Surge Pressure Reduction Apparatus with Convertible Diverter Device and Integrity Verification Device

Abstract

An apparatus for use in the oil and gas industry for installation of drilling and production liners and sub-sea casing strings into a borehole through a drilling fluid on a workstring using a running tool with the benefits of surge pressure reduction is disclosed. In an embodiment, a convertible diverter device has a housing with diverting flow path which diverts fluid from its axial passageway to the annular space outside the convertible diverter device, and a closing sleeve, residing within the housing, the closing sleeve having a diverting position and a closed position. In the diverting position, the diverting flow path is not blocked by the closing sleeve, and in the closed position the closing sleeve sealingly blocks the diverting flow path, so only the axial passageway through the housing is accessible for passage of fluid and tools. The closing sleeve is shifted by use of a frangible activation seat, in combination with an activation plug, whereby the frangible activation seat is pulverized after the closing sleeve converts to the closed position. Thereby, the axial passageway is left with an effective internal diameter that may be equal to the internal diameter of the closing sleeve, which may ensure safe passage of fluids and cementing plugs through the converted diverter during casing cementing operations.

What is claimed is: 
     
         1 . An apparatus for surge pressure reduction for installation of well casing with a convertible diverter device comprising:
 a) a housing assembly having an axial internal passageway, and a diverting flow path extending from the axial internal passageway through an outer surface of the housing assembly;   b) the housing assembly being connected within a length of a workstring on upper and lower ends of the housing assembly;   c) a closing sleeve releasably connected to the housing assembly;   d) the closing sleeve having a first position where its lower end is above the diverting flow path and a second position where the closing sleeve covers the diverting flow path, and seals are engaged within the housing assembly so substantially no fluid passes from the axial internal passageway through the outer surface of the housing assembly;   e) a frangible activation seat containing an axial hole therethrough, which is configured to catch and seal to an activation plug;   f) the activation plug is conveyed through the workstring to the convertible diverter device;   g) the frangible activation seat is releasably connected to the closing sleeve via a supporting sleeve so that hydraulic pressure applied above the frangible activation seat causes the frangible activation seat, the supporting sleeve, and the closing sleeve to move from the first position to the second position within the housing assembly;   h) the frangible activation seat subsequently releasing from the closing sleeve so the frangible activation seat falls into an impact surface so that the frangible activation seat breaks into small particles and the small particles, along with the activation plug, are moved through the workstring and well casing; and   i) leaving the convertible diverter device with an axial passageway that is about equal in diameter to the closing sleeve or the supporting sleeve, whichever is smaller.   
     
     
         2 . The apparatus of  claim 1 , wherein the frangible activation seat is glass. 
     
     
         3 . The apparatus of  claim 1 , wherein the activation plug is a ball. 
     
     
         4 . The apparatus of  claim 3 , wherein the activation plug has an elastomeric outer layer. 
     
     
         5 . The apparatus of  claim 1 , including an integrity verification device positioned below the convertible diverter device, the integrity verification device comprising:
 a) a verification housing assembly having an axial internal passageway;   b) the verification housing assembly being connected within the length of the workstring on upper and lower ends of the verification housing assembly;   c) a frangible verification seat containing an axial hole therethrough, which is configured to catch and seal to the activation plug;   d) the frangible verification seat is releasably connected to the verification housing assembly via a verification supporting sleeve so that hydraulic pressure applied above the frangible verification seat causes the frangible verification seat and the verification supporting sleeve to move from a test position to an open position within the verification housing assembly;   e) the frangible verification seat falls into an impact surface so that the frangible verification seat breaks into small particles and the small particles, along with the activation plug, are moved through the workstring and the well casing; and   f) leaving the integrity verification device with an axial passageway that is about equal in diameter to the verification housing or the verification supporting sleeve, whichever is smaller.