BR102020005492A2 - TOP DRIVE AND TOP DRIVE OPERATION METHOD - Google Patents

Abstract

method for operating the top drive (7) on a drill rig (1), in which the top drive (7) is connected to a drill string (2), the method comprising: defining a rotation speed (rs) and an applied torque from the top drive (7) to a defined level, where the applied torque is limited by an operating torque limit (otl); identify a potential or actual event of reverse rotation (backspin); and temporarily increasing the torque limit of the top drive (7) to a torque limit of reverse rotation prevention (btl) in response to the identification of the potential or actual reverse rotation event a top drive (7) is also provided for a probe drilling (1), in which the top drive (7) is connected to a controller (8) having a processor with a program incorporated in a non-transitory computer-readable medium to execute a method for operating the top drive (7).

Description

TOP DRIVE AND TOP DRIVE OPERATION METHOD

[001] The present invention relates to a top drive unit and a method of operating a top drive unit, including but not limited to these top drive units used on drilling platforms to operate a drilling column from perforation drill.

BACKGROUND OF THE INVENTION

[002] In drilling operations, it is common to build a tubular column, like a drilling column, on a drill floor above an opening in the center of the well. The column is usually assembled using a series of threaded pipe sections, in which the threaded connections are made (or cut) using appropriate machines, such as pipe handling machines and power tongs.

[003] The drill string can be connected to a top drive, which rotates the drill string and the drill bit for the drilling operation. The drill string comprises a plurality of drill tubes which are connected to each other, screwing the end of a drill tube into the open end of the previous drill tube to construct the drill string.

[004] During operations, the drill column and drill bit can be subject to very demanding conditions at the bottom of the well. It is not uncommon for the drill bit or part of the drill string to get stuck in the hole.

[005] In these cases, the drilling operation can be interrupted and the actions taken to release the drilling column, for example, through jamming.

[006] Such events can lead to costly downtime in the drilling operation and may also have safety implications in the event of damage to tools or equipment. There is therefore a need to improve techniques and solutions to ensure the functionality and reliability of the drilling rig and the integrity of the drill string. The present invention aims to improve the safety of a drilling operation, especially but not limited to such events when the drilling column or drill bit becomes stuck, or to provide other advantages compared to known solutions.

BRIEF DESCRIPTION OF THE INVENTION

• - definir uma velocidade de rotação e um torque aplicado do top drive para um nível definido, em que o torque aplicado é limitado por um limite de torque operacional;
• - identificar um evento potencial ou real de rotação reversa (backspin); e
• - aumentar temporariamente o limite de torque do top drive para um limite de torque de prevenção de rotação reversa em resposta à identificação do evento potencial ou real de rotação reversa.

[007] In one embodiment, a method is provided for operating a top drive on a drill rig, in which the top drive is connected to a drill string and the method comprises the following steps:

• - set a rotation speed and an applied torque of the top drive to a defined level, where the applied torque is limited by an operational torque limit;
• - identify a potential or real event of reverse rotation (backspin); and
• - temporarily increase the torque limit of the top drive to a reverse rotation prevention torque limit in response to the identification of the potential or actual reverse rotation event.

[008] In one embodiment, a top drive is provided for a drilling rig, in which the top drive is connected to a controller with a processor with a program embedded in a non-transitory computer-readable medium to execute a method for top drive operation.

[009] The following detailed description and the accompanying dependent claims describe other embodiments in accordance with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Several characteristics will be clear from the following description of the illustrative embodiments, given as non-restrictive examples, with reference to the accompanying drawings, in which:

[0011] Figure 1 illustrates a drill rig with a top drive that rotates a drill column of the drill rig.

[0012] Figure 2 illustrates the speed and torque curve of a top drive.

[0013] Figures 3 and 4 illustrate the speed and torque curves of a top drive.

DETAILED DESCRIPTION OF THE INVENTION

[0014] Embodiments of the present invention refer to the top drives for a drilling rig, including, but not limited to, such top drives used for drilling exploration or production wells in the oil and gas industry, or other drilling applications, such as diamond core drilling (DCR) or reverse circulation drilling (RC) in goods exploration drilling.

