Wellbore circulation assembly

Abstract

In some embodiments, a circulation assembly can direct all or substantially all fluid downstream in a drill string in a first mode of operation, and some or all fluid to an annulus in a second mode. Operation of the circulation assembly can be repeatedly changed between the modes of operation. In some embodiments, the circulation assembly can comprise other modes wherein fluid is apportioned between the annulus and the downstream drill string.

1 . A flow management assembly for selectable direction of working fluid in an hydraulic system for well operation, the assembly comprising:
 a fluid inlet at an upstream end of the assembly configured to receive fluid from an upstream component of the system;   a first fluid outlet at a downstream end of the assembly configured to deliver fluid to downstream component of the system;   a first passage connecting the fluid inlet to the first fluid outlet;   a second fluid outlet configured to discharge fluid from the system;   a second passage connecting the fluid inlet to the second fluid outlet;   a valve movable repeatedly between a first configuration wherein discharge of fluid from the system through the second fluid outlet is inhibited and a second configuration wherein the discharge of fluid from the system through the second fluid outlet is greater than in the first configuration.   
     
     
         2 . The assembly of  claim 1 , wherein the discharge of fluid through the second passage is substantially prevented when said valve is in the first configuration. 
     
     
         3 . The assembly of  claim 1 , wherein the valve comprises a spring that biases the valve to the closed configuration. 
     
     
         4 . The assembly of  claim 1 , wherein the valve is operable at least partially in response to upstream pressure of the working fluid. 
     
     
         5 . The assembly of  claim 1 , wherein the valve is operable in a first mode wherein the valve is responsive to increase of upstream pressure to move the valve to the open configuration, and a second mode wherein the valve is not responsive to increase of upstream pressure to move the valve to the open configuration. 
     
     
         6 . The assembly of  claim 5 , wherein the valve comprises an index to switch the operation of the valve between the first mode and the second mode. 
     
     
         7 . The assembly of  claim 1 , further comprising a pressure compensated chamber operatively connected to the valve. 
     
     
         8 . The assembly of  claim 1 , wherein said valve is operable from outside of the wellbore when the assembly is positioned within the wellbore. 
     
     
         9 . The assembly of  claim 1 , wherein said valve is changeable from said first configuration to said second configuration in response to pressure changes. 
     
     
         10 . The assembly of  claim 1 , wherein said valve is positioned at least partially within said second passage. 
     
     
         11 . The assembly of  claim 1 , wherein delivery of fluid to the downstream component through the first fluid outlet is inhibited in the second configuration. 
     
     
         12 . The assembly of  claim 11 , wherein delivery of fluid to the downstream component through the first fluid outlet is substantially prevented in the second configuration. 
     
     
         13 . A method for directing fluid flow within an hydraulic system for operation in a wellbore, comprising:
 receiving fluid from an upstream component of the system;   directing the fluid toward a downstream component of the system;   opening a passage to discharge at least a portion of the fluid from the system;   closing the passage to direct all of the fluid toward the downstream component.   
     
     
         14 . The method of  claim 13 , wherein the passage is opened in response to an increase in upstream pressure of the fluid. 
     
     
         15 . The method of  claim 14 , wherein the passage is closed in response to a decrease in the upstream pressure of the fluid. 
     
     
         16 . The method of  claim 15 , wherein after the passage has been opened, the passage is reopened in response to an increase of upstream pressure only after a series of upstream pressure changes comprising an increase in the upstream pressure, and a subsequent decrease in the upstream pressure. 
     
     
         17 . The method of  claim 13 , further comprising reopening the passage. 
     
     
         18 . The method of  claim 13 , further comprising adjusting a value of the upstream pressure at which the passage is opened based at least partially on a pressure exterior to the system. 
     
     
         19 . The method of  claim 13 , wherein the hydraulic system comprises one of coiled tubing, jointed tubing, and drill pipe 
     
     
         20 . The method of  claim 13 , wherein fluid is directed toward the downstream component of the system, which comprises one of a tractor, a nozzle sub, an anti-stall tool, a logging tool, a perforation gun, a sand washing tool, a measurement-while-drilling tool, a logging-while-drilling tool, a downhole motor, a drill bit, a milling bit, a steering assembly, and a special actuation tool. 
     
     
         21 . A downhole assembly, comprising:
 a coiled tubing drill string;   a circulation assembly comprising an upstream connector, a downstream connector, a first passage between the upstream connector and the downstream connector, a second passage between the upstream connector and an exterior of the system, a valve communicating with the second passage, an index mechanism configured to operate in cooperation with the valve; and   at least one of a tractor and a bottom hole assembly.   
     
     
         22 . The downhole assembly of  claim 21 , wherein the circulation assembly further comprises a flow divider at an intersection of the first passage and the second passage. 
     
     
         23 . The downhole assembly of  claim 21 , wherein the circulation assembly further comprises a pressure compensated chamber configured to apply pressure to the valve in opposition to pressure asserted on the valve by fluid within the second passage. 
     
     
         24 . The downhole assembly of  claim 23 , wherein the index mechanism is positioned between the valve and the pressure compensated chamber. 
     
     
         25 . The downhole assembly of  claim 21 , wherein the bottom hole assembly comprises at least one of a nozzle sub, a logging tool, a perforation gun, a sand washing tool, a drilling tool, a motor, a drill bit, and a milling bit. 
     
     
         26 . The downhole assembly of  claim 21 , comprising a tractor, the tractor being directly connected to the circulation assembly. 
     
     
         27 . The downhole assembly of  claim 21 , comprising a tractor, the tractor being spaced from the circulation assembly.