초록 ▼

In accordance with illustrative embodiments disclosed herein, a formation testing tool suspended in a well on a pipe string includes a valve actuator control system which responds to a command signal having a certain signature. The command signal is applied at the surface to the well annulus, and in

In accordance with illustrative embodiments disclosed herein, a formation testing tool suspended in a well on a pipe string includes a valve actuator control system which responds to a command signal having a certain signature. The command signal is applied at the surface to the well annulus, and includes a series of two or more low level pressure pulses which are detected at the downhole tool, each pressure pulse having, for example, a certain peak value which lasts for a certain time. On detection of the command signal, a control system within the testing tool permits selective application of hydrostatic pressure which forces the valve actuator to shift from one position to another, thereby to open or close an associated valve element.

대표청구항 ▼

Apparatus for use in operating a downhole well tool that includes a pressure responsive member which is adapted to be shifted from one position to another position comprising: a pressure responsive surface on said member; and means for supplying a working medium to said surface at a pressure substan

Apparatus for use in operating a downhole well tool that includes a pressure responsive member which is adapted to be shifted from one position to another position comprising: a pressure responsive surface on said member; and means for supplying a working medium to said surface at a pressure substantially equal to the hydrostatic pressure of well fluid to shift said member from said one position to said other position in response to a comand signal applied to said well fluid, said command signal including at least one low level pressure pulse having a predetermined signature. A method of controlling the operation of a downhole well tool having a pressure responsive member which is adapted to be shifted from one position to another position, said member having pressure responsive surface means, comprising the steps of: applying a command signal to fluids in the well, said command signal including at least one low level pressure pulse having a predetermined signature; detecting said command signal at said well tool; and supplying a working medium at a pressure substantially equal to hydrostatic pressure to said pressure responsive surface means in response to detection of said command signal to shift said pressure responsive member from said one position to said other position.