Patent Description:
Advances in the petroleum industry have allowed access to oil and gas drilling locations and reservoirs that were previously inaccessible due to technological limitations. For example, technological advances have allowed drilling of offshore wells at increasing water depths and in increasingly harsh environments, permitting oil and gas resource owners to successfully drill for otherwise inaccessible energy resources. Likewise, drilling advances have allowed for increased access to land based reservoirs.

Much of the time spent in drilling to reach these reservoirs is wasted "non-productive time" (NPT) that is spent in doing activities which do not increase well depth, yet may account for a significant portion of costs. For example, when drill pipe is pulled out of or lowered into a previously drilled section of well it is generally referred to as "tripping. " Accordingly, tripping-in may include lowering drill pipe into a well (e.g., running in the hole or RIH) while tripping-out may include pulling a drill pipe out of the well (pulling out of the hole or POOH). Tripping operations may be performed to, for example, install new casing, change a drill bit as it wears out, clean and/or treat the drill pipe and/or the wellbore to allow more efficient drilling, run in various tools that perform specific jobs required at certain times in the oil well construction plan, etc. However, the tripping process may also lead to well pressure variations, for example, due to the movement of the drill string resulting in additional drag, inertial and local resistances, and pressure losses. Such pressure variations may induce surge and swab pressures that could affect the well stability leading to a well control intervention.

<CIT> discloses an automated pipe tripping apparatus. A control system varies the tripping speed based on feedback of a pressure sensor located at the end of a tubular member within the tripping apparatus. The pressure sensor monitors of any change in pressure during a continuous tripping operation.

In one aspect of the present disclosure there is provided a system according to claim <NUM> and a tangible, non-transitory computer-readable medium according to claim <NUM>.

When introducing elements of various embodiments, the articles "a," "an," "the," and "said" are intended to mean that there are one or more of the elements.

Present embodiments are directed to components, systems, and techniques (e.g., a tripping speed determination system) utilized in conjunction with a continuous tripping system. Pressure variations that may occur during continuous tripping induce surge and swab pressures that could affect the well stability leading to a well control intervention. Surges (or surge pressures) may describe an increase in pressures in a well (e.g., an increase in a pressure generated by drilling fluid in the well) based upon a tripping-in operation inclusive of movement of a drill string when lowering drill pipe into a well (e.g., running in the hole or RIH), for example, due to frictional forces between the movement of the pipe and the drilling fluid (e.g., drilling mud). Swabs (or swab pressures) may describe a decrease in pressures in a well (e.g., a decrease in a pressure generated by drilling fluid in the well) based upon a tripping-out operation inclusive of movement of a drill string when pulling a drill pipe out of the well (pulling out of the hole or POOH), for example, due to frictional forces between the movement of the pipe and the drilling fluid (e.g., drilling mud).

Accordingly, present embodiments are related to determination and/or control of surge and swab pressure variations with respect to pore pressures (e.g., the pressure of fluids within the pores of a formation rock) and/or fracture pressures (e.g., pressures above which injection of fluids will cause a formation to hydraulically fracture), for example, to avoid undesirable influxes or mud losses. In some embodiments, this may be accomplished through the use of a hardware suite of one or more processors, as well as a suite of one or more software programs (e.g., instructions configured to be executed by a processor, whereby the instructions are stored on a tangible, non-transitory computer-readable medium such as memory) that may operate in conjunction to determine limiting speeds for continuous tripping operations and, in some embodiments, operate to control speeds of continuous tripping operations.

With the foregoing in mind, <FIG> illustrates an offshore platform <NUM> as a drillship. Although the presently illustrated embodiment of an offshore platform <NUM> is a drillship (e.g., a ship equipped with a drilling system and engaged in offshore oil and gas exploration and/or well maintenance or completion work including, but not limited to, casing and tubing installation, subsea tree installations, and well capping), other offshore platforms <NUM> such as a semi-submersible platform, a jack up drilling platform, a spar platform, a floating production system, or the like may be substituted for the drillship. Indeed, while the techniques and systems described below are described in conjunction with a drillship, the techniques and systems are intended to cover at least the additional offshore platforms <NUM> described above. Likewise, while an offshore platform <NUM> is illustrated and described in <FIG>, the techniques and systems described herein may also be applied to and utilized in onshore (e.g., land based) drilling activities. These techniques may also apply to at least vertical drilling or production operations (e.g., having a rig in a primarily vertical orientation drill or produce from a substantially vertical well) and/or directional drilling or production operations (e.g., having a rig in a primarily vertical orientation drill or produce from a substantially non-vertical or slanted well or having the rig oriented at an angle from a vertical alignment to drill or produce from a substantially non-vertical or slanted well).

As illustrated in <FIG>, the offshore platform <NUM> includes a riser string <NUM> extending therefrom. The riser string <NUM> may include a pipe or a series of pipes that connect the offshore platform <NUM> to the seafloor <NUM> via, for example, a BOP <NUM> that is coupled to a wellhead <NUM> on the seafloor <NUM>. In some embodiments, not being part of the present invention the riser string <NUM> may transport produced hydrocarbons and/or production materials between the offshore platform <NUM> and the wellhead <NUM>, while the BOP <NUM> may include at least one BOP stack having at least one valve with a sealing element to control wellbore fluid flows. In some embodiments, not being part of the present invention the riser string <NUM> may pass through an opening (e.g., a moonpool) in the offshore platform <NUM> and may be coupled to drilling equipment of the offshore platform <NUM>. As illustrated in <FIG>, it may be desirable to have the riser string <NUM> positioned in a vertical orientation between the wellhead <NUM> and the offshore platform <NUM> to allow a drill string made up of drill pipes <NUM> to pass from the offshore platform <NUM> through the BOP <NUM> and the wellhead <NUM> and into a wellbore below the wellhead <NUM>. Also illustrated in <FIG> is a drilling rig <NUM> (e.g., a drilling package or the like) that may be utilized in the drilling and/or servicing of a wellbore below the wellhead <NUM>.

