Hybrid drill bit

Abstract

A boring tool having downhole hammered impact elements that present to the bore face from platforms or plateaux of the work face of the tool, such work face having shear cutters able to benefit over the bore face from disruption caused by the impact elements.

1 . A boring tool for use downhole for hole boring or core taking when connected so as to depend and rotate with a drill string about an axis of rotation aligned to that of the drill string, the tool comprising or including
 a body member or assembly (“body”), the body to depend from the drill string and defining a profiled work face to be presented against the bore face and to accord substantially to the area and shape of the bore face, such bore face to be bounded by a circle if the tool is for hole boring and such bore face to be annular if the tool is for core taking,   shear cutters carried by the profiled work face, and   impact elements, whether of a common component or not, supported by the body so as to be movable through the profiled work face of the body and able to be hammered directly or indirectly from behind the profiled work face of the body to provide, or be, localised impact emergences beyond localities of the profiled work face;   wherein said profiled work face defines recessed or non-protuberant regions amongst non-recessed or protuberant regions;   and wherein the localised impact emergences are each from a non-recessed or protuberant region of the profiled work face of the body   and wherein the localised impact emergences and bit features of the profiled bit will act in concert across the bore face.   
     
     
         2 . The tool of  claim 1  wherein said impact elements are emergent of non-recessed or protuberant regions of the profiled work face and said shear cutters are on the non-recessed or protuberant regions, the recessed or non-protuberant regions, or both. 
     
     
         3 . The tool of  claim 1  or wherein each said impact element can rotate about their own reciprocation axis. 
     
     
         4 . The tool as claimed in  claim 3  wherein said reciprocation axis is at least substantially parallel to said axis of rotation of said tool. 
     
     
         5 . The tool of  claim 1  wherein the body includes porting to allow a fluid egress. 
     
     
         6 . The tool of  claim 1  wherein the impact emergences are spread about the work face of the impact elements and the spread involves localities of different radii from said axis of rotation. 
     
     
         7 . The tool of  claim 1  wherein shear cutters are on said non-recessed or protuberant regions. 
     
     
         8 . The tool of  claim 1  wherein the tool is for core taking and said impact elements are on an at least substantially common radius from said axis of rotation and said sheer cutters act inwardly and outwardly of the locus of that at least substantially common radius. 
     
     
         9 . The tool of  claim 1  wherein said impact elements are rotatable through the profiled work face of the body. 
     
     
         10 . A hybrid drill bit suitable for use downhole, for hole boring, the hybrid drill bit comprising or including an assembly which when associated with a drill string defines, or will define,
 a profiled bit or bit assembly (“bit”) able to be rotated about an axis of rotation to have an effect on a bore face over its diameter of operation, the profiled bit having bit features able to effect, in use, a shear cutting affect, a chip sweeping affect or a scraping affect, or any combination of the affects, and   impact elements, whether of a common component or not, able to be hammered directly or indirectly to provide, or be, localised impact emergences beyond localities of the profiled bit;   wherein the localised impact emergences, upon rotation of the profiled bit, and thus the hybrid drill bit, have   (a) plural radiused loci of rotation, or   (b) plural radiused loci of rotation and a location at the axis of rotation;   and wherein the localised impact emergences and the bit features of the profiled bit act in concert across said diameter of operation of the profiled bit.   
     
     
         11 . The hybrid drill bit of  claim 9  wherein said profiled bit is profiled at least in part by shear cutters or wear resistant members [“shear cutters”] as inserts presenting from a bit body. 
     
     
         12 . The hybrid drill bit of  claim 10  wherein said bit body itself is profiled to present both
 (i) protuberant regions and 
 (ii) less protuberant or recessed regions. 
 
     
     
         13 . The hybrid drill bit of  claim 9  wherein fluid outlets are disposed in said bit body in said less protuberant or recessed regions. 
     
     
         14 . The hybrid drill bit of  claim 9  wherein the profiled bit is splined to a captive hammering assembly. 
     
     
         15 . The hybrid drill bit of  claim 13  wherein said hammering assembly comprises or includes an annular hammer able to duct fluid. 
     
     
         16 . The hybrid drill bit of  claim 14  wherein a ported member to receive fluid via said annular hammer receives and conveys the impacts of the hammer to the impact elements and conveys received fluid to outlets of the bit body. 
     
     
         17 . The hybrid drill bit of  claim 9  wherein said impact elements are individually rotatable relative to said profiled bit. 
     
     
         18 . The hybrid drill bit of  claim 9  wherein each impact element is of a profiled bit captive wear resistant material held by or impactable upon by a captive guided hammerable member. 
     
     
         19 . A downhole tool comprising or including
 a bit profiled by at least multiple shear cutting inserts or shear cutters (“shear cutters”) able to be presented to a bore face as the bit is rotated, and   multiple impact elements rotatable with the bit yet hammerable directly or indirectly so as to emerge or further emerge from the bit to act in concert with the shear cutters;   wherein the shear cutters are arrayed so as, in use as the tool is rotated and the impacted elements are hammered directly or indirectly, to at least substantially fully sweep/shear cut on loci of rotation about the rotational axis of the bit that will follow disruption of the or a bore face caused by the hammered emergence, or further emergence, of said impact elements that rotate on loci of rotation about the rotational axis of the bit to be intermittently disruptive over at least all of the area of the or said bore face.   
     
     
         20 . The tool of  claim 18  wherein the bit has a bit body with a profiled face presentable to a bore face in use, said profiled face having more protuberant regions and less protuberant or recessed regions, the impact elements being emergent each from an opening through a protuberant region. 
     
     
         21 . The tool of  claim 19  wherein shear cutters as insets are carried by some or all of said protuberant regions. 
     
     
         22 . The tool of  claim 19  wherein ports for fluid emergence are provided through some or all of said less protuberant or recessed regions. 
     
     
         23 . The apparatus of  claim 9  positioned downhole to rotate with a drill string and provided with a hammering mechanism actuable to directly or indirectly hammer the impact elements. 
     
     
         24 . The apparatus of  claim 22  positioned downhole to rotate with a drill string and provided with a hammering mechanism actuable to directly or indirectly hammer the impact elements.