Patent ID: 8069926
Filing Date: 2011-12-06
Classification: E21B,Y10T

Abstract:
1. A method of retaining a column of fluid in a tubular body, the method comprising: providing a fluid flow-responsive member comprising a sleeve having a normally closed valve at an end thereof axially moveable within the tubular body and having a nozzle therein acting across a cross-sectional area thereof, the normally closed valve scatable in a valve scat of the tubular body, the fluid flow-responsive member in a first configuration to only partially restrict passage of a working fluid through a central bore in the normally closed valve in a portion of the tubular body; increasing a first fluid pressure differential across a first area in the tubular body to create a first actuating force, the first actuating force moving said fluid flow-responsive member towards a second configuration; flowing fluid through the valve seat to maintain the valve open; and reducing the fluid flow rate to allow the valve to close and retain a column of fluid thereabove.