Downhole pressure pulse generator in tubing string housing

摘要

Pressure pulse generator used for communicating information between points a well bore through fluid flowing in a tubing string, comprises (a) a housing connected in the string so that fluid flowing in the string partially flows through the housing; (b) a fixed stator within the housing; (c) a rotatable rotor within the housing adjacent the stator, so arranged that both the rotor and stator have spaced lobes so providing a number of ports allowing fluid passage, the movement of the rotor with respect to the stator creating maximum and then minimum fluid passage-ways, and hence fluid flow through the housing will be interrupted to cause the generation and transmission up stream of a pressure pulse signal; and (d) means for establishing fluid dynamic forces in response to the flow of fluid through the housing that bias the rotor generally into an orientation in which the ports provide the greatest fluid passageway. The dynamic forces are developed from the fluid flow by providing each lobe of the rotor with sides outwardly tapered in the downstream direction and with underlap relative to the stator lobes. The taper on each side of the rotor lobes is preferably in the range of 8-30 degrees with respect to the vertical axis.