Downhole assemblies and methods for isolating a wellbore. A downhole tool can include a body having a bore or flowpath formed therethrough, and one or more sealing members disposed therein. The one or more sealing members can include an annular base and a curved surface having an upper face and a lower face, wherein one or more first radii define the upper face, and one or more second radii define the lower face, and wherein, at any point on the curved surface, the first radius is greater than the second radius. The sealing members can be disposed within the bore of the tool using one or more annular sealing devices disposed about the one or more sealing members.

A piston initiator is used on an assembly having a milling tool and a whipstock for creating a sidetrack in a wellbore. A piston disposed in an uphole position in a bore of the milling tool seals the bore from communicating with the port. A line from the port can communicate pressure to components on the whipstock for initiating their activation. The piston is movable from the uphole position, but is held by a releasable connection configured to release the piston in response to a predetermined force from fluid flow in a downhole direction against an exposed surface area of the piston. An uphole shoulder in the milling tool prevents movement of the piston in an uphole direction so the piston does not stress the releasable connection in response to reverse fluid flow through the milling tool.

A device can include a collar positioned in a wellbore that can include an outer wall. The outer wall can define an inner area of the collar and can prevent fluid flow between the inner area of the collar and an outer area of the collar during a hydraulic fracturing process. The collar can be removed or dissolved to form a flow path to allow production fluid to flow between the inner area of the collar and the outer area of the collar subsequent to the hydraulic fracturing process.

Provided are cement plugging apparatuses and methods of use. An example cement plugging apparatus comprises a detachable plug fundament assembly comprising: a throughbore, a first plurality of wiper elements, and a second plurality of wiper elements. The examples cement plugging apparatus further comprises a cement diverting assembly coupled to the plug fundament assembly, wherein the cement diverting assembly comprises: a plurality of hoses, a body, a throughbore in the body, and a plurality of flow paths extending through the body and having openings for each individual flow path in the throughbore; wherein each individual hose in the plurality is coupled to an individual flow path in the plurality; and wherein each individual hose in the plurality extends away from the body of the cement diverting assembly.

A non-explosive downhole tool for creating openings in tubulars and or earthen formations includes a carrier holding a non-explosive material, such as thermate, a head connected with the carrier and having a port to eject a product of the ignited material from the head and a communication path extending from the material to the port and a moveable member in a closed position blocking the communication path and in an open position opening the communication path.

Example of the present disclosure relate to a frac plug. More specifically, embodiments are directed towards a frac plug with a flapper, wherein the flapper is configured to set and unset based on a pressure differential and/or fluid flow associated with the frac plug.

A method of activating an anchor with an anchor activation system including a housing having an outer surface and an inner surface defining an internal chamber includes introducing a first activation force to a trigger comprising a piston arranged in a piston cylinder extending radially through the outer surface to the internal chamber, sensing that the first activation force did not activate the anchor, and introducing a second activation force to the trigger without reconfiguring the anchor activation system to break a shear element retaining the piston with the first activation to release the piston and activate the anchor

A downhole apparatus comprises a casing string with a degradable plug therein to block flow therethrough. A flow barrier is positioned in the casing below the degradable plug and the degradable plug and the flow barrier defining a buoyancy chamber therebetween. An annular fluid reservoir holds a degrading fluid. The fluid reservoir has first and second rupture disks at upper and lower ends. Fluid from the annular fluid reservoir is communicated to the degradable plug after the first and second rupture disks rupture.

A system and method for injecting bailer content utilizing a dump bailer having an elongated, flexible bailer receptacle secured between a head assembly and an injection assembly. Disposed within the dump bailer are first and second piston assemblies, each of which includes a piston having a central fluid passage with a pressure actuated flow control mechanism in the form of a rupture disk disposed along the fluid passage of the piston. An electric, positive displacement pump within the head assembly draws wellbore fluid into the dump bailer assembly to drive the first piston assembly towards the second piston assembly so as to release bailer content into a wellbore. The elongated flexible bailer receptacle may be a hose stored on a bailer receptacle reel, which hose may be paid out by the reel to a length that corresponds with a volume of bailer content to be released into the wellbore.

A well barrier can include an inner mandrel, a flow passage, and a releasably secured plug. The plug blocks fluid flow through the flow passage, and includes a shoulder that prevents the plug from displacing completely through the inner mandrel. A method of treating a subterranean well can include treating a deeper zone, setting a well barrier in the well between the deeper zone and a shallower zone, then treating the shallower zone, and then applying a pressure differential from the deeper to the shallower zone, thereby displacing a plug out of the well barrier. A well treatment system can include a well barrier with a plug releasably secured to an inner mandrel. The plug is released by application of a pressure differential in a longitudinal direction, and fluid communication is unblocked by application of a pressure differential in an opposite longitudinal direction.