Continuous sucker rod and method of using same

Abstract

A continuous sucker rod preferably comprising fiberglass or composite material for use in an well is described herein. The continuous sucker rod may be connected at one end to a pump drive, via a polished rod, and at a second end to a downhole pump, via sinker bars or other weights. The continuous sucker rod preferably has at least two end fittings, one at each end of the continuous sucker rod. The end fittings, each having two ends and each being attached, at one end, to a respective end of the continuous sucker rod. The end fittings are preferably configured to enable connection to the polished rod and sinker bars respectively. The end fittings are connected to the continuous sucker rod so as to form wedges which enhance the connectability of the end fitting to the rod, and further, the wedge or wedges approach the rod asymptotically so as to avoid any abrupt discontinuities in the wedge or wedges thus substantially eliminating stress concentration areas and potential failure areas in the rod.

1 . A method for manufacturing a continuous sucker rod comprising the steps of:
 providing a plurality of glass fiber rovings and/or mats;   feeding and/or pulling said rovings and/or mats into a thermosetting resin bath;   wetting the oriented rovings and/or mats in the thermosetting resin bath, said resin creating adhesion between said rovings and/or mats and the resin filling spaces defined by the plurality of rovings and/or mats;   pulling and/or pushing said wetted rovings and/or mats through at least one die, wherein said die forms the wetted rovings and/or mats in a desired cross sectional shape;   curing said die formed shape, wherein the combination of said rovings and/or mats and said resin form a composite laminate; and   attaching at least one end fitting to the cured die formed shape.   
     
     
         2 . The method of  claim 1 , wherein the desired constant cross sectional shape is substantially polygonal shape. 
     
     
         3 . The method of  claim 1 , further comprising the step of winding said cured sucker rod on a reel, wherein said reel is sized such that the diameter of said reel is large enough to prevent damage to the rod during winding. 
     
     
         4 . The method of  claim 1 , further comprising placing a sub-surface pump in communication with said at least one end fitting. 
     
     
         5 . The method of  claim 1 , wherein attaching said at least one end fitting further comprises the step of flowably inserting a body of an initially flowable adhesive that cures to bond to an outer surface of said first end of said rod and to solidify to form at least one wedge to maintain attachment of said end fitting with said rod. 
     
     
         6 . The method of  claim 1 , wherein said at least one end fitting comprises a rod receptacle having a closed axially inner end and an open axially outer end and having at least one integrally formed, outwardly converging, axially aligned annulus, said annulus approaching the rod asymptotically and being tapered to be of decreasing diameter towards said open end, and defining a transition surface between said annulus and said open end, wherein said transition surface comprises a continuous function surface having no abrupt change in curvature. 
     
     
         7 . A method for using a continuous sucker rod comprising the steps of:
 forming and curing a continuous sucker rod, said rod having a first end and a second end;   attaching at least one end fitting to said first end of said rod, wherein said end fitting is adapted to be placed in communication with a sub-surface pump;   placing said sub-surface pump in communication with said at least one end fitting;   lowering said sub-surface pump and the continuous sucker rod into a well to a desired depth; and   attaching a second end fitting to said second end of said rod, wherein said second fitting is capable of interfacing with a pump drive unit, and wherein said pump drive unit actuates said sub-surface pump by stroking said pump by alternately pushing and pulling said continuous sucker rod.   
     
     
         8 . The method of  claim 7  wherein attaching said at least one end fitting further comprises the step of flowably inserting a body of an initially flowable adhesive that cures to bond to an outer surface of said first end of said rod and to solidify to form at least one wedge to maintain attachment of said end fitting with said rod. 
     
     
         9 . The method of  claim 7 , wherein said at least one end fitting comprises a rod receptacle having a closed axially inner end and an open axially outer end and having at least one integrally formed, outwardly converging, axially aligned annulus, said annulus approaching the rod asymptotically and being tapered to be of decreasing diameter towards said open end, and defining a transition surface between said annulus and said open end, wherein said transition surface comprises a continuous function surface having no abrupt change in curvature. 
     
     
         10 . The method of  claim 7 , wherein forming comprises die forming the rod to a predetermined cross-sectional shape. 
     
     
         11 . The method of  claim 10 , wherein the predetermined cross-sectional shape is substantially polygonal shaped. 
     
     
         12 . The method of  claim 7 , wherein the continuous sucker rod comprises more than one continuous sucker rod assembled together to form a sucker rod string capable of extending between the sub-surface pump and the pump drive unit.