Downhole apparatus

Abstract

Downhole apparatus is described having a tubular main body and at least one flow channel formed on the body. The channel has at least one non-uniform dimension. A flow guide is located adjacent an end of the channel, and the flow guide and the channel together define a flow path for flow of a downhole medium along the body. The downhole apparatus may for example be a casing reamer shoe, a drill pipe, or a motor sleeve.

1 . A downhole apparatus comprising: a tubular main body; at least one flow channel, the channel extending at least part way along a length of the body and at least one dimension of the channel being non-uniform; and at least one flow guide located adjacent an end of the channel, the flow guide and the channel together defining a flow path for flow of a downhole medium along the body.  
   
   
       2 . The apparatus as claimed in  claim 1 , wherein the apparatus is dimensioned to be a close fit with tubing or a borehole in which the apparatus is located.  
   
   
       3 . The apparatus as claimed in  claim 1 , further provided with at least one of a cutting or reaming surface.  
   
   
       4 . The apparatus as claimed in  claim 1 , wherein the channel is adapted to be bound on one side by an internal wall of tubing or a borehole, such that all or most of the flow of downhole medium past the body is directed along the channel.  
   
   
       5 . The apparatus as claimed in  claim 1 , wherein the apparatus is a centraliser for centralising a body such as a tubing or tool string within an open hole or within existing downhole tubing.  
   
   
       6 . The apparatus as claimed in  claim 1 , wherein the apparatus is a stabiliser for stabilising a drill string within an open hole or within existing downhole tubing.  
   
   
       7 . The apparatus as claimed in  claim 1 , wherein the apparatus is provided as an integral part of a drill pipe.  
   
   
       8 . The apparatus as claimed in  claim 1 , wherein the apparatus forms part of a shoe.  
   
   
       9 . Apparatus as claimed in  claim 8 , wherein the apparatus forms part of a casing shoe reamer which includes reaming surfaces for reaming the borehole wall.  
   
   
       10 . Apparatus as claimed in  claim 8 , wherein the apparatus forms part of a drill shoe reamer which includes reaming surfaces for reaming the borehole wall.  
   
   
       11 . The apparatus as claimed in  claim 1 , wherein the apparatus is a sleeve of a downhole motor.  
   
   
       12 . The apparatus as claimed in  claim 1 , wherein the apparatus is a wellbore cleaning tool.  
   
   
       13 . The apparatus as claimed in  claim 12 , further comprising at least one of a cleaning or abrading blade, brush, scraper, or a wiper.  
   
   
       14 . The apparatus as claimed in  claim 1 , further comprising a plurality of ribs, each rib upstanding or extending outwardly from an outer surface of the body, and extending at least part way along a length of the body.  
   
   
       15 . The apparatus as claimed in  claim 14 , wherein the ribs are spaced around a circumference of the main body, and the channel is defined between an adjacent pair of ribs.  
   
   
       16 . The apparatus as claimed in  claim 14 , further comprising a plurality of channels, each channel defined or bound by an outer surface of the body and side walls of the adjacent ribs.  
   
   
       17 . The apparatus as claimed in  claim 16 , wherein the side walls of each rib are curved to define a smooth transition between areas of the rib of larger and smaller width.  
   
   
       18 . The apparatus as claimed in  claim 14 , wherein the ribs have a respective rib main axis, and the ribs are disposed on the body such that the rib main axes are substantially parallel with one another.  
   
   
       19 . The apparatus as claimed in  claim 14 , wherein each rib has first and second ends of greater width relative to a portion of the rib at a location between said ends.  
   
   
       20 . The apparatus as claimed in  claim 14 , wherein each rib is elongate and has ends defining lobes with a section extending between the lobes of reduced width.  
   
   
       21 . The apparatus as claimed in  claim 14 , wherein the ribs define an outer surface adapted to abut an inner wall of a borehole or a tubing in which the apparatus is located.  
   
   
       22 . The apparatus as claimed in  claim 1 , wherein the channel defines a corresponding channel axis and the flow guide is located on or parallel to the channel axis and is spaced axially along the body relative to the channel.  
   
