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WO1993018321A1 - Piston plongeur pour puits de petrole - Google Patents

Piston plongeur pour puits de petrole Download PDF

Info

Publication number
WO1993018321A1
WO1993018321A1 PCT/US1993/001708 US9301708W WO9318321A1 WO 1993018321 A1 WO1993018321 A1 WO 1993018321A1 US 9301708 W US9301708 W US 9301708W WO 9318321 A1 WO9318321 A1 WO 9318321A1
Authority
WO
WIPO (PCT)
Prior art keywords
seal
assembly
flutes
seal ring
pressure ports
Prior art date
Application number
PCT/US1993/001708
Other languages
English (en)
Inventor
Glen A. Weeks
Gary M. Miller
Stephen B. Ehlers
Original Assignee
Seal Lift Corporation
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Seal Lift Corporation filed Critical Seal Lift Corporation
Priority to AU37336/93A priority Critical patent/AU3733693A/en
Publication of WO1993018321A1 publication Critical patent/WO1993018321A1/fr

Links

Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
    • E21B37/00—Methods or apparatus for cleaning boreholes or wells
    • E21B37/10—Well swabs
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B53/00—Component parts, details or accessories not provided for in, or of interest apart from, groups F04B1/00 - F04B23/00 or F04B39/00 - F04B47/00
    • F04B53/14—Pistons, piston-rods or piston-rod connections
    • F04B53/143—Sealing provided on the piston