[0015] Figure 1 schematically illustrates parts of a drilling rig (1) for an oil drilling operation. The drilling rig (1) can be onshore or offshore, or on a fixed platform or on a floating drilling vessel. The drill rig (1) comprises a top drive (7) which is connected to a drill string (2). The drill string (2) comprises a plurality of individual drill tube sections (3) and a drill bit (4). The drill pipe sections (3) are connected to each other at the connections (5) which comprise threaded sections (6), so that a drill pipe section (3) is screwed into a next drill pipe section (3 ) through the threaded section (6) to extend the drill pipe (3). The drill pipe sections (3) of the drill column (2) are screwed with an activation torque to make the connection (5) safe under operational conditions. The drill rig (1) can comprise at least one braking mechanism (9), such as a flexible air brake (10) to brake and / or lock the top drive (7) or fix the drill string (2) in a certain position, so that the top drive (7) and the connected drill string (2) stop rotating in any direction. The top drive (7) is connected to a controller (8) that sets the torque and rotation speed of the top drive (7) to a defined level, based on a punch signal and / or a punch control system on the probe (1). The torque of the top drive (7) is, during common operation, limited to an operating limit of OTL torque during drilling, in order to prevent the top drive (7) and associated components from being prevented by failure due to overload.

[0016] During operation in a controlled drilling operation, the top drive (7) is operating at a defined operational rotation speed (RS). The speed (RS) can, for example, be between 60 and 120 rpm in a typical oil well drilling operation. The drill bit (4) is moving to the ground (11) and the drilling operation is proceeding normally. In the event of a potential jamming of the drill bit (4) or part of the drill string (2) located at the bottom of the well, the rotation speed (RS) may decrease despite a constant operating drilling torque applied from top drive (7). Therefore, stress can accumulate in the drill string (2) and is stored as torsional energy in the drill string (2). If the drill string is long enough, the drill string can store a substantial amount of energy (both dynamic rotational energy and potential torsional energy). This accumulation of energy can also continue after the drill bit (4) or part of the drill string (2) is stuck in the hole, as there can be a considerable delay between this happening and the event being detectable and influencing the top drive ( 7). This can lead to a reverse rotation torque (BT) in column 2, which acts in opposition to the top drive torque (7). This can lead to a top drive reverse rotation event (7), if the reverse rotation torque (BT) exceeds the applied drive torque of the top drive (7).

[0017] Such a situation of reverse rotation can be a critical event and considered unsafe, with the worst possible scenario in which one or more of the pre-torque joints in the drilling column can become separated and lead to a scenario of loss of the drilling. Due to the unpredictable nature of the drill string, particularly in deep holes, preventing such events is very challenging. As the drilling column (2) can extend for several kilometers on the ground, through folds and curves and with vertical and horizontal sections, friction can act on the column at different depths to influence the speed rotation locally. The inventors have found that the risk of such events can be substantially reduced with methods and systems in accordance with the present disclosure.

[0018] Illustrated in Figure 2, according to a method in one embodiment, the top drive (7) can be operated to mitigate this reverse rotation event, increasing the operating torque limit (OTL) to a limit of reverse rotation prevention torque (BTL) in case a potential top drive reverse rotation event (7) is detected. The increase in torque limits prevents the top drive (7) from entering a reverse rotation event or reduces the effective reverse rotation torque, so that the drill string (2) and / or the top drive (7) can be locked and prevent the drill string from being unscrewed. Increasing torque in torque with reverse rotation prevention level (BTL) can also release the drill bit (4) or the stuck part of the drill string (2). Alternatively, it can prevent a reverse rotation event and allow the drill bit (4) and / or the drill string (2) to be released in a different way.

[0019] The operating torque limit (OTL) can be temporarily increased after identifying a reverse rotation event. For example, the controller (8) may have a configuration that limits the time that this increased torque limit is allowed to be applied, in order to avoid overheating or other damage to components.

[0020] Preferably, the torque limit of the top drive (7) is increased from the operating torque limit (OTL) to the reverse rotation prevention torque limit (BTL) when the rotation speed (RS) of the top drive (7) falls below a defined limit value. An option to detect a potential reverse rotation event and the increase in reverse rotation torque (BT) in the drill string (2) is a measure of the rotation speed (RS) of the top drive (7). If the rotation speed falls below a defined level, for example, 5%, 10% or 20% of the requested rotation speed, a potential reverse rotation event can be predicted. Optionally, the reverse rotation event can be detected if the speed of rotation falls below zero. A potential reverse rotation event can also be detected with other sensors, such as downhole sensors. For example, the sensors can monitor a torsion stress in the drill string (2) and / or a difference in the rotation speed of the drill bit (4) compared to the rotation speed of the top drive (7).

