A releasable connection for coiled tubing drilling apparatus is presented wherein the connection has an outer body configured with an inner volume, a mandrel located at least partially within the outer body and in the inner volume, a plug located with the outer body and a structural weakpoint apparatus, wherein the structural weakpoint apparatus is configured to structurally fail at a predetermined tensile load placed upon the releasable connection apparatus, wherein the structural weakpoint apparatus is configured at a lower end of the mandrel.

A releasable connection for coiled tubing drilling apparatus is presented wherein the connection has an outer body configured with an inner volume, a mandrel located at least partially within the outer body and in the inner volume, a plug located with the outer body and a structural weakpoint apparatus, wherein the structural weakpoint apparatus is configured to structurally fail at a predetermined tensile load placed upon the releasable connection apparatus, wherein the structural weakpoint apparatus is configured at a lower end of the mandrel.

Certain aspects and features of the present invention are directed to a safety joint that can be disposed in a wellbore through a fluid-producing formation. The safety joint can include a body configured to be disposed in the wellbore, a primary retention mechanism, a secondary retention mechanism, and a time delay mechanism. The primary retention mechanism can be coupled to the body and can prevent the actuation of the safety joint. The secondary retention mechanism can be coupled to the body and can prevent the actuation of the safety joint in response to the primary retention mechanism allowing the actuation of the safety joint. The time delay mechanism can generate a time delay between the primary retention mechanism allowing the actuation of the safety joint and the secondary retention mechanism preventing the actuation of the safety joint.

Certain aspects and features of the present invention are directed to a safety joint that can be disposed in a wellbore through a fluid-producing formation. The safety joint can include a body configured to be disposed in the wellbore, a primary retention mechanism, a secondary retention mechanism, and a time delay mechanism. The primary retention mechanism can be coupled to the body and can prevent the actuation of the safety joint. The secondary retention mechanism can be coupled to the body and can prevent the actuation of the safety joint in response to the primary retention mechanism allowing the actuation of the safety joint. The time delay mechanism can generate a time delay between the primary retention mechanism allowing the actuation of the safety joint and the secondary retention mechanism preventing the actuation of the safety joint.

An apparatus that includes a material that holds a release section in an engaged position. The apparatus also includes a heat source to change the phase of the material, allowing the release section to move to a disengaged position.

Downhole rotary steerable drill including a drilling shaft rotatably supported within a housing, the drilling shaft and housing each having a longitudinal axis. The drill can include a releasable locking mechanism for rotationally locking and releasing the drilling shaft relative to the housing, the releasable locking mechanism transitionable between locked and released configurations. The releasable locking mechanism includes a sliding plunger coupled to the housing by a coupling that permits longitudinal reciprocation of the sliding plunger relative to the housing and prevents rotation of the sliding plunger relative to the housing. The releasable locking mechanism can also include pressure-responsive piston that reciprocates between an unactuated configuration and actuated configuration in response to applied pressure from a pressuring pump.

Downhole rotary steerable drill including a drilling shaft rotatably supported within a housing, the drilling shaft and housing each having a longitudinal axis. The drill can include a releasable locking mechanism for rotationally locking and releasing the drilling shaft relative to the housing, the releasable locking mechanism transitionable between locked and released configurations. The releasable locking mechanism includes a sliding plunger coupled to the housing by a coupling that permits longitudinal reciprocation of the sliding plunger relative to the housing and prevents rotation of the sliding plunger relative to the housing. The releasable locking mechanism can also include pressure-responsive piston that reciprocates between an unactuated configuration and actuated configuration in response to applied pressure from a pressuring pump.

A jar device is provided with a releasable locking mechanism which secures the telescopic portions of the jar device from relative movement until released. The locking mechanism is released by a tensional force which ruptures one or more frangible members.

A jar device is provided with a releasable locking mechanism which secures the telescopic portions of the jar device from relative movement until released. The locking mechanism is released by a tensional force which ruptures one or more frangible members.

A downhole tool has a release device for releasing a downhole device in a wellbore. The downhole tool has a collet with an inner surface and a collet shoulder; a release rod configured to engage the collet shoulder in a locked position and disengage from the collet shoulder in a release position; and a release tube surrounding the release rod and having a release ramp proximate a nose of the release tube.