Method and arrangement for improving cuttings removal and reducing differential pressure sticking of drill strings in wellbores

Claim 3

A method as claimed in claim 1, said step of projecting including the step of projecting a plurality of fluid jets at a tool joint which are circumferentially spaced around the circumference of the tool joint.

Claim 4

A method as claimed in claim 2, said step of projecting including the step of projecting at least three fluid jets at a tool joint which are substantially evenly circumferentially spaced around the circumference of the tool joint.

Claim 5

A method as claimed in claim 1 or 2 or 3, said step of projecting including the step of projecting at a plurality of adjacent tool joints in the deviated wellbore.

Claim 6

A method as claimed in claim 1, said fluid jets being projected radially outwardly from the tool joint box portion of said tool joints.

Claim 7

A method as claimed in claim 1, comprising mounting nozzle means in said drill string to form said jets of outwardly directed drilling fluid into the annulus of said wellbore.

Claim 8

An arrangement for the rotary drilling of a deviated wellbore into the earth's crust which mitigates differential sticking of a drill string, comprised of a plurality of sections of drill pipe interconnected at tool joints and having a drill bit at the lower end thereof, and to improve the removal of cuttings settled in the lower portion of the annulus formed about said drill string in said deviated wellbore, comprising means for circulating a drilling fluid down the center of the drill string such that the fluid is returned from the wellbore in a return stream in the annulus formed about the drill string, means for sweeping the drill cuttings accumulated on the lower side of the deviated wellbore into the main return stream of the drilling fluid flow in the annulus formed about the drill string, including nozzle means provided in said drill string in at least one of the tool joints of said drill string and communicating the interior of said drill string with said annulus whereby a portion of drilling fluid circulated down the drill string is projected as fluid jets by said nozzle means into said wellbore annulus to impart stirring movement to cuttings settled on the low side of said wellbore and facilitate removal thereof by the upwardly flowing fluid in said annulus.

Claim 9

An arrangement for the rotary drilling of a deviated wellbore into the earth's crust which mitigates differential sticking of a drill string, comprised of a plurality of sections of drill pipe interconnected at tool joints and having a drill bit at the lower end thereof, and to improve the removal of cuttings settled in the lower portion of the annulus formed about said drill string in said deviated wellbore, comprising means for circulating a drilling fluid down the center of the drill string such that the fluid is returned from the wellbore in a return stream in the annulus formed about the drill string, means for sweeping the drill cuttings accumulated on the lower side of the deviated wellbore into the main return stream of the drilling fluid flow in the annulus formed about the drill string, including nozzle means provided in said drill string in at least one of the tool joints of said drill string and communicating the interior of said drill string with said annulus whereby a portion of drilling fluid circulated down the drill string is projected as fluid jets by said nozzle means into said wellbore annulus to impart stirring movement to cuttings settled on the low side of said wellbore and facilitate removal thereof by the upwardly flowing fluid in said annulus.

Claim 10

An arrangement as claimed in claim 7, each tool joint having a diameter which is larger in diameter than the nominal diameter of the drill string, such that the tool joints rest on the lower side of the deviated wellbore and support the main portion of the drill string above the cuttings.

Claim 11

An arrangement as claimed in claim 7 or 8, said nozzle means including a plurality of nozzles at a tool joint which are circumferentially spaced around the circumference of the tool joint.

Claim 12

An arrangement as claimed in claim 9, said nozzle means including at least three nozzles at a tool joint which are substantially evenly circumferentially spaced around the circumference of the tool joint.

Claim 13

An arrangement as claimed in claim 9, said nozzle means including nozzles provided at a plurality of adjacent tool joints in the deviated wellbore.

Claim 14

An arrangement as claimed in claim 7, said nozzle means being located in the tool joint box portion of said tool joints.

Claim 15

An arrangement as claimed in claim 7, comprising a check valve in each said nozzle means for closing said nozzle means upon the flow of said drilling fluid in said drill string reaching a predetermined flow volume.

Claim 16

An arrangement as claimed in claim 13, said check valve being responsive to a pressure drop in said drill string for closing said nozzle means.