Drill string diverter apparatus and method

A diverter apparatus connected in a pipe string used to lower a liner into a wellbore, said diverter apparatus comprising:

• a tubular housing having an outer diameter smaller than an outer diameter of said liner and having a longitudinal central opening flow passage communicated with a flow passage of said liner, said tubular housing defining a flow port therethrough to communicate said central opening with an annulus defined between said tubular housing and said wellbore;
• a closing sleeve disposed about said tubular housing, said closing sleeve being movable between a closed position wherein said closing sleeve covers said flow port to prevent flow therethrough and an open position wherein fluid in said tubular housing may be communicated with said annulus through said flow port;
• and
• locking means for permanently locking said closing sleeve in said closed position wherein said closing sleeve will move with the drill string and cannot be reopened either inadvertently or purposely without removing the apparatus from the wellbore.

A method of using a diverter apparatus in a wellbore, comprising the steps of:

• providing said diverter apparatus which comprises:
• a tubular housing having a central opening defined therein, said tubular housing defining a flow port therethrough to provide fluid communication with said central opening;
• a closing sleeve disposed about said tubular housing, said closing sleeve being movable between a closed position wherein said closing sleeve covers said flow port to prevent flow therethrough and an open position wherein fluid may be communicated through said flow port;
• and
• a locking element engageable with a slot defined in said outer surface of said housing to lock said sleeve in place in said closed position;
• connecting said diverter apparatus in a pipe string;
• disposing said pipe string and connected diverter apparatus in a wellbore;
• communicating fluid through said flow port;
• moving said closing sleeve from said open position to said closed position;
• and
• permanently locking said closing sleeve in said closed position wherein said closing sleeve will move with the pipe string and cannot be reopened either inadvertently or purposely without removing the apparatus from the wellbore.