A method and an apparatus for oil production by increasing resistance of borehole wall for improving an energy utilization rate of injection gas includes injecting gas into an oil reservoir so that a gas pressure in the oil reservoir reaches an initial oil reservoir pressure. The initial oil seepage pressure is present at a position where the inside of the production well is in communication with the oil reservoir. The initial oil seepage pressure is less than the initial oil reservoir pressure. The method also includes monitoring gas production and oil production of the production well and increasing the initial oil seepage pressure to an increased oil seepage pressure when a ratio of the gas production to the oil production is higher than a predetermined ratio. The increased oil seepage pressure is smaller than the initial oil reservoir pressure.

A barrier plug assembly for sealing a subterranean wellbore arranged inside a tubing, the barrier plug assembly comprising: at least one frangible barrier element stacked on a carrier ring; a locking sleeve arranged above the carrier ring and located in a closed fluid chamber; a valve arranged on the closed fluid chamber and in pressure communication with the tubing, the valve configured or allowing or preventing pressure communication in between the tubing and the fluid chamber; a retaining device configured for locking the a carrier ring in place; a crushing element arranged a distance below the one frangible barrier element and configured for crushing the at least one frangible barrier element.

A well construction method, and corresponding apparatus, in which a drilled bore (106) is lined with a plurality of successively smaller diameter sections of bore-lining tubing includes at least one casing (108, 110, 112) and at least one liner (120). The well construction method comprises: drilling a final section of a bore (106) to intersect a hydrocarbon-bearing formation (130); providing a shoe (134) at a distal end of a liner and a running tool (150) at a proximal end of the liner, and coupling an inner string (140) between the shoe (134) and the miming tool (150); running the liner (120) into the final section of the bore (106) such that the liner extends into the hydrocarbon-bearing formation (130); pumping a settable material (116) from surface (104), through the inner string (140), and through the shoe (134) to at least partially fill an outer annulus (114) surrounding the liner (120); and retrieving the inner string (140) and the running tool (150).

A fluid control system includes a fluid control device configured to be connected to at least one of two casing elements in a well, for controlling a fluid flow between a bore of the fluid control device and a zone located outside the casing elements; and a tracer material located within an inner chamber of a body of the fluid control device, the tracer material being uniquely associated with the fluid control device. The fluid control device is configured to release, when activated, the tracer material out of the inner chamber.

A downhole secondary flow path member includes a tubular having a first end portion, a second end portion, and an intermediate portion having a flow passage extending therebetween. The tubular includes a first opening arranged adjacent the first end portion and a second opening arranged adjacent the second end portion. A valve assembly is provided on the tubular at the first opening. The valve assembly includes a valve member. A flow tube runs along at least a portion of the tubular. The flow tube has a dissolvable end section mechanically linked to the valve assembly. The dissolvable end segment selectively shields the valve member from exposure to downhole fluids. The valve member changes from an open position to a closed position following dissolution of the dissolvable end segment.

A bridge plug for use in a wellbore having an anchoring system to grip the inner surface of the surrounding wellbore, as well as a sealing system or packing element to seal against the inner surface. A hinged flapper permits flow of fluid in one axial direction through a central through bore, but can selectively contact against a seat to create a fluid pressure seal and prevent fluid flow through said central through bore in an opposite axial direction. The flapper can be manufactured of frangible material and/or dissolvable material, permitting selective removal of the flapper when desired.

A port assembly for controlling fluid flow through a flow port of a port sub. The port assembly comprises a dissolvable barrier, a burst disk for protecting the dissolvable barrier from fluids inside the port sub, and optionally a protective layer for protecting the dissolvable barrier from external fluids. When the burst disk is ruptured by increased fluid pressure inside the port sub, the dissolvable barrier starts disintegrating from exposure to the fluid. When the dissolvable barrier and protective layer are broken through, a flow passage is opened in the port assembly to permit fluid flow therethrough. The flow passage may be positioned tangentially in the port sub. The breakthrough time of the dissolvable barrier may be preconfigured by providing one or more thinner areas therein and/or placing a corrosive material in the port assembly.

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.

A system for deploying an untethered dissolvable frac package for use in a hydraulic fracturing operation includes a dissolvable or degradable frac package with a dissolvable or degradable setting tool. The setting tool of the dissolvable frac package is configured to deploy a dissolvable frac plug at a predetermined position along the wellbore string and dissolve over time in the wellbore.

A ported sub is operated with a pressure actuated shifting sleeve. A first rupture disc is set at a lower pressure than the test pressure for the tubing string that houses the ported sub. The first rupture disc breaks at a lower pressure than the string test pressure to expose well fluids to a disintegrating plug. The plug slowly disintegrates to then expose tubing pressure to a chamber and a second rupture disc with the chamber configured to have no effect on moving the sliding sleeve. When the tubing pressure is then raised to a predetermined pressure below the test pressure for the string, the second disc breaks exposing a piston to tubing pressure on one side and trapped low pressure being the opposite side of the string. The differential moves the sleeve to open a port to let tools be pumped into position without a need to perforate.