A rotary steerable tool for steering a drill string may include a tool collar extending along a longitudinal axis of the tool, a pad pusher, a pad retention housing, and a piston liner. The pad pusher may be rotatable about a pivot axis thereof between retracted and extended positions relative to the tool collar, for steering the drill string. The piston liner may be coupled to the pad retention housing and have a piston channel that defines a curved profile. The piston liner may provide sealing contact against a perimeter of the piston upon pivoting of the pad pusher through the piston channel along the curved profile, relative to the piston liner.

This disclosure presents a downhole device configured as a selectable hole trimmer. The selectable hole trimmer comprises an upper sleeve affixed inside a body via a stop. A charge sleeve is slidable inside the upper sleeve to provide a pressure to a pressurized volume. A catch sleeve is slidable inside the charge sleeve to align a bypsss port and a return port with a drilling mud volume. An actuator is fluidly connected to the pressurized volume via a port. The actuator is configured to provide a pressure to a selectable hole cutter of the body via an actuation port in the transfer sleeve and actuate the selectable hole cutter piston of the selectable hole cutter to move relative to the body, wherein the cutter piston comprises one or more cutters. A manual controller configured to operate the actuator in response to a dropped activation ball.

A rotary steerable tool for steering a drill string can include a tool collar, a plurality of pad pushers, and a plurality of fasteners. The pad pushers can each be positionable within a respective cavity of the tool collar. Each pad pusher can be coupled to a pad retention housing that has an engagement hole and a through hole spaced apart from the engagement hole. The pad pushers can be interconnected by a plurality of fasteners. Each fastener can extend between adjacent pad retention housings to interconnect the plurality of pad pushers around the tool collar.

A flow rate control system includes a housing and a valve assembly slidingly disposed within a housing inner bore. The housing includes bypass openings. The valve assembly includes a valve and an orifice disposed in a valve inner bore. The valve includes a plurality of valve bypass bores extending axially through a valve collar. The valve assembly slides between closed and fully open positions. A spring biases the valve assembly toward the closed position in which the valve closes the housing bypass openings. In the open position, a bypass fluid path is formed including the valve bypass bores and the housing bypass openings. The valve assembly is flow rate controlled in the closed position and pressure controlled in the open position. The valve assembly may slide within a sleeve assembly including sleeve bypass openings, which connect the valve bypass bores and housing bypass openings in the bypass fluid path.

A drilling system for forming a wellbore includes a drill string, a drill bit, and a circulation sub in the drill string. Manipulating the circulation sub forms a passage through a sidewall of the drill string; which diverts some of the drilling fluid flowing inside the drill string into the wellbore. Diverting some of the drilling fluid through the passage reduces the amount of drilling fluid flowing in the wellbore between the drill bit and circulation sub, and which optimizes equivalent circulating density of the drilling fluid. Included in an embodiment of the circulation sub is a cylinder that is indexed into set positions by engagement with a J-slot profile in a housing of the circulation sub. A sleeve in the sub is responsive to cylinder positions, and has a port that registers with a slot in the sub walls to form the passage.

A mud loss treatment drilling tool includes the tool having an upper tooljoint to a lower end of an above drill pipe string, one or more tanks with a through channel for a drilling fluid flow, a lower tooljoint connected to a BHA assembly at least comprising a drill bit; the tank arranged for holding a swellable sealant agent; the swellable sealant agent arranged for mixing with water to swell; the tank provided with an outlet to the through channel for the swellable sealant agent, so as for, when an undesired mud loss is detected, for flushing all or part of the swellable sealant agent into the through channel, so as for a mixture of the swellable agent and the water to start reacting to swell during the time it takes the mixture to reach a fracture extending from a well under drilling by said BHA, so as for continuing to swell and block the fracture to stop the undesired mud loss.

A system for producing fluids from a wellbore extending from a well surface to a fluid-producing formation has a Y-tool installed in fluid communication with the tubing string placed in the wellbore. A pump, which may be an electric submersible pump (ESP), is installed in the Y-tool for lifting fluids from the formation to the surface. A blanking plug is positioned in the tubing string between the upper and lower connections of the Y-tool. A flushing tank is run downhole to a position just above the blanking plug. Flushing fluid is dumped from an orifice or nozzle on the lower end of the flushing tank to agitate and disperse any accumulated sand, scale and other particulate matter on top of the blanking plug.

A tieback assembly for insertion into a wellbore may include a tieback stem seal, a check valve, and a circulating sub. The tieback stem seal may be engaged into a tieback receptacle of a liner in the wellbore and may isolate an annular space of the wellbore. The circulating sub may pass kill fluid from the tieback assembly into the annular space of the wellbore. The check valve may control a flow of fluid. A method of isolating an annular space of a wellbore may include inserting a tieback assembly into the wellbore, engaging the tieback stem seal of the tieback assembly at a tieback receptacle of a liner in the wellbore, passing a kill fluid into the annular space of the wellbore, and displacing an annulus fluid in the annular space of the wellbore with the kill fluid to isolate the annular space of the wellbore.

A surge flow mitigation tool can include a surge flow valve that permits one-way fluid flow through a flow passage, and a bypass flow path that opens when a differential pressure across the surge flow valve is greater than a predetermined level. A method of mitigating surge flow in a well can include producing fluid through a tubular string with a bottom hole assembly including a surge flow mitigation tool connected downhole of a packer, the surge flow mitigation tool including a surge flow valve that permits the fluid to flow toward surface via the tubular string, but prevents the fluid from flowing into the well via the tubular string, and increasing a differential pressure across the surge flow valve to greater than a predetermined level, thereby opening a bypass flow path that permits injection flow from the tubular string into the well downhole of the packer.

A method can include directing fluid flow longitudinally through a well tool connected in a tubular string downstream of a longitudinally compressed circulating valve assembly, thereby causing the well tool to operate, and longitudinally elongating the circulating valve assembly while the fluid flow is ceased, and then increasing the fluid flow, thereby causing the fluid flow after the elongating to pass outwardly through a housing of the circulating valve assembly to an external annulus. Another method can include directing a fluid flow through a well tool connected in a tubular string downstream of a circulating valve assembly, thereby causing the well tool to operate, and decreasing then increasing a flow rate of the fluid flow, thereby causing the fluid flow to pass outwardly through a housing assembly of the circulating valve assembly to an external annulus. Circulating valve assemblies are also disclosed.