Adjustable Diameter Fishing Tool

Abstract

A technique utilizes a fishing tool that enables fishing operations for retrieval of well tools that may have a variety of sizes and configurations. The fishing tool is adjustable to enable selection of a desired size for engagement with a specific wellbore tool. The fishing tool is moved downhole to the well tool and engaged with the well tool. Once the fishing tool is engaged, the well tool can be retrieved to the surface.

1 . A method of making an adjustable fishing tool, comprising:
 preparing a mandrel with a mandrel end having a radially directed slope;   providing a fishing dog structure with a plurality of fishing dogs having attachment ends;   mounting the fishing dog structure around the mandrel for movement along the mandrel; and   positioning the attachment ends for sliding contact with the radially directed slope during movement of the fishing dog structure along the mandrel to enable engagement with wellbore tools having a variety of sizes.   
   
   
       2 . The method as recited in  claim 1 , further comprising spring biasing the attachment ends toward a larger diameter region of the mandrel end. 
   
   
       3 . The method as recited in  claim 2 , further comprising forming the fishing dog structure to create a chamber into which a fluid is pumped to move the fishing dog structure and the attachment ends against the spring bias. 
   
   
       4 . The method as recited in  claim 3 , further comprising pumping the fluid down through an internal passageway of the mandrel. 
   
   
       5 . The method as recited in  claim 1 , further comprising forming the mandrel with a lower mandrel portion attached to an upper mandrel portion. 
   
   
       6 . The method as recited in  claim 5 , further comprising positioning a soft spacer around the lower mandrel portion to provide a sliding surface for the attachment ends. 
   
   
       7 . The method as recited in  claim 6 , further comprising replacing the soft spacer with a soft spacer of another thickness to further enhance adjustability of the adjustable fishing tool. 
   
   
       8 . The method as recited in  claim 1 , further comprising forming the attachment ends with teeth to facilitate gripping a wellbore tool during a fishing operation. 
   
   
       9 . A device for use in a well, comprising:
 a fishing tool to engage well tools of a variety of sizes during a fishing operation, the fishing tool comprising:
 a mandrel having a mandrel end that transitions from a small diameter region to a large diameter region; and 
 a fishing dog structure slidably mounted along the mandrel, the fishing dog structure having attachment ends positioned against the mandrel end, wherein movement of the fishing dog structure along the mandrel moves the attachment ends between the small diameter region and the large diameter region to change the size of the fishing tool. 
   
   
   
       10 . The device as recited in  claim 9 , wherein the mandrel end has a radially outward slope. 
   
   
       11 . The device as recited in  claim 9 , wherein the fishing tool further comprises a top housing coupled to the mandrel opposite the mandrel end. 
   
   
       12 . The device as recited in  claim 11 , wherein the fishing tool comprises a spring positioned between the top housing and the fishing dog structure to bias the fishing dog structure toward the mandrel end. 
   
   
       13 . The device as recited in  claim 12 , wherein the fishing tool comprises a fluid flow path to a fluid chamber created by the fishing dog structure to enable movement of the fishing dog structure against the bias of the spring by pumping fluid along the fluid flow path. 
   
   
       14 . The device as recited in  claim 9 , wherein the fishing tool further comprises a sleeve positioned around at least a portion of the fishing dog structure to protect the fishing dog structure. 
   
   
       15 . The device as recited in  claim 9 , wherein the fishing tool comprises a soft spacer positioned around the mandrel to form a surface along which the attachment ends slide. 
   
   
       16 . The device as recited in  claim 15 , wherein the mandrel is formed with a lower mandrel portion attached to an upper mandrel portion. 
   
   
       17 . A method, comprising:
 moving a fishing tool downhole to a wellbore tool;   actuating the fishing tool to a configuration for engagement with any of a plurality of wellbore tools having different sizes; and   retrieving the wellbore tool with the fishing tool.   
   
   
       18 . The method as recited in  claim 17 , further comprising using the fishing tool to engage and retrieve another wellbore tool having a different size. 
   
   
       19 . The method as recited in  claim 17 , wherein actuating comprises setting a plurality of attachment ends at a desired diametrical placement. 
   
   
       20 . The method as recited in  claim 19 , wherein actuating comprises moving the attachment ends along a sloped surface of a mandrel to a desired diameter. 
   
   
       21 . The method as recited in  claim 20 , wherein actuating comprises changing the diametrical position of the attachment ends after engagement of the fishing tool with the wellbore tool to be retrieved. 
   
   
       22 . A device for performing a fishing operation, comprising:
 a fishing tool having attachment ends designed to engage a wellbore tool to be fished from a wellbore, the fishing tool further comprising an actuation mechanism to enable engagement of the attachment ends with wellbore tools of multiple sizes.   
   
   
       23 . The device as recited in  claim 22 , wherein the actuation mechanism comprises a mandrel having a mandrel end with a radially outward slope along which the attachment ends move. 
   
   
       24 . The device as recited in  claim 22 , wherein the attachment ends are spring biased to an expanded position. 
   
   
       25 . The device as recited in  claim 22 , wherein the actuation mechanism comprises a replaceable soft spacer.