In a tripping-in operation consistent with embodiments of the present disclosure, as depicted in <FIG>, a tripping apparatus <NUM> is positioned on the drilling floor <NUM> in the drilling rig <NUM> above the wellbore <NUM> (e.g., the drilled hole or borehole of a well which may be, as illustrated in <FIG>, proximate to the drilling floor <NUM> in land based drilling operations or which may be, in conjunction with <FIG>, below the wellhead <NUM>). The drilling rig <NUM> may include one or more of, for example, the tripping apparatus <NUM>, floor slips <NUM> positioned in rotary table <NUM>, drawworks <NUM>, a crown block <NUM>, a travelling block <NUM>, a top drive <NUM>, an elevator <NUM>, and a tubular handling apparatus <NUM>. The tripping apparatus <NUM> may operate to couple and decouple tubular segments (e.g., drill pipe <NUM> to and from a drill string) while the floor slips <NUM> may operate to close upon and hold a drill pipe <NUM> and/or the drill string passing into the wellbore <NUM>. The rotary table <NUM> may be a rotatable portion of the drilling floor <NUM> that may operate to impart rotation to the drill string either as a primary or a backup rotation system (e.g., a backup to the top drive <NUM>).

The drawworks <NUM> may be a large spool that is powered to retract and extend drilling line <NUM> (e.g., wire cable) over a crown block <NUM> (e.g., a vertically stationary set of one or more pulleys or sheaves through which the drilling line <NUM> is threaded) and a travelling block <NUM> (e.g., a vertically movable set of one or more pulleys or sheaves through which the drilling line <NUM> is threaded) to operate as a block and tackle system for movement of the top drive <NUM>, the elevator <NUM>, and any tubular member (e.g., drill pipe <NUM>) coupled thereto. The top drive <NUM> may be a device that provides torque to (e.g., rotates) the drill string as an alternative to the rotary table <NUM> and the elevator <NUM> may be a mechanism that may be closed around a drill pipe <NUM> or other tubular members (or similar components) to grip and hold the drill pipe <NUM> or other tubular members while those members are moving vertically (e.g., while being lowered into or raised from the wellbore <NUM>). The tubular handling apparatus <NUM> may operate to retrieve a tubular member from a storage location <NUM> (e.g., a pipe stand) and position the tubular member during tripping-in to assist in adding a tubular member to a tubular string. Likewise, the tubular handling apparatus <NUM> may operate to retrieve a tubular member from a tubular string and transfer the tubular member to a storage location <NUM> (e.g., a pipe stand) during tripping-out to remove the tubular member from the tubular string.

During a tripping-in operation, the tubular handling apparatus <NUM> may position a first tubular segment <NUM> (e.g., a first drill pipe <NUM>) so that the segment <NUM> may be grasped by the elevator <NUM>. The elevator <NUM> may be lowered, for example, via the block and tackle system towards the tripping apparatus <NUM> to be coupled to a second tubular segment <NUM> (e.g., a second drill pipe <NUM>) as part of a drill string. As illustrated in <FIG>, the tripping apparatus <NUM> may include tripping slips <NUM> inclusive of slip jaws <NUM> that engage and hold the second tubular segment <NUM> as well as a forcing ring <NUM> that operates to provide force to actuate the slip jaws <NUM>. The tripping slips <NUM> may, thus, be activated to grasp and support the segment, and, accordingly, an associated tubular string (e.g., drill string) when the tubular string is disconnected from the block and tackle system. The tripping slips <NUM> may be actuated hydraulically, electrically, pneumatically, or via any similar technique.

The tripping apparatus <NUM> may further include a roughneck <NUM> that may operate to selectively make-up and break-out a threaded connection between tubular segments <NUM> and <NUM> in a tubular string. In some embodiments, the roughneck <NUM> may include one or more of fixed jaws <NUM>, makeup/breakout jaws <NUM>, and a spinner <NUM>. In some embodiments, the fixed jaws <NUM> may be positioned to engage and hold the second (lower) tubular segment <NUM> below a threaded joint <NUM> thereof. In this manner, when the first (upper) tubular segment <NUM> is positioned coaxially with the second tubular segment <NUM> in the tripping apparatus <NUM>, the second tubular segment <NUM> may be held in a stationary position to allow for the connection of the first tubular segment <NUM> and the second tubular segment (e.g., through connection of the threaded joint <NUM> of the second tubular segment <NUM> and a threaded joint <NUM> of the first tubular segment <NUM>).

To facilitate this connection, the spinner <NUM> and the makeup/breakout jaws <NUM> may provide rotational torque. For example, in making up the connection, the spinner <NUM> may engage the first tubular segment <NUM> and provide a relatively high-speed, low-torque rotation to the first tubular segment <NUM> to connect the first tubular segment <NUM> to the second tubular segment <NUM>. Likewise, the makeup/breakout jaws <NUM> may engage the first tubular segment <NUM> and may provide a relatively low-speed, high-torque rotation to the first tubular segment <NUM> to provide, for example, a rigid connection between the tubular segment <NUM> and <NUM>. Furthermore, in breaking- out the connection, the makeup/breakout jaws <NUM> may engage the first tubular segment <NUM> and impart a relatively low-speed, high-torque rotation on the first tubular segment <NUM> to break the rigid connection. Thereafter, the spinner <NUM> may provide a relatively high-speed, low-torque rotation to the first tubular segment <NUM> to disconnect the first tubular segment <NUM> from the second segment <NUM>.

In some embodiments, the roughneck <NUM> may further include a mud bucket <NUM> that may operate to capture drilling fluid, which might otherwise be released during, for example, the break-out operation. In this manner, the mud bucket <NUM> may operate to prevent drilling fluid from spilling onto drill floor <NUM>. In some embodiments, not being part of the present invention the mud bucket <NUM> may include one or more seals that aid in fluidly sealing the mud bucket <NUM> as well as a drain line that operates to allow drilling fluid contained within mud bucket <NUM> to return to a drilling fluid reservoir.

Returning to <FIG>, the tripping apparatus <NUM> may be movable with respect to the drill floor <NUM> (e.g., towards and away from the drill floor <NUM>) and, in some embodiments, relative to the tripping slips <NUM>. In other embodiments, the tripping apparatus <NUM> can be moved along the direction of the rig towards and away from the drilling floor <NUM> in conjunction with slanted well operations when the rig is oriented at an angle from a vertical alignment to respectively drill or produce from a substantially non-vertical or slanted well. Movement of the tripping apparatus <NUM> may be accomplished through the use of hydraulic pistons, jackscrews, racks and pinions, cable and pulley, a linear actuator, or the like along one or more supports <NUM>. This movement may be beneficial to aid in proper location of the roughneck <NUM> during a make-up or break-out operation (e.g., during a tripping-in or tripping-out operation).

