Plunger with novel sealing

Abstract

A plunger for use in downhole tubulars in wells which produce fluids and/or gases under variable pressure. The plunger is slidingly engageable within the tubulars and capable of movement up and down the tubulars, and has a jacket comprised of segments mounted about a core which have sealing, holding, and lifting capabilities. An inner turbulent or labyrinth-type seal is accomplished by circumferential grooves on the core and/or fingers which project inwardly from the underside of the segments. When the pressure inside the tubulars above the plunger is reduced, the plunger and fluids move upwardly to the surface.

1 . A plunger for use in a gas/fluid lift system in downhole tubulars in wells producing fluids and/or gases under variable pressures, comprising: 
 a body slidingly engageable within the tubulars and capable of movement up and down said tubulars;    said body having a top end and a bottom end;    an inner core within the body for internal sealing;    a flexible jacket having plurality of segments mounted about said core, each of said segments having a convex outer surface and an inner surface, first and second sides, and top and bottom ends;    said jacket having an inner surface providing an internal seal, and an outer surface being radially expandable to provide an external seal against the interior of said tubulars;    a flow path for fluids and/or gases between said core and the inner surface of said jacket;    wherein each of said internal and external seals retards the upward flow of fluids and/or gases which thereby increases pressure below the plunger to thereby move the plunger and accumulated well fluids upwardly to the surface when the pressure inside the tubulars above the plunger is reduced.    
     
     
         2 . The plunger of  claim 1 , wherein the inner surface of each said segment has at least one rigid finger protruding radially inward toward the core, with the finger of each said segments cooperating to encircle the core and being separated from the core unless the fingers are pushed to their most inward position.  
     
     
         3 . The plunger of  claim 2 , wherein the finger has a flat bottom side and a flat top side, a curved concave inner surface, and first and second sides which are flat and angularly aligned with the side edges of the adjacent segments.  
     
     
         4 . The plunger of  claim 1 , having at least one circumferential groove in the surface of the core.  
     
     
         5 . The plunger of  claim 2 , having at least one circumferential groove in the surface of the core, wherein the finger is adjacent to the groove and fits into the groove.  
     
     
         6 . The plunger of  claim 2 , having a plurality of circumferential grooves in the surface of the core and a plurality of fingers on the inner surface of each said segment, wherein the fingers of each said segment project inwardly and cooperate to encircle said core.  
     
     
         7 . The plunger of  claim 6 , wherein the plurality of fingers and grooves creates a tortuous path of flow for fluids and/or gases and an increased surface area between the segments and the core which energizes the segments and pushes the segments outwardly to cause an outer seal with the tubulars.  
     
     
         8 . The plunger of  claim 5 , wherein at least one biasing means is placed between the inner surface of each segment and the core.  
     
     
         9 . The plunger of  claim 5 , wherein at least one groove has at least one blind hole which accommodates a biasing means, with the biasing means disposed between the core and the segment and biasing the segment outwardly from the core.  
     
     
         10 . The plunger of  claim 5 , wherein at least one the finger has a blind hole which accommodates a biasing means, with the biasing means disposed between the core and the finger and biasing the segment outwardly from the core.  
     
     
         11 . The plunger of  claim 8 , wherein the biasing means is a spring.  
     
     
         12 . The plunger of  claim 1 , having a core with at least one raised circumferential band.  
     
     
         13 . The plunger of  claim 1 , having at least one furrow on the underside of each segment.  
     
     
         14 . The plunger of  claim 12 , having at least one furrow on the underside of each segment with the band being adjacent to said furrow and fitting into the furrow, wherein said band is separated from said furrow unless said segments are pushed to their most inward position.  
     
     
         15 . The plunger of  claim 14 , wherein at least one band has at least one blind hole which accommodates a biasing means, the biasing means being disposed between the band and the furrow.  
     
     
         16 . The plunger of  claim 14 , wherein at least one furrow has a blind hole which accommodates the biasing means, the biasing means being disposed between the band and the furrow.  
     
     
         17 . The plunger of  claim 14 , having upper and lower retaining rings, the upper retaining ring being adjacent to the top end of the segments and the lower retaining ring being adjacent to the bottom ends of the segments, the retaining rings limiting the outward radial movement of the segments.  
     
     
         18 . The plunger of  claim 5 , having an upper and lower retaining ring wherein the interface between at least one finger and at least one groove prevents detachment and loss of the segments and/or biasing means if a retaining ring fails.  
     
     
         19 . The plunger of  claim 5 , wherein the segments have first and second sides with a tab or slot which is mutually and slidably engageable with the corresponding tab or slot of the adjacent segments.  
     
     
         20 . The plunger of  claim 19 , wherein the tabs and slots have stepped portions to maintain the overlapping between the tabs and slots in all of the radial positions and to guide the segments inwardly and outwardly.  
     
     
         21 . The plunger of  claim 19 , wherein the top and bottom ends of the segments are inwardly tapered.  
     
     
         22 . The plunger of  claim 19 , wherein the segments have notched top and bottom ends which slidably fit under the retaining rings  
     
     
         23 . The plunger of  claim 18 , wherein the segments have a notch in the outer surface of the top end and a notch in the outer surface of the bottom end, and wherein the retaining rings have a hollow inner surface and first and second ends, with the first end being positioned opposite to said segments and the second end of each retaining ring being positioned next to said segments and having at least one downwardly projecting lug which fits into said notch in each said segment.  
     
