Sidewall drilling tool with hydraulically operated anchoring member and drilling member

A method for drilling through a sidewall in a tubular in a well, the method comprising:

• deploying a Bottom Hole Assembly (BHA) into the well to the depth at which the sidewall of the tubular is to be drilled, the BHA comprising:
• a motive assembly having a downhole torque generator which comprises a rotatable shaft;
• the BHA further comprising a fixed volume of downhole hydraulic fluid contained therein, defining a downhole hydraulic fluid supply;
• and
• a drilling tool coupled to the rotatable shaft, the drilling tool being adapted to connect to said downhole hydraulic fluid supply, wherein the drilling tool comprises:
• one or more anchoring members having an inner face contactable by hydraulic fluid from said downhole hydraulic fluid supply:
• a drilling member having a longitudinal axis and having an inner face contactable by hydraulic fluid from said downhole hydraulic fluid supply, wherein the inner face of the anchoring member is in fluid communication via said hydraulic fluid with the inner face of the drilling member such that both respective inner faces experience the same pressure of the said hydraulic fluid acting upon them;
• and
• a movement mechanism for rotating the drilling member about its longitudinal axis, wherein the drilling tool is further adapted to also connect to the downhole torque generator and wherein at least a portion of the said movement mechanism of the drilling tool is coupled to the rotatable shaft which provides said rotational movement:
• the method further comprising:
• operating the downhole torque generator of the motive assembly to rotate the rotatable shaft to rotate at least a portion of the movement mechanism of the drilling tool, and thereby rotating the drilling member around an axis perpendicular to the longitudinal axis of the drilling tool;
• operating the downhole torque generator of the motive assembly to additionally pressurise said hydraulic fluid for supply to the drilling tool;
• applying fluid pressure from said downhole hydraulic fluid supply to the inner face of the one or more anchoring members to firstly move the one or more anchoring members radially into contact with an inner surface of the well in response to modification of the fluid pressure;
• and
• applying fluid pressure from said downhole hydraulic fluid supply to the inner face of the drilling member to secondly move the drilling member radially in response to modification of the fluid pressure.

A drilling tool for use in a well, the drilling tool being adapted to connect to a downhole hydraulic fluid supply, the drilling tool having a longitudinal axis;

• the drilling tool comprising:
• at least one anchoring member having an inner face contactable by hydraulic fluid from said downhole hydraulic fluid supply and being moveable radially, by means of pressurised hydraulic fluid from said downhole hydraulic fluid supply acting upon said inner face, with respect to the longitudinal axis of the drilling tool, between:—
• a retracted position in which the at least one anchoring member is spaced apart from an inner surface of the well;
• and
• an extended position in which the anchoring member contacts an inner surface of the well;
• and
• a drilling member having a longitudinal axis and having an inner face contactable by hydraulic fluid from said downhole hydraulic fluid supply, the drilling member being rotatable in use about said longitudinal axis, wherein the drilling member is arranged within the drilling tool such that the longitudinal axis of said drilling member is substantially perpendicular to said longitudinal axis of said drilling tool;
• and
• wherein said drilling member is also moveable radially, by means of pressurised downhole hydraulic fluid from said downhole hydraulic fluid supply acting upon said inner face thereof, with respect to the longitudinal axis of the drilling tool between:—
• a retracted position in which the drilling member is spaced apart from an inner surface of the well;
• and
• an extended position in which the drilling member contacts an inner surface of the well;
• wherein the inner face of the anchoring member is in fluid communication via said hydraulic fluid with the inner face of the drilling member such that both respective inner faces experience the same pressure of the said hydraulic fluid acting upon them;
• wherein the drilling tool further comprises a movement mechanism for rotating the drilling member about its longitudinal axis;
• wherein the movement mechanism comprises a rotational translation movement mechanism arranged to translate rotational movement of a shaft rotatable in use about a longitudinal axis coincident and/or parallel with said longitudinal axis of the drilling tool into rotational movement of the drilling member about its longitudinal axis;
• wherein the drilling tool is further adapted to also connect to a downhole torque generator which comprises a rotatable shaft and wherein at least a portion of the said movement mechanism of the drilling tool is coupled to the rotatable shaft which provides said rotational movement;
• wherein the drilling tool is coupled to a motive assembly having said rotatable shaft, wherein operation of the motive assembly is configured to rotate the rotatable shaft and rotate said at least a portion of the movement mechanism of the drilling tool;
• wherein the operation of the motive assembly is configured to rotate the rotatable shaft and pressurise hydraulic fluid for supply to the drilling tool;
• wherein the drilling tool and the motive assembly when coupled together form a bottom hole assembly which is adapted to provide a fixed volume for the downhole hydraulic fluid, where:—
• the drilling tool is adapted to accommodate at least a portion of the said fixed volume of downhole hydraulic fluid at any given time;
• and
• the motive assembly is adapted to accommodate the remaining portion of the said fixed volume of downhole hydraulic fluid at said given time, and vice versa.

