invention. For example, one or more seals providing sealing engagement between the sleeve  42  and the housing assembly  12   b  could be disengaged from sealing engagement with the sleeve and/or the housing assembly when the sleeve  42  is displaced downwardly. 
     Referring additionally now to FIG. 4, a method  50  of utilizing a remote actuated plug apparatus is representatively illustrated. In the method  50 , a remote actuated plug apparatus  52  is interconnected as a part of a tubular string  54  installed in a subterranean well. The plug apparatus  52  may be similar to one of the above-described plug apparatus  10 ,  30 ,  40 , or it may be another type of remote actuated plug apparatus. 
     Another well tool  56  may be interconnected in the tubular string  54 . In the method  50  as depicted in FIG. 4, the well tool  56  is a hydraulically settable packer of the type well known to those skilled in the art. The packer  56  is positioned between the plug apparatus  52  and the earth&#39;s surface. It is to be clearly understood, however, that the well tool  56  may be a tool or item of equipment other than a packer, and it may be otherwise positioned in the well, without departing from the principles of the present invention. 
     A control line or other type of flow passage  58  is connected to a conventional fluid source, such as a pump (not shown), at the earth&#39;s surface. The term “fluid source” as used herein means a device or apparatus which forcibly transmits fluid, such as a pump, a pressurized accumulator or another fluid pressurizing device. The line  58  extends downwardly from the earth&#39;s surface, extends through the packer  56 , and connects externally to the plug apparatus  52 , such as at the ports  24 ,  24   a ,  24   b  described above. Of course, the line  58  or other type of flow passage could be internally disposed relative to the tubular string  54 , could be formed in a sidewall of the tubular string, etc., without departing from the principles of the present invention. For example, in the packer  56 , the flow passage  58  could be formed in a sidewall of a mandrel of the packer. 
     With the plug apparatus  52  initially preventing fluid flow through the tubular string  54 , fluid pressure may be applied to the tubular string to set the packer  56  in the well, and then fluid pressure may be applied to the line  58  to open the plug apparatus to fluid flow therethrough. If the plug apparatus  52 , like the plug apparatus  40  described above, is actuatable by application of fluid pressure to the tubular string  54 , the line  58  may not be necessary, and the plug apparatus may be set up so that the predetermined fluid pressure needed to open the plug apparatus is greater than the fluid pressure needed to set the packer  56 . Alternatively, the packer  56  could be settable by application of fluid pressure to the line  58 , and the plug apparatus  56  could be actuated by application of fluid pressure to the line greater than that needed to set the packer. As another alternative, the packer  56  could be settable by fluid pressure in the line  58 , and the plug apparatus  52  could be actuatable by fluid pressure in the tubular string  54 . Thus, it will be readily appreciated that the plug apparatus  52  permits increased versatility in wellsite operations, without requiring intervention into the well for its actuation. 
     Referring additionally now to FIG. 5, another method  60  embodying principles of the present invention is representatively illustrated. Elements shown in FIG. 5 which are similar to elements previously described are indicated in FIG. 5 using the same reference numbers, with an added suffix “c”. 
     Note that, in the method  60 , the line  58   c  does not extend to a fluid source at the earth&#39;s surface. Instead, the line  58   c  extends to a fluid source  62  installed in the well as a part of the tubular string  54   c . The fluid source  62  may be a pump, hydraulic accumulator or differential pressure-driven piston of the type well known to those skilled in the art. Additionally, the fluid source  62  may apply fluid pressure to the line  58   c  in response to receipt of a signal transmitted thereto from the earth&#39;s surface or other remote location, such as another location within the well. 
     The fluid source  62  could include a pump or other fluid pressurizing device coupled with the tubular string  54   c  for supplying the predetermined fluid pressure to actuate the plug apparatus  52   c . For example, a slickline, wireline, coiled tubing, or otherwise-conveyable fluid pressurizing device could be positioned in the tubular string  54   c  and coupled therewith. An example of such a fluid pressurizing device is described in U.S. Pat. No. 5,492,173. Another fluid pressurizing device is the model DPU available from Halliburton Energy Services, Inc. of Dallas, Tex. The DPU or other fluid pressurizing device may be engaged with the tubular string  54   c , such as via an internal latching profile, to form the fluid source  62  and to place the DPU in fluid communication with the line  58   c . The DPU could then be actuated to provide pressurized fluid, which is then delivered to the plug apparatus  52   c  via the line  58   c.    
     Of course, many modifications, additions, deletions, substitutions and other changes may be made to the various embodiments of the present invention described herein, which would be obvious to a person skilled in the art, and these changes are contemplated by the principles of the present invention. For example, in the method  60 , the fluid source  62  could be positioned between the packer  56   c  and the plug apparatus  52   c , and could be attached directly to the plug apparatus. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims.

Technology Classification (CPC): 4