Full-opening annulus pressure operated sampler valve with reverse circulation valve

An apparatus for use in testing an oil well having a testing string in a borehole providing an open flow path therethrough extending from the surface of the earth to a formation to be tested, comprising:

• a cylindrical housing adapted to be incorporated in said testing string having an open bore therethrough forming a part of said open flow path, and a power port through the wall thereof;
• a power mandrel in said open bore having an annular piston for moving said power mandrel in a first axial direction responsive to fluid pressure exterior of said cylindrical housing communicated to said annular piston through said power port;
• frangible restraining means between said power mandrel and said cylindrical housing for holding said power mandrel in a first position until the pressure exterior of said housing exceeds a predetermined value, and for frangibly releasing said power mandrel when said pressure exterior of said housing exceeds said predetermined value allowing said power mandrel to move in said first direction toward a second position;
• operating mandrel means in said open bore releasably connected to said power mandrel, and co-engaged with said cylindrical housing for forming an oil chamber between said housing and a portion of said operating mandrel means;
• disconnecting means between said power mandrel and said operating mandrel means for disconnecting said operating mandrel from said power mandrel when said power mandrel reaches said second position;
• dividing means between said operating mandrel means and said housing for dividing said oil chamber and including a flow passage therethrough for passing oil in said oil chamber from one side of said dividing means to the other side of said dividing means as said operating mandrel means moves in concert with said power mandrel while said power mandrel moves from said first position to said second position;
• metering means in said flow passage for hydraulically controlling the rate at which oil in said oil chamber moves from one side of said dividing means to the other side of said dividing means;
• and
• sampler valve means including two ball valve means in said open bore and operatively connected to said operating mandrel means for simultaneously moving from an open position providing a fully open flow path to a closed position responsive to movement of said operating mandrel means as said power mandrel moves from said first position to said second position, and for entrapping a sample of fluid in the open bore between said ball valves upon the closing of said ball valves.