Improvement relating to drill rods

Abstract

A drill rod for assembly with other drill rods to form a drillstring used for fluid reverse circulation drilling comprising: an outer drill rod comprising a lightweight drill rod used in core drilling with a bore, an inner drill rod comprising a bore, a first coupling member removably coupled to one end of the inner drill rod, a second coupling member removably coupled to a second end of the inner drill rod, wherein the first and second coupling members centre the inner drill rod within the outer drill rod.

1 . A drill rod and coupling arrangement for assembly with other drill rods into a drillstring used for fluid reverse circulation drilling, and then for re-assembly into a drillstring used for core drilling, the drill rod and coupling arrangement comprising, when used for fluid reverse circulation drilling utilizing a fluid activated hammer/vibration apparatus:
 an outer drill rod comprising a lightweight drill rod used in core drilling with a bore,   an inner drill rod comprising a bore,   a first coupling member removably coupled to one end of the inner drill rod,   a second coupling member removably coupled to a second end of the inner drill rod,   wherein the first and second coupling members center the inner drill rod within the outer drill rod.   
     
     
         2 . A drill rod and coupling arrangement according to  claim 1  wherein the first coupling member provides a first removable coupling and the second coupling member provides a second removable coupling to enable a corresponding first and/or second coupling member in another dual walled drill rod to be coupled. 
     
     
         3 . A drill rod and coupling arrangement according to any one  claim 1  wherein a third member is provided that is removably coupled to the outer drill rod to retain either the first and/or second coupling member within the outer drill rod. 
     
     
         4 . A drill rod and coupling arrangement according to  claim 3  wherein the third member is a coupling member that comprises the second coupling member as an inner coupling member and also comprises an outer coupling member. 
     
     
         5 . A drill rod and coupling arrangement according to  claim 1  wherein the second coupling member forms part of an outer coupling member that comprises the second coupling member as an inner coupling member and also comprises an outer coupling. 
     
     
         6 . A drill rod and coupling arrangement according to  claim 1  wherein the second coupling member is further removably coupled to a first end of the outer drill rod, wherein the second coupling member comprises:
 a first inner coupling that removably couples the second coupling member to the second end of the inner drill rod, and 
 a first outer coupling that removably couples the second coupling member the first end of the outer drill rod. 
 
     
     
         7 . A drill rod and coupling arrangement according to  claim 6  wherein the second coupling member also couples the outer drill rod to another outer drill rod in a drill string. 
     
     
         8 . A drill rod and coupling arrangement according to  claim 1  wherein the first coupling member is a box, the second coupling member is a pin, and the third member is a third coupling member. 
     
     
         9 . A drill rod and coupling arrangement according to  claim 3  wherein the third coupling member also couples the outer drill rod to another outer drill rod in a drill string. 
     
     
         10 . A drill rod and coupling arrangement according to  claim 3  wherein the third coupling member forms part of the outer drill rod. 
     
     
         11 . A drill rod and coupling arrangement according to  claim 3  wherein the third coupling member has an outside diameter larger than the outer drill rod. 
     
     
         12 . A drill rod and coupling arrangement according to  claim 8  wherein the box or pin is provided with a seal. 
     
     
         13 .- 21 . (canceled) 
     
     
         22 . A coupling for coupling drill rods into a drillstring with a fluid activated hammer/vibration apparatus used for reverse circulation drilling, and then into a drillstring used for core drilling,
 the drill rods comprising:
 inner drill rods comprising a bore, and 
 lightweight outer drill rods used in core drilling with a bore, and 
   the coupling comprising:
 a first coupling member for removable coupling to one end of an inner drill rod, 
 a second coupling member for removable coupling to a second end of the inner drill rod, 
   wherein the first and second coupling members centre center the inner drill rod within an outer drill rod.   
     
     
         23 . A coupling according to  claim 22  further comprising a third member for removable coupling to the outer drill rod to retain either the first and/or second coupling member within the outer drill rod. 
     
     
         24 . A coupling according to  claim 23  wherein the third member is a coupling member that comprises the second coupling member as an inner coupling member and also comprises an outer coupling member. 
     
     
         25 . A coupling according to  claim 22  wherein the second coupling member forms part of an outer coupling member that comprises the second coupling member as an inner coupling member and also comprises an outer coupling, 
     
     
         26 . A coupling according to  claim 22  wherein the second coupling member is further removably coupled to a first end of the outer drill rod, wherein the second coupling member comprises:
 a first inner coupling that removably couples the second coupling member to the second end of the inner drill rod, and 
 a first outer coupling that removably couples the second coupling member the first end of the outer drill rod. 
 
     
     
         27 . (canceled) 
     
     
         28 . A drill rod for assembly with other drill rods to form a drillstring with a fluid activated hammer/vibration apparatus used for fluid reverse circulation drilling, and then to form a drillstring for core drilling, the drill rods comprising:
 an outer drill rod comprising a lightweight drill rod used in core drilling with a bore,   an inner drill rod comprising a bore,   a first coupling member removably coupled to one end of the inner drill rod,   a second coupling member removably coupled to a second end of the inner drill rod and one end of the outer drill rod,   wherein the first and second coupling members center the inner drill rod within the outer drill rod.   
     
     
         29 . A method of reverse circulation (RC) drilling and core sampling comprising:
 assembling a first drillstring with dual walled drill rods according to  claim 1 ,   coupling a third member to the outer drill rod to retain either the first and/or second coupling member within the outer drill rod,   operating the first drillstring using a lightweight drill rig to perform fluid RC drilling, resulting in a borehole,.   upon completion of RC drilling, extracting the drill string from the borehole,   disassembling the drill rods of the first drillstring by removing the third member from the outer drill rod and removing the inner drill rod from the outer drill rod,   assembling a second drill string with the outer drill rods, along with core sampling components,   deploying and operating the second drillstring in the borehole using the lightweight drill rig to perform a core sampling.