| 主权项 |
1. A downhole disconnect device for disconnecting an intervention tool string from a wireline, said device comprising:
a tubular body having a first part directly or indirectly coupleable to the wireline and a second part connectable directly or indirectly to an intervention tool string; an actuator for disconnecting the second part of the tubular body from the first part of the tubular body; at least one sensor to detect when the tool string is stuck in use and to produce an output signal accordingly; a controller configured to receive the output signal and selectively operate the actuator accordingly; and a power source; wherein the tubular body is adapted to house the actuator, sensor, controller and power source and wherein the device further comprises a timer configured to delay operation of the actuator by a predetermined time on receipt of the output signal from the sensor, wherein the first part comprises a first tubular body and the second part comprises a second tubular body wherein the first tubular body is releasably connected to the second tubular body where, in use in a vertical wellbore, the second tubular body is disposed below the first tubular body, and at least the actuator, power source, sensor and controller are housed in the first tubular body and a disconnect mechanism is at least partially housed in the second tubular body, wherein the actuator is a motor which rotatably drives a drive shaft engageable with the disconnect mechanism, wherein the disconnect mechanism comprises an axially disposed elongate member having a first end engageable with the drive shaft and a second end, wherein the elongate member is slidably mounted in at least the second tubular body to move in an axial direction and the elongate member is prevented from rotating by a constraint while being allowed to move axially, wherein the first end of the elongate member comprises a threaded bore corresponding to a screw thread on the drive shaft thereby to cause the elongate member to move in an axial direction on rotation of the drive shaft by the motor, wherein the elongate member is further supported by the first tubular body when the first and second tubular bodies are connected, wherein the disconnect mechanism comprises at least one locking member to lock the first and second tubular bodies together during normal operating conditions and a locking sleeve slideably and axially arranged inside the second tubular body and having a throughbore to slideably receive the second end of the elongate member, wherein a first end of the locking sleeve is adapted to receive a portion of the second end of the first tubular body when the first and second tubular bodies are connected, and wherein the at least one locking member is arranged between the second end portion of the first tubular body and the first end of the locking sleeve, wherein the at least one locking member slideably engages with an inner surface of the locking sleeve while being lockably engagable with the first tubular body, wherein the locking sleeve is coupled to the elongate member thereby to move axially therewith when driven by the motor, wherein the disconnect mechanism is adapted to axially move the locking sleeve a limited distance corresponding to a space required for the at least one locking member to move laterally outwardly into the space while providing a limit to the at least one locking member in the axial direction, and wherein a first end of the locking sleeve provides the axial limit when the locking members are in an outwardly unlocked position. |