A drilling tool for use in a well, the drilling tool being adapted to connect to a downhole hydraulic fluid supply, the drilling tool having a longitudinal axis;

• the drilling tool comprising:
• at least one anchoring member having an inner face contactable by hydraulic fluid from said downhole hydraulic fluid supply and being moveable radially, by means of pressurised hydraulic fluid from said downhole hydraulic fluid supply acting upon said inner face, with respect to the longitudinal axis of the drilling tool, between:—
• a retracted position in which the at least one anchoring member is spaced apart from an inner surface of the well;
• and
• an extended position in which the anchoring member contacts an inner surface of the well;
• and
• a drilling member having a longitudinal axis and having an inner face contactable by hydraulic fluid from said downhole hydraulic fluid supply, the drilling member being rotatable in use about said longitudinal axis, wherein the drilling member is arranged within the drilling tool such that the longitudinal axis of said drilling member is substantially perpendicular to said longitudinal axis of said drilling tool;
• and
• wherein said drilling member is also moveable radially, by means of pressurised downhole hydraulic fluid from said downhole hydraulic fluid supply acting upon said inner face thereof, with respect to the longitudinal axis of the drilling tool between:—
• a retracted position in which the drilling member is spaced apart from an inner surface of the well;
• and
• an extended position in which the drilling member contacts an inner surface of the well;
• wherein the inner face of the anchoring member is in fluid communication via said hydraulic fluid with the inner face of the drilling member such that both respective inner faces experience the same pressure of the said hydraulic fluid acting upon them;
• wherein the drilling tool further comprises a movement mechanism for rotating the drilling member about its longitudinal axis;
• wherein the movement mechanism comprises a rotational translation movement mechanism arranged to translate rotational movement of a shaft rotatable in use about a longitudinal axis coincident and/or parallel with said longitudinal axis of the drilling tool into rotational movement of the drilling member about its longitudinal axis;
• wherein the drilling tool is further adapted to also connect to a downhole torque generator which comprises a rotatable shaft and wherein at least a portion of the said movement mechanism of the drilling tool is coupled to the rotatable shaft which provides said rotational movement;
• wherein the drilling tool is coupled to a motive assembly having said rotatable shaft, wherein operation of the motive assembly is configured to rotate the rotatable shaft and rotate said at least a portion of the movement mechanism of the drilling tool;
• wherein the motive assembly comprises a battery pack and a motor;
• and
• wherein the tool further comprises a rotary assembly operatively coupled to the motive assembly, wherein the rotary assembly comprises a piston, and wherein the motor is capable of being operated in reverse rotation which reverses rotation of the rotatable shaft and reduces fluid pressure within the tool due to retraction of the piston.

A method for drilling through a sidewall in a tubular in a well, the method comprising:

• deploying a drilling tool into the well to the depth at which the sidewall of the tubular is to be drilled, wherein the drilling tool comprises:
• one or more anchoring members and a drilling member and a drive shaft rotatably connected to the drilling member;
• the method further comprising:
• rotating the drive shaft and thereby rotating the drilling member around an axis perpendicular to a longitudinal axis of the drilling tool;
• and
• applying fluid pressure to an inner face of the one or more anchoring members to firstly move the one or more anchoring members radially into contact with an inner surface of the well in response to modification of the fluid pressure;
• applying fluid pressure to an inner face of the drilling member to secondly move the drilling member radially in response to modification of the fluid pressure;
• reducing fluid pressure to the inner face of the drilling member to firstly move said drilling member into a retracted position in which the drilling member is spaced apart from an inner surface of the well;
• reducing fluid pressure to the inner face of one or more anchoring members to secondly move said one or more anchoring members into a retracted position in which the at least one anchoring member is spaced apart from an inner surface of the well;
• and
• reversing the direction of rotation of the drive shaft to reduce fluid pressure within the tool to firstly move said drilling member and secondly move said one or more anchoring members into said respective retracted positions.