Definitions

  • This invention relates to an improved oil well pump or plunger, and specifically, to an improved reciprocating subsurface oil well plunger used to extract crude oil from subsurface oil formations.
  • the plunger travels in a well barrel or cylinder of slightly larger diameter than the plunger and reciprocates in a vertical up and down motion.
  • Pumps of this type are generally known in the art, and typically include a ball valve assembly attached to the bottom of the plunger which closes on the up stroke of the pump to allow hydrostatic pressure from a column of fluid above the plunger to radially expand a plurality of seal rings supported on the plunger. This action seals off the barrel so that the fluid cannot pass between the plunger and the barrel, thereby causing the column of fluid to be lifted to the surface while drawing more fluid into the reservoir behind it.
  • the ball valve opens, relaxing the seal rings and allowing fluid to flow past the plunger. This reciprocating motion repeats itself several times per minute.
  • a fluted stem receives a plurality of annular seals supported by a radial shoulder of a lower portion of the stem, and held in place by a lock nut threadably received over the ' upper portion of the stem flutes. Fluid pressure from fluid in the flow channels (between the flutes) during the up stroke of the pump causes radial expansion of the seals into contact with the well bore wall or cylinder.
  • Examples subsurface well pump constructions of this general type may be found in U.S. Patent Nos. 4,229,149; 4,395,204; and 4,762,476. Such constructions have not always proven completely satisfactory however.
  • a disadvantage of one known construction is the incorporation of four fluid channels as defined by four flutes in the stem. This arrangement tends to restrict flow into the plunger, and, because of the relatively few pressure ports by which the fluid is permitted to communicate with the seals, non-uniform pressure and hence non-uniform seal expansion may result. Moreover, a mechanical lock is required to prevent rotation of the seal rings relative to the stem during pumping. This is necessary to insure that the pressure ports maintain alignment with the fluid flow channels between the flutes, i.e., insuring that the pressure ports do not align themselves with the flutes and thereby preclude expansion of the rings.
  • Another disadvantage lies in the absence of a well defined, relatively large hydraulic pressurization channel on the inside surface of the seal ring, thereby also hindering uniformity of expansion.
  • Another disadvantage lies in the fact that ' a pressure differential between the inside and outside surfaces of the seal ring may not always occur, and absent such a differential, the rings will not radially expand as intended.
  • Still another disadvantage of conventional pump constructions relates to the compression of the axially aligned seal rings after the locking nut is in place, because the seal ring itself was designed to be "taller", i.e., axially longer, than the underlying support ring surface.
  • the seal elements themselves are sandwiched together under compression, thereby hindering free expansion and contraction of the seal rings during reciprocatory motion of the pump.
  • the present invention relates to an improved bottom hole or subsurface plunger for well bores which overcomes all of the above mentioned disadvantages of prior pump constructions.
  • the down hole pump or plunger comprises a constant diameter, elongated stem or body which is formed at one end with a cylindrical portion having an internally threaded bore for attachment to a conventional sucker rod
  • stem flutes are formed in the stem by three, equally spaced flutes extending axially to the opposite end of the stem.
  • the lowermost ends of the stem flutes are threaded on their exterior surfaces to receive a cylindrical, lower coupler.
  • the lower coupler is provided with interior threads at its lowermost end to receive a conventional ball valve assembly.
  • a plurality of annular seal assemblies are slidably received over the stem and seated on the upper end of the coupler, held in place by a lock nut threadably received on the fluted portion of the stem.
  • Each seal assembly includes a support ring and a seal ring element.
  • the support ring includes a cylindrical body portion with a radially outwardly extending flange at one end thereof. The seal ring is received snugly over the support ring body, into abutting relationship with a shoulder provided by the radial flange.
  • the support ring body portion is also provided with a plurality of holes or pressure ports (for example, six) equally spaced about the support ring body, which allow oil flowing through the flute channels to exert pressure against the seal ring elements to thereby radially expand the seal ring elements against the barrel during the up stroke of the plunger.
  • Each seal ring element is formed with an annular channel in its interior surface so as to be in communication with the pressure ports in the
  • each support ring radial flange is grooved in order to reduce the fluid pressure on the outside of the seal ring.
  • the seal ring width is chosen to be slightly less than the length of the underlying body portion of the support ring. This is intended to allow the rings to "float” between adjacent support rings and thereby enhance the radial expansion and contraction movements of the seaJT"ring elements without undue friction when held in place by the lock nut.
  • an oil well plunger assembly comprising: an elongated stem having an upper portion provided with an interiorly threaded bore at an upper end thereof, and a plurality of equally spaced, axially extending flutes defining a corresponding number of flow channels therebetween; a lower coupler component secured to a lower end of the plurality of flutes, the coupler having an upper end face; a seal assembly slidably received over the flutes and supported on the upper end face of the lower coupler; and a locking element secured to the flutes above the seal assembly; wherein the seal assembly comprises a plurality of axially adjacent seals, each seal comprising a support ring and a seal ring element, the support ring formed with, a seal ring element receiving surface and a radial flange providing an abutment shoulder for the seal ring element, the radial flange having a radial end face provided with an outwardly facing groove.
  • an oil well plunger assembly comprising: an elongated stem having an upper portion provided with anInteriorly threaded bore at an upper end thereof, and a plurality of equally spaced, axially extending flutes defining a corresponding number of flow channels therebetween; a lower coupler component secured to a lower end of the plurality of flutes, the coupler having an upper end face; a plurality of seals slidably received over the flutes and supported on the upper end face of the lower coupler, each seal including a support ring and a seal ring supported thereon, each support ring provided with a plurality of pressure ports for communicating the flow channels with a associated seal ring element; wherein the plurality of pressure ports is larger in number than the plurality of flutes.
  • the invention provides an oil well plunger assembly comprising: an elongated stem having an upper portion provided with an interiorly threaded bore at an upper end thereof, and a plurality of equally spaced, axially extending flutes defining a corresponding number of flow channels therebetween; a lower coupler component secured to a lower end of the plurality of flutes, the coupler having an upper end face; a seal assembly slidably received over the flutes and supported on the upper end face of the lower coupler, the seal assembly comprising a plurality of seal rings seated on associated support rings, each support ring having a seal ring receiving surface; and a locking element secured to the flutes above the seal assembly for retaining the seal assembly on the stem; wherein the seal element receiving surface has an axial length greater than a corresponding axial le ⁇ gth of the seal ring.
  • FIGURE 1 is a perspective view of an exemplary plunger in accordance with the present invention.
  • FIGURE 2 is a side section view of the plunger illustrated in Figure 1;
  • FIGURE 3 is a side view of an elongated stem portion of the plunger illustrated in Figures 1 and 2;
