Downhole pressure fluctuating tool

摘要

A downhole pressure fluctuating tool having an improved acoustical circuit using a fluid oscillator to generate out-of-phase pressure fluctuations in two output legs, one connected to an acoustical compliance inside the tool and the other connected to an acoustical compliance exterior of the tool in a cavity partially formed by the wall of the well. An acoustical inertance with a pressure node at its midregion connects the two acoustical compliances, and said midregion communicates with the annulus between the body of the tool and the wall of the well to discharge fluid from the body at the pressure node to minimize acoustical losses in the annulus.