Rotary directional drilling apparatus and method of use

Abstract

An apparatus for steering a drill string that includes at least one blade fixedly disposed on an exterior surface of the drill string, such that the at least one blade is rotatable about the drill string in response to fluid flow through a fluid passage in association with said at least one blade, and the at least one blade rotates independent of the drill string for imparting an asymmetrical moment to the drill string in a selected direction for orienting a drill bit attached to the drill string, thereby steering the drill string.

1 . An apparatus for steering a drill string, the apparatus comprising:
 at least one blade fixedly disposed on an exterior surface of the drill string, wherein the at least one blade is independently rotatable about the drill string in response to fluid flow through a first fluid passage disposed within a rotor, and wherein the at least one blade is configured to impart a force on the drill string in a direction responsive to the fluid flow in order to orient a drill bit attached to the drill string, thereby steering the drill string.   
     
     
         2 . The apparatus of  claim 1 ., wherein said at least one blade is disposed on a rotatable portion of a drilling motor in communication with the drill string, and wherein the rotor is operatively disposed within the drilling motor. 
     
     
         3 . The apparatus of  claim 2 , wherein the drilling motor further comprises a stator disposed at least partially concentrically around the motor, and a second fluid passage in fluid communication with the first fluid passage. 
     
     
         4 . The apparatus of  claim 3 , wherein the rotor is disposed substantially longitudinally within the drill string and at least partially concentrically with the motor, and wherein the drilling motor comprises a third fluid passage in fluid communication with the first fluid passage and the second fluid passage. 
     
     
         5 . The apparatus of  claim 4 , further comprising a valve disposed in the rotor configured for selectively controlling the flow of fluid through a rotatable portion for controlling rotation of the rotatable portion and thereby controlling the position of the at least one blade. 
     
     
         6 . The apparatus of  claim 5 , further comprising a measurement while drilling device in communication with the drill string, wherein the valve is controllable in response to data from the measurement while drilling device. 
     
     
         7 . The apparatus of  claim 1  further comprising a measurement while drilling device to control the rotational position of the at least one blade so that the blade remains stationary relative to a borehole during rotary drilling operations. 
     
     
         8 . The apparatus of  claim 1 , wherein the force is asymmetrical. 
     
     
         9 . The apparatus of  claim 1 , wherein during rotary steering the fluid flow maintains the at least one blade in a stationary position relative to a bore hole while applying the force to the drill string. 
     
     
         10 . The apparatus of  claim 1 , wherein rotary steering is achieved by controlling the at least one blade positioning, thereby enabling reorientation of a drill bit. 
     
     
         11 . An apparatus for steering a drill string, the apparatus comprising:
 a drilling motor comprising a rotor, a stator, a first fluid passage disposed through the rotor for flowing drilling fluid from the rotor to a drill bit, and a second fluid passage disposed between the rotor and the stator and in fluid communication with at least a portion of the first fluid passage, wherein the stator is rotatably disposed at least partially concentrically about the rotor; and   a valve configured for selectively controlling the flow of drilling fluid from the first fluid passage to the second fluid passage for controlling the rotation of the stator.   
     
     
         12 . The apparatus of  claim 11 , wherein the stator is configured for counter rotation relative to the rotor in response to fluid flow through the second fluid passage. 
     
     
         13 . The apparatus of  claim 12 , wherein the rotation of the stator is controllable by the flow of drilling fluid through the second fluid passage. 
     
     
         14 . The apparatus of  claim 10 , the apparatus further comprising:
 at least one blade fixedly disposed on an exterior surface of the stator, wherein rotation of the stator controls placement of said at least one blade to provide a force to the drill string and achieve a desired orientation of the drill bit for steering the drill string.   
     
     
         15 . The apparatus of  claim 14 , wherein rotary steering is achieved by controlling the at least one blade orientation. 
     
     
         16 . The apparatus of  claim 11 , wherein rotary steering is achieved by controlling the rotation of the stator. 
     
     
         17 . A method for steering a drill string, the method comprising the steps of:
 connecting a drilling motor to a portion of the drill string;   flowing fluid through a first fluid passage disposed within the drilling motor;   operating the drilling motor to cause an asymmetrical moment about the drill string, wherein the asymmetrical moment offsets at least a portion of the drill string from a rotational center axis to achieve a desired change in orientation of a drill bit connected to the drill string; and   controlling the operation of the drilling motor with a flow of fluid through a fluid passage disposed within the drilling motor.   
     
     
         18 . The method of  claim 17 , wherein the asymmetrical moment is rotatably moveable in response to the flow of fluid through the fluid passage. 
     
     
         19 . The method of  claim 17 , wherein the step of controlling the operation of the drilling motor further comprises a measurement while drilling-controlled valve disposed in the drilling motor, wherein the valve is configured to control the asymmetrical moment so that the asymmetrical moment acts upon a borehole for steering the drill string.