  • FIGURE 4 is a bottom plan view of the elongated stem illustrated in Figure 3;
  • FIGURE 5 is a side sectional view of a lower coupling portion of the plunger illustrated in Figures 1 and 2;
  • FIGURE 6 is a side section view of a seal support ring of the type employed in the plunger construction illustrated in Figures 1 and 2;
  • FIGURE 7 is a top plan view of the support ring illustrated in Figure 6;
  • FIGURE 8 is a side section view of a seal ring element of the type shown in the plunger construction illustrated in Figures 1 and 2;
  • "-FIGURE 9 is an enlarged cross sectional view of the seal ring element illustrated in Figure 8;
  • FIGURE 10 is a side sectional view of a lock nut of the type used in the plunger construction illustrated in Figures 1 and 2;
  • FIGURE 11 is a top plan view of the lock nut illustrated in Figure 10.
  • the improved plunger of this invention is shown at 10, and generally includes an elongated stem component 12, a lower coupler 14 threadably secured to the lower end of the stem 12, and a seal assembly 16 comprising a plurality of annular seals (three in the exemplary embodiment) supported on an upper end face 18 of the coupler 14, and held in place by a lock nut 20 which is threadably secured to the stem 12.
  • the elongated stem 12 is generally cylindrical in shape and includes an upper portion 22 which is formed with an interior threaded bore 24 by which the stem may be attached to the lowermost sucker rod of a sucker string in the usual manner.
  • each flute 26, 28 and 30 is formed with an exteriorly threaded section 38 by which the lower coupler 14 is threadably secured to the stem.
  • intermediate portions of the respective flutes 26, 28 and 30 are also threaded as at 40 so as to enable the lock nut 20 to be secured to the stem.
  • the seal supporting surfaces 42 of the flutes have an outside diameter slightly greater than the diameter of the elongated stem in that portion above the intermediate threaded portions 40.
  • the lower coupler 14 is generally cylindrical in shape, the exterior surface of which is substantially smooth.
  • the interior surface 44 of the coupler is provided at its upper end with an interiorly threaded portion 46 and at its lower end with a similar interiorly threaded portion 48. These threaded portions are separated by a reduced diameter smooth bore portion 50.
  • the upper threaded portion 46 enables the lower coupler to be secured to the lower threaded portion 38 of the elongated stem 14, while the lower threaded portion 48 is adapted to receive a ball valve assembly (not shown) which those skilled in the art will appreciate may be any one of several commercially available ball valve assemblies. As such, the ball valve assembly per se forms no part of 11
  • seal assembly 16 will be described in detail.
  • three annular seals 52, 54 and 56 are slidably received over the elongated stem 12 supported by the upper end face 18 of the lower coupler 14, and the smooth external surfaces 42 of flutes 26, 28 and 30.
  • the annular seals 52, 54 and 56 are identical and, therefore, only one need be described in detail.
  • seal 52 comprises an annular support ring 58 and an annular seal ring element 60.
  • the support ring 58 best seen in Figures 6 and 7, has a generally cylindrical shape with a smooth bore inner surface 62 of constant diameter.
  • the outer surface of the support ring includes a first cylindrical portion 64 and an enlarged diameter portion which forms a radially outwardly extending flange 66 which provides an abutment shoulder 68 against which the seal ring element 60 abuts as will be described in further detail below.
  • the support ring 58 is provided with a plurality of pressure ports 70 (six preferred for a three flute stem, eight for a four flute stem), equally spaced abo ⁇ t the circumference of the support ring and axially, located so as to be substantially centered relative to the interior surface of the seal ring element as also described below.
  • the end face 72 of the.radial flange 64 is formed with an annular groove 74 which, as noted above, and as further described below, causes a pressure differential between the inner and outer surfaces of the seal ring element 60 during pumping.
  • Figures 8 and 9 illustrate the annular seal ring element 60, the element having an annular shape and formed with a smooth exterior surface 76 and a grooved interior surface 78. More specifically, the interior surface is machined to provide a groove or pressurization channel 80 centered between the ends of the seal element.
  • the seal element 60 may be constructed of a suitable thermoplastic material such as Arlon 1000TM or other suitable material which can be machined to very close tolerances thereby allowing the pressurization channel 80 to be precisely formed so that uniform expansion of the seal ring element 60 during pumping is insured.
  • the pressure ports 70 formed in the support ring 58 will be centered relative to, and in fluid communication with, the pressurization channel 80 when the seal ring element 60 is press fit onto the support ring 58, with the end of the seal element engaged with the abutment shoulder 68 of the support ring 58.
  • the width (or axial length) of the cylindrical support portion 62 of the support ring 58 is slightly greater (for example, 0.505 + .002 inch) than the width (or axial length) of the seal ring element 60 (for example, 0.500 - .002 inch) so that when the seals 52, 54 and 56 of the seal assembly 16 are mounted in place on the elongated stem 12 and held there by the lock nut 20, the individual seal ring elements 60 will not be 13
  • the lock nut 20 is also of substantially cylindrical shape having a generally smooth exterior surface 82, formed with opposed flats 84 which provide suitable tool engaging surfaces for tightening and loosening the lock nut.
  • the interior surface of the lock nut 20 is threaded as shown at 86 thereby enabling the lock nut to be secured to the elongated stem 12 via threaded portions 40 on the flutes 26, 28 and 30.
  • the individual seals 52, 54 and 56 (each comprising a support ring 58 and seal ring element 60) are slidably received over the elongated stem (with the radial flange portion 66 of each support ring 58 facing upwardly), the seal assembly resting on the upper end face 18 of the lower coupler 14.
  • the diameter of the flute surfaces 42 is closely matched to the interior diameter of the support rings 58 to permit sliding motion therebetween, but without any substantial play.
  • the inner diameter of the support rings 58 may be 2.312 + .002 inches, while the diameter of the elongated stem 12 along the. support surfaces 42 may be 2.284 - .0094 inch. Further in this regard, the outer diameter of the lower coupler, 14
  • the.outer diameter of the seal ring elements, and the radial flange portion of the seal support rings may be 2.747 - .002 inches.
  • the ball valve In use, and during an upward pumping stroke, the ball valve is closed and hydrostatic pressure from the column of fluid above the ball valve and within the flow channels 32, 34 and 36, will be transmitted through the pressure ports 70 to the pressurization channels 80 of the respective seal ring elements 60, causing radially outward expansion of the individual seal ring elements 60 to thereby seal off the barrel so that no fluid is able to pass between the plunger and the barrel. As a result, the column of fluid is lifted to the surface while drawing more fluid into the cylinder or barrel behind it. During the down stroke, the ball valve will open, relaxing the seal ring elements 60 and allowing fluid to flow past the plunger between the plunger and the barrel.
  • the carefully machined pressuri-zation channel 80 permits more uniform distribution of pressure and thus more uniform expansion of the seal ring elements than in prior known constructions.
  • the elongated stem 12, lower coupler 14, lock nut 20, and support rings 58 are preferably formed of a hardenable steel material, for example, 4140 steel alloy bar stock. This material is significantly stronger than the conventionally used aluminum bronze material, and thus allows cross sectional area reductions which further improve fluid flow capacity.
  • the hardenable steel material selected to have a Rockwell C-hardness of 40 or greater is better suited to the extremely abrasive environment in which the plunger is used.