   
       23 . The apparatus as claimed in  claim 1 , wherein the flow guide is located such that a downhole medium flowing out of the channel impinges on the flow guide.  
   
   
       24 . The apparatus as claimed in  claim 1 , wherein the flow guide has a first inward end, relative to the channel, and a second outward end, relative to the channel.  
   
   
       25 . The apparatus as claimed in  claim 24 , wherein the first, inward end of the flow guide is generally triangular and in a shape of an arrow head.  
   
   
       26 . The apparatus as claimed in  claim 1 , wherein the channel has first and second axial ends, and the apparatus comprises two flow guides associated with the channel, one located adjacent to the first end of the channel and the other located adjacent the second end.  
   
   
       27 . The apparatus as claimed in  claim 1 , wherein the apparatus comprises at least two flow guides associated with each channel.  
   
   
       28 . The apparatus as claimed in  claim 1 , wherein the channel width is non-uniform along a length of the channel.  
   
   
       29 . The apparatus as claimed in  claim 1 , wherein the channel defines at least one flow restriction where the width of the channel is reduced compared to an adjacent portion or area of the channel.  
   
   
       30 . The apparatus as claimed in  claim 29 , wherein the at least one flow restriction defines a nozzle which serves, in use, for increasing a velocity of medium flowing therethrough.  
   
   
       31 . The apparatus as claimed in  claim 29  wherein the channel defines two such restrictions, one adjacent each end of the channel, with a relatively unrestricted portion at a location between the restrictions in a direction along the length of the channel.  
   
   
       32 . The apparatus as claimed in  claim 1 , wherein the apparatus comprises a plurality of flow guides spaced around a circumference of the body, adjacent flow guides defining part of a flow path.  
   
   
       33 . The apparatus as claimed in  claim 32 , wherein the adjacent flow guides define an opening therebetween, which defines an inlet or outlet of one or more flow paths.  
   
   
       34 . The apparatus as claimed in  claim 33 , wherein the openings are circumferentially spaced or staggered relative to axes of the channels.  
   
   
       35 . The apparatus as claimed in  claim 1 , wherein the apparatus comprises at least one cutting, abrading or reaming surface for abrading the borehole/tubing wall.  
   
   
       36 . The apparatus as claimed in  claim 1 , wherein the flow guide is shaped to define a plurality of cutting surfaces, and one or both of first and second ends of the flow guide define a cutting surface.  
   
   
       37 . The apparatus as claimed in  claim 36 , wherein the apparatus comprises a plurality of flow guides spaced around a circumference of the body, adjacent flow guides defining part of a flow path, wherein the second end of one or both of the flow guides defines a relatively aggressive cutting surface, whilst the first end of one or both of the flow guides define a less aggressive cutting surface.  
   
   
       38 . The apparatus as claimed in  claim 37 , wherein the second end of the flow guide provided, in use, lowermost on the apparatus defines the relatively aggressive cutting surface.  
   
   
       39 . A downhole apparatus comprising: a tubular main body; 
 and a plurality of elongate ribs upstanding from an outer surface of the main body and extending at least part way along a length thereof, adjacent pairs of ribs defining a flow channel therebetween for flow of a downhole medium along the body; wherein the ribs are shaped such that at least one dimension of each channel is non-uniform and such that respective axes of the channels are disposed substantially parallel to a longitudinal axis of the body.    
   
   
       40 . A downhole apparatus comprising: a tubular main body; 
 at least one flow channel for flow of a downhole medium along the body, the flow channel having a respective flow channel main axis, the channel extending at least part way along a length of the body and at least one dimension of the channel being non-uniform; and at least one flow guide located adjacent an end of the channel and disposed on the flow channel axis.    
   
   
       41 . A downhole tubing shoe comprising: a tubular main body; at least one flow channel for flow of a downhole medium along the body, the channel extending at least part way along a length of the body, at least one dimension of the channel being non-uniform, and an axis of the channel being disposed substantially parallel to a longitudinal axis of the body.  
   
   
       42 . A downhole tubing shoe as claimed in  claim 41 , wherein the shoe is selected from the group consisting of a casing shoe, a drill shoe and a reamer shoe and a drill shoe reamer.