Casing landing and cementing tool and methods of use

Abstract

A casing landing and cementing tool has a wellbore obstruction-clearing tool at a downhole end thereof and a check valve uphole of any fluid vulnerable components to isolate the vulnerable components from the threat of cement incursion. The check valve is manufactured of drillable materials, the plunger being axially actuable but non-rotatable, the valve body being threadably secured within the tool. In one aspect the tool is a sleeve bit rotatably and reciprocally coupled about a mandrel secured to a non-rotating casing string, the check valve located in the mandrel. In another aspect, the tool is a bit coupled to a rotatable casing string, the check valve located in the bit.

We claim: 
     
         1 . A casing landing and cementing tool for a wellbore comprising:
 a casing string having a casing bore;   an obstruction clearing tool at a downhole end of the casing string and having a tool bore in fluid communication with the casing bore, the tool having a vulnerable interface in fluid communication between the wellbore and the tool bore; and   a check valve in the tool bore uphole of the vulnerable interface.   
     
     
         2 . The tool of  claim 1  further comprising a check valve, the check valve comprising:
 an uphole seat body having a bore and a seal seat; 
 a plunger having an uphole head and a seal face about the head for sealable engagement with the seal seat in a closed position and a downhole guide shaft for axially guiding the plunger, the shaft having one or more ribs extending axially and radially therefrom; and 
 a downhole retainer body having a bore contiguous with the seal body's bore and an upstanding guide boss having a guide bore for slidably receiving the shaft, the boss having one or more axially extending slots open to the guide bore, each slot receiving a corresponding shaft rib for guiding the plunger axially between the closed position and an open position without relative rotation of the plunger. 
 
     
     
         3 . A check valve for a cementing string for a wellbore comprising:
 an uphole seat body having a bore and a seal seat;   a plunger having an uphole head and a seal face about the head for sealable engagement with the seal seat in a closed position and a downhole guide shaft for axially guiding the plunger, the shaft having one or more ribs extending axially and radially therefrom; and   a downhole retainer body having a bore contiguous with the seal body's bore and an upstanding guide boss having a guide bore for slidably receiving the shaft, the boss having one or more axially extending slots open to the guide bore, each slot receiving a corresponding shaft rib for guiding the plunger axially between the closed position and an open position without relative rotation of the plunger.   
     
     
         4 . The check valve of  claim 3  wherein the seal body, the retainer body and the plunger are drillable. 
     
     
         5 . The check valve of  claim 3  further comprising a spring about the plunger's guide shaft and sandwiched between the retainer body and the plunger for biasing the plunger to the closed position. 
     
     
         6 . A method for landing casing in a wellbore and cementing an wellbore annulus thereabout comprising:
 providing an obstruction clearing tool with a check valve adjacent and uphole of a vulnerable fluid path between the tool and the annulus;   running in a casing string with the obstruction clearing tool at a downhole end thereof;   clearing obstructions in the wellbore with the tool;   landing the casing string at target depth; and   delivering cement through the check valve located at the tool for cementing the casing string therein.   
     
     
         7 . The method of  claim 6  further comprising:
 rotating a downhole end of the tool to clear the obstructions; and 
 delivering the cement through the check valve at above the rotating portion of the tool.