Top mount dual bit well drilling system

Abstract

A top mount dual bit well drilling mechanism has a rotary driven tubular housing having a top mount body within an upper end portion of the housing to which the upper end of a mud motor is mounted for support within the housing. A reamer bit is connected for rotation by the tubular housing upon rotation by a well drilling string and defines a core removing bit chamber that is recessed within the reamer bit and has communication with the core receiving receptacle. A core removing bit is rotated within the core removal bit chamber by the mud motor and continuously cuts away the upper end of a formation core that enters the receptacle as the reamer bit cuts into the formation.

I claim: 
     
         1 . A top mount dual bit well drilling mechanism for drilling attachment to a tubular well drilling string extending from a drilling rig located at the Earth's surface, comprising:
 a tubular housing for connection with a tubular well drilling string;   a top mount body having an upper end portion mounted in non-rotatable relation within said tubular housing and having a connecting end;   a drilling fluid energized rotary motor being supported within said tubular housing by said connecting end of said top mount body;   a reamer bit being connected with said tubular housing and having a plurality of spaced cutter retaining blades each having multiplicity of formation cutter elements mounted thereto and defining a downwardly facing core receiving receptacle, said reamer bit being rotated by said tubular housing upon rotation of said tubular housing by said tubular well drilling string, said reamer bit defining a core removing bit chamber therein in communication with said downwardly facing core receiving receptacle;   a core removing bit being disposed for rotation within said core removal bit chamber and having a cutting face oriented for engaging and removing a formation core that remains and enters said downwardly facing core receiving receptacle as said formation cutter elements of said reamer bit cut a wellbore into the formation; and   a bit drive shaft being driven by said drilling fluid energized rotary motor and being connected in rotary driving relation with said core removing bit.   
     
     
         2 . The top mount dual bit well drilling mechanism of  claim 1 , comprising:
 said reamer bit having an axis of rotation;   said tubular housing of said drilling mechanism having a longitudinal center-line being concentric with said axis of rotation of said reamer bit;   said drilling fluid energized rotary motor having a longitudinal center-line;   said top mount body supporting said drilling fluid energized rotary motor with said longitudinal center-line thereof being laterally offset from said longitudinal center-line of said tubular housing of said drilling mechanism; and   said core removing bit being rotatable about said longitudinal center-line of said drilling fluid energized rotary motor.   
     
     
         3 . The top mount dual bit well drilling mechanism of  claim 1 , comprising:
 said reamer bit having an axis of rotation;   said tubular housing of said well drilling mechanism having a longitudinal center-line being concentric with said axis of rotation of said reamer bit;   said drilling fluid energized rotary motor having a longitudinal center-line;   said top mount body supporting said drilling fluid energized rotary motor with said longitudinal center-line thereof in concentric relation with said longitudinal center-line of said tubular housing of said well drilling mechanism; and   said core removing bit being rotatable about said longitudinal center-line of said drilling fluid energized rotary motor.   
     
     
         4 . The top mount dual bit well drilling mechanism of  claim 1 , comprising:
 said reamer bit defining a cutting face;   said core removing bit defining a cutting face being recessed within said reamer bit and located inwardly of said cutting face of said reamer bit and permitting formation core stabilization of said reamer bit within said downwardly facing core receiving receptacle.   
     
     
         5 . The top mount dual bit well drilling mechanism of  claim 1 , comprising:
 said drilling fluid energized rotary motor having a tubular motor housing;   a stator member being located within said tubular motor housing;   a rotor member being located within said stator member and being rotated by drilling fluid flow between said stator and rotor members; and   a bit drive shaft being rotationally driven by said rotor member and having driving connection with said core removing bit.   
     
     
         6 . The top mount dual bit well drilling mechanism of  claim 1 , comprising:
 said reamer bit having right hand rotation during well drilling; and   said drilling fluid energized rotary motor rotating said core removing bit to the left during well drilling.   
     
     
         7 . The top mount dual bit well drilling mechanism of  claim 1 , comprising:
 said reamer bit having right hand rotation during well drilling; and   said drilling fluid energized rotary motor rotating said core removing bit to the right during well drilling.   
     
     
         8 . The top mount dual bit well drilling mechanism of  claim 1 , comprising:
 internal splines being defined within said tubular housing;   external splines being defined by said top mount body and engaging said internal splines and establishing a non-rotatable relationship of said top mount body within said tubular housing;   a retainer and adjustment member being threaded within said tubular housing and having retaining and adjusting engagement with said top mount body;   said drilling fluid energized rotary motor having a tubular motor housing being connected with and supported by said top mount body and being seated within said reamer bit body; and   a bit drive shaft extending through said tubular housing and into said core removing bit chamber and being in threaded driving connection with said core removing bit.   
     
     
         9 . The top mount dual bit well drilling mechanism of  claim 1 , comprising:
 drilling fluid flow passages being defined within said tubular housing and both internally and externally of said drilling fluid energized rotary motor.   
     