In some embodiments, moving of the tripping apparatus <NUM> into position (whether in conjunction with a continuous tripping operation in which the tubular segments <NUM> and <NUM> are moving towards or away from the drill floor <NUM> while being made-up or broken-out or in conjunction with a static tripping operation in which the tubular segments <NUM> and <NUM> remain in a static position relative to the drill floor <NUM> while being made-up or broken-out) may be undertaken in conjunction with a tripping operation at a fixed speed. However, it may be advantageous to instead utilize techniques and one or more systems to determine a variable speed for the tripping operation undertaken in conjunction with the tripping apparatus <NUM> to facilitate a make-up or break-out (e.g., tripping) operation at speeds that may be variable based upon sensitivities of surge and swab pressures.

To facilitate this determination of when to adjust the speeds of a tripping operation, a computing system <NUM> may be present and may operate to control the speed of a tripping operation (e.g., to control the rate and/or timing of moving tripping apparatus <NUM> into position as well as the operation of the tripping apparatus <NUM> as well as to control the rate and/or timing of the operation of the floor slips <NUM> positioned in rotary table <NUM>, the drawworks <NUM>, the top drive <NUM>, the elevator <NUM>, the tubular handling apparatus <NUM>, for example. This control of the speed of a tripping operation may be based on, for example, determined or calculated pressure values (e.g., pore pressures, fracture pressures, etc.) for a well in which drill pipe <NUM> is present as well as surge and/or swab pressures related to the determined or calculated pressure values at various tripping operation speeds. In some embodiments, the computing system <NUM> may be communicatively coupled to a separate main control system <NUM>, for example, a control system in a driller's cabin that may provide a centralized control system for drilling controls, automated pipe handling controls, and the like. In other embodiments, the computing system <NUM> may be a portion of the main control system <NUM> (e.g., the control system present in the driller's cabin).

<FIG> illustrates the computing system <NUM>. It should be noted that the computing system <NUM> may be a standalone unit (e.g., a control monitor) that may operate to generate output control signals (e.g., to form a control system). Likewise, the computing system <NUM> may be configured to operate in conjunction with the tripping apparatus <NUM>, one or more of the drawworks <NUM>, the top drive <NUM>, and the elevator <NUM>, and/or the tubular handling apparatus <NUM>. The computing system <NUM> may be a general purpose or a special purpose computer that includes a processing device <NUM>, such as one or more application specific integrated circuits (ASICs), one or more processors, or another processing device that interacts with one or more tangible, non-transitory, machine-readable media (e.g., memory <NUM>) of the computing system <NUM>, which may operate to collectively store instructions executable by the processing device <NUM> to perform the methods and actions described herein. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by the processing device <NUM>. In some embodiment, the instructions executable by the processing device <NUM> are used to generate, for example, control signals to be transmitted to, for example, one or more of the tripping apparatus <NUM> (e.g., the roughneck <NUM> and/or one or more of the fixed jaws <NUM>, the makeup/breakout jaws <NUM>, and the spinner <NUM>), the tubular handling apparatus <NUM>, one or more of the drawworks <NUM>, the top drive <NUM>, and the elevator <NUM> or a controller thereof, and/or the main control system <NUM> (e.g., to be utilized in the control of the tripping apparatus <NUM>, the roughneck <NUM>, the fixed jaws <NUM>, the makeup/breakout jaws <NUM>, the spinner <NUM>, the drawworks <NUM>, the top drive <NUM>, the elevator <NUM>, and/or the tubular handling apparatus <NUM>) to operate in a manner described herein.

The computing system <NUM> may operate in conjunction with software systems implemented as computer executable instructions stored in a non-transitory machine readable medium of computing system <NUM>, such as memory <NUM>, a hard disk drive, or other short term and/or long term storage. Particularly, the processing device <NUM> may operate in conjunction with software systems implemented as computer executable instructions (e.g., code) stored in a non-transitory machine readable medium of computing system <NUM>, such as memory <NUM>, that may be executed to receive information (e.g., signals or data) related to sensitivities of surge and/or swab pressures characteristics as well as well pressure characteristics. This information can be used by the computing system <NUM> (e.g., by the processing device <NUM> executing computer executable instructions stored in memory <NUM>) to generate or otherwise calculate a tripping schedule that may be utilized to limiting tripping operation speeds to predetermined levels at predetermined times and/or well depths. Additionally, this determined tripping schedule can be used to initiate or control movement and/or operation of the tripping apparatus <NUM> and/or the associated tripping elements (e.g., the drawworks <NUM>, the top drive <NUM>, the elevator <NUM>, and/or the tubular handling apparatus <NUM>) to facilitate a make-up or break-out (e.g., tripping) operation by the computing system <NUM>, the main control system <NUM>, or by local controller(s) of the tripping apparatus <NUM> and/or the associated tripping elements (e.g., the drawworks <NUM>, the top drive <NUM>, the elevator <NUM>, and/or the tubular handling apparatus <NUM>).

In some embodiments, the computing system <NUM> may also include one or more input structures <NUM> (e.g., one or more of a keypad, mouse, touchpad, touchscreen, one or more switches, buttons, or the like) to allow a user to interact with the computing system <NUM>, for example, to start, control, or operate a graphical user interface (GUI) or applications running on the computing system <NUM> and/or to start, control, or operate the tripping apparatus <NUM> (e.g., the roughneck <NUM> and/or one or more of the fixed jaws <NUM>, the makeup/breakout jaws <NUM>, and the spinner <NUM>), the tubular handling apparatus <NUM>, and/or additional systems of the drilling rig <NUM>. Additionally, the computing system <NUM> may include a display <NUM> that may be a liquid crystal display (LCD) or another type of display that allows users to view images generated by the computing system <NUM>. The display <NUM> may include a touch screen, which may allow users to interact with the GUI of the computing system <NUM>. Likewise, the computing system <NUM> may additionally and/or alternatively transmit images to a display of the main control system <NUM>, which itself may also include a processing device <NUM>, a non-transitory machine readable medium, such as memory <NUM>, one or more input structures <NUM>, a display <NUM>, and/or a network interface <NUM>.

