Patent Description:
Natural resources, such as oil and gas, are used as fuel to power vehicles, heat homes, and generate electricity, in addition to various other uses. Once a desired resource is discovered below the surface of the earth, drilling and production systems are often employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of the desired resource. Further, such systems may include a wide variety of components, such as various casings, fluid conduits, tools, and the like, that facilitate extraction of the resource from a well during drilling or extraction operations.

Whether onshore or offshore, a drilling rig can be provided to drill a well to access the desired resource. A drill string can be suspended from the drilling rig and rotated to drill the well. While the drill string can be suspended from a kelly and driven by a rotary table on the drill floor of the drilling rig, in some instances the drill string is instead suspended from and driven by a top drive of the drilling rig. Such a top drive generally includes a drive stem (also referred to as a main shaft) that can be connected to the drill string. A motor in the top drive is connected to the drive stem to drive rotation of the drill string via the drive stem. The top drive can be raised and lowered via a mast and a hoisting system to raise and lower the drill string within the well.

The drilling rig also includes a hoisting system configured to raise and to lower drilling equipment relative to the drill floor. The hoisting system typically includes a crown block, a traveling block, a drawworks system, and a cable assembly (e.g., wire) that extends from the drawworks system and couples the crown block to the traveling block. As the number of reeves or lines of the hoisting system increase, the speed of the system decreases, and can decrease to a point where the speed is too low. Therefore, the cable assembly of hoisting system must be re-reeved so that it has fewer lines (e.g. <NUM> lines to <NUM> lines). The opposite is also true when a higher load capacity is needed.

<CIT> describes a hoisting mechanism for use on a vessel comprising a mast with cable blocks on the top side thereof, a trolley displaceably attached to the mast, with cable blocks on the top side thereof and means for picking up a load on the underside thereof and hoisting means including a hoisting cable guided over the cable blocks of both the mast and the trolley and allowing movement of the trolley with respect to the mast. A compensator in the form of a pneumatic or hydraulic cylinder is provided for damping movements of the vessel, the hoisting cable being guided over cable pulleys connected to the end of the compensator to exert force on the hoisting cable.

<CIT> describes a hoist system for a derrick including a splittable block connected to the derrick top side, a hoisting cable guided through the splittable block a moveable trolley connected to the splittable block and removably secured on the derrick and a hoist winch adapted to pull the hoisting cable over the derrick top side and through the splittable block to move the moveable trolley relative to the derrick.

<CIT> describes a crown block/traveling block system for a well drilling derrick, the system being formed of elevationally stationary multi-sheave upper and lower crown blocks arranged in tandem and supported to the derrick support structure, an elevationally moveable multi-sheave traveling block adapted to support drilling equipment which is raised and lowered in the derrick, and a multi-sheave intermediate block. In one mode, the multi-sheave intermediate block is attached in tandem arrangement below the upper and lower crown blocks to form a part of a three-block crown block assembly and in a second mode, the intermediate block is attached to the traveling block to form a traveling block assembly, the modes being selected according to the weight of equipment to be supported during drilling operations.

Further, the document <CIT> discloses a hoisting system according to the preamble of claim <NUM>.

The present invention resides in a hoisting system as defined in claim <NUM>. Preferred embodiments are defined in claims <NUM> to <NUM>.

In another aspect, the invention resides in a a method to lift a load using a hoisting system as defined in claim <NUM>. Preferred embodiments of the method are defined in claims <NUM> and <NUM>.

Various features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying figures in which like characters represent like parts throughout the figures, wherein:.

These described embodiments are only exemplary of the present disclosure.

The present embodiments are generally directed to drilling and production system comprising a hoisting system that may be utilized to support and lift a load (e.g., pipe section, drill pipe collar, casing section, or the like) within a drilling and production system.

To facilitate discussion, certain embodiments disclosed herein refer to pipe sections and drill strings; however, it should be understood that the disclosed embodiments may be adapted for use with any of a variety of tubular structures, including drill pipe collars, casing sections, or the like. Additionally, certain embodiments relate to a subsea (e.g., offshore) drilling and production system; however, it should be understood that the disclosed embodiments may be adapted for use within an onshore (e.g., land-based) drilling and production system.