[0021] In a preferred embodiment of the method, the torque limit of the top drive (7) is increased from the operating torque limit (OTL) to the reverse rotation prevention torque limit (BTL) by a factor calculation in relation to the rotation speed (RS) of the top drive (7). Using a calculation factor to increase torque is a simple way to increase torque from the operating torque limit (OTL) to the reverse rotation prevention torque limit (BTL). It can be easily implemented on the controller (8) of the top drive (7) and prevent reverse drive events from the top drive (7). For example, the torque limit of the top drive can be increased linearly from (OTL) when speed is zero, to 110% of (OTL) when speed is -10 rpm.

[0022] In an alternative embodiment of the method, the torque limit of the top drive (7) is increased from the operating torque limit (OTL) to the reverse rotation prevention torque limit (BTL) by a value constant in relation to the rotation speed (RS) of the top drive (7).

[0023] In yet another embodiment of the method, the torque limit of the top drive (7) is increased from the operating torque limit (OTL) to the reverse rotation prevention torque limit (BTL) by a value regulated which is a function of the rotation speed (RS) of the top drive (7).

[0024] Optionally, a braking mechanism (9), such as a flexible air brake (10), a hydraulic brake or a brake lever with a mechanical locking mechanism can be activated to fix the top drive (7) when the rotation speed (RS) of the top drive (7) drops to zero. Increasing the reverse rotation prevention (BTL) torque limit helps to prevent the top drive (7) from being rotated against its operational direction. If the increased torque limit is still not sufficient and the reverse rotation torque exceeds the increased torque limit, the top drive (7) can be mechanically blocked by the braking mechanism (9) to prevent a reverse rotation event. For this purpose, a positive connection is made between the braking mechanism (9) and the output shaft of the top drive (7). Alternatively, a friction connection between the braking mechanism (9) and the output shaft of the top drive (7) can be made to lock the motor in its current position and prevent the top drive (7) from entering an event of reverse rotation.

[0025] Alternatively or additionally, the drilling column (2) can be fixed by a braking mechanism (9) such as a flexible air brake (10), a hydraulic brake or a brake lever with a mechanical locking mechanism to fix the drill string (2) in its current position and prevent the drill string (2) from performing a reverse rotation event on the top drive (7).

[0026] If a reverse rotation event has been detected and the braking mechanism (9) engaged, the braking mechanism (9) can be released gradually in order to avoid dynamics of the drilling column (2), which can lead to unscrewing the connections (5). If the drill bit (4) or the stuck part of the drill string (2) is released again, the top drive (7) can be restarted with the operating torque limit (OTL) and the drilling operation continues.

[0027] The braking mechanism (9) can comprise a flexible air brake (10). Flexible air brakes (10) are known for drilling platforms (1) as drum brakes, disc brakes or caliper brakes to apply high braking performance with low inertia. Therefore, they are used to stop the top drive (7) or the drill string (2) in an emergency.

[0028] Alternatively or additionally, the rate of the drill bit (speed) can be reduced (or made negative), if a calculation of the energy stored in the drill column is raised to a level where a reverse rotation is possible.

[0029] The top drive (7) can be connected to a controller (8) to control the rotation speed (RS) and the operating torque limit (OTL) of the top drive (7). In the event that a potential reverse rotation event is detected, the controller (8) increases the torque limit of the top drive (7) to a reverse rotation prevention torque limit (BTL) to prevent a reverse rotation event and prevent that the drill string (2) unscrew due to the torsion energy stored in the drill string (2) and the dynamics of the drill string (2) and the top drive (7). The controller (8) can be an electronic controller that adjusts the electrical voltage and / or electrical current that is supplied to the top drive (7) to set the rotation speed (RS) and the operating torque to a reset level.

