Running bore-lining tubulars
A method of running a tubular string into a wellbore comprises running a bore-lining tubular string into a wellbore substantially without rotation, while rotating a cutting structure at a distal leading end of the tubular string. Other methods provide for rotation of the string and the provision of a non-rotating stabiliser towards the leading end of the string.
1. An apparatus ( 3 ) for use in running a bore-lining tubular string into a bore, comprising:
a cutting structure ( 5 );
a drive unit ( 4 ) coupled to the cutting structure ( 5 ) and operable to rotationally drive the cutting structure ( 5 ), wherein the drive unit and cutting structure comprise at least one of a frangible, drillable, soluble, and degradable portion, wherein the drive unit is completely removable from the bore by the action of drilling, dissolving or degrading; and
an end connector ( 13 ) coupled to the drive unit ( 4 ) and adapted for connection to the bore-lining tubular.
2. The apparatus of claim 1 , wherein the drive unit ( 4 ) comprises a housing ( 14 ) and a drive shaft ( 15 ) rotatably supported within the housing ( 15 ).
3. The apparatus of claim 2 , wherein the drive unit ( 4 ) further comprises a turbine arrangement ( 18 ) attached to the drive shaft ( 15 ).
4. The apparatus of claim 3 , wherein the turbine arrangement comprises a plurality of stator blades ( 19 ) attached to the housing ( 14 ) and a plurality of rotor blades ( 20 ) attached to the drive shaft ( 15 ).
5. The apparatus of claim 4 , wherein the cutting structure ( 5 ) is fixed to the drive shaft ( 15 ).
6. The apparatus of claim 2 , wherein the drive unit ( 4 ) further comprises a motor ( 21 ) having a helical shaft ( 22 in FIG. 6A ) and stator ( 23 ), wherein the helical shaft ( 22 ) rolls inside of the stator ( 23 ).
7. The apparatus of claim 6 , wherein the helical shaft ( 22 ) is coupled to the drive shaft ( 15 ) via a flexible joint.
8. The apparatus of claim 2 , further comprising an external stabilizing feature ( 25 ) positioned around a circumference of the housing ( 14 ).
9. The apparatus of claim 8 , wherein the external stabilizing feature ( 25 ) and housing ( 14 ) have an effective outside diameter substantially equal to or less than an outside diameter of the cutting structure ( 5 ).
10. A downhole apparatus, comprising:
a bore-lining tubular string;
a cutting structure;
a drive unit coupled to the cutting structure and operable to rotationally drive the cutting structure, wherein the drive unit and cutting structure comprises a frangible, readily-drillable, soluble, or degradable portion, wherein the drive unit is completely removable from the tubular string by action of drilling, dissolving or degrading; and
an end connector for coupling the drive unit to an end of the bore-lining tubular string.
11. A method of running a bore-lining tubular string into a bore, comprising:
attaching an apparatus to a leading edge of the bore-lining tubular string, the apparatus comprising a cutting structure and a drive unit coupled to the cutting structure and operable to rotationally drive the cutting structure, wherein the drive unit and cutting structure comprises a frangible, readily-drillable, malleable, soluble, or degradable portion;
running the bore-lining tubular string with the attached apparatus into the bore; and
drilling out the apparatus.
12. The method of claim 11 , further comprising circulating drilling fluid through the bore-lining tubular string while running the bore-lining tubular string into the bore.
13. The method of claim 12 , further comprising using downhole sensors together with predictive models of the bore to adjust surface variables.
14. The method of claim 11 , further comprising cementing the bore-lining tubular string to the bore.