     
         10 . The top mount dual bit well drilling mechanism of  claim 1 , comprising:
 a drilling fluid supply chamber being located within said tubular housing and externally of said top mount body and said drilling fluid energized rotary motor;   a substantially centrally located drilling fluid flow passage extending longitudinally through said top mount body and providing a supply of drilling fluid to said fluid energized rotary motor;   a flow diverting passage being defined in said top mount body and being in communication with said substantially centrally located drilling fluid flow passage and diverting a portion of the drilling fluid being supplied by the well drilling string into said drilling fluid supply chamber; and   reamer bit supply passages being defined within said reamer bit and conducting flows of drilling fluid from said drilling fluid supply chamber to spaces between said cutter retaining blades.   
     
     
         11 . The top mount dual bit well drilling mechanism of  claim 10 , comprising:
 replaceable flow control nozzles being located within designated drilling fluid flow passages to control the volume of drilling fluid flow for operation of said drilling fluid energized rotary motor, for cooling drilling components and to supply drilling fluid flow for efficient operation of said reamer bit and said core removing bit.   
     
     
         12 . A top mount dual bit well drilling mechanism for drilling attachment to a tubular well drilling string extending from a drilling rig located at the Earth's surface, comprising:
 a tubular housing having a mounting sub at the upper end thereof for rotary driven connection with a tubular well drilling string;   a top mount body defining a drilling fluid flow passage therethrough and having an upper end portion mounted in non-rotatable relation within said tubular housing and having a connecting end;   a drilling fluid energized rotary motor being supported within said tubular housing by said connecting end of said top mount body and defining a motor operation chamber in communication with said drilling fluid flow passage of said top mount body;   a reamer bit being connected with said tubular housing and having a plurality of spaced cutter retaining blades each having multiplicity of formation cutter elements mounted thereto and defining a reamer bit cutting face, said reamer bit defining a downwardly facing centrally located core receiving receptacle and being rotated by said tubular housing upon rotation of said tubular housing by said tubular well drilling string, said reamer bit defining a core removing bit chamber therein in communication with said downwardly facing core receiving receptacle;   a core removing bit being disposed for rotation within said core removal bit chamber and having a cutting face thereof located inwardly of said cutting face of said reamer bit and oriented for engaging and removing a formation core that remains and enters said downwardly facing core receiving receptacle as said formation cutter elements of said reamer bit cut a wellbore into the formation; and   a bit drive shaft being driven by said drilling fluid energized rotary motor and being connected in rotary driving relation with said core removing bit.   
     
     
         13 . The top mount dual bit well drilling mechanism of  claim 12 , comprising:
 said reamer bit having an axis of rotation;   said tubular housing of said drilling mechanism having a longitudinal center-line being concentric with said axis of rotation of said reamer bit;   said drilling fluid energized rotary motor having a longitudinal center-line;   said top mount body supporting said drilling fluid energized rotary motor with said longitudinal center-line thereof being laterally offset from said longitudinal center-line of said tubular housing of said drilling mechanism; and   said core removing bit being rotatable about said longitudinal center-line of said drilling fluid energized rotary motor.   
     
     
         14 . The top mount dual bit well drilling mechanism of  claim 12 , comprising:
 said reamer bit having an axis of rotation;   said tubular housing of said well drilling mechanism having a longitudinal center-line being concentric with said axis of rotation of said reamer bit;   said drilling fluid energized rotary motor having a longitudinal center-line;   said top mount body supporting said drilling fluid energized rotary motor with said longitudinal center-line thereof in concentric relation with said longitudinal center-line of said tubular housing of said well drilling mechanism; and   said core removing bit being rotatable about said longitudinal center-line of said drilling fluid energized rotary motor.   
     
     
         15 . The top mount dual bit well drilling mechanism of  claim 12 , comprising:
 said drilling fluid energized rotary motor having a tubular motor housing;   a stator member being located within said tubular motor housing;   a rotor member being located within said stator member and being rotated by drilling fluid flow between said stator and rotor members; and   a bit drive shaft being rotationally driven by said rotor member and having driving connection with said core removing bit.   
     
     
         16 . The top mount dual bit well drilling mechanism of  claim 12 , comprising:
 internal splines being defined within said tubular housing;   external splines being defined by said top mount body and engaging said internal splines and establishing a non-rotatable relationship of said top mount body within said tubular housing;   a retainer and adjustment member being threaded within said tubular housing and having retaining and adjusting engagement with said top mount body;   said drilling fluid energized rotary motor having a tubular motor housing being connected with and supported by said top mount body and being seated within said reamer bit body; and   a bit drive shaft extending through said tubular motor housing and into said core removing bit chamber and being in threaded driving connection with said core removing bit.   
     
     
         17 . The top mount dual bit well drilling mechanism of  claim 16 , comprising:
 drilling fluid flow distribution passages being defined within said core removing bit;   said drilling fluid energized rotary motor having a stator within said tubular motor housing and having a rotor with said stator being rotated by drilling fluid flow between said stator and rotor;   said rotor having a non-circular output shaft drive member;   a flex shaft having non-rotatable connection with said non-circular output shaft drive member and cushioning shock forces of said rotor;   a tubular bit drive shaft being connected in driven relation with said flex shaft and being connected in driving relation with said core removing bit and having a drilling fluid flow passage therein in communication with said drilling fluid flow distribution passages of said core removing bit.