Patent ID: 7814993
Filing Date: 2010-10-19
Classification: E21B

Abstract:
1. A generator for positioning downhole in a drill string to generate rotary power for powering one or more downhole tools, comprising: a generally tubular housing for positioning within the drill string and including one or more ports extending radially through the housing; a rotary shaft positioned at least partially within the housing; a progressive cavity housing having its bore in fluid communication with the one or more ports, a radial spacing between the drill string and an exterior surface of the progressive cavity housing defining a flow annulus; a progressive cavity rotor within the progressive cavity housing, the progressive cavity rotor rotating in response to fluid passing through the progressive cavity housing to rotate the rotary shaft; and a restriction in the annulus downstream from the one or more ports for controlling the fluid flow in the flow annulus and past the restriction, and thereby the fluid flow through the progressive cavity housing.