Packer bypass

• US 4,756,364 A
• Filed: 12/10/1986
• Issued: 07/12/1988
• Est. Priority Date: 12/10/1986
• Status: Expired due to Term

• Current Assignee: Halliburton Company
• Original Assignee: Halliburton Company
• Inventors: Zeller, Vincent P., Beck, Harold K., Christensen, Jon B.
• Primary Examiner(s): Massie, IV, Jerome
• Assistant Examiner(s): MELIUS, TERRY L
• Application Number:
  US06/940,882
• Time in Patent Office: 580 Days
• Field of Search: 166/101, 166/106, 166/129, 166/133, 166/184, 166/185, 166/186, 166/187, 166/323, 166/332, 166/237
• US Class Current: 166/101
• CPC Class Codes: E21B 33/1246 inflated by down-hole pumping means operated by a pipe string
• CPC Class Codes: E21B 34/125 with time delay systems, e.g. hydraulic impedance mechanisms

Abstract

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.

Claims

1. 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.

2. The apparatus of claim 1 wherein:

said latch is one of a plurality of angularly spaced latches; and

said biasing means comprises a garter spring disposed around said latches.

3. The apparatus of claim 1, wherein said releasing means comprises a tapered surface in said case for engaging an upper end of said latch and pivoting said lower end of said latch to said released position.

4. 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;

sealing means for sealing between said mandrel and said flow tube when said mandrel is in said open position whereby said flow passageway is separated into upper and lower portions;

check valve means for venting said upper portion of said flow passageway through said bypass passageway in said mandrel when a differential pressure between said upper portion of said flow passageway and said well annulus exceeds a predetermined level;

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 mandrel 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.

5. A packer bypass apparatus for use in a testing string with a pump and an inflatable packer, said apparatus comprising:

case means defining a central opening therethrough;

piston means reciprocably disposed in said central opening of said case means and movable between a first position and a second position;

mandrel means disposed in said central opening of said case means and having a bypass position for providing communication between said packer and a well annulus and further having a sealed position preventing communication between said packer and said well annulus,

wherein said mandrel means is movable from said bypass position to said sealed position in response to a differential pressure between said pump and said well annulus acting across a portion of said mandrel means; and

pivotable latching means in operative association with said piston means for latchingly engaging said mandrel means when said mandrel means is in said sealed position and said piston means is in said second position, whereby said mandrel means may be moved from said sealed position to said bypass position by moving said piston means from said second position to said first position.

6. A packer bypass apparatus for use in a testing string with a pump and an inflatable packer, said apparatus comprising:

case means defining a central opening therethrough;

piston means reciprocably disposed in said central opening of said case means and movable between a first position and a second position;

mandrel means disposed in said central opening of said case means and having a bypass position for providing communication between said packer and a well annulus and further having a sealed position preventing communication between said packer and said well annulus;

pivotable latching means in operative association with said piston means for latchingly engaging said mandrel means when said mandrel means is in said sealed position and said piston means is in said second position, whereby said mandrel means may be moved from said sealed position to said bypass position by moving said piston means from said second position to said first position; and

overpull prevention means for preventing movement of said mandrel means until a predetermined force is overcome,

wherein said overpull prevention means is characterized by a differential area on said mandrel means, said area being exposed to pump pressure on one side thereof and well annulus pressure on an opposite side thereof.

7. A packer bypass apparatus for use in a testing string with a pump and an inflatable packer, said apparatus comprising:

case means defining a central opening therethrough;

piston means reciprocably disposed in said central opening of said case means and movable between a first position and a second position;

mandrel means disposed in said central opening of said case means and having a bypass position for providing communication between said packer and a well annulus and further having a sealed position preventing communication between said packer and said well annulus;

pivotable latching means in operative association with said piston means for latchingly engaging said mandrel means when said mandrel means is in said sealed position and said piston means is in said second position, whereby said mandrel means may be moved from said sealed position to said bypass position by moving said piston means from said second position to said first position; and

pressure balancing means for balancing pressure between said case means and said piston means for minimizing downward force on said packer.

8. A packer bypass apparatus for use in a testing string with a pump and an inflatable packer, said apparatus comprising:

case means defining a central opening therethrough;

piston means reciprocably disposed in said central opening of said case means and movable between a first position and a second position;

mandrel means disposed in said central opening of said case means and having a bypass position for providing communication between said packer and a well annulus and further having a sealed position preventing communication between said packer and said well annulus;

pivotable latching means in operative association with said piston means for latchingly engaging said mandrel means when said mandrel means is in said sealed position and said piston means is in said second position, whereby said mandrel means may be moved from said sealed position to said bypass position by moving said piston means from said second position to said first position; and

inner flow tube means disposed in said case means such that an annular flow passageway is defined between said case means and said flow tube means;

wherein;

said piston means has an annular portion disposed in said flow passageway; and

said mandrel means is characterized by a generally annular mandrel disposed in said flow passageway.

9. 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

pivotable 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,

wherein said mandrel defines an annular shoulder thereon and movement of said mandrel from said closed position to said open position is prevented until an upward force on said piston latched to said mandrel exceeds a downward force on said mandrel due to a differential pressure between said flow passageway above said mandrel and said well annulus acting across an area defined by said shoulder.

10. 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;

pivotable 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; and

pressure balancing means between said piston and said case for balancing pump pressure acting on said case for minimizing a downward force on said case and said packer.

11. The apparatus of claim 10 wherein said pressure balancing means includes:

a recess defined in said case; and

an annular shoulder on said piston extending into said recess such that a cavity is formed therebetween with an upper portion in communication with said pump and a lower portion in communication with said well annulus.

12. 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.