Returning to the computing system <NUM>, as may be appreciated, the GUI may be a type of user interface that allows a user to interact with the computer system <NUM> and/or the computer system <NUM> and one or more sensors that transmit data to the computing system through, for example, graphical icons, visual indicators, and the like. Additionally, the computer system <NUM> may include network interface <NUM> to allow the computer system <NUM> to interface with various other devices (e.g., electronic devices). The network interface <NUM> may include one or more of a Bluetooth interface, a local area network (LAN) or wireless local area network (WLAN) interface, an Ethernet or Ethernet based interface (e.g., a Modbus TCP, EtherCAT, and/or ProfiNET interface), a field bus communication interface (e.g., Profibus), a/or other industrial protocol interfaces that may be coupled to a wireless network, a wired network, or a combination thereof that may use, for example, a multi-drop and/or a star topology with each network spur being multi-dropped to a reduced number of nodes.

In some embodiments, one or more of the tripping apparatus <NUM> (and/or a controller or control system associated therewith), the tubular handling apparatus <NUM> (and/or a controller or control system associated therewith), associated tripping elements (e.g., the drawworks <NUM>, the top drive <NUM>, the elevator <NUM>, and/or the tubular handling apparatus <NUM>), and/or the main control system <NUM> may each be a device that can be coupled to the network interface <NUM>. In some embodiments, the network formed via the interconnection of one or more of the aforementioned devices should operate to provide sufficient bandwidth as well as low enough latency to exchange all required data within time periods consistent with any dynamic response requirements of all control sequences and closed-loop control functions of the network and/or associated devices therein. It may also be advantageous for the network to allow for sequence response times and closed-loop performances to be ascertained, the network components should allow for use in oilfield/drillship environments (e.g., should allow for rugged physical and electrical characteristics consistent with their respective environment of operation inclusive of but not limited to withstanding electrostatic discharge (ESD) events and other threats as well as meeting any electromagnetic compatibility (EMC) requirements for the respective environment in which the network components are disposed). The network utilized may also provide adequate data protection and/or data redundancy to ensure operation of the network is not compromised, for example, by data corruption (e.g., through the use of error detection and correction or error control techniques to obviate or reduce errors in transmitted network signals and/or data).

The computing system <NUM> may operate in conjunction with additional embodiments of drilling rigs. For example, <FIG> illustrates another embodiment of a drilling rig <NUM> that may be utilized in a tripping operation consistent with embodiments of the present disclosure and that may operate in conjunction with the computing system <NUM> of <FIG>. As illustrated in <FIG>, the tripping apparatus <NUM> is positioned above drill floor <NUM> in the drilling rig <NUM> above the wellbore <NUM> (e.g., the drilled hole or borehole of a well which may be proximate to the drill floor <NUM> or which may be, in conjunction with <FIG>, below the wellhead <NUM>). However, as will be discussed in greater detail below, the tripping apparatus <NUM> may be moved towards and away from the drill floor <NUM> during a tripping operation. As illustrated, the drilling rig <NUM> may include one or more of, for example, the tripping apparatus <NUM>, a movable platform <NUM> (that may include floor slips <NUM> positioned in rotary table <NUM>, as illustrated in <FIG>), drawworks <NUM>, a crown block <NUM>, a travelling block <NUM>, a top drive <NUM>, an elevator <NUM>, and a tubular handling apparatus <NUM>. The tripping apparatus <NUM> may operate to couple and decouple tubular segments (e.g., couple and decouple drill pipe <NUM> to and from a drill string) while the floor slips <NUM> may operate to close upon and hold a drill pipe <NUM> and/or the drill string passing into the wellbore <NUM>. The rotary table <NUM> may be a rotatable portion that can be locked into positon co-planar with the drill floor <NUM> and/or above the drill floor <NUM>. The rotary table <NUM> can, for example, operate to impart rotation to the drill string either as a primary or a backup rotation system (e.g., a backup to the top drive <NUM>) as well as utilize its floor slips <NUM> to support tubular segments, for example, during a tripping operation or may be a false rotary table that does not impart rotation to the drill string while still allowing for support of tubular segments utilizing its floor slips <NUM>.

The drawworks <NUM> may be a large spool that is powered to retract and extend drilling line <NUM> (e.g., wire cable) over a crown block <NUM> (e.g., a vertically stationary set of one or more pulleys or sheaves through which the drilling line <NUM> is threaded) and a travelling block (e.g., a vertically movable set of one or more pulleys or sheaves through which the drilling line <NUM> is threaded) to operate as a block and tackle system for movement of the top drive <NUM>, the elevator <NUM>, and any tubular segment (e.g., drill pipe <NUM>) coupled thereto. In some embodiments, the top drive <NUM> and/or the elevator <NUM> may be referred to as a tubular support system or the tubular support system may also additionally include the block and tackle system described above.

The top drive <NUM> may be a device that provides torque to (e.g., rotates) the drill string as an alternative to the rotary table <NUM> and the elevator <NUM> may be a mechanism that may be closed around a drill pipe <NUM> or other tubular segments (or similar components) to grip and hold the drill pipe <NUM> or other tubular segments while those segments are moving vertically (e.g., while being lowered into or raised from a wellbore <NUM>) or directionally (e.g., during slant drilling). The tubular handling apparatus <NUM> may operate to retrieve a tubular segment from a storage location <NUM> (e.g., a pipe stand) and position the tubular segment during tripping-in to assist in adding a tubular segment to a tubular string. Likewise, the tubular handling apparatus <NUM> may operate to retrieve a tubular segment from a tubular string and transfer the tubular segment to a storage location (e.g., a pipe stand) during tripping-out to remove the tubular segment from the tubular string.

During a tripping-in operation, the tubular handling apparatus <NUM> may position a tubular segment <NUM> (e.g., a drill pipe <NUM>) so that the segment <NUM> may be grasped by the elevator <NUM>. Elevator <NUM> may be lowered, for example, via the block and tackle system towards the tripping apparatus <NUM> to be coupled to tubular segment <NUM> (e.g., a drill pipe <NUM>) as part of a drill string. In some embodiments, the tripping apparatus <NUM> may operate as discussed in conjunction with <FIG> above during a tripping operation. However, in addition to the operation of the tripping apparatus <NUM>, continuous tripping operations (tripping tubular segments without halting the movement of the tubular string at a fixed position) may be facilitated and/or accelerated through the inclusion of the movable platform <NUM>.

