Plunger for performing artificial lift of well fluids

1. A plunger for performing artificial lift in a gas producing well, the plunger comprising:

a plunger body for sealingly engaging a tubing of the well;

a fluid path through the plunger body;

a narrow passageway within the fluid path; and

a central orifice at an end of the narrow passageway, wherein the narrow passageway comprises a removable plug having a bore therethrough.

2. A plunger as defined in claim 1 , further comprising a radially inwardly directed lip within the fluid path spaced above the central orifice.

3. A plunger as defined in claim 2 , wherein the distance between the central orifice and the lip is between 10% and 60% of the total length of a body of the plunger.

4. A plunger as defined in claim 2 , wherein the fluid path comprises a lower chamber below the narrow passageway and an upper chamber above the narrow passageway.

5. A plunger as defined in claim 4 , wherein the radially inwardly directed lip is on an upper edge of the upper chamber.

6. A plunger as defined in claim 4 , wherein the upper chamber, the lower chamber, the central orifice, and the lip all have a circular cross-section and are all concentric about a longitudinal centerline of the plunger.

7. A plunger as defined in claim 1 , further comprising a one-way valve disposed to permit fluid flow only from the lower chamber to the upper chamber through the narrow passageway.

8. A plunger as defined in claim 1 , wherein the plunger is approximately 25 cm long with a diameter of approximately 5 cm and weighs less than 1.8 kg.

9. A plunger as defined in claim 8 , wherein the plunger weighs approximately 0.9 kg.

10. A plunger as defined in claim 1 , wherein a majority of the material of the plunger by volume is a material having a density of less than 4.54 g/cm 3 .

11. A plunger as defined in claim 1 , wherein the ratio of the diameter of the central orifice to the ratio of the diameter of the plunger is in the range of 1:25 to 1:2.5.

12. A plunger as defined in claim 11 , wherein the ratio of the diameter of the central orifice to the ratio of the diameter of the plunger is about 1:10.

13. A kit comprising a plunger as defined in claim 1 and two removable plugs, wherein the bore of each of the two removable plugs has a different diameter.

14. A plunger for performing artificial lift in a gas producing well, the plunger comprising:

a plunger body for sealingly engaging a tubing of the well;

a fluid path through the plunger body;

a narrow passageway within the fluid path; and

a central orifice at an end of the narrow passageway, wherein the plunger comprises an upper half and a lower half detachably coupled together.

15. A plunger as defined in claim 14 , wherein the upper half comprises a magnetic metallic material and the lower half comprises titanium.

16. A plunger for performing artificial lift in a gas producing well, the plunger comprising:

a plunger body for sealingly engaging a tubing of the well;

a fluid path through the plunger body;

a narrow passageway within the fluid path;

a central orifice at an end of the narrow passageway; and

an instrument for measuring one or more of temperature and pressure, wherein the narrow passageway comprises an internal threaded portion and the instrument is secured to the internal threaded portion.

17. A plunger for performing artificial lift in a gas producing well, the plunger comprising:

a plunger body for sealingly engaging a tubing of the well;

a fluid path through the plunger body;

a narrow passageway within the fluid path;

a central orifice at an end of the narrow passageway; and

a bypass valve, the bypass valve comprising:

a cage coupled to the bottom end of the plunger body; and

a pin having a head and a shaft, the pin being slideably retained within the cage and movable between an open position wherein the bypass valve allows gas and liquid to flow through the fluid path and a closed position wherein the pin engages a bottom of the plunger body to limit the flow of gas and liquid through the fluid path,

wherein the narrow passageway extends through the head of the pin.

18. A plunger as defined in claim 17 , wherein the passageway comprises three symmetrically disposed fluid passageways extending through the head of the pin, the three fluid passageways being in fluid communication with the central orifice.

19. A plunger as defined in claim 17 , further comprising an internal constriction within the fluid path above the narrow passageway.

20. A plunger for performing artificial lift in a gas producing well, the plunger comprising:

a plunger body for sealingly engaging a tubing of the well;

a fluid path through the plunger body;

a narrow passageway within the fluid path;

a central orifice at an end of the narrow passageway; and

a bypass valve, wherein the bottom end of the plunger comprises a seat for receiving a seal, the seat comprising one or more grooves configured to permit fluid to flow to the narrow passageway when the seal is sealingly engaged with the seat.

21. A plunger as defined in claim 20 , wherein the seal is a ball and the seat is curved to sealingly engage the ball.

22. A plunger for performing artificial lift in a gas producing well, the plunger comprising:

a plunger body for sealingly engaging a tubing of the well;

a fluid path through the plunger body;

a narrow passageway within the fluid path;

a central orifice at an end of the narrow passageway;

a bypass valve; and

fluid channels through the body of the plunger for permitting fluid to flow through the narrow passageway when the bypass valve is in a closed position.

23. A method of using a plunger to perform artificial lift in a gas-producing well, the method comprising the steps of:

allowing a plunger having a plunger body with a fluid path therethrough to fall within a tubing of a well to the bottom of the well the body sealingly engaging the tubing;

allowing gas pressure to move the plunger upwardly within the tubing; and

while the plunger is moving upwardly:

allowing fluid to pass through a narrow passageway within the fluid path, the narrow passageway defined by a removable plug in the plunger body, the plug having a bore therethrough, the narrow passageway further having a central orifice at one end.

24. A method as defined in claim 23 , further comprising the step of allowing the fluid exiting the central orifice to interact with a radially inwardly directed lip on the plunger.

25. A method as defined in claim 23 , wherein the plunger has a weight of 2.3 kg or less and is operated to travel in the tubing at maximum speeds of at least 4 m/s.

26. A method as defined in claim 25 , wherein the steps of allowing the plunger to fall and allowing gas pressure to move the plunger upwardly are repeated at a frequency of up to 6 times per hour.

27. A plunger having a bypass valve for performing artificial lift in a gas producing well, the plunger comprising:

a plunger body for sealingly engaging a tubing of the well, the plunger body having a fluid path therethrough;

a cage coupled to the bottom end of the plunger body;

a pin having a head and a shaft, the pin being slideably retained within the cage and movable between an open position wherein the bypass valve allows fluid to flow through the bypass valve and a closed position wherein the pin engages a bottom portion of the plunger body to limit the flow of gas and liquid through the bypass valve;

at least one fluid channel through the head of the pin in fluid communication with a central orifice in the pin, the central orifice being in fluid communication with the fluid path; and

a radially inwardly directed lip within the fluid path spaced above the central orifice.