Indexing sleeve for single-trip, multi-stage fracing

A wellbore fluid treatment system, comprising:

• a plurality of plugs deploying down a tubing string;
• a first sliding sleeve deploying on the tubing string, the first sliding sleeve detecting passage of one or more of the plugs through the first sliding sleeve and activating a catch in response to a first detected number of the one or more plugs, the catch engaging a given one of the plugs passing in the first sliding sleeve once activated, the first sliding sleeve opening fluid communication between the tubing string and an annulus in response to fluid pressure applied down the tubing string to the given plug engaged in the catch;
• and
• a second sliding sleeve deploying on the tubing string uphole from the first sliding sleeve, the second sliding sleeve detecting passage of one or more of the plugs and activating a catch in response to a second detected number of the one or more plugs, the catch engaging a given one of the plugs passing in the second sliding sleeve once activated, the second sliding sleeve opening fluid communication between the tubing string and the annulus in response to fluid pressure applied down the tubing string to the given plug engaged in the catch,
• wherein at least one of the first or second sliding sleeves comprises:
• a first insert disposed in a bore and movable from a first position to a second position in response to fluid pressure from a first port;
• a second insert movably disposed in the bore relative to a second port, the second insert having the catch for moving the second insert, the catch disposed in an interior passage of the second insert, the catch having an inactive condition engaged by a portion of the first insert when the first insert has the first position, the catch having a default active condition disengaged by the portion of the first insert and exposed in the bore when the first insert moves toward the second position, the second insert movable from a closed condition restricting fluid communication through the second port to an opened condition permitting fluid communication through the second port;
• and
• a controller opening fluid communication through the first port in response to the detected number of the one or more plugs.

A wellbore fluid treatment method, comprising;

• deploying sliding sleeves on a tubing string in a wellbore, each sliding sleeve set to activate a catch therein after detecting passage of a predetermined number of plugs therethrough;
• counting one or more first plugs deployed down the tubing string as they pass through the sliding sleeves;
• activating a first catch on a first of the sliding sleeves automatically in response to the passage of the predetermined number of the one or more first plugs in the first sliding sleeve by:
• opening fluid pressure through a first port in the first sliding sleeve,
• moving a first insert in the first sliding sleeve in response to the fluid pressure from the first port,
• disengaging the first insert from the first catch in an inactive condition engaged by a portion of the first insert, and
• exposing the first catch in the first sliding sleeve to a default active condition disengaged by the first insert;
• landing a second plug deployed down the tubing string on the activated first catch;
• and
• opening a second insert relative to a second port in the first sliding sleeve by pumping fluid through the tubing string against the second plug landed in the first catch in the first sliding sleeve.

A downhole flow tool, comprising:

• a housing having a bore and defining first and second ports communicating the bore outside the housing;
• a first insert disposed in the bore and movable from a first position to a second position in response to fluid pressure from the first port;
• a second insert movably disposed in the bore relative to the second port, the second insert having a first catch for moving the second insert, the first catch having an inactive condition when the first insert has the first position, the first catch having an active condition when the first insert moves toward the second position, the second insert movable from a closed condition restricting fluid communication through the second port to an opened condition permitting fluid communication through the second port;
• and
• a controller comprising a sensor, a timer, and a valve, the sensor responsive to passage of a sensing element relative thereto, the timer activating a predetermined time interval in response to a response by the sensor, the valve activated in response to passage of the predetermined time interval and opening fluid communication through the first port.

A downhole flow tool, comprising:

• a housing having a bore and defining first and second ports communicating the bore outside the housing;
• a first insert disposed in the bore and movable from a first position to a second position in response to fluid pressure from the first port;
• a second insert movably disposed in the bore relative to the second port, the second insert having a catch for moving the second insert, the catch comprising a profile defined in an interior passage of the second insert, the profile having an inactive condition being covered by a portion of the first insert when the first insert has the first position, the profile having an active condition being exposed when the first insert moves toward the second position, the second insert movable from a closed condition restricting fluid communication through the second port to an opened condition permitting fluid communication through the second port;
• and
• a controller opening fluid communication through the first port in response to a predetermined signal.

A downhole flow tool, comprising:

• a housing having a bore and defining first and second ports communicating the bore outside the housing;
• a first insert disposed in the bore and movable from a first position to a second position in response to fluid pressure from the first port;
• a second insert movably disposed in the bore relative to the second port, the second insert having an interior passage and having a catch for moving the second insert, the catch having an inactive condition when the first insert has the first position, the catch having an active condition when the first insert moves toward the second position, the second insert movable from a closed condition restricting fluid communication through the second port to an opened condition permitting fluid communication through the second port;
• one or more plugs deployable through the bore of the housing and through the interior passage of the second insert, the one or more plugs having one or more sensing elements;
• and
• a controller opening fluid communication through the first port in response to a predetermined signal from the one or more sensing elements of the one or more plugs.