The movable platform <NUM> may be raised and lowered with a cable and sheave arrangement (e.g., similar to the block and tackle system for movement of the top drive <NUM>) that may include a winch or other drawworks element positioned on the drill floor <NUM> or elsewhere on the offshore platform <NUM> or the drilling rig <NUM>. The winch or other drawworks element may be a spool that is powered to retract and extend a line (e.g., a wire cable) over a crown block (e.g., a stationary set of one or more pulleys or sheaves through which the line <NUM> is threaded) and a travelling block (e.g., a movable set of one or more pulleys or sheaves through which the line <NUM> is threaded) to operate as a block and tackle system for movement of the movable platform <NUM> and, thus, the rotary table <NUM> therein and the tripping apparatus <NUM> thereon. Additionally and/or alternatively, one or more direct acting cylinders, a suspended winch and cable system, or other internal or external actuation systems may be used to move the movable platform <NUM> along support <NUM>.

In some embodiments, the support <NUM> may be one or more guide mechanisms (e.g., guide tracks, such as top drive dolly tracks) that provide support (e.g., lateral support) to the movable platform <NUM> while allowing for movement towards and away from the drill floor <NUM>. Additionally, as illustrated in <FIG>, one or more lateral supports <NUM> may be used to couple the movable platform <NUM> to the support <NUM>. For example, the lateral supports <NUM> may be, for example, pads that may be made of Teflon-graphite material or another low-friction material (e.g., a composite material) that allows for motion of the movable platform <NUM> relative to drill floor <NUM> and/or the tubular segment support system with reduced friction characteristics. In addition to, or in place of the aforementioned pads, other lateral supports <NUM> including bearing or roller type supports (e.g., steel or other metallic or composite rollers and/or bearings) may be utilized. The lateral supports <NUM> may allow the movable platform <NUM> to interface with a support <NUM> (e.g., guide tracks, such as top drive dolly tracks) so that the movable platform <NUM> is movably coupled to the support <NUM>. Accordingly, the movable platform <NUM> may be movably coupled to a support <NUM> to allow for movement of the movable platform <NUM> (e.g., towards and away from the drill floor <NUM> and/or the tubular segment support system while maintaining contact with the guide tracks or other support <NUM>) during a tripping operation (e.g., a continuous tripping operation).

As further illustrated in <FIG>, the movable platform <NUM> may have guide pins <NUM> or similar devices to provide coarse and fine alignment when moving in and out of the drill floor <NUM> (e.g., into a planar position with the drill floor <NUM> or raised above the drill floor <NUM>). Additionally, one or more locking mechanisms <NUM> may be employed to affix the movable platform <NUM> into a desired position with respect to the drill floor <NUM>, for example, when a tripping operation is complete or is otherwise not being immediately performed. In this fixed position, the rotary table <NUM> may operate in conjunction with the top drive <NUM> and/or as a backup system to the top drive <NUM>. The locking mechanisms <NUM> may be automatic (e.g., controllable) such that they can be actuated without human contact (e.g., a control signal may cause pins or other locking mechanisms to engage an aperture between the drill floor <NUM> and the movable platform <NUM>). It is envisioned that the locking mechanisms will interface with the drill floor <NUM> or an element beneath the drill floor (if the movable platform <NUM> is to be locked in a position planar with the drill floor <NUM>) and that in some embodiments, the locking mechanisms will be an aperture to be engaged by pins or other locking mechanisms, for example, in the drill floor <NUM>.

Returning to <FIG>, a computing system <NUM> may be present and may operate in conjunction with one or more of the tripping apparatus <NUM>, the movable platform <NUM>, an actuating system used to move the tripping apparatus <NUM> vertically with respect to the movable platform <NUM> (e.g., to move the tripping apparatus <NUM> into vertical position to engage, for example, the tubular members), an actuating system used to move the tripping apparatus <NUM> horizontally across the movable platform <NUM> (e.g., to move the tripping apparatus <NUM> into and out of an operational position in which the tripping apparatus <NUM> is aligned with, for example, the tubular members) and/or an actuating system used to move the movable platform <NUM>. This computing system <NUM> may also operate to control one or more of the tubular segment support system and/or the tubular handling apparatus <NUM>. It should be noted that the computing system <NUM> may be similar to the computing system of <FIG>, with the added aspects of control of the movable platform <NUM> and/or the floor slips <NUM> of the movable platform <NUM>.

Additionally, tripping operations involving singular tubular segments <NUM> (e.g., drill pipe <NUM>) has been discussed with respect to <FIG>. However, as illustrated in <FIG>, it is envisioned that a stand <NUM> of tubular segments <NUM> (e.g., two, three, or more tubular segments <NUM> coupled together) may be the tubular segments being tripped-in or tripped-out. The operation described herein may apply to tripping stands <NUM> as illustrated in <FIG>. For example, when ascertaining the tripping speed limits for a tripping operation, control of the tripping apparatus <NUM>, the tubular support system, the tubular handling apparatus <NUM>, and/or the movable platform <NUM> may be controlled by the computer system <NUM>. For example, an output signal generated by the computer system <NUM> may be applied by the computer system <NUM>. For example, the computer system <NUM> (e.g., the processing device <NUM> or the processing device <NUM> operating in conjunction with software systems implemented as computer executable instructions stored in a non-transitory machine readable medium of computing system <NUM>, such as memory <NUM>, and that may be executed) may control the operation of local controllers or may operate as a control system itself so as to transmit one or more control signals to control where and when to move the tripping apparatus <NUM> into position (e.g., tool joint recognition) to perform a tripping operation as part of a tripping operation performed at a predetermined or calculated speed.

Additionally or alternatively, the computer system <NUM> may operate as a control system itself so as to transmit a control signal to control the activation of one or more slips <NUM> and/or <NUM> to secure one of the stands <NUM>, control the activation of the tubular handling apparatus <NUM>, the tubular support system, and/or the movable platform <NUM> so the aforementioned components function together as a continuous tripping system to operate a tripping operation at a predetermined or calculated speed. Likewise, external control systems may instead receive one or more output control signals from the computer system <NUM> and use the output control signals, respectively, to control the activation of one or more slips <NUM> and/or <NUM> to secure one of the stands <NUM>, control the activation of the tubular handling apparatus <NUM>, the tubular support system, and/or the movable platform <NUM> so the aforementioned components function together as a continuous tripping system to operate a tripping operation at a predetermined or calculated speed. Determination of the predetermined or calculated speed by the computer system <NUM> will be described in greater detail below.

