초록 ▼

A packer bypass for use between a pump and packer in a testing string for venting said pump and packer to a well annulus after completion of a testing operation. The packer bypass comprises a case with an inner flow tube disposed therein such that an annular passageway is defined therebetween. A pis

A packer bypass for use between a pump and packer in a testing string for venting said pump and packer to a well annulus after completion of a testing operation. The packer bypass comprises a case with an inner flow tube disposed therein such that an annular passageway is defined therebetween. A piston having a lower portion is reciprocably disposed in the annular passageway. A plurality of latching fingers are pivotally mounted to the lower end of the piston and biased towards a latching position. A bypassing mandrel is reciprocably disposed in the annular passageway below the piston and has an open position for bypassing pump pressure thereabove and packer pressure therebelow to the well annulus and also has a closed position in which bypassing is prevented. The mandrel may be raised from the closed position to the open position by lowering the piston and engaging the latching fingers with a flange on the mandrel. When the mandrel is moved to the open position, the latching fingers are automatically released. The mandrel may be pumped back to the closed position for another test. Hydraulic pressure across the mandrel prevents overpull, and pressure balancing on the piston prevents undesired downward force on the packer.

대표청구항 ▼

A packer bypass apparatus for use in a testing string having a pump in an upper testing string portion and a packer in a lower testing string portion, said bypass apparatus comprising: a case adapted for attachment to said lower testing string portion and having a longitudinally central opening ther

A packer bypass apparatus for use in a testing string having a pump in an upper testing string portion and a packer in a lower testing string portion, said bypass apparatus comprising: a case adapted for attachment to said lower testing string portion and having a longitudinally central opening therethrough with at least one transverse port therein; an inner flow tube disposed in said central opening of said case such that said case and said flow tube define a substantially annular flow passageway therebetween in communication with said packer; a bypass mandrel reciprocably disposed in said flow passageway and movable between an open and a closed position, said mandrel defining a bypass passageway therein for providing communication between said flow passageway and a well annulus when in said open position; a piston having an upper portion adapted for attachment to said upper testing string portion and a lower portion disposed in said flow passageway above said mandrel and reciprocable between a first position and a second position; and latching means on said lower portion of said piston for latchingly engaging said mandrel in said closed position when said piston is moved to said second position, whereby said mandrel may be moved from said closed position to said open position as said piston is moved from said second position to said first position, said latching means comprising: a latch pivotally attached to said lower portion of said piston, said latch comprising a lower end having a latching position and a released position; and biasing means for biasing said lower end of said latch toward said latching position. A downhole testing tool comprising: a pump attached to an upper testing string portion; an inflatable packer disposed below said pump and positionable adjacent a well formation to be tested; and a packer bypass disposed between said pump and packer for allowing communication between said pump and packer when in a closed position and venting said pump and packer to a well annulus when in an open position, said packer bypass comprising: a case; a reciprocable mandrel disposed in said case and having closed and open positions corresponding to said closed and open positions of said packer bypass; releasable pivoting latching means vertically movable with said upper testing string portion and latchingly engageable with said mandrel when in said closed position, whereby said mandrel may be moved to said open position and released at said open position; and overpull prevention means for preventing premature movement of said mandrel to said open position, wherein: said overpull prevention means includes an annular area defined on said mandrel, and a differential pressure between said pump and well annulus acts against said area for providing a downward force on said mandrel.