[0030] Figure 3 illustrates a reverse rotation event. During normal drilling, the rotation speed of the top drive (and the drill string) is relatively stable around a speed setpoint, defined by the drill (or automatic drilling system) and regulated by the top drive controller ( 8). The torque required by the top drive to maintain this speed can vary, depending on the conditions in the hole, the behavior of the drill string, etc. At the moment (t1), the torque resistance of the drill string reaches a value greater than that of the top drive (OTL). From that moment on, the top drive cannot increase the torque to maintain the desired rotation speed, and the speed starts to drop after (t1). This can, for example, be triggered by the drill bit or a part of the drill string gets stuck in the hole.

[0031] The top drive continues to rotate the drill string, albeit at a lower speed. At some point (t2), the torsion stress in the drill string and its behavior at the bottom of the well may be such that a reverse rotation is triggered, that is, the rotation speed drops below zero. The torque applied by the top drive can still be constant, at the limit of (OTL). At some point, the reverse rotation will be reduced, for example, due to the torsional stress being discharged and / or the interaction between the drilling column and the well hole, and the rotation speed approaching zero again. During this deceleration period (30), there is a particularly high risk of unwanted joint release, for example, due to the rotational inertia of parts of the column in combination with unpredictable interaction effects between the column and the well hole (for example, trap-slip effects with part of the spine being stuck or partially stuck and therefore stopping).

[0032] Figure 4 illustrates a similar event using a system or method according to one or more of the embodiments described in this document. As described in relation to Figure 3, the drilling process normally continues until a time (t1), in which the speed drops due, for example, to the drilling column being stuck in the hole. As the speed approaches a predetermined value, in this case zero (but that predetermined value can be, for example, 5%, 10% or another fraction of the speed setpoint) in time (t2), the operating torque top drive maximum is increased above the (OTL) limit to a reverse rotation prevention (BTL) torque limit.

[0033] This reduces the reverse rotation and, therefore, the risk of undesirable effects, and the rotation speed can be stabilized at zero and the situation resolved in a controlled manner.

[0034] The change from (OTL) to (BTL) can be temporary, for example, when a time limit is defined by how long the top drive can operate on (BTL). This can be beneficial, for example, if (OTL) is a safety setting that defines the maximum permanent operating limit for the top drive, in order to avoid overheating or overloading components.

[0035] Although the illustrations in Figures 3 and 4 show the speed of the top drive, they can also be representative of a section of the drilling column at the bottom of the well. Due to the length of the drill string, this local reverse rotation can produce the same risks as those reverse rotations on the top drive, and the system and method according to the embodiments can also be employed to reduce the risk of this reverse rotation and the potential negative consequences associated with it.

[0036] Optionally, the DOP (Operational Drilling Plan) for a drilling well can highlight areas where reverse rotation is more likely to occur, and the controller reverse rotation functionality (8) can be activated based on these known data . The method can therefore receive information from the DOP representative of a risk of reverse rotation events for a given operational scenario and enable or disable the reverse rotation control functionality based on information received from the DOP. Alternatively, or in addition, the controller (8) can receive information from the DOP representative of a risk of reverse rotation events for a specific operational scenario and adjust the (BTL) in response to the information received from the (DOP).

[0037] Alternatively, or in addition, the controller (8) can receive information from a well model to enable or disable the reverse rotation control functionality, or to adjust the (BTL) in response to information received from the model. The well model can, for example, be a computer based on a logical calculation that calculates and / or simulates a risk of reverse rotation events based on parameters such as the length of the drill string, design of the drill string or physical parameters, an amount of energy applied to the drill string before it gets stuck, and the characteristics of the well, such as well length, open hole and packaged length, geological parameters, penetration rate, mud flow rate, gravel flow rate, etc.

[0038] Optionally, an alert / alarm or early notification system can be provided in the system or method. The controller (8) can be configured to display an alert or an alarm in a drilling control system, representing a risk of reverse rotation events for a specific operational scenario.

[0039] Optionally, the method may include providing an operating signal to the lifting system for the top drive (7) to reduce the weight in the drill or ROP, or starting to raise the drill string (2), by identification of a real or potential reverse rotation event. This, together with the temporary increase in the torque limit, can reduce the risk of undesirable effects, as described above, and allow the drilling operation to return to the normal state. For example, reducing the weight on the drill or the ROP can reduce the risk of high friction local sections between the drill string (2) and the well hole.

