Patent ID: 8607896

Claim:
A fluid driven turbodrill for drilling and well servicing applications, comprising: a housing defining a fluid volume and a plurality of stators through which a flow of pressurized fluid can be directed; a pressure balanced turbine rotor, at least a portion of which is disposed coaxially within the housing, the turbine rotor including a proximal end and a distal end, the distal end being connected to drive a tool for drilling or well servicing, the turbine rotor being configured to rotate relative to the housing and to move axially relative to the housing, the turbine rotor having a plurality of rotor vanes configured to engage the flow of pressurized fluid, such that the flow of pressurized fluid causes the turbine rotor to rotate relative to the housing; a pressure balance volume defined by the housing and the turbine rotor, the pressure balance volume being disposed adjacent to the proximal end of the turbine rotor; a bypass channel configured to selectively place the pressure balance volume in fluid communication with an ambient volume, as a function of an axial position of the turbine rotor relative to the housing, the bypass channel being disposed so that an axial load applied to the turbine rotor as a result of the tool pressing against an external object moves the turbine rotor axially to a position within the housing that reduces the flow of pressurized fluid through the bypass channel, so that at least a portion of the pressurized fluid that was flowing through the bypass channel instead flows through the turbine rotor to rotatably drive the tool; and a first seal assembly disposed at a first location between the housing and the turbine and having separable proximal and distal portions and a second seal disposed at a second location between the housing and the turbine, the housing and turbine rotor adapted to accept a range of inner and outer first and second seal diameters, the seal diameters selectable to control a particular weight on bit at which the turbine moves to an upper position, the first seal proximal and distal portions configured to separate and form a gap as a function of an axial position of the turbine rotor relative to the housing, thereby placing the pressure balanced volume in fluid communication with an ambient volume.