The invention relates to a single-throttling-channel
pressure control drilling method and a single-throttling-channel
pressure control drilling device suitable for high-flow change, and is applied to the field of well tube pressure and flow control during
petroleum and
natural gas drilling. The device consists of a vertical
pipe measurement
system, a
back pressure compensation manifold and flow measurement
system, a connection manifold, an automatic throttling manifold, a
wellhead return flow measurement
system and a
signal acquisition and
logic control system. The device can precisely measure the pressure at the bottom of a well, the vertical pressure at a
wellhead, the sleeving pressure and pump-in and returning flow of
drilling fluid; furthermore, due to the analysis of the
logic control system, a working condition of the bottom of the well is judged, and a closed-
loop control or block experience mode is selected according to the working condition, so that the
back pressure applied by the throttling manifold to the
wellhead is automatically adjusted in real time, and perfect well shaft
pressure control is implemented; therefore the complicated underground problems of a narrow density window, spraying and leakage coexistence and the like are effectively solved.