Method for operating a well to remove production limiting or flow restrictive material

• US 4,921,577 A
• Filed: 08/02/1988
• Issued: 05/01/1990
• Est. Priority Date: 08/02/1988
• Status: Expired due to Term

• Current Assignee: Dennis R. Eubank
• Original Assignee: Dennis R. Eubank
• Inventors: Eubank, Dennis R.
• Primary Examiner(s): Dang, Hoang C.
• Application Number:
  US07/227,148
• Time in Patent Office: 637 Days
• Field of Search: 166/312, 166/311, 166/313, 166/370, 166/115-117, 166/177, 166/99, 166/158, 166/164, 166/165, 166/169
• US Class Current: 166/311
• CPC Class Codes: E21B 37/00 Methods or apparatus for cleaning boreholes or wells E21B21/00 takes precedence

Abstract

A method and downhole well installation for facilitating the removal of detrimental material such as sand accumulated within a well penetrating a subterranean hydrocarbon formation. A tubing string in the well extends to a production interval open to the formation. A production stinger is slidably disposed in the tubing string and extends downwardly from the bottom of the tubing string into the production interval. A seal is provided between the stinger and the tubing string which permits slidable movement of the stinger but provides for a seal against fluid flow upwardly in the stinger-tubing string annulus. A longitudinal passage extends through the stinger and opens into the tubing string above the seal. At least one inflow opening to the longitudinal passage is provided in the stinger near the bottom thereof. Thus, when the stinger comes to rest upon the sand or other unwanted material accumulated in the well, the inflow opening is located adjacent the surface of the unwanted material. A pressure gradient is established through the inflow opening into the stinger passage. Fluid such as gas from the formation flows through the inflow opening into the longitudinal passage and entrains particulate material and carries it to the stinger passage to form a fluid stream containing entrained particulate material. The fluid-particulate material mixture passes upwardly through the stinger passage and into the tubing string above the seal.

Claims

1. In a method for the operation of a well penetrating a subterranean formation and having a production interval open to said formation through which gaseous fluids may be produced from said formation into said well and which is subject to the accumulation of particulate material within said well, said well having a tubing string extending to said production interval, the steps comprising:

(a) forming a production stinger by providing a nose sub having a longitudinal passage and at least one inflow opening providing ingress to said passage, securing an assemblage of a plurality of tubing joints having lengths of at least thirty feet to said nose sub, and securing a landing section including an annular seal slidable within the internal bore of said well tubing string to said assemblage of tubing stands to produce said production stinger,

(b) lowering said production stinger through said tubing string until a portion of said stinger including said nose sub having said inflow opening protrudes from said well tubing string, said stinger establishing a longitudinal flow passage within said well extending to said production interval through said seal in said tubing string above said production interval;

(c) establishing a pressure gradient from said production interval into said longitudinal flow passage through said inflow opening placing said longitudinal flow passage in fluid communication with said production interval at a location adjacent the upper surface of a column of particulate material accumulated in said production interval;

(d) flowing gaseous formation fluid under said pressure gradient from said production interval into said longitudinal flow passage through said inflow opening, said fluid entraining particulate material from said accumulated particulate material and carrying said particulate material through said inflow passage and into said longitudinal passage to produce a fluid stream having particulate material entrained therein; and

(e) flowing said fluid containing said entrained particulate material through said longitudinal flow passage and into said well tubing string above said seal as said production stinger is lowered through said tubing string seal.

2. The method of claim 1 wherein the fluid flowing from said well production interval through said inflow opening into said passage is in a turbulent flow condition at a location adjacent said inflow opening.

3. The method of claim 1 further comprising the step of progressively lowering said inflow opening as the accumulation of particulate material in said production interval is decreased to maintain said inflow opening adjacent the upper level of said column of accumulated material.

4. The method of claim 1 wherein said longtudinal flow passage is provided by a tubular stinger which is slidably disposed within a tubing string in said well and extends downwardly from said tubing string into said production interval, said well having a packer closing the annulus around said tubing string.

5. The method of claim 4 wherein said inflow opening is adjacent the lower end of said stinger and has a vertically elongated configuration in which the average vertical dimension is at least twice the average horizontal dimension.

6. The method of claim 4 wherein said tubular stinger has an open upper end to provide for straight-through vertical fluid flow from said stinger into said tubing string.