     
         24 . The plunger of  claim 6 , wherein at least one outer top edge of one of said grooves is angularly reduced to allow installation of the segments underneath said retaining rings.  
     
     
         25 . The plunger of  claim 5 , having a fishing piece attached to the top end of said body.  
     
     
         26 . The plunger of  claim 5 , having an end cap attached to the bottom end of said body.  
     
     
         27 . A plunger for use in a gas/fluid lift system in downhole tubulars in wells producing fluids and/or gases under variable pressures, comprising: 
 a body slidingly engageable within the tubulars and capable of movement up and down said tubulars;    said body having a top end and a bottom end;    an inner core within the body for internal sealing;    an external sealing means having an outside surface and an underside surface mounted about said core radially expandable to seal against the interior of said tubulars;    a flow path for fluids and/or gases between said core and the underside of said external sealing means;    an internal sealing means disposed between or on the core and/or the underside of said external sealing means;    said internal and external sealing means retarding the upward flow of fluids and/or gases which thereby increases pressure below the plunger to thereby move the plunger and accumulated well fluids upwardly to the surface when the pressure inside the tubulars above the plunger is reduced.    
     
     
         28 . The plunger of  claim 27 , wherein the external sealing means comprises a plurality of segments mounted around the core, the segments having a convex outer surface and an inner surface, first and second sides, and top and bottom ends, said segments being slidingly and sealingly engageable with the tubulars based upon the pressure effected between the segments and the core, and having the largest diameter of the plunger in an expanded radial position.  
     
     
         29 . The plunger of  claim 28 , wherein the segments have first and second sides with a tab or slot, the tab or slot being mutually and slidably engageable with the corresponding tab or slot in the sides of the adjacent segments and assisting with the inner and outer radial movement of the segments.  
     
     
         30 . The plunger of  claim 28 , wherein the internal sealing means comprises at least one rigid finger on the inner surface of the segments, the finger protruding radially inward toward the core, with the fingers of said segments cooperating to encircle the core and being separated from the core unless the fingers are pushed to their most inward position.  
     
     
         31 . The plunger of  claim 30 , wherein the finger has a flat bottom side and a flat top side, a curved concave inner surface, and first and second edges which are flat and angularly aligned with the first and second adjacent edges of the segment.  
     
     
         32 . The plunger of  claim 28 , wherein the internal sealing means comprises at least one circumferential groove in the surface of the core.  
     
     
         33 . The plunger of  claim 30 , wherein the internal sealing means further comprises at least one circumferential groove in the surface of the core, wherein the finger is adjacent to the groove and fits into the groove.  
     
     
         34 . The plunger of  claim 33 , wherein the elevation of the finger or fingers is at least as great as the depth of the groove.  
     
     
         35 . The plunger of  claim 33 , wherein the elevation of the finger or fingers is less than the depth of the groove.  
     
     
         36 . The plunger of  claim 33 , wherein the separation between the grooved core and the underside of said segments and said fingers create a tortuous path of flow and effect a turbulent inner seal.  
     
     
         37 . The plunger of  claim 33 , wherein the external sealing means further comprises retaining means which limits the outward radial movement of the external sealing means.  
     
     
         38 . The plunger of  claim 37 , wherein the retaining means is upper and lower retaining rings having a hollow inner surface, the upper retaining ring being adjacent to the top end of the segments, and the lower retaining ring being adjacent to the bottom ends of the segments.  
     
     
         39 . The plunger of  claim 33 , wherein the internal sealing means also comprises at least one biasing means disposed between the external sealing means and the core, and biasing the segment outwardly from the core.  
     
     
         40 . The plunger of  claim 39 , wherein at least one groove has at least one blind hole which accommodates a biasing means, and wherein at least one the finger has a blind hole which accommodates the same biasing means, with the biasing means disposed between the groove and the finger, and biasing the segment outwardly from the core.  
     
     
         41 . The plunger of  claim 39 , having an upper and lower retaining ring wherein the interface between at least one finger and at least one groove prevents detachment and loss of the segments and/or biasing means if a retaining ring fails.  
     
     
         42 . The plunger of  claim 38 , wherein the segments have notched top and bottom ends which slidably fit under the retaining rings.  
     
     
         43 . The plunger of  claim 38 , wherein the segments have a notch in the outer surface of the top end and a notch in the outer surface of the bottom end, and wherein said retaining rings have first and second ends, with the first end being positioned opposite to said segments and the second end being positioned next to said segments and having at least one downwardly projecting lug which fits into the notch in each said segments.  
     
     
         44 . The plunger of  claim 39 , wherein the biasing means is a spring.  
     
     
         45 . A method of lifting well fluids and/or gases from a subterranean reservoir to the surface in tubulars in wells comprising: placing a plunger having an inner core and an external sealing means mounted about said core radially expandable to provide an external seal against the interior of said tubulars and an internal sealing means disposed between or on the core and/or beneath said external sealing means which comprises at least one rigid finger and at least one circumferential groove disposed between or on said core and the external sealing means inside said tubulars to retard the upward flow of fluids and/or gases, allowing said plunger to descend or gravitate to the bottom of the well or a well stop, using internal sealing means to create a tortuous path of flow between said core and said external sealing means thereby effecting a turbulent inner seal which thereby pushes the external sealing means outwardly to cause an external seal with the tubulars, allowing the pressure to build up in the well to predetermined level, opening a valve connected to the tubulars which decreases the pressure inside the tubulars, thereby elevating the plunger and the accumulated well fluids to the surface.