The computing system <NUM> may operate as a limiter to provide a variable upper threshold speed at which a tripping operation is not to exceed based on, for example, sensitivities of surge and swab pressure characteristics and/or pressure characteristics of the well. In some embodiments, pressure characteristics of the well may be measurable. For example, a formation a leak-off test of the well can be undertaken to determine the maximum pressure or mud weight that may be applied to a well. In some embodiments, the measured pressures (i.e., the pressure characteristics of the well) may include determination of a fracture pressure and a pore pressure, both of which may be observed and stored in the computing system as threshold values (e.g., whereby the fracture pressure is not to be exceeded by the well pressure and the well pressure is not to fall below the pore pressure).

Additionally, sensitivities of surge and swab pressure characteristics may be determined based on a set of input values. For example, these input values that affect the surge and swab pressure characteristics may include, for example, one or more of a tripping speed, a pipe end condition as open or closed, a well depth, a size of the drill pipe <NUM>, a bit jet area, rheological properties of the drilling fluid (mud) utilized, or other characteristics. The tripping speed may include to the RIH and POOH tripping speed, respectively. The pipe end condition as open or closed may include to a flowrate as related to the displacement of an open ended drill pipe <NUM> as a volume of fluid that will be displaced by the drill pipe <NUM> when placed into the fluid with an open end allowing the drill pipe <NUM> to receive the fluid and a flowrate as related to the displacement of a closed ended drill pipe <NUM> as a volume of fluid that will be displaced by the drill pipe <NUM> when placed into the fluid with an closed end preventing the drill pipe <NUM> from receiving the fluid. The well depth may include effects on surge and swab pressures in relation to differing well depths. The size of the drill pipe <NUM> may include a measurement of a distance of the drill pipe such as the diameter or other physical aspects of the drill pipe <NUM>. The bit jet area may include a measurement of a flow area of a bit nozzle that allows drilling fluid to exit into the well. The rheological properties of the mud may include, for example, one or more of the density of the mud utilized, a mud plastic viscosity as related to a flow resistance of the mud, which may be caused by mechanical friction within the mud, and a yield point of the mud as related to a flow resistance of the mud, which may be caused by electrochemical forces within the mud, and/or additional mud characteristics.

In some embodiments, the impact of the pipe end condition as open or closed, the well depth, the size of the drill pipe <NUM>, the bit jet area, and the rheological properties of the drilling fluid (mud) utilized may vary in relation to the tripping speed and, therefore, may operate to adjust the effects of the surge and swab pressure characteristics at differing tripping speeds as depths of the well increase (i.e., leading to a more complete representation of the sensitivities of surge and swab pressure characteristics at various tripping speeds relative to a determination of the sensitivities of surge and swab pressure characteristics at various tripping speeds alone). Accordingly, <FIG> illustrate various tripping speeds and their impact with respect to surge and swab pressure characteristics affecting pressure characteristics of the well.

<FIG> illustrates a graph <NUM> of mud loss due to an RIH continuous tripping operation and an RIH non-continuous tripping operation. As illustrated, the x-axis <NUM> represents bit depth in feet increasing from the origin <NUM> and the y-axis <NUM> represents pressure in pounds per square inch (psi) increasing from the origin <NUM>. The fracture pressure <NUM> of the well and the pore pressure of the well <NUM> are additionally illustrated in addition to the pressure in the well due to an RIH continuous tripping operation <NUM> at a first speed and the pressure in the well due to an RIH non-continuous tripping operation <NUM> at the same first speed. At depth <NUM>, the RIH non-continuous tripping operation <NUM> pressure at the first speed (in feet per minute) exceeds the fracture pressure <NUM> of the well, which may lead to a well event.

Similarly the graph <NUM> illustrates that at depth <NUM> (greater than depth <NUM>), the RIH continuous tripping operation <NUM> pressure at the first speed (in feet per minute) exceeds the fracture pressure <NUM> of the well. Thus, graph <NUM> illustrates a shorter mud loss duration for an RIH continuous tripping operation <NUM>, which would lead to lower mud loss risks and the associated safety gains. Additionally, this graph <NUM> illustrates that the RIH continuous tripping operation <NUM> may be faster than the RIH non-continuous tripping operation <NUM>, thus leading to advantageous tripping time gains and, accordingly, reduced down time for the well (e.g., to match the lower mud loss of the RIH continuous tripping operation <NUM>, the RIH non-continuous tripping operation <NUM> would need to be run at a slower rate than the RIH continuous tripping operation <NUM>). Similar advantages may be present in POOH continuous tripping operations.

<FIG> illustrates a graph <NUM> of influx due to a POOH continuous tripping operation and a POOH non-continuous tripping operation. As illustrated, the x-axis <NUM> represents bit depth in feet increasing from the origin <NUM> and the y-axis <NUM> represents pressure in pounds per square inch (psi) increasing from the origin <NUM>. The fracture pressure <NUM> of the well and the pore pressure of the well <NUM> are additionally illustrated in addition to the pressure in the well due to a POOH continuous tripping operation <NUM> at a first speed and the pressure in the well due to a POOH non-continuous tripping operation <NUM> at the same first speed. At depth <NUM>, the POOH non-continuous tripping operation <NUM> pressure at the first speed (in feet per minute) falls below the pore pressure <NUM> of the well, which may lead to a well event.

Similarly the graph <NUM> illustrates that at depth <NUM> (greater than depth <NUM>), the POOH continuous tripping operation <NUM> pressure at the first speed (in feet per minute) falls below the pore pressure <NUM> of the well. Thus, graph <NUM> illustrates a shorter influx duration for a POOH continuous tripping operation <NUM>, which would lead to reduced well kick risks (e.g., a well control event in which the pressure found within the drilled rock is higher than the mud pressure acting on the borehole or rock face such that fluids are forced into the wellbore <NUM>) and the associated safety gains. Additionally, this graph <NUM> illustrates that the POOH continuous tripping operation <NUM> may be faster than the POOH non-continuous tripping operation <NUM>, thus leading to advantageous tripping time gains and, accordingly, reduced down time for the well (e.g., to match the shorter influx duration of the POOH continuous tripping operation <NUM>, the POOH non-continuous tripping operation <NUM> would need to be run at a slower rate than the POOH continuous tripping operation <NUM>).