7. In a method for the operation of a well penetrating a subterranean hydrocarbon bearing formation, a production interval in said well open to said formation, a tubing string extending to said production interval, and a column of liquid in at least a portion of said tubing string, said well having a column of accumulated particulate material therein below the bottom of said tubing string, the steps comprising:

(a) running an elongated production stinger having a longitudinal passage into said well and downwardly through said tubing string;

(b) providing a sliding seal between said stinger and said tubing string as said stinger is lowered through said tubing string;

(c) providing for liquid flow from the exterior of said stinger through said longitudinal passage from below said seal to above said seal and then from said passage to the exterior of said stinger above said seal whereby liquid flows through said stinger passage as said stinger is lowered through said tubing to provide for pressure equalization above and below said seal;

(d) lowering a portion of said stinger through the mouth of said tubing string and into contact with the column of particulate material in said well to place at least one inflow opening for said particulate material extending from the exterior to the interior of said stinger adjacent the surface of said particulate material; and

(e) placing said well on production to produce hydrocarbon fluids from said formation into said production interval and maintaining a pressure gradient through said at least one inflow opening to cause hydrocarbon fluids from said formation to entrain particulate material and pass into said inflow opening to produce a fluid stream having entrained particulate material therein which flows upwardly through said stinger and into said well tubing above said seal as said production stinger is lowered through said tubing string.

8. The method of claim 7 further comprising continuing the production of said well to reduce the amount of said particulate material in said well and moving said stinger downwardly through said tubing string as said particulate material is removed to retain said inflow opening in the vicinity of the top of the column of particulate material.

9. The method of claim 7 wherein liquid flow from said longitudinal passage in said stinger to the exterior of said stinger above said seal occurs through at least one equalization port above said sliding seal and wherein said longitudinal passageway is at least partially closed above said equalization port by an obstruction in said passageway during the running in of said production stinger, and further comprising the step of removing said obstruction so that after said well is placed on production, said fluid stream having entrained material therein flows vertically upward as it exits said stinger and passes into said tubing string.

10. The method of claim 7 wherein said inflow opening is of a vertically elongated configuration having a vertical dimension which is greater than the horizontal dimension of said opening.

11. The method of claim 10 wherein said stinger has a plurality of inflow openings of said vertically elongated configuration disposed circumferentially in the wall of said stinger.

22. The method of claim 7, wherein said production stinger is assembled at the surface of said well by securing an assemblage of a plurality of tubing joints having lengths of at least 30 feet to a nose sub in which said at least one inflow opening is located and securing a landing section including said sliding seal on the exterior thereof to said assemblage of tubing joints.

23. The method of claim 7, wherein said seal comprises a plurality of inverted sealing cups secured in tandem to the outer surface of said production stinger whereby a positive pressure gradient from below to above said seal causes the sealing action of said cups to be enhanced.

24. The method of claim 23, further comprising providing a shoulder upset from said production stringer below said sealing cups which moves in advance of said sealing cups as said stinger is moved through said tubing string.

12. In a method for the operation of a well penetrating a subterranean formation having a production interval in said well open to said formation, a casing, a tubing string within said casing extending downwardly through said well to said production interval and a column of accumulated particulate material in said well below the bottom of said tubing string, the steps comprising:

(a) running an elongated production stinger having a longitudinal passage therein into said well and downwardly through said tubing string from the surface of said well;

(b) providing a sliding seal between said stinger and said tubing string as said stinger is lowered through said tubing string in step (a);

(c) as said stinger is lowered through said tubing string in steps (a) and (b), providing for fluid flow from the exterior of said stinger through said longitudinal passage from below said sliding seal to above said sliding seal and then from said passage to the exterior of said stinger above said seal whereby fluid flow through said stinger passage as said stinger is lowered through said tubing provides for pressure equalization above and below said seal;

(d) lowering a portion of said stinger through the mouth of said tubing string and into contact with said column of particulate material in said well to place at least one inflow opening which extends from the exterior to the interior of said stinger, adjacent the surface of said particulate material;

(e) establishing a pressure gradient within said production interval extending from the exterior of said stinger through said at least one inflow opening into the interior of said stinger to cause fluid to flow from said production interval into said stinger along with particulate material from said column of accumulated particulate material to produce a fluid stream having entrained particulate material which flows upwardly through said stinger and into said well tubing above said seal; and

(f) concomitantly with step (e) lowering said stinger while maintaining a sliding seal between said stinger and said tubing string as accumulated detrital material is removed.

13. The method of claim 12 wherein said pressure gradient is established by injecting a circulating fluid down the annulus between said tubing and casing and into said production interval to establish said pressure gradient and wherein said circulating fluid entrains said particulate material and passes into said inflow opening to produce said fluid stream having entrained particulate material therein.

