Nitinol Through Tubing Bridge Plug

Abstract

A bridge plug assembly having a nickel titanium alloy flexible member that can be selectively radially expanded so its outer surface sealingly engages a surrounding tubular. The flexible member can comprise an annular membrane like member having coaxial rings on the opposing ends of the flexible member. The percentage of weight of nickel can range up to about 40 to about 58%, 55% or to about 60%.

1 . A bridge member for use in a bridge plug assembly, the bridge member comprising:
 a pair of spaced apart and substantially coaxial annular collars;   a plurality of elongated and superelastic ribs, each rib having opposing ends respectively coupled with the collars and a mid-portion projecting radially outward with respect to the ends of the ribs; and   a plurality of superelastic webs spanning between each adjacently spaced rib, so that when one of the collars is rotated with respect to the other collar, the mid-portion of the ribs is drawn radially inward, the bridge member elongates, and folds are formed in the webs.   
     
     
         2 . The bridge member of  claim 1 , wherein the ribs and webs comprise material that includes an alloy having nickel of about 55% to about 57% by weight and titanium of about 45% to about 43% by weight. 
     
     
         3 . The bridge member of  claim 1 , wherein when at least a portion of one of the ribs or webs is deformed from an applied load, the deformed portion undergoes an elastic phase transformation from an austenite to a deformed martensite. 
     
     
         4 . The bridge member of  claim 1 , wherein the rib thickness ranges from about one to three times the thickness of the web. 
     
     
         5 . The bridge member of  claim 1 , further comprising an annular elastomeric seal circumscribing the mid-portion of the ribs and having an outer surface in sealing contact with a tubular. 
     
     
         6 . The bridge member of  claim 1 , wherein the web elastically deforms at a value of up to about 8% along the folds. 
     
     
         7 . The bridge member of  claim 1 , wherein the web is subjected to a stress of about 733×10 8  N/m 2 . 
     
     
         8 . A method of blocking a tubular comprising:
 (a) providing a bridge plug assembly comprising: a mandrel, a bulbous membrane circumscribing the mandrel and formed from a superelastic material, a pair of end collars coupled on each end of the bridge member and circumscribing the mandrel   (b) configuring the membrane for travel within a tubular by rotating one of the collars with respect to the other collar and elastically forming folds within the membrane thereby drawing the membrane radially inward toward the mandrel;   (c) retaining a resistive force on the said one of the collars thereby elastically maintaining stress along the folds in the membrane;   (d) inserting the bridge plug assembly into the tubular,   (e) releasing the resistive force on the said one of the collars, so that the elastically maintained stress unfolds and expands the membrane to the configuration of step (a) to block the tubular.   
     
     
         9 . The method of  claim 8  further comprising, repeating step (b) and removing the bridge plug assembly from the tubular. 
     
     
         10 . The method of  claim 8 , wherein the bridge plug assembly further comprises ribs coupled with the membrane that are substantially aligned with the mandrel in step (a) and oblique with the mandrel in one of steps (b)-(d). 
     
     
         11 . The method of  claim 8 , wherein the membrane comprises material that includes an alloy having nickel of about 55% to about 57% by weight and titanium of about 45% to about 43% by weight. 
     
     
         12 . The method of  claim 8 , further comprising injecting liquid into the membrane. 
     
     
         13 . The method of  claim 8 , wherein step (b) further comprises preloading the bridge member. 
     
     
         14 . The method of  claim 8  wherein the tubular is within a wellbore. 
     
     
         15 . The method of  claim 8  wherein undulations are defined along outer circumference of the membrane. 
     
     
         16 . The method of  claim 8 , wherein the folds in step (b) are alternatingly facing 
     
     
         17 . A bridge plug assembly comprising:
 a bulbous and substantially hollow member that is formed from a superelastic material and comprising a membrane having a series of strategically located foldable regions;   a mandrel circumscribed by the member; and   a pair of spaced apart and annularly shaped ends that circumscribe the mandrel and are coupled to opposing ends of the member, so that when a rotational force is applied to one of the ends with respect to the other end, the outer diameter of the member reduces and folds form along the foldable regions that retain therein at least a portion of the force applied to said one of the ends   
     
     
         18 . The bridge plug assembly of  claim 17 , wherein the annularly shaped ends comprise a first annularly shaped end and a second annularly shaped end and the member further comprises elongated ribs coupled with the membrane that project from the first annularly shaped end into engagement with the second annularly shaped end, wherein the ribs are substantially parallel with the mandrel and oblique with the mandrel after the rotational force is applied to one of the ends. 
     
     
         19 . The bridge plug assembly of  claim 17  wherein the membrane comprises material having a nickel titanium alloy. 
     
     
         20 . The bridge plug assembly of  claim 17 , wherein the member comprises segments joined together, each segment having a raised mid, portion aligned with the mandrel so that the outer circumference of the member defines an undulating surface.