Abstract: A downhole actuator (30) comprises a tubular housing (34) which includes an indexing profile (42) on an inner surface thereof, and an indexing sleeve (46) mounted within the housing (34). The indexing sleeve (46) comprises an engaging arrangement including first and second axially spaced engagement members (52, 54) which cooperate with the indexing profile (42) of the housing (34) to be sequentially engaged by an actuation object (48) passing through a central bore (50) of the indexing sleeve (46) to drive the indexing sleeve (46) one discrete step of movement through the housing (34) towards an actuation site.

Abstract: A downhole tool (32) comprises a tool housing (34) defining a central bore (35) and including a fluid port (20), and a valve member (40) mounted within the housing (34) and being movable from a closed position in which the fluid port (20) is blocked to an open position in which the fluid port (20) is opened. The tool (32) further comprises a catching arrangement (41) mounted within the housing (34) and comprising one or more radially movable seat members (106), and being configurable from a free configuration in which the seat members (106) permit an object (48) to pass through the tool (32), to a catching configuration in which the seat members (106) catch an object (48) passing through the tool (32).

Abstract: A downhole tool (32) comprises a tool housing (34) defining a central bore (35) and including a fluid port (20), and a valve member (40) mounted within the housing (34) and being moveable from a closed position in which the fluid port (20) is blocked to an open position in which the fluid port (20) is opened. The tool (32) further comprises a catching arrangement (41) mounted within the housing (34) and comprising one or more radially moveable seat members (106), and being configurable from a free configuration in which the seat members (106) permit an object (48) to pass through the tool (32), to a catching configuration in which the seat members (106) catch an object (48) passing through the tool (32).

Abstract: A downhole actuator (30) comprises a tubular housing (34) which includes an indexing profile (42) on an inner surface thereof, and an indexing sleeve (46) mounted within the housing (34). The indexing sleeve (46) comprises an engaging arrangement including first and second axially spaced engagement members (52, 54) which cooperate with the indexing profile (42) of the housing (34) to be sequentially engaged by an actuation object (48) passing through a central bore (50) of the indexing sleeve (46) to drive the indexing sleeve (46) one discrete step of movement through the housing (34) towards an actuation site.

Abstract: A downhole tool (32) comprises a tool housing (34) defining a central bore (35) and including a fluid port (20), and a valve member (40) mounted within the housing (34) and being moveable from a closed position in which the fluid port (20) is blocked to an open position in which the fluid port (20) is opened. The tool (32) further comprises a catching arrangement (41) mounted within the housing (34) and comprising one or more radially moveable seat members (106), and being configurable from a free configuration in which the seat members (106) permit an object (48) to pass through the tool (32), to a catching configuration in which the seat members (106) catch an object (48) passing through the tool (32).

Abstract: A query generator is operable to generate a query for retrieving data that satisfy a conditional expression from a database, and/or perform an arbitrary calculation on at least part of the retrieved data. The query generator can receive an input query and analyze the query to ascertain whether it contains a replaceable token. If the query contains a replaceable token, the query generator can replace that token with user input specifying a parameter of the conditional expression and/or the arbitrary calculation, thereby generating an output query for retrieving the data that satisfy the conditional expression and/or performing the arbitrary calculation on the retrieved data.

Abstract: A downhole tool (32) comprises a tool housing (34) defining a central bore (35) and including a fluid port (20), and a valve member (40) mounted within the housing (34) and being moveable from a closed position in which the fluid port (20) is blocked to an open position in which the fluid port (20) is opened. The tool (32) further comprises a catching arrangement (41) mounted within the housing (34) and comprising one or more radially moveable seat members (106), and being configurable from a free configuration in which the seat members (106) permit an object (48) to pass through the tool (32), to a catching configuration in which the seat members (106) catch an object (48) passing through the tool (32).

Abstract: A downhole actuator (30) comprises a tubular housing (34) which includes an indexing profile (42) on an inner surface thereof, and an indexing sleeve (46) mounted within the housing (34). The indexing sleeve (46) comprises an engaging arrangement including first and second axially spaced engagement members (52, 54) which cooperate with the indexing profile (42) of the housing (34) to be sequentially engaged by an actuation object (48) passing through a central bore (50) of the indexing sleeve (46) to drive the indexing sleeve (46) one discrete step of movement through the housing (34) towards an actuation site.

Abstract: A downhole actuator (30) comprises a tubular housing (34) which includes an indexing profile (42) on an inner surface thereof, and an indexing sleeve (46) mounted within the housing (34). The indexing sleeve (46) comprises an engaging arrangement including first and second axially spaced engagement members (52, 54) which cooperate with the indexing profile (42) of the housing (34) to be sequentially engaged by an actuation object (48) passing through a central bore (50) of the indexing sleeve (46) to drive the indexing sleeve (46) one discrete step of movement through the housing (34) towards an actuation site.

Abstract: A downhole tool (32) comprises a tool housing (34) defining a central bore (35) and including a fluid port (20), and a valve member (40) mounted within the housing (34) and being moveable from a closed position in which the fluid port (20) is blocked to an open position in which the fluid port (20) is opened. The tool (32) further comprises a catching arrangement (41) mounted within the housing (34) and comprising one or more radially moveable seat members (106), and being configurable from a free configuration in which the seat members (106) permit an object (48) to pass through the tool (32), to a catching configuration in which the seat members (106) catch an object (48) passing through the tool (32).

Abstract: A query generator is operable to generate a query for retrieving data that satisfy a conditional expression from a database, and/or perform an arbitrary calculation on at least part of the retrieved data. The query generator can receive an input query and analyze the query to ascertain whether it contains a replaceable token. If the query contains a replaceable token, the query generator can replace that token with user input specifying a parameter of the conditional expression and/or the arbitrary calculation, thereby generating an output query for retrieving the data that satisfy the conditional expression and/or performing the arbitrary calculation on the retrieved data.

Abstract: A query generator is operable to generate a query for retrieving data that satisfy a conditional expression from a database, and/or perform an arbitrary calculation on at least part of the retrieved data. The query generator can receive an input query and analyze the query to ascertain whether it contains a replaceable token. If the query contains a replaceable token, the query generator can replace that token with user input specifying a parameter of the conditional expression and/or the arbitrary calculation, thereby generating an output query for retrieving the data that satisfy the conditional expression and/or performing the arbitrary calculation on the retrieved data.

Abstract: A query generator is operable to generate a query for retrieving data that satisfy a conditional expression from a database, and/or perform an arbitrary calculation on at least part of the retrieved data. The query generator can receive an input query and analyze the query to ascertain whether it contains a replaceable token. If the query contains a replaceable token, the query generator can replace that token with user input specifying a parameter of the conditional expression and/or the arbitrary calculation, thereby generating an output query for retrieving the data that satisfy the conditional expression and/or performing the arbitrary calculation on the retrieved data.