Downhole tool and method

Abstract

A downhole tool ( 10 ) configured to condition a borehole (B) and deliver a settable material, such as cement slurry, into a borehole annulus (A) for securing and supporting a casing string (C) in the borehole (B) comprises a body in the form of tubular housing ( 12 ), a shaft ( 14 ) rotatably mounted within the housing ( 12 ), a head portion ( 22 ) and a drive arrangement ( 20 ). In use, borehole cleaning and cementing operations may be carried out by directing a drive fluid, such as drilling mud, through the drive arrangement ( 20 ) to drive rotation of the head portion ( 22 ) to clean or condition the borehole (b). A cement slurry or the like, may then be directed through the casing string (C) or via a cementing string (S) into the shaft ( 14 ), and through the drive arrangement ( 20 ), the fluid then being ejected from the head portion ( 22 ).

What is claimed is: 
     
         1 . A downhole tool for cleaning or conditioning a well borehole, the downhole tool comprising:
 a body;   a head portion;   a drive arrangement for rotating the head portion; and   at least one bore-engaging member disposed on the head portion, the at least one bore-engaging member engaging the borehole to clean or condition the borehole on rotation of the head portion.   
     
     
         2 . The downhole tool according to  claim 1 , wherein the drive arrangement is selectively operable and/or wherein the drive arrangement is selectively operable in response to a fluid flow rate through the drive arrangement. 
     
     
         3 . The downhole tool according to  claim 1 ,
 wherein the downhole tool is configured to deliver a settable material, such as cement, into the borehole, and/or   wherein the head portion is configured to deliver the settable material, and/or   wherein the drive arrangement conditions the settable material in the borehole at least one of: maintaining the settable material in a fluid condition; and/or altering the condition of the settable material downhole.   
     
     
         4 . The downhole tool according to  claim 3 ,
 comprising directing the settable material into and/or through the drive arrangement, and/or   comprising driving the drive arrangement using the settable material directed through the drive arrangement.   
     
     
         5 . A method for conditioning a well borehole, the method comprising:
 providing a downhole tool comprising a body; a head portion; a drive arrangement for rotating the head portion; and at least one bore-engaging member disposed on the head portion; and   operating the drive arrangement to rotate the head portion, whereby the at least one bore-engaging member engages the borehole to clean or condition the borehole.   
     
     
         6 . Use of a downhole drive arrangement in the delivery of a settable material into a borehole, wherein the drive arrangement conditions the settable material in the borehole. 
     
     
         7 . The use according to  claim 6 , wherein the drive arrangement conditions the settable material by at least one of: maintaining the settable material in a fluid condition; and/or altering the condition of the settable material downhole; and/or wherein:
 the drive arrangement is configured to condition the settable material by at least one of:
 mixing, chopping, or churning the settable material as it passes through the tool; and 
   altering the pressure and/or flow rate of the settable material as it passes through the drive arrangement.   
     
     
         8 . The use according to  claim 7 , comprising at least one of:
 directing the settable material into and/or through the drive arrangement; and   driving the drive arrangement using the settable material directed through the drive arrangement.   
     
     
         9 . The use according to  claim 8 , wherein the drive arrangement is configured to agitate the settable material in contact with the drive arrangement as the settable material is directed through the drive arrangement. 
     
     
         10 . A downhole tool for use in the delivery of a settable material into a well borehole, the tool comprising a drive arrangement configured to condition the settable material in the borehole for delivery. 
     
     
         11 . The downhole tool according to  claim 10 , wherein the drive arrangement is configured to condition the settable material by at least one of:
 maintaining the settable material in a fluid condition; and/or altering the condition of the settable material downhole;   mixing, chopping, or churning the settable material as it passes through the tool; and   altering the pressure and/or flow rate of the settable material as it passes through the drive arrangement.   
     
     
         12 . The downhole tool according to  claim 10 , wherein at least one of:
 the tool is configured to direct the settable material into and/or through the drive arrangement;   the tool defines or provides mounting for a fluid conduit for directing the settable material into and/or through the drive arrangement;   the tool is configured such that the drive arrangement is driven by the settable material directed through the drive arrangement; and   the drive arrangement is configured to agitate the settable material in contact with the drive arrangement as the settable material is directed through the drive arrangement.   
     
     
         13 . The downhole tool according to  claim 10 , wherein at least one of:
 the tool comprises, is operatively associated with, or is coupled to, at least one of: a cementing tool; a cement circulation tool; a reaming tool; a drilling tool; and a bore-cleaning tool;   the drive arrangement comprises a rotary drive arrangement; and   the drive arrangement is selectively operable in response to a fluid flow rate.   
     
     
         14 . The downhole tool according to  claim 10 , wherein the drive arrangement comprises one of:
 a fluid turbine;   a positive displacement motor (PDM);   a vane motor;   a pelton wheel.   
     
     
         15 . The downhole tool according to  claim 10 , wherein the tool comprises a body and a shaft and/or
 wherein the body comprises or provides mounting for a stator and the shaft defines or provides mounting for a rotor; and/or   wherein the body comprises or provides mounting for a rotor and the shaft comprises or provides mounting for a stator.   
     
     
         16 . The downhole tool according to  claim 10 , wherein the tool comprises a head portion, and/or wherein at least one of:
 the tool is configured to distribute the settable medium from the head portion;   the tool is configured to distribute the settable medium from the head portion and to eject the settable material in a given direction;   the tool is configured to distribute the settable medium from the head portion and to eject the settable material in a radial direction;   the tool is configured to distribute the settable medium from the head portion and to eject the settable material in an axial direction;   the tool is configured to distribute the settable medium from the head portion and to eject the settable material in at least one of: an uphole direction; and a downhole direction;   the tool is configured to distribute the settable medium from the head portion and to eject the settable material in the same direction as the direction of rotation of the head portion; and   the tool is configured to distribute the settable medium from the head portion and to eject the settable material at a given velocity or flow rate.   
     
     
         17 . The downhole tool according to  claim 10 , wherein the tool comprises at least one fluid port and/or wherein the tool comprises a plurality of fluid ports and at least one of:
 the number, size and/or arrangement of the ports is configured to condition the settable material for delivery or at delivery;   the number, size and/or arrangement of the ports is configured to assist in even distribution of the settable material;   the number, size and/or arrangement of the ports is configured to circulate the settable material;   the number, size and/or arrangement of the ports may be configured to control the direction of the settable material;   at least one port is configured to eject the settable material in an uphole direction; and   at least one port may be configured to eject the settable material in a downhole direction.   
     
     
         18 . The downhole tool of  claim 10 , wherein at least one of:
 the tool comprises a bore engaging member;   the tool comprises a bore engaging member or members configured to condition or clean the borehole;   the tool comprises a bore engaging member and a head portion and the bore engaging member is disposed on the head portion; and   the tool comprises a bore engaging member comprising at least one of: a brush, a reaming member and/or a cutter.   
     
     
         19 . The downhole tool of  claim 10 , wherein at least part of the tool is configured to facilitate drilling through the tool and/or wherein the downhole tool comprises or defines an access bore to facilitate the drill through of the downhole tool. 
     
     
         20 . A method comprising:
 operating a drive arrangement of a downhole tool in a borehole to condition a settable material for delivery or maintain the condition of the settable material for said delivery.