Wellbore isolation apparatus, and method for tripping pipe during underbalanced drilling

The apparatus for maintaining a wellbore condition of claim 12, wherein:

• the tubular string is a string of drill pipe;
• the setting/releasing tool is rotationally locked with the drill pipe;
• and
• the wellbore operation tool is disposed below the wellbore isolation member.

A wellbore isolation apparatus for use during a drilling operation, the wellbore isolation apparatus being connected to a working string within the wellbore, and the wellbore isolation apparatus comprising:

• a tubular plug, the plug comprising:
• a tubular plug body,
• a sealing element disposed around the plug body,
• an anchoring member;
• and
• a flapper valve disposed along an inner surface of the tubular plug body, the flapper valve being moveable between an open position and a closed position, and being biased to its closed position;
• a setting/releasing tool connected to the working string, the setting/releasing tool comprising:
• a tubular inner mandrel having a top end and a bottom end,
• setting system for urging the sealing element and the anchoring member outward into engagement with the surrounding wellbore when the setting system is actuated, and
• a releasing system for urging the sealing element and the anchoring member inward towards the plug body when the releasing system is actuated;
• a releasable connector for releasably connecting the setting/releasing tool from the tubular plug;
• and wherein the bottom end of the tubular inner mandrel of the setting/releasing tool holds the flapper valve in its open position when the setting/releasing tool is connected to the plug, but clears the flapper valve to close when the setting/releasing tool is released from the plug and raised within the wellbore.

A method for isolating a condition in a wellbore during a wellbore operation, comprising the steps of:

• coupling a wellbore operation tool to a selectively actuatable wellbore isolation member:
• running the wellbore operation tool and coupled wellbore isolation member into the wellbore on a pipe string;
• conducting at least a part of the wellbore operation;
• setting the wellbore isolation member in the wellbore a first time in order to isolate a condition in the wellbore below the wellbore isolation member;
• releasing at least a portion of the remaining pipe string from the wellbore isolation member;
• retrieving the wellbore operation tool and coupled wellbore isolation member from the wellbore
• manipulating the wellbore operation tool;
• re-running the wellbore operation tool and coupled wellbore isolation member into the wellbore;
• setting the wellbore isolation member in the wellbore a second time in order to again isolate a condition in the wellbore below the wellbore isolation member.

A method for isolating formation pressure in a wellbore during a wellbore operation, the wellbore having a string of pipe therein, the pipe having a plug and a wellbore operation tool attached to the lower end of the pipe, the method comprising the steps of:

• setting the plug a first time so as to isolate formation pressures in the wellbore below the plug;
• releasing the string of pipe from the plug;
• removing the released string of pipe from the wellbore;
• releasing the set plug a first time from the wellbore;
• removing the plug and wellbore operation tool with a wireline;
• manipulating the wellbore operation tool at the surface;
• re-running the plug and wellbore operation tool into the wellbore on the wireline;
• setting the plug a second time so as to again isolate formation pressures in the wellbore below the plug;
• and
• releasing the set plug a second time so as to allow pressure communication through the plug.

A wellbore isolation apparatus for use during a drilling operation for drilling a lateral wellbore, the wellbore isolation apparatus being disposed within a primary wellbore, the wellbore isolation apparatus comprising:

• an anchor body having a first end and a second end;
• a sleeve slideably disposed on the anchor body, the sleeve being movable from a first position relative to the anchor body below the point of the lateral wellbore, to a second position relative to the anchor body above the point of the lateral wellbore;
• and
• a sealing element adjacent to the sleeve, the sealing element being place into sealing engagement with the surrounding primary wellbore when the sleeve is in the second position.

A method for isolating formation pressure in a primary wellbore during a sidetrack drilling operation, the method comprising the steps of:

• forming a lateral wellbore at a point of the primary wellbore;
• placing a wellbore isolation apparatus in the primary wellbore at a depth below the point of the lateral wellbore, the wellbore isolation apparatus comprising:
• an anchor body having a first end and a second end;
• a sleeve slideably disposed along the first end of the anchor body, the sleeve being movable from a first released position proximal to the anchor body to a second set position distal to the anchor body;
• and
• a sealing element adjacent to the sleeve proximate to an end opposite the anchor body, the sealing element being placed into sealing engagement with the surrounding primary wellbore when the sleeve is extended to its second set position;
• actuating the wellbore isolation apparatus so as to move the sleeve to its second position above the point of the lateral borehole.