Downhole Tool with Directional Nozzle and a Drill String Thereof

Abstract

A downhole tool and a drill string (18″) comprising such a downhole tool is disclosed. The downhole tool comprises a housing having a first end and a second end, wherein a first fluid conduit (5) extends from an opening in the first end to an opening in the second end. A second (8″) and a third fluid conduit is further arranged in the housing, wherein the second (8) and third fluid conduits extend from an inner opening connected to the first fluid conduit (5) to an outer opening arranged in the outer side surface of the housing. The second and third fluid conduits (8, 24) are placed in acute angles relative to a longitudinal direction of the downhole tool. The second fluid conduit (8) is orientated so that it faces towards the first end. The third fluid conduit (24) is orientated so that it faces towards the first or second end. This provides an improved cleaning effect and transport effect without generating a Vortex around the outer opening of the second and third fluid conduits (8, 24).

1 . A downhole tool, such as a circulating sub or a cleaning tool, for cleaning a borehole, comprising a housing defining a longitudinal direction, a first fluid conduit extending from an opening in a first end of the housing to an opening in a second end of the housing, and an activation mechanism configured to at least activate the downhole tool, the housing further has an outer side surface facing an inner wall of the borehole, when positioned in the borehole, and an inner side surface facing the first fluid conduit, the first fluid conduit is configured to lead a drilling fluid from the first end to the second end when the downhole tool is not activated, the housing further has at least a second fluid conduit extending from at least a first opening connected to the first fluid conduit to a second opening arranged in the outer surface, at least a first nozzle is arranged at the second opening of the at least second fluid conduit, wherein the at least second fluid conduit is placed in a first acute angle relative to at least the longitudinal direction so that the at least second fluid conduit substantially extends towards one of the first and second ends, ∞, and wherein at least a third fluid conduit extends from a third opening connected to the first fluid conduit to a fourth opening arranged in the outer surface and at least a second nozzle is arranged at the fourth opening of the at least third fluid conduit, wherein the at least third fluid conduit is placed in a second acute angle of relative to at least the longitudinal direction so that the at least third fluid conduit substantially extends towards one of the first and second ends and wherein said first and second acute angle is between 30° and 65°. 
     
     
         2 . A downhole tool according to  claim 1 , wherein the at least second fluid conduit is configured to lead a part of a drilling fluid from the first fluid conduit to an annulus between the downhole tool and the inner wall of the borehole, when the downhole tool is activated, while the remaining drilling fluid is lead through the downhole tool via the first fluid conduit. 
     
     
         3 . A downhole tool according to  claim 1 , wherein the downhole tool further comprises at least a fourth fluid conduit extending from a fifth opening connected to the first fluid conduit to a sixth opening arranged in the outer surface, at least a third nozzle is arranged at the sixth opening of the at least fourth fluid conduit, wherein the at least fourth fluid conduit is placed in a third acute angle relative to at least the longitudinal direction so that the at least third fluid conduit substantially extends towards the drill bit end of the down hole tool. 
     
     
         4 . A downhole tool according to  claim 1 , wherein the second fluid conduit and the at least third fluid conduit substantially extend towards opposite ends or towards the same end. 
     
     
         5 . A downhole tool according to  claim 3 , wherein the first acute angle differs from the at least second acute angle. 
     
     
         6 . A downhole tool according to  claim 5 , wherein the at least second fluid conduit is placed in a first acute angle between 30° to 50°, and the at least third fluid conduit is placed in a second acute angle between 50° to 65°. 
     
     
         7 . A downhole tool according to  claim 3 , wherein the first nozzle and the at least second nozzle have different sizes. 
     
     
         8 . A downhole tool according to  claim 1 , wherein the housing further defines a circumferential direction, wherein at least one of the second and third fluid conduits is placed in a combined first or second acute angle relative to the longitudinal direction and the circumferential direction. 
     
     
         9 . A downhole tool according to  claim 1 , wherein the activation mechanism comprises at least one movable valve element connected to at least one actuator unit controlled by a control unit, the at least one actuator unit is configured to move, e.g. repeatedly, the at least one valve element relative to at least the second fluid conduit or the at least third fluid conduit between an open position and a closed position. 
     
     
         10 . A drill string for positioning in a borehole, comprising at least two downhole tools according to  claim 1 , wherein a first downhole tool is placed at a first position and at least a second downhole tool is placed at a second position relative to the first downhole tool along the length of the drill string. 
     
     
         11 . A drill string according to  claim 10 , wherein a lowermost downhole tool is positioned at least 10 metres from a drill bit of the drill string.