Frac Plug

Abstract

A plug apparatus comprises a wedge, a sealing ring, and a slip. The wedge comprises an axial wedge bore. A seat is defined in the wedge bore. The seat is adapted to receive a ball. The wedge has a tapered outer surface which decreases in diameter from the upper to the lower extent of the tapered outer surface. The sealing ring is received around the tapered outer surface of the wedge. The sealing ring has an axial ring bore and is radially expandable. The slip comprises an axial slip bore having a tapered inner surface. The tapered inner surface decreases in diameter from the upper to the lower extent of the tapered inner surface. The inner surface is adapted to receive the wedge. The wedge is adapted for displacement from an unset position generally above the slip to a set position wherein the wedge is received in the slip bore.

1 . A plug apparatus, comprising:
 (a) a wedge comprising:
 i) an axial wedge bore, 
 ii) a seat defined in said wedge bore adapted to receive a ball, and 
 iii) a tapered outer surface, said tapered outer surface decreasing in diameter from the upper extent of said tapered outer surface toward the lower extent of said tapered outer surface; 
   (b) a sealing ring received around said tapered outer surface of said wedge, said sealing ring having an axial ring bore and being radially expandable; and   (c) a slip comprising an axial slip bore, said slip bore:
 i) providing said slip with a tapered inner surface, said tapered inner surface decreasing in diameter from the upper extent of said tapered inner surface toward the lower extent of said tapered inner surface, and 
 ii) being adapted to receive said wedge along said tapered outer surface of said wedge; 
   (d) wherein said wedge is adapted for displacement from an unset position generally above said slip to a set position wherein said wedge is received in said slip bore along said tapered outer surface of said wedge.   
     
     
         2 . (canceled) 
     
     
         3 . The plug apparatus of  claim 1 , wherein said sealing ring includes:
 (a) an annular ring body comprising:
 i) a tapered ring bore complementary to said tapered outer surface of said wedge, 
 ii) an annular inner groove defined in said ring bore, and 
 iii) an annular outer groove defined in the outer surface of said ring body; 
   (b) an inner elastomeric seal received in said inner groove; and   (c) an outer elastomeric seal received in said outer groove.   
     
     
         4 . (canceled) 
     
     
         5 . The plug apparatus of  claim 1 , wherein said sealing ring and said slip are adapted to expand radially from an unset condition, in which said sealing ring and said slip have nominal outer diameters, to a set condition, in which said sealing ring and said slip have enlarged outer diameters, as said wedge is displaced from its said unset position to its said set position. 
     
     
         6 . (canceled) 
     
     
         7 . The plug apparatus of  claim 1 , wherein said sealing ring includes an annular ring body constructed of a sufficiently ductile material such that said ring body can expand radially to its said set condition without breaking. 
     
     
         8 . The plug apparatus of  claim 1 , wherein said annular ring body is fabricated from plastic. 
     
     
         9 . The plug apparatus of  claim 8 , wherein said annular ring body is fabricated from plastics selected from the group consisting of polycarbonates, polyamides, polyether ether ketones, and polyetherimides and copolymers and mixtures thereof. 
     
     
         10 . The plug apparatus of  claim 1 , wherein said annular ring body is fabricated from plastic and has a elongation factor of at least about 10%. 
     
     
         11 . The plug apparatus of  claim 1 , wherein said wedge and slip are fabricated from drillable composite materials. 
     
     
         12 . The plug apparatus of  claim 1 , wherein said ball seat is located in said wedge bore such that when said wedge is in its said set position said ball seat is situated axially proximate to said sealing ring. 
     
     
         13 . The plug apparatus of  claim 1 , wherein said ball seat is located in said wedge bore axially below the upper end of said wedge bore. 
     
     
         14 . The plug apparatus of  claim 1 , wherein said ball seat is located in said wedge bore such that when said wedge is in its said set position said ball seat is situated axially between the upper end of said sealing ring and the lower end of said slip. 
     
     
         15 . The plug apparatus of  claim 1 , wherein said ball seat is located in said wedge bore such that when said wedge is in its said set position said ball seat is situated axially below the midpoint of said slip bore. 
     
     
         16 . The plug apparatus of  claim 1 , wherein said ball seat is provided by an upward facing tapered reduction in the diameter of said wedge bore. 
     
     
         17 . The plug apparatus of  claim 16 , wherein said tapered reduction in diameter is approximately 15° off center. 
     
     
         18 . The plug apparatus of  claim 1 , wherein said tapered outer surface of said wedge is a truncated, inverted cone and said tapered inner surface of said slip is a truncated, inverted cone. 
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . The plug apparatus of  claim 1 , wherein said slip comprises a plurality of separate slip segments, each said slip segment configured generally as lateral segments of an open cylinder. 
     
     
         22 . The plug apparatus of  claim 21 , wherein said slip segments are aligned axially and, when said wedge is in its said unset position, circumferentially abut along their sides, said slip segments thereby providing a substantially continuous said inner tapered surface of said slip. 
     
     
         23 . The plug apparatus of  claim 1 , wherein the upper end of said slip abuts said sealing ring about the lower end of said sealing ring as said wedge moves from its said unset position to its said set position. 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . (canceled) 
     
     
         30 . (canceled) 
     
     
         31 . (canceled) 
     
     
         32 . (canceled) 
     
     
         33 . (canceled) 
     
     
         34 . (canceled) 
     
     
         35 . (canceled) 
     
     
         36 . (canceled) 
     
     
         37 . (canceled) 
     
     
         38 . A method of plugging a liner bore; said method comprising:
 (a) running a plug into a liner to a location to be plugged;   (b) setting said plug in said liner; and   (c) dropping a ball onto a ball seat provided in a wedge of said plug.   
     
     
         39 . A plug apparatus, comprising:
 (a) a wedge;   (b) a plastic sealing ring received around a tapered outer surface of said wedge, said sealing ring having an axial ring bore and being radially expandable; and   (c) a slip.