Weight and pressure operated well testing apparatus and its method of operation

An apparatus, for use in conjunction with a testing string having a central flow passage therethrough and located in a fluid filled bore of an oil well extending from the earth's surface to an underground formation, comprising:

• a packer, at the lower end of said testing string, for operably selectively isolating the underground formation from that portion of the well bore above said packer, and for supporting a portion of the weight of the testing string after said packer is operated to isolate the underground formation;
• weight responsive valve means, located in the testing string and having a normally closed position and an open position, for controlling fluid communication with the underground formation through the central flow passage of the testing string;
• delay means, within said weight responsive valve means, for delaying the movement of said valve means from its normally closed position to its open position for a predetermined period after a portion of the weight of the testing string is supported by said packer;
• weight and pressure responsive valve means, having a normally opened position and a closed position, a sealed annular chamber in the wall thereof, and located in the testing string adjacent said weight responsive valve means, for controlling fluid communication with the underground formation through the central flow passage of the testing string when said weight responsive valve means is in its open position;
• a cylindrical mandrel in said weight and pressure responsive valve means, movable in one direction responsive to weight in the drill string, and movable in a second opposite direction responsive to pressure increases in the fluid in the well bore, wherein movement of said mandrel in the first direction opens said weight and pressure responsive valve means and increases the volume of said sealed chamber, and wherein movement of said mandrel in the second direction closes said weight and pressure responsive valves means and decreases the volume of said sealed chamber;
• a length of intermediate conduit means, in said drill string above said weight and pressure responsive valve means and connected to said cylindrical mandrel, for adding weight to the testing string sufficient to open said weight responsive valve means, and to move said cylindrical mandrel in said first direction;
• and,
• slip joint means, in said drill string above said intermediate conduit means, for providing telescopic movement in the testing string, thereby allowing said cylindrical mandrel to move in the second direction responsive to pressure increases in the well bore, and allowing said cylindrical mandrel to move in the first direction responsive to the weight of said intermediate conduit means when said annulus pressure increases are removed.

A valve operating mechanism for use in a testing string having a flow channel therethrough, and operable to test an underground formation intersected by a fluid filled well bore, comprising:

• slip joint means in said testing string, for isolating movement in the testing string below said slip joint means from the testing string above said slip joint means;
• a tubular housing in said testing string spaced apart from and below said slip joint means, said tubular housing including pressure containing means for isolating a pressure contained therein from said testing string flow channel and for providing a pressure differential between said contained pressure and fluid pressure in the well bore when said testing string is positioned in said well bore;
• and
• operating mandrel means slidably located within said housing, and connected to that portion of the testing string between said slip joint means and said tubular housing, said operating mandrel means having means responsive to said pressure differential and including a central bore therethrough communicating with said testing string flow channel, and being operable for moving in a first direction responsive to the weight of the testing string portion between said slip joint means and said tubular housing, and operable for moving in a second opposite direction responsive to fluid pressure increases in the well bore wherein said pressure increases cause increases in said pressure differential sufficient to overcome said weight thereby moving said operating mandrel means in said second direction.

In a testing string having a central flow passage therethrough and located in a fluid filled bore of an oil well extending from the earth's surface to an underground formation, a valving apparatus comprising:

• tubular housing means, including pressure containing means for isolating a pressure contained therein from said testing string flow channel and for providing a pressure differential between said contained pressure and fluid pressure in the well bore, and having a central bore therethrough for communicating at one end thereof with the flow passage of that portion of the testing string below said tubular housing;
• tubular operating mandrel means located within said housing means central bore, including means responsive to said pressure differential and having a central bore therethrough for communicating at one end thereof with the flow passage of that portion of said testing string above said operating mandrel and communicating at the other end thereof with the central bore of said tubular housing means to thereby form a continuous flow channel through said tubular housing means and said tubular mandrel means, for moving in a first direction responsive to weight in the testing string, and in a second opposite direction responsive to fluid pressure increases in the well bore wherein said pressure increases causes increases in said pressure differential sufficient to overcome said weight thereby moving said operating mandrel means in said second direction;
• and, valve means located in the central bore of said housing means and operably connected to said operating mandrel means, for closing said continuous flow channel when said mandrel means moves in said first direction, and for opening said continuous flow channel when said mandrel means moves in said second direction, thereby providing control of fluid communication in the flow passage of the testing string responsive to weight and well bore pressure increases.