Reaming Device and Method

Abstract

A reaming device including reamers that are prevented from cutting until the reaming device encounters a wellbore restriction, such as a restricted diameter of the wellbore or a ledge. The reamers are shielded in the reaming device's default position until the device is activated by a wellbore restriction, thereby moving the device into the activated position in which the reamers are allowed to cut or clean the wellbore. The reaming device of the present invention is passively activated; no communication with the surface is necessary for activation.

We claim: 
     
         1 . A reaming device, comprising:
 a tool body;   two reamers disposed on the tool body, wherein each reamer extends beyond an outer diameter of the tool body, wherein the two reamers are separated by an axial separation distance, wherein each reamer includes a plurality of cutting mechanisms, wherein an outer cutting edge of the reamer is defined by the cutting mechanisms;   one or more shields extending beyond the outer diameter of the tool body, wherein each shield is proximate to at least one of the reamers;   wherein each shield is biased toward a default position in which the shield extends beyond the outer cutting edge of at least one of the reamers to which the shield is proximate; wherein each shield is configured to be activated by a predetermined activation force; wherein when activated each shield is configured to move from the default position into an activated position in which the shield is disposed radially inward of the outer cutting edge of at least one of the reamers to which the shield is proximate.   
     
     
         2 . The reaming device of  claim 1 , wherein each shield is configured to be passively activated by the predetermined activation force. 
     
     
         3 . The reaming device of  claim 1 , wherein the tool body is generally cylindrical. 
     
     
         4 . The reaming device of  claim 3 , wherein the tool body includes one or more segments or pieces. 
     
     
         5 . The reaming device of  claim 1 , wherein the two reamers are diametrically opposed. 
     
     
         6 . The reaming device of  claim 1 , wherein the two reamers are angularly aligned. 
     
     
         7 . The reaming device of  claim 1 , further comprising one or more additional reamers extending beyond the outer diameter of the tool body. 
     
     
         8 . The reaming device of  claim 1 , wherein at least a portion of each shield is biased in a generally outward direction. 
     
     
         9 . The reaming device of  claim 8 , wherein each shield has an outer surface that is angularly aligned with the cutting mechanisms of the reamer to which the shield is proximate; wherein at least a portion of each shield is configured to move in a generally inward direction when the shield is activated. 
     
     
         10 . The reaming device of  claim 9 , wherein each shield includes a curved pad. 
     
     
         11 . The reaming device of  claim 9 , wherein each shield is configured to pivot around a hinge from the default position to the activated position. 
     
     
         12 . The reaming device of  claim 8 , wherein each shield includes a plurality of protrusions each angularly aligned with at least one of the cutting mechanisms of the reamer to which the shield is proximate; wherein each protrusion is configured to move in an inward direction when the shield is activated. 
     
     
         13 . The reaming device of  claim 8 , wherein each shield is biased by a spring, by a compressible fluid, or by a spring or compressible fluid in communication with a non-compressible fluid chamber. 
     
     
         14 . The reaming device of  claim 8 , wherein each shield is formed of a leaf spring. 
     
     
         15 . The reaming device of  claim 1 , wherein each shield is biased in a rotational direction. 
     
     
         16 . The reaming device of  claim 15 , wherein each shield includes an eccentric sleeve having a variable thickness; wherein a shield portion of the eccentric sleeve is angularly aligned with all cutting mechanisms of the reamer to which the shield is proximate; and wherein the eccentric sleeve is configured to rotate around the tool body when the shield is activated. 
     
     
         17 . A method of cleaning or opening a wellbore using a reaming device while running into the wellbore or while drilling the wellbore, wherein the reaming device reams the wellbore only when the reaming device encounters a restriction in the wellbore. 
     
     
         18 . The method of  claim 17 , wherein the restriction is a restricted wellbore diameter, a restriction in the wellbore, a ledge in the wellbore, or loose rock in the wellbore. 
     
     
         19 . The method of  claim 17 , wherein the reaming device is passively activated when the reaming device encounters the restriction in the wellbore. 
     
     
         20 . The method of  claim 19 , wherein the reaming device comprises a tool body; two reamers disposed on the tool body, wherein each reamer extends beyond an outer diameter of the tool body, wherein the two reamers are separated by an axial separation distance, wherein each reamer includes a plurality of cutting mechanisms, wherein an outer cutting edge of the reamer is defined by the cutting mechanisms; one or more shields extending beyond the outer diameter of the tool body, wherein each shield is proximate to at least one of the reamers; wherein each shield is biased toward a default position in which the shield extends beyond the outer cutting edge of at least one of the reamers to which the shield is proximate; wherein each shield is activated by the restriction in the wellbore thereby moving the shield from the default position into an activated position in which the shield is disposed radially inward of the outer cutting edge of at least one of the reamers to which the shield is proximate. 
     
     
         21 . The method of  claim 20 , wherein at least a portion of each shield is biased in a generally outward direction; and wherein each shield moves in a generally inward direction when activated by the restriction in the wellbore. 
     
     
         22 . The method of  claim 20 , wherein at least a portion of each shield is biased in a rotational direction; and wherein each shield rotates around the tool body when activated by the restriction in the wellbore.