Drill stem testing methods and apparatus utilizing inflatable packer elements

• US 3,876,003 A
• Filed: 10/29/1973
• Issued: 04/08/1975
• Est. Priority Date: 10/29/1973
• Status: Expired due to Term

• Current Assignee: James W. Kisling III
• Original Assignee: James W. Kisling III
• Inventors: Kisling, James W. III
• Primary Examiner(s): Novosad, Stephen J.
• Application Number:
  US05/410,944
• Time in Patent Office: 526 Days
• Field of Search: 166/250,113,138,186,187,216,240,191,315 73/151
• US Class Current: 166/387
• 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
• CPC Class Codes: E21B 49/088 combined with sampling

Abstract

Methods and apparatus for isolating a well bore interval utilizing spaced inflatable packer elements and a pump suspended in the well on a pipe string. The pump includes an inner member connected to the packer elements and an outer member connected to the pipe string, said members defining a working volume that is contracted during upward movement of said outer member for supplying fluids under pressure to said packing element to effect inflation thereof, and enlarged and filled with well fluids during downward movement. Since the power stroke of the pump is in the upward direction, a weight indicator can be monitored at the surface and provides positive indication of downhole equipment performance, including development of inflation pressures and the opening of relief valves when preselected inflation pressures have been generated.

Claims

1. A method for isolating an interval of earth formations with a packer means having at least one inflatable packing element that can be expanded in response to operation of a pump means having relatively movable inner and outer members defining a working volume, one of said members being connected to said packer means and the other of said members being connected to a pipe string extending upwardly to the surface, comprising the steps of:

releasably locking said members against relative movement to temporarily disable said pump means;

lowering said packer means and pump means into a fluid filled well bore on the pipe string;

at setting depth, anchoring said packer means and said one member against downward movement in the well bore and releasing said members for movement relative to each other to enable operation of said pump means;

moving said pipe string upwardly and downwardly to effect corresponding movement of said other member relative to said one member;

during upward movement of said pipe string and said other member discharging fluid under pressure into the interior of said packing element to inflate and expand it outwardly; and

during downward movement of said pipe string and said other member drawing well fluids into said pump means for discharge during the next subsequent upward movement.

2. The method of claim 1 including the further step of venting fluid from the pump means to the well annulus when the pressure interiorly of said packing element reaches a predetermined maximum value.

3. The method of claim 2 including the further steps of providing an indication at the surface of the increase in the amount of force required to move said pipe string upwardly as the pressure interiorly of said packer element increase;

and discontinuing upward and downward movement of the pipe string when the amount of force required to cause such upward movement ceases to increase and thus indicates that said fluids are being vented to the well annulus.

4. The method of claim 3 including the further steps of performing a drill stem test by flowing formation fluids from below said packing element into the pipe string for a first period of time;

shutting in the formation interval for a second period of time; and

instrumentally recording the pressure of the fluids in said isolated interval during said periods of time.

5. The method of claim 4 including the further steps of deflating said packer means to enable said packing element to retract to substantially its normal transverse dimension so that said packer means and pump means can be moved longitudinally through the well bore.

6. A method for isolating an interval of earth formations off the bottom of a well bore, comprising the steps of:

lowering vertically spaced, upper and lower inflatable packer elements, and a pump means into the well bore on a pipe string, said pump means having a working volume provided between an inner member connected to said upper packer means and an outer member connected to said pipe string;

anchoring said packer elements and said inner member against downward movement in the borehole;

moving said pipe string upwardly and downward to effect corresponding movement of said outer member relative to said inner member;

during each upward movement pumping fluid under pressure into the respective interiors of said upper and lower packing elements to expand them outwardly; and

during each downward movement resupplying said pump means with fluids to be discharged to said packer elements during the next subsequent upward movement of said pipe string.

7. The method of claim 6 including the further step of monitoring the inflation pressure within the packing elements at the surface, and discontinuing upward movements of the pipe string when an indication is given that the inflation pressure has reached a predetermined maximum value.

8. The method of claim 7 including the further step of exhausting fluids from the pump means to the well bore when said maximum value of inflation pressure is reached.

9. The method of claim 8 wherein the monitoring step is carried out through observation of the amount of force required to lift the pipe string during successive upward movements thereof, said discontinuing step being carried out as soon as an appreceable increase in the amount of force required to lift the pipe string during successive upward movements is no longer observed.

10. The method of claim 9 including a further step of equalizing the pressure of fluids in the well bore above the upper packing element with the pressure of fluids in the well bore below the lower packing element.

11. Apparatus for use in isolating an interval of earth formations traversed by a well bore, comprising:

packer means having at least one inflatable element adapted to be expanded into sealing contact with a surrounding well bore wall;

pump means for inflating said element, said pump means including relatively movable inner and outer members defining a working volume, one of said members being connected to said packer means and the other of said members being connected to a pipe string extending upwardly to the surface;

releasable clutch means for preventing relative movement of said members as said apparatus is being moved longitudinally in a well bore;

means for anchoring said packer means and said one member against downward movement in the well bore;

first means for feeding fluid under pressure from said working volume to the interior of said packing element during upward movement of said other member relative to said one member; and

second means for drawing well fluids into said working volume during downward movement of said other member relative to said one member.

12. The apparatus of claim 11 wherein said first means includes an inflation passage leading from said working volume to the interior of said packing element, and valve means for enabling fluid to flow via said passage in a direction to enable expansion of said packing element during said upward movement and for preventing the flow of fluids in the reverse direction.

13. The apparatus of claim 12 wherein said second means includes an entry passage leading from the well annulus to said working volume, and valve means for enabling fluids to enter said working volume means via said entry passage during said downward movement and for normally preventing fluid flow in the reverse direction.

14. The apparatus of claim 13 further including a normally closed vent passage for exhausting fluid from said working volume to the well annulus;

and pressure responsive relief valve means for enabling fluids to vent to the well annulus via said vent passage during said upward movement of said other member only after a predetermined maximum inflation pressure has been generated within said packing element.

15. The apparatus of claim 14 further including a test passage extending generally longitudinally through said packer means and said pump means;

and test valve means for selectively opening and closing said test passage to enable performance of a drill stem test.