<FIG> illustrates a graph <NUM> of the effects of tripping speeds during a POOH continuous tripping operation at various speeds. As illustrated, the x-axis <NUM> represents bit depth in feet increasing from the origin <NUM> and the y-axis <NUM> represents pressure in pounds per square inch (psi) increasing from the origin <NUM>. The fracture pressure <NUM> of the well and the pore pressure of the well <NUM> are additionally illustrated in addition to the pressure in the well due to a POOH continuous tripping operation at a first speed ("x"), the pressure in the well due to a POOH continuous tripping operation <NUM> at a second speed greater than the first speed (e.g., the second speed having a speed of approximately <NUM>. 25x, <NUM>. 75x, 2x, or another value), and the pressure in the well due to a POOH continuous tripping operation <NUM> at a third speed greater than the first speed and greater than the second speed (e.g., the third speed having a speed of approximately <NUM>. 25x, <NUM>. 75x, 3x, <NUM>. 25x, <NUM>. 75x, 4x or another value).

At depth <NUM>, the pressure in the well due to the POOH continuous tripping operation <NUM> at the third speed (in feet per minute) falls below the pore pressure <NUM> of the well, which may lead to a well event. Similarly, the graph <NUM> illustrates that at depth <NUM> (greater than depth <NUM>), the pressure in the well due to the POOH continuous tripping operation <NUM> pressure at the second speed (in feet per minute) falls below the pore pressure <NUM> of the well. However, at depth <NUM>, the pressure in the well due to the POOH continuous tripping operation <NUM> pressure at the first speed (in feet per minute) remains above the pore pressure <NUM> of the well.

Thus, graph <NUM> illustrates that the pressure in the well due to the POOH continuous tripping operation <NUM> pressure at the first speed will not fall below the pore pressure <NUM> of the well at the illustrated depths, the pressure in the well due to the POOH continuous tripping operation <NUM> pressure at the second speed will fall below the pore pressure <NUM> of the well at depth <NUM>, and the pressure in the well due to the POOH continuous tripping operation <NUM> pressure at the third speed will fall below the pore pressure <NUM> of the well at depth <NUM>. Accordingly, reduced well kick risks and the associated safety gains may be realized by implementing the POOH continuous tripping operation <NUM> at the first speed. However, the slower tripping rate relative to the POOH continuous tripping operation <NUM> at the second speed and the POOH continuous tripping operation <NUM> at the third speed leading to reductions in advantageous tripping time gains and, accordingly, increased down time for the well when the POOH continuous tripping operation <NUM> at the first speed is implemented.

Accordingly, in some embodiments, the computing system <NUM> may operate as a limiter to provide a variable upper threshold speed at which a tripping operation is not to exceed based on, for example, sensitivities of surge and swab pressure characteristics and/or pressure characteristics of the well. This variable upper threshold speed is illustrated in the graph <NUM> of <FIG> with respect to a POOH continuous tripping operation. As illustrated, the x-axis <NUM> represents bit depth in feet increasing from the origin <NUM> and the y-axis <NUM> represents pressure in pounds per square inch (psi) increasing from the origin <NUM>. A first depth <NUM> is illustrated at or near the origin <NUM> (e.g., at approximately <NUM> feet). A second depth <NUM> greater than the first depth <NUM>, a third depth <NUM> greater than the first depth <NUM> and the second depth <NUM>, and a fourth depth <NUM> greater than the first depth <NUM>, the second depth <NUM>, and the third depth <NUM> are also illustrated. A variable tripping speed <NUM> of the POOH continuous tripping operation is further illustrated in <FIG>.

In connection with the graph <NUM> of <FIG>, the variable tripping speed <NUM> of the POOH continuous tripping operation illustrated in the graph <NUM> of <FIG> may be approximately equal to the POOH continuous tripping operation <NUM> at the first speed at fourth depth <NUM>. The variable tripping speed <NUM>, for example, may continue to be approximately equal to the POOH continuous tripping operation <NUM> at the first speed between the fourth depth <NUM> and the third depth <NUM> so that the pressure of the POOH continuous tripping operation <NUM> at the first speed will not fall below the pore pressure <NUM> of the well. Alternatively, as the depth decreases between the fourth depth <NUM> and the third depth <NUM>, the variable tripping speed <NUM> of the POOH continuous tripping operation may increase in speed at a rate that maintains POOH continuous tripping operation pressure of the well associated with the variable tripping speed <NUM> above the pore pressure <NUM> of the well.

As further illustrated in the graph <NUM>, the variable tripping speed <NUM> of the POOH continuous tripping operation may be approximately equal to the POOH continuous tripping operation <NUM> at the second speed at third depth <NUM>. The variable tripping speed <NUM>, for example, may continue to be approximately equal to the POOH continuous tripping operation <NUM> at the second speed between the third depth <NUM> and the second depth <NUM> so that the pressure of the POOH continuous tripping operation <NUM> at the second speed will not fall below the pore pressure <NUM> of the well. Alternatively, as the depth decreases between the third depth <NUM> and the second depth <NUM>, the variable tripping speed <NUM> of the POOH continuous tripping operation may increase in speed at a rate that maintains POOH continuous tripping operation pressure of the well associated with the variable tripping speed <NUM> above the pore pressure <NUM> of the well.

Likewise, the variable tripping speed <NUM> of the POOH continuous tripping operation may be approximately equal to the POOH continuous tripping operation <NUM> at the third speed at second depth <NUM>. The variable tripping speed <NUM>, for example, may continue to be approximately equal to the POOH continuous tripping operation <NUM> at the third speed between the second depth <NUM> and the first depth <NUM> so that the pressure of the POOH continuous tripping operation <NUM> at the third speed will not fall below the pore pressure <NUM> of the well. Alternatively, as the depth decreases between the second depth <NUM> and the first depth <NUM>, the variable tripping speed <NUM> of the POOH continuous tripping operation may increase in speed at a rate that maintains POOH continuous tripping operation pressure of the well associated with the variable tripping speed <NUM> above the pore pressure <NUM> of the well.

