Shaped element for rotary drilling equipment, and a drillrod including at least one shaped element

Abstract

The shaped element has at least one stirring and entrainment zone in which the outside surface of the shaped element has recessed portions and projecting portions configured substantially in the form of helices about the axis of rotation of the drillrod, said portions being wound in a direction such as to encourage the flow of a drilling fluid in the upward direction in an annular space between the drillrod and the wall of a borehole under the effect of the drillrod rotating. The angle of inclination of the helices in which the recessed portions and the projecting portions of the shaped element are configured increases in the flow direction of the drilling fluid in the annular space.

What is claimed is:  
     
         1 / A shaped element for rotary drilling equipment such as a drillrod, the element being generally in the form of a body of revolution of axis coinciding with the drilling axis of rotation and having an outside surface with projecting portions and recessed portions extending in radial directions perpendicular to the axis in configurations that are substantially helical about the axis of the shaped element so as to produce an effect of controlled stirring and accelerated rise of a drilling fluid with cuttings in an annular space between the shaped element of the drilling equipment and the wall of a borehole while the drilling equipment is rotating, wherein each helix along which the projecting portions and the recessed portions of the shaped element are disposed has an angle of inclination relative to a plane perpendicular to the axis of the shaped element that increases in the axial flow direction of the drilling fluid in the annular space, i.e. upwards when the drilling equipment is in its operating position, the axial flow of the drilling fluid being accelerated along the projecting portions and the recessed portions because of the direction of rotation of the drillrod.  
     
     
         2 / A shaped element according to  claim 1 , wherein, in the flow direction of the drilling fluid in the annular space, the recessed portions of the shaped element constituted by grooves present a decrease in at least one of width in a circumferential direction of the shaped element and depth in a radial direction perpendicular to the axis of the shaped element, and thus present a decrease in cross-section in a plane perpendicular to the axis of the shaped element.  
     
     
         3 / A shaped element according to  claim 1 , further comprising, on either side in the axial direction of a stirring and entrainment zone in which the shaped element presents projecting portions and recessed portions disposed in helices, a pre-loading zone in which the drillrod presents a portion projecting radially outwards, and a bearing zone in which the drillrod also presents a portion projecting radially outwards with a maximum diameter greater than the maximum diameter of the shaped element in the stirring and entrainment zone and greater than the nominal diameter of the drillrod in its ordinary portions disposed on either side in the axial direction of the shaped element.  
     
     
         4 / A shaped element according to  claim 1 , including a second loading zone or post-loading zone analogous to the pre-loading zone, said second loading zone being situated downstream from the bearing zone in the flow direction of the drilling fluid in the annular space.  
     
     
         5 / A shaped element according to  claim 3 , further comprising, on either side of the pre-loading zone disposed upstream of the stirring and entrainment zone in the flow direction of the drilling fluid in the annular space, a prior stirring and entrainment zone situated upstream and a turbulence zone situated downstream in the flow direction of the drilling fluid in the annular space, the outside surface of the shaped element presenting a diameter that increases in the flow direction of the drilling fluid in the prior stirring and entrainment zone and a diameter that decreases in the flow direction of the drilling fluid in the annular space in the turbulence zone.  
     
     
         6 / A shaped element according to  claim 5 , further comprising, in the prior stirring and entrainment zone and in the pre-loading zone, at least one of a plurality of recessed elements and a plurality of projecting elements spaced apart in the circumferential direction of the shaped element, configured in helices about the axis of the shaped element with an angle of inclination relative to a transverse plane perpendicular to the axis of the shaped element that increases in the flow direction of the drilling fluid in the annular space.  
     
     
         7 / A shaped element according to  claim 6 , further comprising, in the prior stirring and entrainment zone and in the pre-loading zone, recessed portions constituted by grooves machined in helices in the outside surface of the shaped element of the drillrod.  
     
     
         8 / A shaped element according to  claim 6 , further comprising, in the prior stirring and entrainment zone, projecting portions constituted by ribs configured in helices between which the outside surface of the shaped element of the drillrod is machined to constitute the recessed portions.  
     
     
         9 / A shaped element according to  claim 1 , further comprising, at least in a stirring and entrainment zone having recessed portions and projecting portions configured in helices, at least one nozzle passing through a tubular wall of the shaped element of a drillrod between an internal central space for a flow of drilling fluid in the drillrod and the annular space outside the shaped element of the drillrod, the nozzle comprising an inlet channel extending substantially radially perpendicularly to the axis of the shaped element of the drillrod and opening out into the inside space of the shaped element of the drillrod, and an outlet channel communicating with the inlet channel and opening out to the outside of the shaped element of the drillrod, the outlet channel being directed in a direction that is substantially parallel to the axis of the shaped element in the flow direction of the drilling fluid in the annular space, i.e. upwards when the drillrod is in its operating position.  
     
     
         10 / A shaped element according to  claim 1 , comprising at least one stirring and entrainment zone having recessed portions and projecting portions configured in helices about the axis of the shaped element, and in axial alignment with the at least one stirring and entrainment zone, it further comprises at least one mechanical activation and bearing zone in which the drillrod presents a maximum diameter and has, in its outside surface, at least one helical groove.  
     
     
         11 / A shaped element according to  claim 10 , wherein the at least one mechanical activation and bearing zone comprises, in the direction of the axis of the shaped element of the drillrod, a first portion of maximum diameter of the drillrod machined in its outside surface to form at least one substantially continuous helical groove analogous to a thread, a middle zone of diameter smaller than the maximum diameter of the drillrod and without any helical groove, and a second portion of maximum diameter of the drillrod machined in its outside surface to present at least one substantially continuous helical groove.  
     
     
         12 / Drilling equipment such as a drillrod including at least one shaped element according to  claim 1.