With the foregoing in mind, <FIG> is a schematic diagram of a portion of a drilling and production system <NUM>, in accordance with an embodiment of the present disclosure. As shown, the system <NUM> includes a derrick <NUM> supported by a platform <NUM> (e.g., floating platform or vessel). The system <NUM> includes a hoisting system <NUM> configured to raise and to lower drilling equipment relative to the drill floor <NUM>. In the illustrated embodiment, the hoisting system <NUM> includes a crown block <NUM>, a traveling block <NUM>, a drawworks system <NUM>, and a cable assembly <NUM> (e.g., wire) that extends from the drawworks system <NUM> and couples the crown block <NUM> to the traveling block <NUM>. In the illustrated embodiment, a top drive <NUM> is coupled to the traveling block <NUM>, and a drill string <NUM> supporting a drill bit (not shown) is suspended from the top drive <NUM> and extends through the platform <NUM> into a wellbore <NUM>. The top drive <NUM> may be configured to rotate the drill string <NUM>, and the hoisting system <NUM> may be configured to raise and to lower the top drive <NUM> and the drill string <NUM> relative to the platform <NUM> to facilitate drilling of the wellbore <NUM>.

Schematically represented on <FIG> is an example of a hoisting system <NUM> of the disclosure, enabling to increase load capacity. In embodiments, the hoisting system <NUM> comprises a drawworks system <NUM> including a cable assembly <NUM>, a crown block <NUM>, a traveling block <NUM> and a deadline anchor <NUM>. In some embodiments, the hoisting system <NUM> may include a compensator such as a top mounted compensator <NUM> of a kind known in the art to allow hook load variations to be addressed directly to the crown block <NUM>.

In embodiments, the hoisting system <NUM> comprises a sheave assembly <NUM> that is attached to the crown block <NUM> or top mounted compensator <NUM> in "Low Load / High Speed" mode, as schematically illustrated in <FIG>, and attached to the traveling block <NUM> in "High Load / Low Speed" mode, as schematically illustrated in <FIG> show a hoisting system <NUM> for <NUM> lines 24B-H, <NUM>-Q in Low Load / High Speed mode and <NUM> lines 24B-Q in High Load / Low Speed mode. (Fast line 24A and deadline 24R are not included in the line count when calculating load and speed for the hoisting system <NUM>. ) By alternately connecting the sheave assembly <NUM> to the crown or traveling blocks <NUM>, <NUM>, the hoisting system <NUM> is provided a different load and speed capability without the need to re-reeve the cable assembly <NUM>.

In the embodiment presented on <FIG>, the hoisting system <NUM> of the disclosure comprises a sheave assembly <NUM> and, in the presented example, enables to increase the load capacity from a <NUM>-lines hoisting system <NUM> in Low Load / High Speed mode to an <NUM>-lines hoisting system <NUM> in High Load / Low Speed mode. As previously stated, fast line 24A and deadline 24R do not count when calculating the load and speed.

In embodiments, connection of the sheave assembly <NUM> to either the top mounted compensator <NUM> or crown block <NUM>, or to the traveling block <NUM>, is done remotely from a drilling control room, for example. A control module <NUM> is in electronic or network communication with failsafe locking means <NUM> for locking and unlocking the sheave assembly <NUM> to the crown and traveling blocks <NUM>, <NUM>. The control module <NUM> may include one or more PLCs or microprocessors with associated software for providing the desired control. Appropriate control logic is employed to ensure the sheave assembly <NUM> is connected to one but not both of the blocks <NUM>, <NUM>. Sensors 58A, 58B are used to provide positive verification that the locking means 52A, 52B is in a locked (connected) or unlocked (disconnected) state. In some embodiments, the failsafe locking means <NUM> may include a hydraulic driver or supply <NUM> or its equivalent. The supply <NUM> may be located in a top drive loop, with the lock/unlock signal and control coming from the derrick side of the hoisting system <NUM>.

Sheave assembly <NUM> may include a yoke <NUM> having an upper end <NUM> releasably connectable to the crown block <NUM> or top mounted compensator <NUM> and a lower end <NUM> releasably connectable to the traveling block <NUM>. Failsafe locking means, which can be hydraulically actuatable and controlled from the drilling control room, are provided for releasably connecting the sheave assembly to the crown and traveling blocks. For example, the upper end <NUM> may include arms <NUM> received by an arm receiver <NUM> of the crown block <NUM>. In some embodiments the arm receiver <NUM> is a cross bar. The drawworks system <NUM> applies the necessary force to engage the arms <NUM> with the cross bar <NUM>.

