| 摘要 |
<p>A control system and method utilizing a race between two responses to a changing stimulus are disclosed. An example of a changing stimulus is pressure which increases at a decreasing rate of change during a closed-in period of a drill stem test in an oil or gas well. In a preferred embodiment two components are moved in different directions, but in a net first direction, until the rate of change of the pressure is sufficiently low (e.g., near steady state), at which time the rates of movement of the two components produce net movement in a second direction. In a preferred embodiment, the change in direction of the net movement moves a control valve which communicates a pressure control signal for opening a bypass valve to commence a flow period of the drill stem test.</p> |
