IMPROVED ANNULUS PRESSURE OPERATED WELL TESTING APPARATUS AND ITS METHOD OF OPERATION

摘要

A full opening, annulus pressure responsive, formation testing method and apparatus wherein both valve closing and valve opening biasing forces are generated in response to annulus pressure and wherein a full opening, formation fluid flow passage is provided by the testing valve. A disabling mechanism may be employed which would be operable, in response to removal of the apparatus from a well bore, to vitiate an annulus pressure generated biasing force tending to urge the testing valve to a closed condition.