Shut-in tools

摘要

A downhole shut-in tool includes in one aspect a pilot valve which when opened places a differential pressure across a piston which in turn operably engages a shut-in valve element to close the shut-in tool. An electronic timer assembly and electric drive motor are provided for controlling the action of the pilot valve. The drive motor is controlled by a load sensor which senses that the motor has stalled when an actuator engages a movement limiting abutment. In another aspect a pilot valve is provided which can selectively communicate the pressure differential across the piston so as to repeatedly open and close the shut-in valve element. Efficient methods of drawdown and buildup testing using such an automated multiple operating shut-in tool are provided. Associated automated sampling tools are also disclosed.