By way of another example, the lower end <NUM> may include a pin <NUM> received by a pin receiver <NUM> of the traveling block <NUM>. Moving the traveling block <NUM> toward the crown block <NUM> permits the pin <NUM> to be received by the receiver <NUM>. As the traveling block <NUM> then moves away from the crown block <NUM>, the pin <NUM> remains engaged and sheave assembly <NUM> remains connected to the traveling block <NUM> and disengages from the crown block <NUM>. The receiver <NUM> may be hydraulically actuatable and controlled from the drilling control room.

When connected, to the top mounted compensator <NUM>, the sheave assembly <NUM> might be parallel to the sheaves in the traveling block <NUM>. When connected to the traveling block <NUM>, the sheave assembly <NUM> might be parallel to the sheaves in the traveling block and, therefore, to compensate for the angle between the top mounted compensator <NUM> (or crown block <NUM>) and the traveling block <NUM>.

The sheave assembly <NUM> of the disclosure may comprise any number of sheaves <NUM>, from <NUM> sheave and upwards. In examples, the number of lines (wire or cable parts) in a hoisting system <NUM> of the disclosure might be increased from <NUM> lines to <NUM> lines as shown in <FIG>, with <NUM> sheaves <NUM> in the sheave assembly <NUM>). In other examples, the lines might be increased from <NUM> and up, for example increasing from <NUM> lines to <NUM> lines (with <NUM> sheaves <NUM> in the sheave assembly <NUM>).

In examples of the hoisting system <NUM> of the disclosure, the top mounted compensator <NUM>, crown block <NUM>, or traveling block <NUM> (or some combination thereof) might be designed to accommodate the sheave assembly <NUM>. Therefore, the travelling block's sheave cluster might include a gap <NUM>. To each side of the gap <NUM>, the cable assembly <NUM> runs from the crown block <NUM> to the travelling block <NUM>. Within the gap <NUM>, the cable assembly <NUM> runs from the crown block <NUM> to the sheave assembly <NUM>. The gap <NUM> can be the distance represented by the sheaves <NUM> of the sheave assembly <NUM>. In other words, the sheaves <NUM>, rather than being located on the traveling block <NUM>, are moved to the sheave assembly <NUM>, thereby leaving gap <NUM> in the traveling block's sheave cluster.

In embodiments, the sheave assembly <NUM> might be connected to the top mounted compensator <NUM> or crown block <NUM> as well as to the traveling block <NUM> in a way that enables the assembly <NUM> to accommodate the difference in angle between the compensator <NUM> and traveling block <NUM> or between the crown and traveling blocks <NUM>, <NUM>.

The disclosed hoisting system <NUM> thus enables to increase the system load capacity compared to known hoisting systems without the need for increasing any horsepower on the drawworks system <NUM>, for example, or increasing the cable size. Further, the cable might not have to be re-reeved.

Claim 1:
A hoisting system (<NUM>) comprising:
a crown block (<NUM>);
a traveling block (<NUM>); and
at least one sheave assembly (<NUM>) moveable between and alternatively connectable to the crown (<NUM>) and traveling (<NUM>) blocks;
the hoisting system (<NUM>) having a first load capacity when the at least one sheave assembly (<NUM>) is connected to the crown block; and a second higher load capacity when the at least one sheave assembly (<NUM>) is connected to the traveling block (<NUM>);
characterized by
a failsafe locking means (52A, 52B) for releasably connecting the at least one sheave assembly (<NUM>) to the crown and traveling blocks (<NUM>, <NUM>), the failsafe locking means including sensors (58A, 58B) to provide positive verification that the locking means (52A, 52B) is in a locked or unlocked state; and
a control module (<NUM>) in electronic or network communication with the failsafe locking means (52A, 52B) for locking and unlocking the at least one sheave assembly (<NUM>) to the crown (<NUM>) and traveling (<NUM>) blocks, the control module (<NUM>) configured to ensure that the at least one sheave assembly (<NUM>) is connected to one of the crown block (<NUM>) or traveling block (<NUM>), but not to both the crown block (<NUM>) and the traveling block (<NUM>).