An autonomous flow control device with pilot amplification includes a primary valve responsive to changes in fluid composition, and a pilot valve responsive to and more sensitive to changes in fluid composition than the primary valve and configured to aid change in position of the primary valve in the event of a change in fluid composition

A running tool sets and cements a liner in a borehole. While the tool’s bypass section is closed, a plug deployed to the tool diverts hydraulic pressure to set a liner hanger in the borehole. The setting plug is unseated, and the bypass section is switched opened by deploying another plug to an opening seat and shifting a control sleeve open relative to a bypass port. While the tool’s packoff remains sealed in the hanger, cement pumped out the bypass port is bullheaded into a lap of the liner and borehole. When cementing is complete, the bypass section is switched closed by deploying another plug to a closing seat and shifting the control sleeve closed relative to the bypass port. The bypass section is then placed in a flow-through condition where fluid communication is reestablished through the tool to the liner by allowing fluid to flow past the plugs in the tool.

A downhole motor includes a driveshaft assembly including a driveshaft housing and a driveshaft rotatably disposed within the driveshaft housing, and a bearing assembly including a bearing housing and a bearing mandrel rotatably disposed within the bearing housing, wherein the bearing mandrel is configured to couple with a drill bit, wherein the bearing assembly is configured to provide a first flowpath extending into a central passage of the bearing mandrel from an annulus formed between the bearing mandrel and the bearing housing and a second flowpath separate from the first flowpath, that extends through a bearing of the bearing assembly that is disposed radially between the bearing mandrel and the bearing housing, wherein a plurality of rotary seals are positioned radially between the bearing mandrel and the bearing housing to form an sealed chamber that is spaced from the bearing of the bearing assembly.

A cementing tool and a method for cementing a casing string using the cementing tool is provided. The cementing tool comprises threaded top and bottom openings for attaching to a casing string, a plurality of ports, and a plurality of shear plugs shaped to fit within the ports. In the method, a casing string comprising the cementing tool is run into a well and the cementing process of the casing string is initiated. When the casing shoe of the casing string becomes plugged, the cementing tool is activated without removing the casing string from the well. Activation of the cementing tool releases pressure trapped in the cementing tool, thereby releasing the shear plugs from the ports and opening the ports to create alternative passages for the cement to complete the cementing process.

A system and method for stall recovery of mud motors may be implemented in a steering control system. The stall recovery system and method may involve automatic detection of a stall of a mud motor during drilling controlled by the steering control system, and may respond to the stall in a rapid and controlled manner to avoid or minimize damage to the mud motor, such as by immediately reducing mud pressure and stopping rotary drilling, if used, faster than a typical human operator could perform. The stall recovery system and method may farther take actions to automatically restart drilling.

A body defines a central flow passage. A check valve is located within the central flow passage. The check valve is supported by the body. The check valve is arranged such that a fluid flow travels in a downhole direction during operation of the float collar. An auxiliary flow passage is substantially parallel to the central flow passage and is defined by the body. The auxiliary flow passage includes an inlet upstream of the check valve and an outlet at a downhole end of the float collar. A rupture disk seals the inlet of the auxiliary flow passage. The rupture disk is configured to burst at a specified pressure differential.

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 bypass 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 downhole tool includes a bore isolation valve, a sensor configured to receive to a downlink signal, an annular pressure sensor, a valve actuation mechanism coupled to the bore isolation valve and responsive to the downlink signal, a pressure relief mechanism configured to provide a negative pressure pulse signal indicative of the annular pressure by venting fluid from a bore of the tool body, and a battery. A method includes drilling a well with a drill bit coupled to an on demand annular pressure tool initially in a deactivated mode, and activating the tool by a downlink signal when fluid flow out of the annulus drops below the fluid flow into the well to close a bore of the tool, pressurizing the drill string, holding pressure in the drill string, measuring annular pressure with the tool, and sending a negative pressure pulse signal indicative of the annular pressure.

Fluid flow control devices and methods to reduce overspeed of a fluid flow control device are presented. A fluid flow control device includes a port and a rotatable component that rotates about an axis in response to fluid flow from the port. The fluid flow control device also includes a mechanical component disposed on the rotatable component and configured to reduce rotational speed of the rotatable component.

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.