Thus, graph <NUM> illustrates that the pressure in the well due to the POOH continuous tripping operation at the variable tripping speed <NUM> will not fall below the pore pressure <NUM> of the well at the illustrated depths. Accordingly, reduced well kick risks and the associated safety gains may be realized by implementing the POOH continuous tripping operation <NUM> at the variable tripping speed <NUM> across the depths between the first depth <NUM> and the fourth depth <NUM>. Moreover, the increased tripping rate relative to the POOH continuous tripping operation at the first speed (as illustrated in <FIG>) leads to increases in advantageous tripping time gains and, accordingly, decreased down time for the well relative to implementation of the POOH continuous tripping operation at the first speed. Additionally, while <FIG> discuss POOH continuous tripping operation, it is envisioned that a similar operation may be performed in connection with an RIH continuous tripping operation.

<FIG> illustrates a flow chart <NUM> used in conjunction with a tripping speed modification system, in accordance with an embodiment. Particularly, the processing device <NUM> may operate in conjunction with software systems implemented as computer executable instructions (e.g., code) stored in a non-transitory machine readable medium of computing system <NUM>, such as memory <NUM>, that may be executed to receive information (e.g., signals or data) related to sensitivities of surge and/or swab pressures characteristics as well as well pressure characteristics to determine the variable tripping speed <NUM> as well as implement the variable tripping speed as a control parameter for a tripping operation.

In step <NUM>, initial information may be received and/or calculated by the computing system <NUM> regarding plans for days tripping operations will occur and the type of tripping operations to occur. Additionally, the computing system in step <NUM> may receive or determine well pressures, such as a fracture pressure and a pore pressure of a well, both of which may be observed and stored in the computing system <NUM> as threshold values (e.g., whereby the fracture pressure is not to be exceeded by the well pressure and the well pressure is not to fall below the pore pressure). Additionally, a set of input values that affect the surge and swab pressure characteristics may be received in step <NUM> by the computing system <NUM> that may include, for example, one or more of a tripping speed, a pipe end condition as open or closed, a well depth, a size of the drill pipe <NUM>, a bit jet area, rheological properties of the drilling fluid (mud) utilized, or other characteristics. These input values may be stored, for example, in the memory <NUM> of the computing system <NUM>.

In step <NUM>, the initial information from step <NUM> may be utilized (for example, by the processing device <NUM> or the processing device <NUM> operating in conjunction with software systems implemented as computer executable instructions stored in a non-transitory machine readable medium of computing system <NUM>, such as memory <NUM>, that may be executed) to calculate a variable tripping speed for one or more POOH continuous tripping operations scheduled and for one or more RIH continuous tripping operations scheduled. Thus, each respective POOH continuous tripping operation and RIH continuous tripping operation may have a corresponding variable tripping speed assigned to it as a limited tripping speed not to be exceed (e.g., to maximize the speed of the respective tripping operation while maintaining the well pressure below the fracture pressure and above the pore pressure of the well at the respective depths for the respectively scheduled tripping operations). This calculated variable tripping speed for each tripping operation can be stored, for example, in the memory <NUM> until the respective tripping operation is scheduled to begin. Alternatively, the variable tripping speed can be calculated dynamically by the processing device <NUM> or the processing device <NUM> operating in conjunction with software systems implemented as computer executable instructions based on the stored input values from step <NUM> as the respective tripping operations are to begin.

In step <NUM>, the computer system <NUM> (e.g., the processing device <NUM> or the processing device <NUM> operating in conjunction with software systems implemented as computer executable instructions stored in a non-transitory machine readable medium of computing system <NUM>, such as memory <NUM>, that may be executed) may apply a respective calculated variable tripping speed to its corresponding tripping operation to generate output data from the computer system <NUM>. In some embodiments, this output data may be an indication of the speeds at which a tripping operation may operate at for a period of time and at corresponding depths. In some embodiments, the output data may be used by respective controllers as a determined tripping schedule that can be used to initiate or control movement and/or operation of the tripping apparatus <NUM> and/or the associated tripping elements (e.g., the drawworks <NUM>, the top drive <NUM>, the elevator <NUM>, and/or the tubular handling apparatus <NUM>) to facilitate a make-up or break-out (e.g., tripping) operation at varying speeds that match the determined variable tripping speed for the respective tripping operation undertaken. Alternatively, the generated output data in step <NUM> may be transmitted by the computing system <NUM> or by the main control system <NUM> as respective control signals to initiate or control movement and/or operation of the tripping apparatus <NUM> and/or the associated tripping elements (e.g., the drawworks <NUM>, the top drive <NUM>, the elevator <NUM>, and/or the tubular handling apparatus <NUM>) to facilitate a make-up or break-out (e.g., tripping) operation at varying speeds that match the determined variable tripping speed for the respective tripping operation undertaken.

In step <NUM>, the output signal generated by the computer system <NUM> may be applied by the computer system <NUM>, the main control system <NUM>, or the aforementioned local controllers of, for example, the tripping apparatus <NUM> and/or the associated tripping elements (e.g., the drawworks <NUM>, the top drive <NUM>, the elevator <NUM>, and/or the tubular handling apparatus <NUM>) to facilitate a make-up or break-out (e.g., tripping) operation at varying speeds that match the determined variable tripping speed for the respective tripping operation undertaken. In some embodiments, this process in step <NUM> allows for automatic control of the continuous tripping system to insure a limited speed is not exceeded.

Claim 1:
A system, comprising:
a processing device (<NUM>) configured to:
determine a tripping operation to be undertaken;
calculate a variable tripping speed for the tripping operation to vary a speed of the tripping operation; and
generate an output to control operation of a portion of a continuous tripping system to implement the tripping operation at the variable tripping speed, wherein the tripping operation comprises movement of a first tubular segment (<NUM>) and a second tubular segment (<NUM>) towards a drill floor (<NUM>) while being made up without halting or movement of the first tubular segment and the second tubular segment away from the drill floor while being broken out without halting, wherein the processing device is configured to calculate the variable tripping speed based on a depth of a well into which a tubular string comprising at least one of the first segment and the second segment is moving during the tripping operation to establish a speed of the tripping operation while maintaining a well pressure below a first threshold value and above a second threshold value less than the first threshold value at respective depths of the well, wherein the first threshold value corresponds to a fracture pressure and the second threshold value corresponds to a pore pressure.