Access valve for drill stem testing

摘要

An access valve for communicating a wire line pressure sensing probe with a subsurface formation of a well to conduct continuously monitored shut in pressure tests on said subsurface formation. The access valve includes a tubular body having a cylindrical inner surface. A first passage communicates the subsurface formation with the cylindrical inner surface of the tubular body. A sliding valve sleeve has a cylindrical outer surface slidably received in said cylindrical inner surface of said tubular body, and has a valve sleeve port disposed through a side wall thereof communicating said cylindrical outer surface of said sliding valve sleeve with a cylindrical inner surface of said sliding valve sleeve. The sliding valve sleeve is slidable between a closed position wherein the valve sleeve port is in fluid isolation from the first passage, and an open position wherein the valve sleeve port is in fluid communication with the first passage. A probe nose member has a cylindrical outer surface adapted for sliding insertion within said cylindrical inner surface of said sliding valve sleeve, and includes a chamber for receiving a sensing device and a second passage for communicating the chamber with the valve sleeve port when the probe nose member is fully inserted in the sliding valve sleeve. A bypass allows fluid from the subsurface formation to bypass the tubular body, valve sleeve and probe nose member so that formation pressure may be monitored during either shut in or open flow conditions.