Downhole Apparatus and Method

Abstract

A downhole apparatus ( 10 ) for use in activating a downhole tool (T). The apparatus ( 10 ) comprises a seat ( 18 ) configured to receive an object, such as a ball ( 16 ). The seat ( 18 ) comprises a convex object engaging surface ( 24 ) for engaging the object.

1 . A downhole apparatus or tool comprising:
 a seat configured to receive an object, the seat comprising a convex object engaging surface.   
     
     
         2 . The apparatus of  claim 1 , comprising a tubular body or housing configured to permit passage of the object. 
     
     
         3 . The apparatus of  claim 1 , wherein the object comprises a ball. 
     
     
         4 . (canceled) 
     
     
         5 . The apparatus of  claim 2 , wherein one of:
 the apparatus is configured so that engagement between the object and the seat seals or at least restricts fluid passage through the tubular body;   the apparatus is configured so that engagement between the object and the seat seals or at least restricts fluid passage through the tubular body to increase upstream fluid pressure;   the apparatus is configured so that engagement between the object and the seat seals or at least restricts fluid passage through the tubular body to increase upstream fluid pressure to perform or permit a downhole operation.   
     
     
         6 - 13 . (canceled) 
     
     
         14 . The apparatus of  claim 1 , wherein the apparatus is configured so that engagement between the seat and the object controls or selects the load path of a resultant force transmitted to the seat. 
     
     
         15 . The apparatus of  claim 14 , wherein the apparatus is configured so that the engagement between the seat and the object controls or selects the load path of a resultant force transmitted to the seat to at least one of:
 increase or maximise the transmission of load forces along a particular vector,   increase or maximise the transmission of load forces along a particular vector to activate another component of, or operatively associated with, the apparatus;   eliminate or mitigate moment forces.   
     
     
         16 - 17 . (canceled) 
     
     
         18 . The apparatus of  claim 1 , wherein the object engaging surface comprises, or forms part of, at least one of: an upstream or uphole directed surface of the seat; and a downstream or downhole directed surface of the seat. 
     
     
         19 - 22 . (canceled) 
     
     
         23 . The apparatus of  claim 1 , wherein the object engaging surface is configured to provide a line or point engagement between the seat and the object. 
     
     
         24 . The apparatus of  claim 1 , wherein one of:
 the object engaging surface comprises a curved convex surface portion;   the object engaging surface comprises a hemi-toroidal surface;   the object engaging surface is d-shaped in longitudinal section;   the object engaging surface comprises a linear convex surface;   the object engaging surface comprises a toroidal polyhedron surface;   the object engaging surface is triangular in longitudinal section.   
     
     
         25 - 29 . (canceled) 
     
     
         30 . The apparatus of  claim 2 , wherein the object engaging surface is angled with respect to a longitudinal axis of the body. 
     
     
         31 . (canceled) 
     
     
         32 . The apparatus of  claim 1 , wherein the object engaging surface is annular. 
     
     
         33 . The apparatus of  claim 1 , wherein the apparatus is configured to provide a plurality of distinct points of contact with the object. 
     
     
         34 . The apparatus of  claim 33 , wherein the seat comprises a plurality of circumferentially or radially spaced components or segments. 
     
     
         35 - 40 . (canceled) 
     
     
         41 . The apparatus of  claim 2 , wherein the tubular body comprises a lateral fluid flow passage. 
     
     
         42 . The apparatus of  claim 41 , wherein at least one of:
 the lateral fluid flow passage comprises at least one port;   the lateral fluid flow passage comprises a plurality of ports;   the lateral fluid flow passage comprises a plurality of ports, two or more of the ports are arranged circumferentially;   two or more of the ports are arranged circumferentially, two or more of the ports are arranged axially.   
     
     
         43 - 48 . (canceled) 
     
     
         49 . The apparatus of  claim 2 , wherein the seat is integrally formed with the tubular body. 
     
     
         50 . The apparatus  claim 2 , wherein the seat is coupled to the tubular body. 
     
     
         51 . The apparatus of  claim 50 , wherein the seat is provided, coupled to or formed on a bore member or sleeve operatively associated with the tubular body. 
     
     
         52 - 54 . (canceled) 
     
     
         55 . The apparatus of  claim 51 , wherein the bore member or sleeve comprises a lateral fluid flow passage. 
     
     
         56 . The apparatus of  claim 55 , wherein at least one of:
 the lateral fluid flow passage comprises at least one port;   the lateral fluid flow passage comprises a plurality of ports;   the lateral fluid flow passage comprises a plurality of ports, two or more of the ports arranged circumferentially;   the lateral fluid flow passage comprises a plurality of ports, two or more of the ports arranged axially.   
     
     
         57 - 59 . (canceled) 
     
     
         60 . The apparatus of  claim 1 , wherein the apparatus comprises a collet. 
     
     
         61 . The apparatus of  claim 60 , wherein the seat is formed on, or by, the collet. 
     
     
         62 . The apparatus of  claim 60 , wherein the object engaging surface is formed on, or coupled to, the collet. 
     
     
         63 . The apparatus of  claim 60 , wherein the collet comprises a plurality of collet fingers and the object engaging surface is formed on, or coupled to, at least one of the collet fingers. 
     
     
         64 . The apparatus of  claim 2 , wherein the collet is formed on, or coupled to, the tubular body. 
     
     
         65 . The apparatus of  claim 51 , wherein the collet is formed on, or coupled to, the bore member or sleeve. 
     
     
         66 . The apparatus of  claim 60 , wherein at least one of:
 the collet is configured to catch the object to permit a borehole operation to be carried out;   the collet is configured to release the object.   
     
     
         67 - 68 . (canceled) 
     
     
         69 . The apparatus of  claim 1 , in combination with the object. 
     
     
         70 - 74 . (canceled) 
     
     
         75 . The apparatus of  claim 1 , wherein the apparatus is operatively associated with at least one downhole tool. 
     
     
         76 . The apparatus of  claim 75 , wherein at least one of:
 the downhole tool comprises a sleeve;   the apparatus is configured to pull or push the downhole tool to move the downhole tool from a first configuration to a second configuration.   
     
     
         77 - 78 . (canceled) 
     
     
         79 . The apparatus of  claim 75 , wherein the downhole tool comprises a lateral fluid flow passage. 
     
     
         80 . The apparatus of  claim 79 , wherein at least one of:
 the lateral fluid flow passage comprises at least one fluid port;   the lateral fluid flow passage comprises a plurality of ports;   the lateral fluid flow passage comprises a plurality of ports, two or more of the ports arranged circumferentially;   the lateral fluid flow passage comprises a plurality of ports, two or more of the ports arranged axially.   
     
     
         81 - 89 . (canceled) 
     
     
         90 . A method of constructing a downhole apparatus comprising:
 providing a seat configured to receive an object; and   providing a convex object engaging surface on the seat.   
     
     
         91 . A method of activating a downhole tool comprising:
 providing a downhole apparatus according to  claim 1 ;   engaging an object with the object engaging surface of the seat of said downhole apparatus, the engagement between the object and the seat permitting an applied fluid pressure or applied fluid pressure differential to activate the downhole tool.   
     
     
         92 . (canceled) 
     
     
         93 . Use of a downhole apparatus according to  claim 1  to prevent swaging, jamming or lodging of an object in a seat. 
     
     
         94 . The apparatus of  claim 1 , wherein the seat comprises a plurality of circumferentially or radial components or segments, and wherein the convex object engaging surface is formed on, or coupled to, said components or segments.