Abstract: A device for wellbore operations is configured to self-determine its downhole location in a wellbore in real-time and to self-activate upon arrival at a preselected target location. The device determines its downhole location based on magnetic field and/or magnetic flux signals provided by an onboard three-axis magnetometer. The device optionally comprises one or more magnets. The magnetometer detects changes in magnetic field and/or magnetic flux caused by the device's proximity to or passage through various features in the wellbore. The device can self-activate to deploy an engagement mechanism to engage a target tool downhole from the target location. The engagement mechanism comprises a seal supported by two expandable support rings, each having a respective elliptical face for engagement with the elliptical face of the other support ring.

Abstract: A dart for effecting wellbore operations has an inactivated position and an activated position wherein the exterior profile of the dart is changed when the dart is activated. The change in profile may be achieved by moving (for example, rotating) a portion of the dart relative to the remaining portion. When inactivated, the exterior profile allows the dart to pass freely through a valve. When activated, the dart cannot pass through the valve because the changed exterior profile is caught by the interior profile of the valve. Once caught, the dart creates a seal to open the valve when fluid pressure above the seal is increased. The dart can thus be used in multiple stage applications with valves having seats of the same size so that the dart can be selectively activated to engage a desired valve seat.

Abstract: 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.