Wellbore plug and method

Abstract

Disclosed is a wellbore plug having a design that allows the mandrel of the plug to be made of concrete or other easy-to-drill materials. Disclosed is a wellbore plug assembly with slip and packing assemblies configured to hold the plug in place during setting and use without tensioning the mandrel, thereby allowing the mandrel to be made from easily drillable material, such as concrete.

1 . An improved plug for installation in the wellbore at a subterranean location, the plug having an upper end for being positioned in the wellbore closest to the wellhead and a lower end for being positioned furthest away from the wellhead, the plug comprising a tubular mandrel, having an axially extending passageway, a packing assembly comprising an annular member comprising deformable material, the annular member being of a size and shape such that when it is axially compressed it extends radially into contact with the wellbore, upper and lower opposed slip assemblies positioned on the mandrel, wherein the upper and lower slip assemblies each comprise an annular member with a wedge surface, a slip support comprising an annular shoulder and a plurality of slips located around the mandrel between an annular wedge surface and the annular shoulder of the slip support, the slips being of a size and shape that when the slip assemblies are axially compressed, the slips extend radially into contact with the wellbore, the packing assembly being positioned on the mandrel between the upper and lower opposed slip assemblies and, wherein the improvement comprises the mandrel substantially comprises cementitious material. 
     
     
         2 . The wellbore plug of  claim 1 , wherein the cementitious material comprises concrete. 
     
     
         3 . The wellbore plug of  claim 1 , additionally comprising a setting rod extending into the mandrel passageway in sliding relationship with the mandrel. 
     
     
         4 . The wellbore plug of  claim 3 , wherein the setting rod is releasably connected to the lower end of the wellbore plug. 
     
     
         5 . The wellbore plug of  claim 3 , wherein lower slip assembly comprises a sleeve on the mandrel, wherein the sleeve has an upward facing radial shoulder and wherein the setting rod extends through the mandrel passageway from the upper end of the mandrel and, wherein the setting rod is connected to the lower slip support. 
     
     
         6 . The wellbore plug of  claim 1 , wherein the upper and lower slip assemblies each comprise an annular member with a wedge surface, a slip support comprising an annular shoulder, and a plurality of slips located around the mandrel between an annular wedge surface and the annular shoulder of the slip support, the slips being of a size and shape that when the slip assemblies are axially compressed, the slips extend radially into contact with the wellbore. 
     
     
         7 . The wellbore plug of  claim 1 , wherein the lower slip support is formed on a sleeve connected to the lower end of the mandrel. 
     
     
         8 . The wellbore plug of  claim 4 , wherein the lower slip support is formed integrally on the mandrel. 
     
     
         9 . An improved plug for installation in the wellbore at a subterranean location, the plug having an upper end for being positioned in the wellbore closest to the wellhead and a lower end for being positioned furthest away from the wellhead, the plug comprising a tubular mandrel, having an axially extending passageway, a packing assembly comprising an annular member comprising deformable material, the annular member being of a size and shape such that when it is axially compressed it extends radially into contact with the wellbore, upper and lower opposed slip assemblies positioned on the mandrel, wherein the upper and lower slip assemblies each comprise an annular member with a wedge surface, a slip support comprising an annular shoulder and a plurality of slips located around the mandrel between an annular wedge surface and the annular shoulder of the slip support, the slips being of a size and shape that when the slip assemblies are axially compressed, the slips extend radially into contact with the wellbore, the packing assembly being positioned on the mandrel between the upper and lower opposed slip assemblies, a setting rod extending into the axially extending passageway in sliding relationship with the mandrel and, wherein the improvement comprises the setting rod connected to the lower slip support. 
     
     
         10 . The wellbore plug of  claim 9 , wherein the lower slip support is formed on a sleeve mounted adjacent the lower end of the mandrel and wherein the setting rod is releasably connected to the sleeve at a point substantially adjacent to or below the annular shoulder. 
     
     
         11 . The wellbore plug of  claim 9 , wherein the lower slip support is an annular shoulder is formed mandrel adjacent the lower end of the mandrel and wherein the setting rod is releasably connected to the mandrel at a point substantially adjacent to or below the annular shoulder. 
     
     
         12 . The wellbore plug of  claim 9 , wherein the setting rod is selected from the group consisting of a hollow member, a cable and a solid member. 
     
     
         13 . The wellbore plug according to  claim 9 , wherein releasable means is selected from the group consisting of a shear pin and a breakable portion of the setting rod. 
     
     
         14 . The wellbore plug according to  claim 9 , wherein interior sleeve forms a lining along at least a portion of the passageway wall of the mandrel. 
     
     
         15 . The wellbore plug according to  claim 9 , additionally comprising a check valve located on the mandrel adjacent the mandrel's end, the valve is mounted to block flow into the mandrel passageway and permits flow out of the mandrel passageway. 
     
     
         16 . The wellbore plug of  claim 9 , wherein the mandrel substantially comprises material from the group consisting of cementitious material, sintered metal material and plastic material. 
     
     
         17 . A method of setting and using a plug at a subterranean location in a wellbore to contact wellbore fluids, comprising the steps of:
 providing a wellbore plug, comprising an upper end for being positioned in the wellbore closest to the wellhead and a lower end for being positioned furthest away from the wellhead, a tubular-shaped mandrel, a packing assembly positioned on the mandrel comprising an annular member comprising deformable material, the annular member being of a size and shape such that when it is axially compressed, it extends radially into contact with the wellbore, upper and lower opposed slip assemblies positioned on the mandrel, wherein the upper and lower slip assemblies each comprise an annular member with a wedge surface, a slip support comprising an annular shoulder and a plurality of slips located around the mandrel between an annular wedge surface and the annular shoulder of the slip support, the slips being of a size and shape that when the slip assemblies are axially compressed, the slips extend radially into contact with the wellbore, the packing assembly positioned on the mandrel between the upper and lower opposed slip assemblies;   attaching the plug to a setting tool;   positioning the plug and setting tool in the wellbore at a subterranean location with the upper end of the plug positioned closest to the wellhead; and   setting the plug in the wellbore, without applying axial force to the mandrel, by moving the slips and packing element to the set position into engagement with the wellbore.   
     
     
         18 . The method of  claim 17 , wherein the moving step comprises using the setting tool to apply force to the upper slip assembly in a direction toward the lower end of the plug, and simultaneously applying force to the lower slip support in a direction toward the upper end of the plug, without applying axial force to the mandrel. 
     
     
         19 . The method of  claim 17 , wherein the attaching step additionally comprises positioning a setting rod to extend into the mandrel in sliding relationship and releasably connecting the setting rod to the lower slip support at a point substantially adjacent to or below the radial shoulder of the lower slip support. 
     
     
         20 . The method of  claim 17 , wherein the moving step comprises using the setting tool to push in the downward direction on the slip support of the upper slip assembly while pulling in the upward direction on the slip support of the lower slip assembly, without applying axial force to the mandrel.