| 摘要 |
<p>A control apparatus for a downhole tool comprises a sensor (84), eg. pressure sensor, for sensing a command signal; interpreting means (86), eg. a microprocessor, for interpreting the sensed signal; an electric motor (78) responsive to the interpreting means (86), and a battery (88) for supplying electric current to the interpreting means and to the electric motor. Command signals can be provided by well annulus pressure variations to operate the control apparatus. <IMAGE></p> |
