Catching Apparatus

Abstract

A downhole catching apparatus ( 20 ) comprises a plurality of radially moveable seat members ( 26 ) arranged circumferentially around a longitudinal axis, wherein the seat members are moveable between a radially extended configuration which permits passage of an object ( 64 ) therethrough and a radially retracted configuration which permits an object ( 64 ) to be caught by the apparatus. A releasable lock arrangement ( 44 ) is provided for releasably retaining the seat members in the radially extended configuration.

1 . A downhole catching apparatus for catching an object, comprising:
 a plurality of radially moveable seat members arranged circumferentially around a longitudinal axis, wherein the seat members are moveable between a radially extended configuration and a radially retracted configuration; and   a releasable lock arrangement for releasably retaining the seat members in the radially extended configuration.   
     
     
         2 . The downhole catching apparatus according to  claim 1 , wherein the radially extended configuration permits passage of an object past the seat members, and the radially retracted configuration permits an object to be caught by the seat members. 
     
     
         3 . The downhole catching apparatus according to  claim 1 , wherein the releasable lock arrangement retains the seat members in the radially extended configuration until the occurrence of an actuation event. 
     
     
         4 . The downhole catching apparatus according to  claim 1 , wherein the lock arrangement defines a locked condition and an unlocked condition, and wherein the lock arrangement is moveable from the locked condition to the unlocked condition to permit movement of the seat members towards the retracted configuration. 
     
     
         5 . The downhole catching apparatus according to  claim 4 , wherein the lock arrangement is biased towards the locked condition, optionally by a biasing member. 
     
     
         6 . The downhole catching apparatus according to  claim 4 , wherein the lock arrangement is moveable from the locked condition to the unlocked condition by axial movement. 
     
     
         7 . The downhole catching apparatus according to  claim 4 , wherein the lock arrangement is moveable from the unlocked condition to the locked condition to permit the seat members to again be retained in the extended configuration. 
     
     
         8 . The downhole catching apparatus according to  claim 4 , wherein the lock arrangement is moveable between the locked condition and the unlocked condition a plurality of times. 
     
     
         9 . The downhole catching apparatus according to  claim 1 , wherein at least part of the lock arrangement is defined by a seat member. 
     
     
         10 . The downhole catching apparatus according to  claim 1 , wherein at least pad of the lock arrangement is defined by a structure at least partially surrounding the seat members. 
     
     
         11 . The downhole catching apparatus according to  claim 10 , wherein the structure at least partially surrounding the seat members comprises at least one of a tool, a housing, an annular member, a sleeve, a ring and a washer. 
     
     
         12 . The downhole catching apparatus according to  claim 1 , wherein the lock arrangement comprises a lock profile. 
     
     
         13 . The downhole catching apparatus according to  claim 12 , wherein the lock profile comprises an external profile formed or otherwise provided on one or more of the seat members. 
     
     
         14 . The downhole catching apparatus according to  claim 13 , wherein the lock profile comprises an internal profile formed or otherwise provided on a structure at least partially surrounding the seat members, wherein the internal and external profiles are configured to cooperate with each other to selectively provide locking. 
     
     
         15 . The downhole catching apparatus according to  claim 14 , wherein the internal and external profiles are axially moveable relative to each other, wherein in a first relative axial position the internal and external profiles are engaged to provide locking, and in a second relative axial position the internal and external profiles are hot engaged to provide unlocking. 
     
     
         16 . The downhole catching apparatus according to  claim 13 , wherein the downhole catching apparatus comprises a first internal profile and a second internal profile, wherein the external profile is configured to engage the first internal profile to provide a first locked configuration, and to engage the second internal profile to provide a second locked configuration. 
     
     
         17 . The downhole catching apparatus according to  claim 12 , wherein the, or at least one, lock profile comprises at least one of a hook profile and a barb. 
     
     
         18 . The downhole catching apparatus according to  claim 12 , wherein the, or at least one, lock profile comprises or defines a geometry with an acute angle. 
     
     
         19 . The catching apparatus according to  claim 1 , comprising a housing, wherein the seat members are located within said housing. 
     
     
         20 . The catching apparatus according to  claim 19 , wherein at least a portion of the locking arrangement is defined by the housing. 
     
     
         21 . The catching apparatus according to  claim 19 , wherein at least a portion of the locking arrangement is provided on a locking structure which is mounted within the housing. 
     
     
         22 . The catching apparatus according to  claim 21 , wherein the locking structure comprises a ring member mounted within the housing. 
     
     
         23 . The downhole catching apparatus according to  claim 1 , wherein at least a portion of the lock arrangement is sacrificial to provide erosion protection. 
     
     
         24 . The downhole catching apparatus according to  claim 1 , comprising an erosion resistant coating. 
     
     
         25 . The downhole catching apparatus according to  claim 1 , for use in catching an object passing along a flow path within which the catching apparatus is located. 
     
     
         26 . The downhole catching apparatus according to  claim 1 , comprising a catching sleeve, wherein the seat members are mounted on said catching sleeve. 
     
     
         27 . The downhole catching apparatus according to  claim 1 , wherein the catching apparatus is configured to function as at least one of a flow diverter, a bore plug, a flow restrictor and an actuator when an object is caught. 
     
     
         28 . The downhole catching apparatus according to  claim 1 , for use within a fracturing system or operation. 
     
     
         29 . The downhole catching apparatus according to  claim 1 , wherein the seat members are moveable radially inwardly to be retracted into a central bore of the catching apparatus to define a reduced effective inner diameter, and the seat members are moveable radially outwardly to be radially extended from the central bore to define an increased effective inner diameter. 
     
     
         30 . The downhole catching apparatus according to  claim 29 , wherein when the seat members are positioned radially inwardly and retracted into the central bore said members are positioned into the path of an object passing through the catching apparatus, and when the seat members are positioned radially outwardly and extended from the central bore said members are outside the path of an object passing through the catching apparatus. 
     
     
         31 . The downhole catching apparatus according to  claim 1 , wherein the catching apparatus is reconfigured to or in its catching configuration by radially supporting the seat members in a radially inward position such that outward radial movement is prevented. 
     
     
         32 . A method for catching an object downhole, comprising:
 arranging a downhole catching apparatus within a path of an object travelling downhole, wherein the catching apparatus includes a plurality of seat members which are moveable between a radially extended configuration and a radially retracted configuration;   retaining the seat members in the radially extended configuration by a releasable lock arrangement;   releasing the lock arrangement;   causing the seat members to be radially retracted; and   catching the object.   
     
     
         33 . A downhole tool comprising a catching apparatus, wherein the catching apparatus comprises:
 a plurality of radially moveable seat members arranged circumferentially around a longitudinal axis, wherein the seat members are moveable between a radially extended configuration and a radially retracted configuration; and   a releasable lock arrangement for releasably retaining the seat members in the radially extended configuration.   
     
     
         34 . The downhole tool according to  claim 33 , comprising a tool housing, wherein the catching apparatus is mounted within the tool housing. 
     
     
         35 . The downhole tool according to  claim 34 , wherein the tool housing defines a central bore and a fluid port, wherein the fluid port is configured to permit fluid communication between the central bore and a location external to the housing. 
     
     
         36 . The downhole tool according to  claim 35 , comprising a valve member mounted within the housing, wherein the valve member is moveable from a closed position in which the fluid port is blocked to an open position in which the fluid port is opened. 
     
     
         37 . The downhole tool according to  claim 34 , wherein the catching apparatus is provided within the housing on one side of the flow port and is arranged to catch an object to permit flow diversion through the flow port.