Landscapes

  • Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Mining & Mineral Resources (AREA)
  • Physics & Mathematics (AREA)
  • Environmental & Geological Engineering (AREA)
  • Fluid Mechanics (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Sealing Devices (AREA)

Abstract

L'invention se rapporte à un ensemble (10) piston plongeur pour puits de pétrole qui comporte une tige allongée (12) pourvue d'une section supérieure (22) à trou fileté intérieurement (24) au niveau d'une extrémité supérieure de celle-ci, et une pluralité de cannelures (26, 28, 30) s'étendant axialement et espacées à distances égales, formant entre elles un nombre correspondant de canaux d'écoulement (32, 34, 36); un composant inférieur d'accouplement (14) est fixé à l'extrémité inférieure des cannelures. Un ensemble d'étanchéité (16) est réceptionné de manière coulissante sur les cannelures et est soutenu sur la face terminale supérieure de l'accouplement inférieur (14). L'ensemble d'étanchéité (16) comprend une pluralité de bagues d'étanchéité (52, 54, 56) placées sur des bagues supports combinées (58), chacune d'elles ayant une surface réceptrice pour la bague d'étanchéité. La surface réceptrice pour bague d'étanchéité (44) est formée d'une pluralité de canaux d'écoulement (32, 34, 36) et d'un canal de pressurisation (80) communiquant avec les admissions de pression (70), le nombre d'admissions de pression dépassant le nombre de cannelures.
PCT/US1993/001708 1992-03-03 1993-03-02 Piston plongeur pour puits de petrole WO1993018321A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU37336/93A AU3733693A (en) 1992-03-03 1993-03-02 Oil well plunger

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US84519792A 1992-03-03 1992-03-03
US07/845,197 1992-03-03

Publications (1)

Publication Number Publication Date
WO1993018321A1 true WO1993018321A1 (fr) 1993-09-16

Family

ID=25294627

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1993/001708 WO1993018321A1 (fr) 1992-03-03 1993-03-02 Piston plongeur pour puits de petrole

Country Status (1)

Country Link
WO (1) WO1993018321A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2462257A (en) * 1944-09-19 1949-02-22 John D Cunningham Pump plunger
US4395204A (en) * 1980-10-07 1983-07-26 Turner Richard L Oil well pump
US4762476A (en) * 1985-11-08 1988-08-09 Turner Richard L Oil well pump

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2462257A (en) * 1944-09-19 1949-02-22 John D Cunningham Pump plunger
US4395204A (en) * 1980-10-07 1983-07-26 Turner Richard L Oil well pump
US4762476A (en) * 1985-11-08 1988-08-09 Turner Richard L Oil well pump

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