[0040] Optionally, the method may include the operation of one or more mud pumps to increase a mud flow rate through the drilling column (2) when identifying a real or potential reverse rotation event. This, together with the temporary increase in the torque limit, can reduce the risk of such undesirable effects, as described above, and allow the drilling operation to return to the normal state. For example, an increase in the mud flow rate can provide more effective removal of cuttings in tight areas of the well, so that the risk of high friction local sections between the drill string (2) and the well hole be reduced.

[0041] According to embodiments of the inventions, it is therefore possible to achieve a reduced risk of, for example, unscrewing the connections (5) and thereby reducing the risk of loss of parts of the drill string (2 ).

[0042] The invention is not limited by the embodiments described above; reference should be made to the attached claims.

Claims (14)

METHOD OF OPERATING A TOP DRIVE (7) on a drilling rig (1), in which the top drive (7) is connected to a drilling column (2), characterized by the method comprising the following steps:

• - define a rotation speed (RS) and an applied torque of the top drive (7) at a defined level, where the applied torque is limited by an operating torque limit (OTL);
• - identify a potential or real event of reverse rotation (backspin); and
• - temporarily increase the torque limit of the top drive (7) to a reverse rotation prevention torque limit (BTL) in response to the identification of the potential or actual reverse rotation event.

METHOD, according to claim 1, characterized by the torque limit of the top drive (7) being increased from the operating torque limit (OTL) to the reverse rotation prevention torque limit (BTL) when the rotation speed (RS) of the top drive (7) falls below a defined limit value. METHOD according to any one of claims 1 to 2, characterized in that the torque limit of the top drive (7) is increased from the operating torque limit (OTL) to the reverse rotation prevention torque limit (BTL) by a calculation factor that is a function of the rotation speed (RS) of the top drive (7). METHOD according to any one of claims 1 to 2, characterized in that the torque limit of the top drive (7) is increased from the operating torque limit (OTL) to the reverse rotation prevention torque limit (BTL) by a constant value. METHOD, according to any one of claims 1 to 4, characterized in that it comprises activating a braking mechanism (9) to fix the top drive (7) and / or the drilling column (2), if the rotation speed (RS ) of the top drive (7) drops to zero. METHOD, according to any one of claims 1 to 5, characterized by the step of identifying a potential reverse rotation event comprising the identification of a drop in the rotation speed of the top drive (7) simultaneously with the applied torque being substantially at the limit of operating torque (OTL). METHOD, according to claim 6, characterized by the step of identifying a drop in rotation speed comprising:

• - measure a top drive rotation speed using a top drive speed sensor;
• - measure a rotation speed of the upper column using a column velocity sensor at the top (topside); or
• - measure a lower column rotation speed using a downhole column speed sensor.

METHOD, according to any one of claims 1 to 7, characterized by the step of identifying a potential reverse rotation event comprising monitoring a torsion stress in the drilling column (2), and / or monitoring a difference in rotation speed between a section of the drill string (2) and the top drive (7). METHOD, according to any one of claims 1 to 8, characterized by comprising, when identifying the actual event or potential for reverse rotation, operating a drilling rig lifting system (1) to reduce a weight-in-drill or rate -for penetration of the drill string (2) or to lift the drill string (2). METHOD according to any one of claims 1 to 9, characterized by comprising, when identifying the actual or potential reverse rotation event, operating a drilling rig mud pump (1) to increase a mud flow rate through the perforation column (2). METHOD according to any one of claims 1 to 10, characterized by the step of temporarily increasing the torque limit of the top drive (7) to a reverse rotation prevention torque limit (BTL) in response to the identification of the potential event or Actual reverse rotation can be performed using an automatic controller (8) operable to control the torque limit of the top drive (7). TOP DRIVE (7) for a drilling rig (1), characterized by the top drive (7) being connected to a controller (8) that has a processor with a program incorporated in a non-transitory computer-readable medium to execute a method, as defined in any of claims 1 to 11. TOP DRIVE (7), according to claim 12, characterized in that the top drive (7) is connected to a drilling column (2) of a drilling probe (1), in which the drilling probe (1) comprises at least at least one braking mechanism (9) to rotatively block the drill string (2) and / or the top drive motor (7). TOP DRIVE (7) according to claim 13, characterized in that the braking mechanism (9) comprises a flexible air brake (10).

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