14. The method of claim 12 wherein said formation is a gas producing formation and wherein said pressure gradient is established by placing said well on production to produce gaseous fluids from said formation into said production interval to cause said gaseous fluids to entrain said particulate material and pass into said inflow opening to produce said fluid stream having entrained particulate material.

25. The method of claim 12, wherein said fluid in step (e) is passed through said inflow opening in a vertically elongated flow profile.

26. The method of claim 12, wherein said production stinger is assembled at the surface of said well by securing an assemblage of a plurality of tubing joints having lengths of at least 30 feet to a nose sub in which said at least one inflow opening is located and securing a landing section including said sliding seal on the exterior thereof to said assemblage of tubing joints.

27. The method of claim 12, wherein said seal comprises a plurality of inverted sealing cups secured in tandem to the outer surface of said production stinger whereby a positive pressure gradient from below to above said seal causes the sealing action of said cups to be enhanced.

15. In a method of producing a well penetrating a subterranean gas bearing formation and having a production interval in said well open to said formation and a tubing string extending down said well to said production interval, the steps comprising:

(a) producing fluid from said well with the flow of said fluid into said well from said formation carrying particulate material from said formation to cause an accumulation of a column of particulate material in the production interval of said well;

(b) shutting in said well and injecting liquid into said well in sufficient amount to form a liquid column in the production interval of said well and extending upwardly through at least a portion of said tubing string;

(c) running an elongated production stinger having a longitudinal passage into said well and downwardly through said tubing string and through the column of liquid within said tubing string;

(d) providing a sliding seal between said stinger and said tubing string as said stinger is lowered through said tubing string;

(e) providing for liquid flow from the exterior of said stinger through said longitudinal passage from below said seal to above said seal and then from said passage to the exterior of said stinger above said seal whereby liquid flows through said stinger passage as said stinger is lowered through said tubing to provide for pressure equalization above and below said seal;

(f) lowering a portion of said stinger through the mouth of said tubing string and into contact with the column of particulate material in said well to place at least one inflow opening for said particulate material extending from the exterior to the interior of said stinger adjacent the surface of said particulate material; and

(g) removing the liquid previously introduced into said well from said well and placing said well on production to cause gas to flow from said formation into said production interval and maintaining a pressure gradient through said at least one inflow opening to cause the gaseous fluid from said formation to entrain particulate material and pass into said inflow opening to produce a fluid stream having entrained particulate material therein which flows upwardly through said stinger and into said well tubing above said seal as said production stinger is lowered through said tubing string.

16. The method of claim 15 further comprising continuing the production of said well to reduce the amount of said particulate material in said well and moving said stinger downwardly through said tubing string as said particulate material is removed to retain said inflow opening in the vicinity of the top of the column of particulate material.

17. The method of claim 15 wherein prior to Step (a) said well is subjected to a stimulation procedure involving the injection of a stimulating fluid down said well and into said formation and wherein at least a portion of the fluid flowing into said well from said formation is said stimulating liquid.

18. The method of claim 17 wherein said stimulating procedure is a hydraulic fracturing procedure involving the injection of hydraulic fracturing liquid containing propping agent down said well and into said formation and wherein at least a portion of the particulate material carried from the formation into said well comprises propping agent.

19. In the method of producing a well penetrating a subterranean gas bearing formation and having a production interval in said well open to said formation provided by a casing member having a plurality of vertically disposed perforations in said casing member and a tubing string extending down said well to said production interval, the steps comprising:

(a) providing an elongated production stinger having a longitudinal passage way therethrough in said tubing string, a portion of said stinger extending through the mouth of said tubing string and to a level in said well below at least the predominant portion of said perforations;

(b) providing a slidable seal between said stinger and said tubing string;

(c) providing an inflow opening in said stinger extending from said production interval of said well into the interior of said stinger at a level below at least the predominant portion of said perforations; and

(d) flowing gaseous fluid from said formation through said perforations into said production interval and maintaining a pressure gradient through said at least one inflow opening to cause said gaseous fluid from said formation to flow into said inflow opening and carry accumulated detrimental material in said well upwardly through said stinger and into said well tubing above said seal as said production stinger is lowered through said tubing string.

20. The method of claim 19 wherein said detrimental material comprises water.

21. The method of claim 20 wherein said stinger has an open upper end for said longitudinal passageway to provide for straight through vertical fluid flow from said stinger into said tubing string.